Merge branch 'rolling' into doc

.gitignore

@@ -4,3 +4,4 @@ package-lock.json
 dump.rdb
 .vscode
 megalinter-reports/
+dhat-heap.json

.gitpod.Dockerfile

@@ -1,3 +1,3 @@
 FROM gitpod/workspace-rust
 
-RUN sudo install-packages redis-server nodejs npm
+RUN sudo install-packages redis-server nodejs npm liblua5.4-dev liblua5.3-dev liblua5.2-dev liblua5.1-0-dev libluajit-5.1-dev

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "websurfx"
-version = "0.18.6"
+version = "0.20.7"
 edition = "2021"
 description = "An open-source alternative to Searx that provides clean, ad-free, and organic results with incredible speed while keeping privacy and security in mind."
 repository = "https://github.com/neon-mmd/websurfx"
@@ -8,9 +8,9 @@ license = "AGPL-3.0"
 
 [dependencies]
 reqwest = {version="0.11.20",features=["json"]}
-tokio = {version="1.32.0",features=["full"]}
+tokio = {version="1.32.0",features=["rt-multi-thread","macros"]}
 serde = {version="1.0.188",features=["derive"]}
-handlebars = { version = "4.3.7", features = ["dir_source"] }
+handlebars = { version = "4.4.0", features = ["dir_source"] }
 scraper = {version="0.17.1"}
 actix-web = {version="4.4.0", features = ["cookies"]}
 actix-files = {version="0.6.2"}
@@ -19,14 +19,20 @@ serde_json = {version="1.0.105"}
 fake-useragent = {version="0.1.3"}
 env_logger = {version="0.10.0"}
 log = {version="0.4.20"}
-rlua = {version="0.19.7"}
+mlua = {version="0.8.10", features=["luajit"]}
-redis = {version="0.23.2"}
+redis = {version="0.23.3", features=["tokio-comp","connection-manager"]}
 md5 = {version="0.7.0"}
 rand={version="0.8.5"}
 once_cell = {version="1.18.0"}
 error-stack = {version="0.4.0"}
 async-trait = {version="0.1.73"}
 regex = {version="1.9.4", features=["perf"]}
+smallvec = {version="1.11.0", features=["union", "serde"]}
+futures = {version="0.3.28"}
+dhat = {version="0.3.2", optional = true}
+mimalloc = { version = "0.1.38", default-features = false }
+async-once-cell = {version="0.5.3"}
+actix-governor = {version="0.4.1"}
 
 [dev-dependencies]
 rusty-hook = "^0.11.2"
@@ -47,13 +53,17 @@ rpath = false
 
 [profile.release]
 opt-level = 3
-debug = false
+debug = false # This should only be commented when testing with dhat profiler
+# debug = 1 # This should only be uncommented when testing with dhat profiler
 split-debuginfo = '...'
 debug-assertions = false
 overflow-checks = false
-lto = 'thin'
+lto = true
 panic = 'abort'
 incremental = false
-codegen-units = 16
+codegen-units = 1
 rpath = false
 strip = "debuginfo"
+
+[features]
+dhat-heap = ["dep:dhat"] 

README.md

@@ -51,7 +51,7 @@
 - **Getting Started**
     - [🔭 Preview](#preview-)
     - [🚀 Features](#features-)
-    - [🛠️ Installation and Testing](#installation-and-testing-)
+    - [🛠️ Installation and Testing](#installation-and-testing-%EF%B8%8F)
     - [🔧 Configuration](#configuration-)
 - **Feature Overview**
     - [🎨 Theming](#theming-)

docs/installation.md

@@ -109,7 +109,7 @@ colorscheme = "catppuccin-mocha" -- the colorscheme name which should be used fo
 theme = "simple" -- the theme name which should be used for the website
 
 -- ### Caching ###
-redis_connection_url = "redis://redis:6379" -- redis connection url address on which the client should connect on.
+redis_url = "redis://redis:6379" -- redis connection url address on which the client should connect on.
 
 -- ### Search Engines ###
 upstream_search_engines = { DuckDuckGo = true, Searx = false } -- select the upstream search engines from which the results should be fetched.

public/static/themes/simple.css

@@ -132,6 +132,35 @@ body {
   width: 1.2rem;
   height: 1.2rem;
 }
+.results .result_disallowed,
+.results .result_filtered {
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  gap: 10rem;
+  font-size: 2rem;
+  color: var(--foreground-color);
+  margin: 0rem 7rem;
+}
+
+.results .result_disallowed .user_query,
+.results .result_filtered .user_query {
+  color: var(--background-color);
+  font-weight: 300;
+}
+
+.results .result_disallowed img,
+.results .result_filtered img {
+  width: 30rem;
+}
+
+.results .result_disallowed div,
+.results .result_filtered div {
+  display: flex;
+  flex-direction: column;
+  gap: 1rem;
+  line-break: strict;
+}
 
 /* styles for the footer and header */
 

public/templates/search.html

@@ -1,37 +1,69 @@
 {{>header this.style}}
 <main class="results">
-  {{>search_bar this}}
+    {{>search_bar this}}
-  <div class="results_aggregated">
+    <div class="results_aggregated">
-    {{#if results}} {{#each results}}
+        {{#if results}} {{#each results}}
-    <div class="result">
+        <div class="result">
-      <h1><a href="{{{this.url}}}">{{{this.title}}}</a></h1>
+            <h1><a href="{{{this.url}}}">{{{this.title}}}</a></h1>
-      <small>{{{this.url}}}</small>
+            <small>{{{this.url}}}</small>
-      <p>{{{this.description}}}</p>
+            <p>{{{this.description}}}</p>
-      <div class="upstream_engines">
+            <div class="upstream_engines">
-        {{#each engine}}
+                {{#each engine}}
-        <span>{{{this}}}</span>
+                <span>{{{this}}}</span>
-        {{/each}}
+                {{/each}}
-      </div>
+            </div>
+        </div>
+        {{/each}} {{else}} {{#if disallowed}}
+        <div class="result_disallowed">
+            <div class="description">
+                <p>
+                    Your search - <span class="user_query">{{{this.pageQuery}}}</span> -
+                    has been disallowed.
+                </p>
+                <p class="description_paragraph">Dear user,</p>
+                <p class="description_paragraph">
+                    The query - <span class="user_query">{{{this.pageQuery}}}</span> - has
+                    been blacklisted via server configuration and hence disallowed by the
+                    server. Henceforth no results could be displayed for your query.
+                </p>
+            </div>
+            <img src="./images/barricade.png" alt="Image of a Barricade" />
+        </div>
+        {{else}} {{#if filtered}}
+        <div class="result_filtered">
+            <div class="description">
+                <p>
+                    Your search - <span class="user_query">{{{this.pageQuery}}}</span> -
+                    has been filtered.
+                </p>
+                <p class="description_paragraph">Dear user,</p>
+                <p class="description_paragraph">
+                    All the search results contain results that has been configured to be
+                    filtered out via server configuration and henceforth has been
+                    completely filtered out.
+                </p>
+            </div>
+            <img src="./images/filter.png" alt="Image of a paper inside a funnel" />
+        </div>
+        {{else}}
+        <div class="result_not_found">
+            <p>Your search - {{{this.pageQuery}}} - did not match any documents.</p>
+            <p class="suggestions">Suggestions:</p>
+            <ul>
+                <li>Make sure that all words are spelled correctly.</li>
+                <li>Try different keywords.</li>
+                <li>Try more general keywords.</li>
+            </ul>
+            <img src="./images/no_results.gif" alt="Man fishing gif" />
+        </div>
+        {{/if}} {{/if}} {{/if}}
     </div>
-    {{/each}} {{else}}
+    <div class="page_navigation">
-    <div class="result_not_found">
+        <button type="button" onclick="navigate_backward()">
-      <p>Your search - {{{this.pageQuery}}} - did not match any documents.</p>
+            &#8592; previous
-      <p class="suggestions">Suggestions:</p>
+        </button>
-      <ul>
+        <button type="button" onclick="navigate_forward()">next &#8594;</button>
-        <li>Make sure that all words are spelled correctly.</li>
-        <li>Try different keywords.</li>
-        <li>Try more general keywords.</li>
-      </ul>
-      <img src="./images/no_results.gif" alt="Man fishing gif" />
     </div>
-    {{/if}}
-  </div>
-  <div class="page_navigation">
-    <button type="button" onclick="navigate_backward()">
-      &#8592; previous
-    </button>
-    <button type="button" onclick="navigate_forward()">next &#8594;</button>
-  </div>
 </main>
 <script src="static/index.js"></script>
 <script src="static/pagination.js"></script>

src/bin/websurfx.rs

@@ -3,9 +3,19 @@
 //! This module contains the main function which handles the logging of the application to the
 //! stdout and handles the command line arguments provided and launches the `websurfx` server.
 
+use mimalloc::MiMalloc;
 use std::net::TcpListener;
 use websurfx::{config::parser::Config, run};
 
+/// A dhat heap memory profiler
+#[cfg(feature = "dhat-heap")]
+#[global_allocator]
+static ALLOC: dhat::Alloc = dhat::Alloc;
+
+#[cfg(not(feature = "dhat-heap"))]
+#[global_allocator]
+static GLOBAL: MiMalloc = MiMalloc;
+
 /// The function that launches the main server and registers all the routes of the website.
 ///
 /// # Error
@@ -14,6 +24,10 @@ use websurfx::{config::parser::Config, run};
 /// available for being used for other applications.
 #[actix_web::main]
 async fn main() -> std::io::Result<()> {
+    // A dhat heap profiler initialization.
+    #[cfg(feature = "dhat-heap")]
+    let _profiler = dhat::Profiler::new_heap();
+
     // Initialize the parsed config file.
     let config = Config::parse(false).unwrap();
 

src/cache/cacher.rs

@@ -1,17 +1,24 @@
 //! This module provides the functionality to cache the aggregated results fetched and aggregated
 //! from the upstream search engines in a json format.
 
+use error_stack::Report;
+use futures::future::try_join_all;
 use md5::compute;
-use redis::{Client, Commands, Connection};
+use redis::{aio::ConnectionManager, AsyncCommands, Client, RedisError};
+
+use super::error::PoolError;
 
 /// A named struct which stores the redis Connection url address to which the client will
 /// connect to.
-///
+#[derive(Clone)]
-/// # Fields
-///
-/// * `redis_connection_url` - It stores the redis Connection url address.
 pub struct RedisCache {
-    connection: Connection,
+    /// It stores a pool of connections ready to be used.
+    connection_pool: Vec<ConnectionManager>,
+    /// It stores the size of the connection pool (in other words the number of
+    /// connections that should be stored in the pool).
+    pool_size: u8,
+    /// It stores the index of which connection is being used at the moment.
+    current_connection: u8,
 }
 
 impl RedisCache {
@@ -19,11 +26,25 @@ impl RedisCache {
     ///
     /// # Arguments
     ///
-    /// * `redis_connection_url` - It stores the redis Connection url address.
+    /// * `redis_connection_url` - It takes the redis Connection url address.
-    pub fn new(redis_connection_url: String) -> Result<Self, Box<dyn std::error::Error>> {
+    /// * `pool_size` - It takes the size of the connection pool (in other words the number of
+    /// connections that should be stored in the pool).
+    pub async fn new(
+        redis_connection_url: &str,
+        pool_size: u8,
+    ) -> Result<Self, Box<dyn std::error::Error>> {
         let client = Client::open(redis_connection_url)?;
-        let connection = client.get_connection()?;
+        let mut tasks: Vec<_> = Vec::new();
-        let redis_cache = RedisCache { connection };
+
+        for _ in 0..pool_size {
+            tasks.push(client.get_tokio_connection_manager());
+        }
+
+        let redis_cache = RedisCache {
+            connection_pool: try_join_all(tasks).await?,
+            pool_size,
+            current_connection: Default::default(),
+        };
         Ok(redis_cache)
     }
 
@@ -32,7 +53,7 @@ impl RedisCache {
     /// # Arguments
     ///
     /// * `url` - It takes an url as string.
-    fn hash_url(url: &str) -> String {
+    fn hash_url(&self, url: &str) -> String {
         format!("{:?}", compute(url))
     }
 
@@ -41,9 +62,42 @@ impl RedisCache {
     /// # Arguments
     ///
     /// * `url` - It takes an url as a string.
-    pub fn cached_json(&mut self, url: &str) -> Result<String, Box<dyn std::error::Error>> {
+    pub async fn cached_json(&mut self, url: &str) -> Result<String, Report<PoolError>> {
-        let hashed_url_string = Self::hash_url(url);
+        self.current_connection = Default::default();
-        Ok(self.connection.get(hashed_url_string)?)
+        let hashed_url_string: &str = &self.hash_url(url);
+
+        let mut result: Result<String, RedisError> = self.connection_pool
+            [self.current_connection as usize]
+            .get(hashed_url_string)
+            .await;
+
+        // Code to check whether the current connection being used is dropped with connection error
+        // or not. if it drops with the connection error then the current connection is replaced
+        // with a new connection from the pool which is then used to run the redis command then
+        // that connection is also checked whether it is dropped or not if it is not then the
+        // result is passed as a `Result` or else the same process repeats again and if all of the
+        // connections in the pool result in connection drop error then a custom pool error is
+        // returned.
+        loop {
+            match result {
+                Err(error) => match error.is_connection_dropped() {
+                    true => {
+                        self.current_connection += 1;
+                        if self.current_connection == self.pool_size {
+                            return Err(Report::new(
+                                PoolError::PoolExhaustionWithConnectionDropError,
+                            ));
+                        }
+                        result = self.connection_pool[self.current_connection as usize]
+                            .get(hashed_url_string)
+                            .await;
+                        continue;
+                    }
+                    false => return Err(Report::new(PoolError::RedisError(error))),
+                },
+                Ok(res) => return Ok(res),
+            }
+        }
     }
 
     /// A function which caches the results by using the hashed `url` as the key and
@@ -54,21 +108,45 @@ impl RedisCache {
     ///
     /// * `json_results` - It takes the json results string as an argument.
     /// * `url` - It takes the url as a String.
-    pub fn cache_results(
+    pub async fn cache_results(
         &mut self,
-        json_results: String,
+        json_results: &str,
         url: &str,
-    ) -> Result<(), Box<dyn std::error::Error>> {
+    ) -> Result<(), Report<PoolError>> {
-        let hashed_url_string = Self::hash_url(url);
+        self.current_connection = Default::default();
+        let hashed_url_string: &str = &self.hash_url(url);
 
-        // put results_json into cache
+        let mut result: Result<(), RedisError> = self.connection_pool
-        self.connection.set(&hashed_url_string, json_results)?;
+            [self.current_connection as usize]
+            .set_ex(hashed_url_string, json_results, 60)
+            .await;
 
-        // Set the TTL for the key to 60 seconds
+        // Code to check whether the current connection being used is dropped with connection error
-        self.connection
+        // or not. if it drops with the connection error then the current connection is replaced
-            .expire::<String, u32>(hashed_url_string, 60)
+        // with a new connection from the pool which is then used to run the redis command then
-            .unwrap();
+        // that connection is also checked whether it is dropped or not if it is not then the
-
+        // result is passed as a `Result` or else the same process repeats again and if all of the
-        Ok(())
+        // connections in the pool result in connection drop error then a custom pool error is
+        // returned.
+        loop {
+            match result {
+                Err(error) => match error.is_connection_dropped() {
+                    true => {
+                        self.current_connection += 1;
+                        if self.current_connection == self.pool_size {
+                            return Err(Report::new(
+                                PoolError::PoolExhaustionWithConnectionDropError,
+                            ));
+                        }
+                        result = self.connection_pool[self.current_connection as usize]
+                            .set_ex(hashed_url_string, json_results, 60)
+                            .await;
+                        continue;
+                    }
+                    false => return Err(Report::new(PoolError::RedisError(error))),
+                },
+                Ok(_) => return Ok(()),
+            }
+        }
     }
 }

src/cache/error.rs

@@ -0,0 +1,37 @@
+//! This module provides the error enum to handle different errors associated while requesting data from
+//! the redis server using an async connection pool.
+use std::fmt;
+
+use redis::RedisError;
+
+/// A custom error type used for handling redis async pool associated errors.
+#[derive(Debug)]
+pub enum PoolError {
+    /// This variant handles all errors related to `RedisError`,
+    RedisError(RedisError),
+    /// This variant handles the errors which occurs when all the connections
+    /// in the connection pool return a connection dropped redis error.
+    PoolExhaustionWithConnectionDropError,
+}
+
+impl fmt::Display for PoolError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            PoolError::RedisError(redis_error) => {
+                if let Some(detail) = redis_error.detail() {
+                    write!(f, "{}", detail)
+                } else {
+                    write!(f, "")
+                }
+            }
+            PoolError::PoolExhaustionWithConnectionDropError => {
+                write!(
+                    f,
+                    "Error all connections from the pool dropped with connection error"
+                )
+            }
+        }
+    }
+}
+
+impl error_stack::Context for PoolError {}

src/cache/mod.rs

@@ -1 +1,5 @@
+//! This module provides the modules which provide the functionality to cache the aggregated
+//! results fetched and aggregated from the upstream search engines in a json format.
+
 pub mod cacher;
+pub mod error;

src/config/mod.rs

@@ -1,2 +1,4 @@
+//! This module provides the modules which handles the functionality to parse the lua config
+//! and convert the config options into rust readable form.
+
 pub mod parser;
-pub mod parser_models;

src/config/parser.rs

@@ -3,49 +3,40 @@
 
 use crate::handler::paths::{file_path, FileType};
 
-use super::parser_models::Style;
+use crate::models::parser_models::{AggregatorConfig, RateLimiter, Style};
 use log::LevelFilter;
-use rlua::Lua;
+use mlua::Lua;
 use std::{collections::HashMap, fs, thread::available_parallelism};
 
 /// A named struct which stores the parsed config file options.
-///
-/// # Fields
-//
-/// * `port` - It stores the parsed port number option on which the server should launch.
-/// * `binding_ip` - It stores the parsed ip address option on which the server should launch
-/// * `style` - It stores the theming options for the website.
-/// * `redis_url` - It stores the redis connection url address on which the redis
-/// client should connect.
-/// * `aggregator` -  It stores the option to whether enable or disable production use.
-/// * `logging` - It stores the option to whether enable or disable logs.
-/// * `debug` - It stores the option to whether enable or disable debug mode.
-/// * `upstream_search_engines` - It stores all the engine names that were enabled by the user.
-/// * `request_timeout` - It stores the time (secs) which controls the server request timeout.
-/// * `threads` - It stores the number of threads which controls the app will use to run.
 #[derive(Clone)]
 pub struct Config {
+    /// It stores the parsed port number option on which the server should launch.
     pub port: u16,
+    /// It stores the parsed ip address option on which the server should launch
     pub binding_ip: String,
+    /// It stores the theming options for the website.
     pub style: Style,
+    /// It stores the redis connection url address on which the redis
+    /// client should connect.
     pub redis_url: String,
+    /// It stores the option to whether enable or disable production use.
     pub aggregator: AggregatorConfig,
+    /// It stores the option to whether enable or disable logs.
     pub logging: bool,
+    /// It stores the option to whether enable or disable debug mode.
     pub debug: bool,
-    pub upstream_search_engines: Vec<crate::engines::engine_models::EngineHandler>,
+    /// It stores all the engine names that were enabled by the user.
+    pub upstream_search_engines: Vec<crate::models::engine_models::EngineHandler>,
+    /// It stores the time (secs) which controls the server request timeout.
     pub request_timeout: u8,
+    /// It stores the number of threads which controls the app will use to run.
     pub threads: u8,
-}
+    /// It stores configuration options for the ratelimiting middleware.
-
+    pub rate_limiter: RateLimiter,
-/// Configuration options for the aggregator.
+    /// It stores the level of safe search to be used for restricting content in the
-///
+    /// search results.
-/// # Fields
+    pub safe_search: u8,
-///
-/// * `random_delay` - It stores the option to whether enable or disable random delays between
-/// requests.
-#[derive(Clone)]
-pub struct AggregatorConfig {
-    pub random_delay: bool,
 }
 
 impl Config {
@@ -63,58 +54,80 @@ impl Config {
     /// or io error if the config.lua file doesn't exists otherwise it returns a newly constructed
     /// Config struct with all the parsed config options from the parsed config file.
     pub fn parse(logging_initialized: bool) -> Result<Self, Box<dyn std::error::Error>> {
-        Lua::new().context(|context| -> Result<Self, Box<dyn std::error::Error>> {
+        let lua = Lua::new();
-            let globals = context.globals();
+        let globals = lua.globals();
 
-            context
+        lua.load(&fs::read_to_string(file_path(FileType::Config)?)?)
-                .load(&fs::read_to_string(file_path(FileType::Config)?)?)
+            .exec()?;
-                .exec()?;
 
-            let parsed_threads: u8 = globals.get::<_, u8>("threads")?;
+        let parsed_threads: u8 = globals.get::<_, u8>("threads")?;
 
-            let debug: bool = globals.get::<_, bool>("debug")?;
+        let debug: bool = globals.get::<_, bool>("debug")?;
-            let logging:bool= globals.get::<_, bool>("logging")?;
+        let logging: bool = globals.get::<_, bool>("logging")?;
 
-            if !logging_initialized {
+        if !logging_initialized {
-                set_logging_level(debug, logging);
+            set_logging_level(debug, logging);
+        }
+
+        let threads: u8 = if parsed_threads == 0 {
+            let total_num_of_threads: usize = available_parallelism()?.get() / 2;
+            log::error!(
+                "Config Error: The value of `threads` option should be a non zero positive integer"
+            );
+            log::error!("Falling back to using {} threads", total_num_of_threads);
+            total_num_of_threads as u8
+        } else {
+            parsed_threads
+        };
+
+        let rate_limiter = globals.get::<_, HashMap<String, u8>>("rate_limiter")?;
+
+        let parsed_safe_search: u8 = globals.get::<_, u8>("safe_search")?;
+        let safe_search: u8 = match parsed_safe_search {
+            0..=4 => parsed_safe_search,
+            _ => {
+                log::error!("Config Error: The value of `safe_search` option should be a non zero positive integer from 0 to 4.");
+                log::error!("Falling back to using the value `1` for the option");
+                1
             }
+        };
 
-            let threads: u8 = if parsed_threads == 0 {
+        Ok(Config {
-                let total_num_of_threads: usize =  available_parallelism()?.get() / 2;
+            port: globals.get::<_, u16>("port")?,
-                log::error!("Config Error: The value of `threads` option should be a non zero positive integer");
+            binding_ip: globals.get::<_, String>("binding_ip")?,
-                log::error!("Falling back to using {} threads", total_num_of_threads);
+            style: Style::new(
-                total_num_of_threads as u8
+                globals.get::<_, String>("theme")?,
-            } else {
+                globals.get::<_, String>("colorscheme")?,
-                parsed_threads
+            ),
-            };
+            redis_url: globals.get::<_, String>("redis_url")?,
-
+            aggregator: AggregatorConfig {
-            Ok(Config {
+                random_delay: globals.get::<_, bool>("production_use")?,
-                port: globals.get::<_, u16>("port")?,
+            },
-                binding_ip: globals.get::<_, String>("binding_ip")?,
+            logging,
-                style: Style::new(
+            debug,
-                    globals.get::<_, String>("theme")?,
+            upstream_search_engines: globals
-                    globals.get::<_, String>("colorscheme")?,
+                .get::<_, HashMap<String, bool>>("upstream_search_engines")?
-                ),
+                .into_iter()
-                redis_url: globals.get::<_, String>("redis_url")?,
+                .filter_map(|(key, value)| value.then_some(key))
-                aggregator: AggregatorConfig {
+                .filter_map(|engine| crate::models::engine_models::EngineHandler::new(&engine))
-                    random_delay: globals.get::<_, bool>("production_use")?,
+                .collect(),
-                },
+            request_timeout: globals.get::<_, u8>("request_timeout")?,
-                logging,
+            threads,
-                debug,
+            rate_limiter: RateLimiter {
-                upstream_search_engines: globals
+                number_of_requests: rate_limiter["number_of_requests"],
-                    .get::<_, HashMap<String, bool>>("upstream_search_engines")?
+                time_limit: rate_limiter["time_limit"],
-                    .into_iter()
+            },
-                    .filter_map(|(key, value)| value.then_some(key))
+            safe_search,
-                    .filter_map(|engine| crate::engines::engine_models::EngineHandler::new(&engine))
-                    .collect(),
-                request_timeout: globals.get::<_, u8>("request_timeout")?,
-                threads,
-            })
         })
     }
 }
 
 /// a helper function that sets the proper logging level
+///
+/// # Arguments
+///
+/// * `debug` - It takes the option to whether enable or disable debug mode.
+/// * `logging` - It takes the option to whether enable or disable logs.
 fn set_logging_level(debug: bool, logging: bool) {
     if let Ok(pkg_env_var) = std::env::var("PKG_ENV") {
         if pkg_env_var.to_lowercase() == "dev" {

src/engines/duckduckgo.rs

@@ -4,14 +4,14 @@
 
 use std::collections::HashMap;
 
-use reqwest::header::{HeaderMap, CONTENT_TYPE, COOKIE, REFERER, USER_AGENT};
+use reqwest::header::HeaderMap;
 use scraper::{Html, Selector};
 
-use crate::results::aggregation_models::SearchResult;
+use crate::models::aggregation_models::SearchResult;
 
-use super::engine_models::{EngineError, SearchEngine};
+use crate::models::engine_models::{EngineError, SearchEngine};
 
-use error_stack::{IntoReport, Report, Result, ResultExt};
+use error_stack::{Report, Result, ResultExt};
 
 /// A new DuckDuckGo engine type defined in-order to implement the `SearchEngine` trait which allows to
 /// reduce code duplication as well as allows to create vector of different search engines easily.
@@ -19,30 +19,13 @@ pub struct DuckDuckGo;
 
 #[async_trait::async_trait]
 impl SearchEngine for DuckDuckGo {
-    /// This function scrapes results from the upstream engine duckduckgo and puts all the scraped
-    /// results like title, visiting_url (href in html),engine (from which engine it was fetched from)
-    /// and description in a RawSearchResult and then adds that to HashMap whose keys are url and
-    /// values are RawSearchResult struct and then returns it within a Result enum.
-    ///
-    /// # Arguments
-    ///
-    /// * `query` - Takes the user provided query to query to the upstream search engine with.
-    /// * `page` - Takes an u32 as an argument.
-    /// * `user_agent` - Takes a random user agent string as an argument.
-    /// * `request_timeout` - Takes a time (secs) as a value which controls the server request timeout.
-    ///
-    /// # Errors
-    ///
-    /// Returns an `EngineErrorKind` if the user is not connected to the internet or if their is failure to
-    /// reach the above `upstream search engine` page or if the `upstream search engine` is unable to
-    /// provide results for the requested search query and also returns error if the scraping selector
-    /// or HeaderMap fails to initialize.
     async fn results(
         &self,
-        query: String,
+        query: &str,
         page: u32,
-        user_agent: String,
+        user_agent: &str,
         request_timeout: u8,
+        _safe_search: u8,
     ) -> Result<HashMap<String, SearchResult>, EngineError> {
         // Page number can be missing or empty string and so appropriate handling is required
         // so that upstream server recieves valid page number.
@@ -61,38 +44,19 @@ impl SearchEngine for DuckDuckGo {
         };
 
         // initializing HeaderMap and adding appropriate headers.
-        let mut header_map = HeaderMap::new();
+        let header_map = HeaderMap::try_from(&HashMap::from([
-        header_map.insert(
+            ("USER_AGENT".to_string(), user_agent.to_string()),
-            USER_AGENT,
+            ("REFERER".to_string(), "https://google.com/".to_string()),
-            user_agent
+            (
-                .parse()
+                "CONTENT_TYPE".to_string(),
-                .into_report()
+                "application/x-www-form-urlencoded".to_string(),
-                .change_context(EngineError::UnexpectedError)?,
+            ),
-        );
+            ("COOKIE".to_string(), "kl=wt-wt".to_string()),
-        header_map.insert(
+        ]))
-            REFERER,
+        .change_context(EngineError::UnexpectedError)?;
-            "https://google.com/"
-                .parse()
-                .into_report()
-                .change_context(EngineError::UnexpectedError)?,
-        );
-        header_map.insert(
-            CONTENT_TYPE,
-            "application/x-www-form-urlencoded"
-                .parse()
-                .into_report()
-                .change_context(EngineError::UnexpectedError)?,
-        );
-        header_map.insert(
-            COOKIE,
-            "kl=wt-wt"
-                .parse()
-                .into_report()
-                .change_context(EngineError::UnexpectedError)?,
-        );
 
         let document: Html = Html::parse_document(
-            &DuckDuckGo::fetch_html_from_upstream(self, url, header_map, request_timeout).await?,
+            &DuckDuckGo::fetch_html_from_upstream(self, &url, header_map, request_timeout).await?,
         );
 
         let no_result: Selector = Selector::parse(".no-results")
@@ -126,8 +90,7 @@ impl SearchEngine for DuckDuckGo {
                         .next()
                         .unwrap()
                         .inner_html()
-                        .trim()
+                        .trim(),
-                        .to_string(),
                     format!(
                         "https://{}",
                         result
@@ -136,15 +99,15 @@ impl SearchEngine for DuckDuckGo {
                             .unwrap()
                             .inner_html()
                             .trim()
-                    ),
+                    )
+                    .as_str(),
                     result
                         .select(&result_desc)
                         .next()
                         .unwrap()
                         .inner_html()
-                        .trim()
+                        .trim(),
-                        .to_string(),
+                    &["duckduckgo"],
-                    vec!["duckduckgo".to_string()],
                 )
             })
             .map(|search_result| (search_result.url.clone(), search_result))

src/engines/engine_models.rs

@@ -1,109 +0,0 @@
-//! This module provides the error enum to handle different errors associated while requesting data from
-//! the upstream search engines with the search query provided by the user.
-
-use crate::results::aggregation_models::SearchResult;
-use error_stack::{IntoReport, Result, ResultExt};
-use std::{collections::HashMap, fmt, time::Duration};
-
-/// A custom error type used for handle engine associated errors.
-///
-/// This enum provides variants three different categories of errors:
-/// * `RequestError` - This variant handles all request related errors like forbidden, not found,
-/// etc.
-/// * `EmptyResultSet` - This variant handles the not results found error provide by the upstream
-/// search engines.
-/// * `UnexpectedError` - This variant handles all the errors which are unexpected or occur rarely
-/// and are errors mostly related to failure in initialization of HeaderMap, Selector errors and
-/// all other errors occurring within the code handling the `upstream search engines`.
-#[derive(Debug)]
-pub enum EngineError {
-    EmptyResultSet,
-    RequestError,
-    UnexpectedError,
-}
-
-impl fmt::Display for EngineError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            EngineError::EmptyResultSet => {
-                write!(f, "The upstream search engine returned an empty result set")
-            }
-            EngineError::RequestError => {
-                write!(
-                    f,
-                    "Error occurred while requesting data from upstream search engine"
-                )
-            }
-            EngineError::UnexpectedError => {
-                write!(f, "An unexpected error occurred while processing the data")
-            }
-        }
-    }
-}
-
-impl error_stack::Context for EngineError {}
-
-/// A trait to define common behavior for all search engines.
-#[async_trait::async_trait]
-pub trait SearchEngine: Sync + Send {
-    async fn fetch_html_from_upstream(
-        &self,
-        url: String,
-        header_map: reqwest::header::HeaderMap,
-        request_timeout: u8,
-    ) -> Result<String, EngineError> {
-        // fetch the html from upstream search engine
-        Ok(reqwest::Client::new()
-            .get(url)
-            .timeout(Duration::from_secs(request_timeout as u64)) // Add timeout to request to avoid DDOSing the server
-            .headers(header_map) // add spoofed headers to emulate human behavior
-            .send()
-            .await
-            .into_report()
-            .change_context(EngineError::RequestError)?
-            .text()
-            .await
-            .into_report()
-            .change_context(EngineError::RequestError)?)
-    }
-
-    async fn results(
-        &self,
-        query: String,
-        page: u32,
-        user_agent: String,
-        request_timeout: u8,
-    ) -> Result<HashMap<String, SearchResult>, EngineError>;
-}
-
-pub struct EngineHandler {
-    engine: Box<dyn SearchEngine>,
-    name: &'static str,
-}
-
-impl Clone for EngineHandler {
-    fn clone(&self) -> Self {
-        Self::new(self.name).unwrap()
-    }
-}
-
-impl EngineHandler {
-    /// parses an engine name into an engine handler, returns none if the engine is unknown
-    pub fn new(engine_name: &str) -> Option<Self> {
-        let engine: (&'static str, Box<dyn SearchEngine>) =
-            match engine_name.to_lowercase().as_str() {
-                "duckduckgo" => ("duckduckgo", Box::new(super::duckduckgo::DuckDuckGo)),
-                "searx" => ("searx", Box::new(super::searx::Searx)),
-                _ => return None,
-            };
-
-        Some(Self {
-            engine: engine.1,
-            name: engine.0,
-        })
-    }
-
-    pub fn into_name_engine(self) -> (&'static str, Box<dyn SearchEngine>) {
-        (self.name, self.engine)
-    }
-}

src/engines/mod.rs

@@ -1,3 +1,7 @@
+//! This module provides different modules which handles the functionlity to fetch results from the
+//! upstream search engines based on user requested queries. Also provides different models to
+//! provide a standard functions to be implemented for all the upstream search engine handling
+//! code. Moreover, it also provides a custom error for the upstream search engine handling code.
+
 pub mod duckduckgo;
-pub mod engine_models;
 pub mod searx;

src/engines/searx.rs

@@ -2,14 +2,13 @@
 //! by querying the upstream searx search engine instance with user provided query and with a page
 //! number if provided.
 
-use reqwest::header::{HeaderMap, CONTENT_TYPE, COOKIE, REFERER, USER_AGENT};
+use reqwest::header::HeaderMap;
 use scraper::{Html, Selector};
 use std::collections::HashMap;
 
-use crate::results::aggregation_models::SearchResult;
+use crate::models::aggregation_models::SearchResult;
-
+use crate::models::engine_models::{EngineError, SearchEngine};
-use super::engine_models::{EngineError, SearchEngine};
+use error_stack::{Report, Result, ResultExt};
-use error_stack::{IntoReport, Report, Result, ResultExt};
 
 /// A new Searx engine type defined in-order to implement the `SearchEngine` trait which allows to
 /// reduce code duplication as well as allows to create vector of different search engines easily.
@@ -17,66 +16,40 @@ pub struct Searx;
 
 #[async_trait::async_trait]
 impl SearchEngine for Searx {
-    /// This function scrapes results from the upstream engine duckduckgo and puts all the scraped
-    /// results like title, visiting_url (href in html),engine (from which engine it was fetched from)
-    /// and description in a RawSearchResult and then adds that to HashMap whose keys are url and
-    /// values are RawSearchResult struct and then returns it within a Result enum.
-    ///
-    /// # Arguments
-    ///
-    /// * `query` - Takes the user provided query to query to the upstream search engine with.
-    /// * `page` - Takes an u32 as an argument.
-    /// * `user_agent` - Takes a random user agent string as an argument.
-    /// * `request_timeout` - Takes a time (secs) as a value which controls the server request timeout.
-    ///
-    /// # Errors
-    ///
-    /// Returns an `EngineErrorKind` if the user is not connected to the internet or if their is failure to
-    /// reach the above `upstream search engine` page or if the `upstream search engine` is unable to
-    /// provide results for the requested search query and also returns error if the scraping selector
-    /// or HeaderMap fails to initialize.
-
     async fn results(
         &self,
-        query: String,
+        query: &str,
         page: u32,
-        user_agent: String,
+        user_agent: &str,
         request_timeout: u8,
+        mut safe_search: u8,
     ) -> Result<HashMap<String, SearchResult>, EngineError> {
         // Page number can be missing or empty string and so appropriate handling is required
         // so that upstream server recieves valid page number.
+        if safe_search == 3 {
+            safe_search = 2;
+        };
+
         let url: String = match page {
-            0 | 1 => format!("https://searx.work/search?q={query}&pageno=1"),
+            0 | 1 => {
-            _ => format!("https://searx.work/search?q={query}&pageno={page}"),
+                format!("https://searx.work/search?q={query}&pageno=1&safesearch={safe_search}")
+            }
+            _ => format!(
+                "https://searx.work/search?q={query}&pageno={page}&safesearch={safe_search}"
+            ),
         };
 
         // initializing headers and adding appropriate headers.
-        let mut header_map = HeaderMap::new();
+        let header_map = HeaderMap::try_from(&HashMap::from([
-        header_map.insert(
+            ("USER_AGENT".to_string(), user_agent.to_string()),
-            USER_AGENT,
+            ("REFERER".to_string(), "https://google.com/".to_string()),
-            user_agent
+            ("CONTENT_TYPE".to_string(), "application/x-www-form-urlencoded".to_string()),
-                .parse()
+            ("COOKIE".to_string(), "categories=general; language=auto; locale=en; autocomplete=duckduckgo; image_proxy=1; method=POST; safesearch=2; theme=simple; results_on_new_tab=1; doi_resolver=oadoi.org; simple_style=auto; center_alignment=1; query_in_title=1; infinite_scroll=0; disabled_engines=; enabled_engines=\"archive is__general\\054yep__general\\054curlie__general\\054currency__general\\054ddg definitions__general\\054wikidata__general\\054duckduckgo__general\\054tineye__general\\054lingva__general\\054startpage__general\\054yahoo__general\\054wiby__general\\054marginalia__general\\054alexandria__general\\054wikibooks__general\\054wikiquote__general\\054wikisource__general\\054wikiversity__general\\054wikivoyage__general\\054dictzone__general\\054seznam__general\\054mojeek__general\\054naver__general\\054wikimini__general\\054brave__general\\054petalsearch__general\\054goo__general\"; disabled_plugins=; enabled_plugins=\"searx.plugins.hostname_replace\\054searx.plugins.oa_doi_rewrite\\054searx.plugins.vim_hotkeys\"; tokens=; maintab=on; enginetab=on".to_string())
-                .into_report()
+        ]))
-                .change_context(EngineError::UnexpectedError)?,
+        .change_context(EngineError::UnexpectedError)?;
-        );
-        header_map.insert(
-            REFERER,
-            "https://google.com/"
-                .parse()
-                .into_report()
-                .change_context(EngineError::UnexpectedError)?,
-        );
-        header_map.insert(
-            CONTENT_TYPE,
-            "application/x-www-form-urlencoded"
-                .parse()
-                .into_report()
-                .change_context(EngineError::UnexpectedError)?,
-        );
-        header_map.insert(COOKIE, "categories=general; language=auto; locale=en; autocomplete=duckduckgo; image_proxy=1; method=POST; safesearch=2; theme=simple; results_on_new_tab=1; doi_resolver=oadoi.org; simple_style=auto; center_alignment=1; query_in_title=1; infinite_scroll=0; disabled_engines=; enabled_engines=\"archive is__general\\054yep__general\\054curlie__general\\054currency__general\\054ddg definitions__general\\054wikidata__general\\054duckduckgo__general\\054tineye__general\\054lingva__general\\054startpage__general\\054yahoo__general\\054wiby__general\\054marginalia__general\\054alexandria__general\\054wikibooks__general\\054wikiquote__general\\054wikisource__general\\054wikiversity__general\\054wikivoyage__general\\054dictzone__general\\054seznam__general\\054mojeek__general\\054naver__general\\054wikimini__general\\054brave__general\\054petalsearch__general\\054goo__general\"; disabled_plugins=; enabled_plugins=\"searx.plugins.hostname_replace\\054searx.plugins.oa_doi_rewrite\\054searx.plugins.vim_hotkeys\"; tokens=; maintab=on; enginetab=on".parse().into_report().change_context(EngineError::UnexpectedError)?);
 
         let document: Html = Html::parse_document(
-            &Searx::fetch_html_from_upstream(self, url, header_map, request_timeout).await?,
+            &Searx::fetch_html_from_upstream(self, &url, header_map, request_timeout).await?,
         );
 
         let no_result: Selector = Selector::parse("#urls>.dialog-error>p")
@@ -117,24 +90,21 @@ impl SearchEngine for Searx {
                         .next()
                         .unwrap()
                         .inner_html()
-                        .trim()
+                        .trim(),
-                        .to_string(),
                     result
                         .select(&result_url)
                         .next()
                         .unwrap()
                         .value()
                         .attr("href")
-                        .unwrap()
+                        .unwrap(),
-                        .to_string(),
                     result
                         .select(&result_desc)
                         .next()
                         .unwrap()
                         .inner_html()
-                        .trim()
+                        .trim(),
-                        .to_string(),
+                    &["searx"],
-                    vec!["searx".to_string()],
                 )
             })
             .map(|search_result| (search_result.url.clone(), search_result))

src/handler/mod.rs

@@ -1 +1,5 @@
+//! This module provides modules which provide the functionality to handle paths for different
+//! files present on different paths and provide one appropriate path on which it is present and
+//! can be used.
+
 pub mod paths;

src/handler/paths.rs

@@ -4,108 +4,116 @@
 use std::collections::HashMap;
 use std::io::Error;
 use std::path::Path;
+use std::sync::OnceLock;
 
 // ------- Constants --------
-static PUBLIC_DIRECTORY_NAME: &str = "public";
+/// The constant holding the name of the theme folder.
-static COMMON_DIRECTORY_NAME: &str = "websurfx";
+const PUBLIC_DIRECTORY_NAME: &str = "public";
-static CONFIG_FILE_NAME: &str = "config.lua";
+/// The constant holding the name of the common folder.
-static ALLOWLIST_FILE_NAME: &str = "allowlist.txt";
+const COMMON_DIRECTORY_NAME: &str = "websurfx";
-static BLOCKLIST_FILE_NAME: &str = "blocklist.txt";
+/// The constant holding the name of the config file.
+const CONFIG_FILE_NAME: &str = "config.lua";
+/// The constant holding the name of the AllowList text file.
+const ALLOWLIST_FILE_NAME: &str = "allowlist.txt";
+/// The constant holding the name of the BlockList text file.
+const BLOCKLIST_FILE_NAME: &str = "blocklist.txt";
 
+/// An enum type which provides different variants to handle paths for various files/folders.
 #[derive(Hash, PartialEq, Eq, Debug)]
 pub enum FileType {
+    /// This variant handles all the paths associated with the config file.
     Config,
+    /// This variant handles all the paths associated with the Allowlist text file.
     AllowList,
+    /// This variant handles all the paths associated with the BlockList text file.
     BlockList,
+    /// This variant handles all the paths associated with the public folder (Theme folder).
     Theme,
 }
 
-static FILE_PATHS_FOR_DIFF_FILE_TYPES: once_cell::sync::Lazy<HashMap<FileType, Vec<String>>> =
+/// A static variable which stores the different filesystem paths for various file/folder types.
-    once_cell::sync::Lazy::new(|| {
+static FILE_PATHS_FOR_DIFF_FILE_TYPES: OnceLock<HashMap<FileType, Vec<String>>> = OnceLock::new();
-        HashMap::from([
-            (
-                FileType::Config,
-                vec![
-                    format!(
-                        "{}/.config/{}/{}",
-                        std::env::var("HOME").unwrap(),
-                        COMMON_DIRECTORY_NAME,
-                        CONFIG_FILE_NAME
-                    ),
-                    format!("/etc/xdg/{}/{}", COMMON_DIRECTORY_NAME, CONFIG_FILE_NAME),
-                    format!("./{}/{}", COMMON_DIRECTORY_NAME, CONFIG_FILE_NAME),
-                ],
-            ),
-            (
-                FileType::Theme,
-                vec![
-                    format!("/opt/websurfx/{}/", PUBLIC_DIRECTORY_NAME),
-                    format!("./{}/", PUBLIC_DIRECTORY_NAME),
-                ],
-            ),
-            (
-                FileType::AllowList,
-                vec![
-                    format!(
-                        "{}/.config/{}/{}",
-                        std::env::var("HOME").unwrap(),
-                        COMMON_DIRECTORY_NAME,
-                        ALLOWLIST_FILE_NAME
-                    ),
-                    format!("/etc/xdg/{}/{}", COMMON_DIRECTORY_NAME, ALLOWLIST_FILE_NAME),
-                    format!("./{}/{}", COMMON_DIRECTORY_NAME, ALLOWLIST_FILE_NAME),
-                ],
-            ),
-            (
-                FileType::BlockList,
-                vec![
-                    format!(
-                        "{}/.config/{}/{}",
-                        std::env::var("HOME").unwrap(),
-                        COMMON_DIRECTORY_NAME,
-                        BLOCKLIST_FILE_NAME
-                    ),
-                    format!("/etc/xdg/{}/{}", COMMON_DIRECTORY_NAME, BLOCKLIST_FILE_NAME),
-                    format!("./{}/{}", COMMON_DIRECTORY_NAME, BLOCKLIST_FILE_NAME),
-                ],
-            ),
-        ])
-    });
 
-/// A helper function which returns an appropriate config file path checking if the config
+/// A function which returns an appropriate path for thr provided file type by checking if the path
-/// file exists on that path.
+/// for the given file type exists on that path.
 ///
 /// # Error
 ///
-/// Returns a `config file not found!!` error if the config file is not present under following
+/// Returns a `<File Name> folder/file not found!!` error if the give file_type folder/file is not
-/// paths which are:
+/// present on the path on which it is being tested.
-/// 1. `~/.config/websurfx/` if it not present here then it fallbacks to the next one (2)
-/// 2. `/etc/xdg/websurfx/config.lua` if it is not present here then it fallbacks to the next
-///    one (3).
-/// 3. `websurfx/` (under project folder ( or codebase in other words)) if it is not present
-///    here then it returns an error as mentioned above.
-
-/// A function which returns an appropriate theme directory path checking if the theme
-/// directory exists on that path.
 ///
-/// # Error
+/// # Example
+///
+/// If this function is give the file_type of Theme variant then the theme folder is checked by the
+/// following steps:
 ///
-/// Returns a `Theme (public) folder not found!!` error if the theme folder is not present under following
-/// paths which are:
 /// 1. `/opt/websurfx` if it not present here then it fallbacks to the next one (2)
 /// 2. Under project folder ( or codebase in other words) if it is not present
 ///    here then it returns an error as mentioned above.
-pub fn file_path(file_type: FileType) -> Result<String, Error> {
+pub fn file_path(file_type: FileType) -> Result<&'static str, Error> {
-    let file_path = FILE_PATHS_FOR_DIFF_FILE_TYPES.get(&file_type).unwrap();
+    let file_path: &Vec<String> = FILE_PATHS_FOR_DIFF_FILE_TYPES
+        .get_or_init(|| {
+            HashMap::from([
+                (
+                    FileType::Config,
+                    vec![
+                        format!(
+                            "{}/.config/{}/{}",
+                            std::env::var("HOME").unwrap(),
+                            COMMON_DIRECTORY_NAME,
+                            CONFIG_FILE_NAME
+                        ),
+                        format!("/etc/xdg/{}/{}", COMMON_DIRECTORY_NAME, CONFIG_FILE_NAME),
+                        format!("./{}/{}", COMMON_DIRECTORY_NAME, CONFIG_FILE_NAME),
+                    ],
+                ),
+                (
+                    FileType::Theme,
+                    vec![
+                        format!("/opt/websurfx/{}/", PUBLIC_DIRECTORY_NAME),
+                        format!("./{}/", PUBLIC_DIRECTORY_NAME),
+                    ],
+                ),
+                (
+                    FileType::AllowList,
+                    vec![
+                        format!(
+                            "{}/.config/{}/{}",
+                            std::env::var("HOME").unwrap(),
+                            COMMON_DIRECTORY_NAME,
+                            ALLOWLIST_FILE_NAME
+                        ),
+                        format!("/etc/xdg/{}/{}", COMMON_DIRECTORY_NAME, ALLOWLIST_FILE_NAME),
+                        format!("./{}/{}", COMMON_DIRECTORY_NAME, ALLOWLIST_FILE_NAME),
+                    ],
+                ),
+                (
+                    FileType::BlockList,
+                    vec![
+                        format!(
+                            "{}/.config/{}/{}",
+                            std::env::var("HOME").unwrap(),
+                            COMMON_DIRECTORY_NAME,
+                            BLOCKLIST_FILE_NAME
+                        ),
+                        format!("/etc/xdg/{}/{}", COMMON_DIRECTORY_NAME, BLOCKLIST_FILE_NAME),
+                        format!("./{}/{}", COMMON_DIRECTORY_NAME, BLOCKLIST_FILE_NAME),
+                    ],
+                ),
+            ])
+        })
+        .get(&file_type)
+        .unwrap();
+
     for (idx, _) in file_path.iter().enumerate() {
         if Path::new(file_path[idx].as_str()).exists() {
-            return Ok(file_path[idx].clone());
+            return Ok(std::mem::take(&mut &*file_path[idx]));
         }
     }
 
     // if no of the configs above exist, return error
     Err(Error::new(
         std::io::ErrorKind::NotFound,
-        format!("{:?} file not found!!", file_type),
+        format!("{:?} file/folder not found!!", file_type),
     ))
 }

src/lib.rs

@@ -1,19 +1,25 @@
 //! This main library module provides the functionality to provide and handle the Tcp server
 //! and register all the routes for the `websurfx` meta search engine website.
 
+#![forbid(unsafe_code, clippy::panic)]
+#![deny(missing_docs, clippy::missing_docs_in_private_items, clippy::perf)]
+#![warn(clippy::cognitive_complexity, rust_2018_idioms)]
+
 pub mod cache;
 pub mod config;
 pub mod engines;
 pub mod handler;
+pub mod models;
 pub mod results;
 pub mod server;
 
 use std::net::TcpListener;
 
-use crate::server::routes;
+use crate::server::router;
 
 use actix_cors::Cors;
 use actix_files as fs;
+use actix_governor::{Governor, GovernorConfigBuilder};
 use actix_web::{dev::Server, http::header, middleware::Logger, web, App, HttpServer};
 use config::parser::Config;
 use handlebars::Handlebars;
@@ -40,15 +46,15 @@ use handler::paths::{file_path, FileType};
 /// let server = run(listener,config).expect("Failed to start server");
 /// ```
 pub fn run(listener: TcpListener, config: Config) -> std::io::Result<Server> {
-    let mut handlebars: Handlebars = Handlebars::new();
+    let mut handlebars: Handlebars<'_> = Handlebars::new();
 
-    let public_folder_path: String = file_path(FileType::Theme)?;
+    let public_folder_path: &str = file_path(FileType::Theme)?;
 
     handlebars
         .register_templates_directory(".html", format!("{}/templates", public_folder_path))
         .unwrap();
 
-    let handlebars_ref: web::Data<Handlebars> = web::Data::new(handlebars);
+    let handlebars_ref: web::Data<Handlebars<'_>> = web::Data::new(handlebars);
 
     let cloned_config_threads_opt: u8 = config.threads;
 
@@ -64,10 +70,17 @@ pub fn run(listener: TcpListener, config: Config) -> std::io::Result<Server> {
             ]);
 
         App::new()
+            .wrap(Logger::default()) // added logging middleware for logging.
             .app_data(handlebars_ref.clone())
             .app_data(web::Data::new(config.clone()))
             .wrap(cors)
-            .wrap(Logger::default()) // added logging middleware for logging.
+            .wrap(Governor::new(
+                &GovernorConfigBuilder::default()
+                    .per_second(config.rate_limiter.time_limit as u64)
+                    .burst_size(config.rate_limiter.number_of_requests as u32)
+                    .finish()
+                    .unwrap(),
+            ))
             // Serve images and static files (css and js files).
             .service(
                 fs::Files::new("/static", format!("{}/static", public_folder_path))
@@ -77,12 +90,12 @@ pub fn run(listener: TcpListener, config: Config) -> std::io::Result<Server> {
                 fs::Files::new("/images", format!("{}/images", public_folder_path))
                     .show_files_listing(),
             )
-            .service(routes::robots_data) // robots.txt
+            .service(router::robots_data) // robots.txt
-            .service(routes::index) // index page
+            .service(router::index) // index page
-            .service(routes::search) // search page
+            .service(server::routes::search::search) // search page
-            .service(routes::about) // about page
+            .service(router::about) // about page
-            .service(routes::settings) // settings page
+            .service(router::settings) // settings page
-            .default_service(web::route().to(routes::not_found)) // error page
+            .default_service(web::route().to(router::not_found)) // error page
     })
     .workers(cloned_config_threads_opt as usize)
     // Start server on 127.0.0.1 with the user provided port number. for example 127.0.0.1:8080.

src/models/aggregation_models.rs

@@ -0,0 +1,181 @@
+//! This module provides public models for handling, storing and serializing of search results
+//! data scraped from the upstream search engines.
+
+use serde::{Deserialize, Serialize};
+use smallvec::SmallVec;
+
+use super::{engine_models::EngineError, parser_models::Style};
+
+/// A named struct to store the raw scraped search results scraped search results from the
+/// upstream search engines before aggregating it.It derives the Clone trait which is needed
+/// to write idiomatic rust using `Iterators`.
+/// (href url in html in simple words).
+#[derive(Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SearchResult {
+    /// The title of the search result.
+    pub title: String,
+    /// The url which is accessed when clicked on it
+    pub url: String,
+    /// The description of the search result.
+    pub description: String,
+    /// The names of the upstream engines from which this results were provided.
+    pub engine: SmallVec<[String; 0]>,
+}
+
+impl SearchResult {
+    /// Constructs a new `RawSearchResult` with the given arguments needed for the struct.
+    ///
+    /// # Arguments
+    ///
+    /// * `title` - The title of the search result.
+    /// * `url` - The url which is accessed when clicked on it
+    /// (href url in html in simple words).
+    /// * `description` - The description of the search result.
+    /// * `engine` - The names of the upstream engines from which this results were provided.
+    pub fn new(title: &str, url: &str, description: &str, engine: &[&str]) -> Self {
+        SearchResult {
+            title: title.to_owned(),
+            url: url.to_owned(),
+            description: description.to_owned(),
+            engine: engine.iter().map(|name| name.to_string()).collect(),
+        }
+    }
+
+    /// A function which adds the engine name provided as a string into a vector of strings.
+    ///
+    /// # Arguments
+    ///
+    /// * `engine` - Takes an engine name provided as a String.
+    pub fn add_engines(&mut self, engine: &str) {
+        self.engine.push(engine.to_owned())
+    }
+
+    /// A function which returns the engine name stored from the struct as a string.
+    ///
+    /// # Returns
+    ///
+    /// An engine name stored as a string from the struct.
+    pub fn engine(&mut self) -> String {
+        std::mem::take(&mut self.engine[0])
+    }
+}
+
+/// A named struct that stores the error info related to the upstream search engines.
+#[derive(Serialize, Deserialize, Clone)]
+pub struct EngineErrorInfo {
+    /// It stores the error type which occured while fetching the result from a particular search
+    /// engine.
+    pub error: String,
+    /// It stores the name of the engine that failed to provide the requested search results.
+    pub engine: String,
+    /// It stores the name of the color to indicate whether how severe the particular error is (In
+    /// other words it indicates the severity of the error/issue).
+    pub severity_color: String,
+}
+
+impl EngineErrorInfo {
+    /// Constructs a new `SearchResult` with the given arguments needed for the struct.
+    ///
+    /// # Arguments
+    ///
+    /// * `error` - It takes the error type which occured while fetching the result from a particular
+    /// search engine.
+    /// * `engine` - It takes the name of the engine that failed to provide the requested search results.
+    pub fn new(error: &EngineError, engine: &str) -> Self {
+        Self {
+            error: match error {
+                EngineError::RequestError => "RequestError".to_owned(),
+                EngineError::EmptyResultSet => "EmptyResultSet".to_owned(),
+                EngineError::UnexpectedError => "UnexpectedError".to_owned(),
+            },
+            engine: engine.to_owned(),
+            severity_color: match error {
+                EngineError::RequestError => "green".to_owned(),
+                EngineError::EmptyResultSet => "blue".to_owned(),
+                EngineError::UnexpectedError => "red".to_owned(),
+            },
+        }
+    }
+}
+
+/// A named struct to store, serialize, deserialize the all the search results scraped and
+/// aggregated from the upstream search engines.
+/// `SearchResult` structs.
+#[derive(Serialize, Deserialize, Default)]
+#[serde(rename_all = "camelCase")]
+pub struct SearchResults {
+    /// Stores the individual serializable `SearchResult` struct into a vector of
+    pub results: Vec<SearchResult>,
+    /// Stores the current pages search query `q` provided in the search url.
+    pub page_query: String,
+    /// Stores the theming options for the website.
+    pub style: Style,
+    /// Stores the information on which engines failed with their engine name
+    /// and the type of error that caused it.
+    pub engine_errors_info: Vec<EngineErrorInfo>,
+    /// Stores the flag option which holds the check value that the following
+    /// search query was disallowed when the safe search level set to 4 and it
+    /// was present in the `Blocklist` file.
+    pub disallowed: bool,
+    /// Stores the flag option which holds the check value that the following
+    /// search query was filtered when the safe search level set to 3 and it
+    /// was present in the `Blocklist` file.
+    pub filtered: bool,
+}
+
+impl SearchResults {
+    /// Constructs a new `SearchResult` with the given arguments needed for the struct.
+    ///
+    /// # Arguments
+    ///
+    /// * `results` - Takes an argument of individual serializable `SearchResult` struct
+    /// and stores it into a vector of `SearchResult` structs.
+    /// * `page_query` - Takes an argument of current page`s search query `q` provided in
+    /// the search url.
+    /// * `engine_errors_info` - Takes an array of structs which contains information regarding
+    /// which engines failed with their names, reason and their severity color name.
+    pub fn new(
+        results: Vec<SearchResult>,
+        page_query: &str,
+        engine_errors_info: &[EngineErrorInfo],
+    ) -> Self {
+        Self {
+            results,
+            page_query: page_query.to_owned(),
+            style: Style::default(),
+            engine_errors_info: engine_errors_info.to_owned(),
+            disallowed: Default::default(),
+            filtered: Default::default(),
+        }
+    }
+
+    /// A setter function to add website style to the return search results.
+    pub fn add_style(&mut self, style: &Style) {
+        self.style = style.clone();
+    }
+
+    /// A setter function that sets disallowed to true.
+    pub fn set_disallowed(&mut self) {
+        self.disallowed = true;
+    }
+
+    /// A setter function to set the current page search query.
+    pub fn set_page_query(&mut self, page: &str) {
+        self.page_query = page.to_owned();
+    }
+
+    /// A setter function that sets the filtered to true.
+    pub fn set_filtered(&mut self) {
+        self.filtered = true;
+    }
+
+    /// A getter function that gets the value of `engine_errors_info`.
+    pub fn engine_errors_info(&mut self) -> Vec<EngineErrorInfo> {
+        std::mem::take(&mut self.engine_errors_info)
+    }
+    /// A getter function that gets the value of `results`.
+    pub fn results(&mut self) -> Vec<SearchResult> {
+        self.results.clone()
+    }
+}

src/models/engine_models.rs

@@ -0,0 +1,159 @@
+//! This module provides the error enum to handle different errors associated while requesting data from
+//! the upstream search engines with the search query provided by the user.
+
+use super::aggregation_models::SearchResult;
+use error_stack::{Result, ResultExt};
+use std::{collections::HashMap, fmt, time::Duration};
+
+/// A custom error type used for handle engine associated errors.
+#[derive(Debug)]
+pub enum EngineError {
+    /// This variant handles all request related errors like forbidden, not found,
+    /// etc.
+    EmptyResultSet,
+    /// This variant handles the not results found error provide by the upstream
+    /// search engines.
+    RequestError,
+    ///  This variant handles all the errors which are unexpected or occur rarely
+    /// and are errors mostly related to failure in initialization of HeaderMap,
+    /// Selector errors and all other errors occurring within the code handling
+    /// the `upstream search engines`.
+    UnexpectedError,
+}
+
+impl fmt::Display for EngineError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            EngineError::EmptyResultSet => {
+                write!(f, "The upstream search engine returned an empty result set")
+            }
+            EngineError::RequestError => {
+                write!(
+                    f,
+                    "Error occurred while requesting data from upstream search engine"
+                )
+            }
+            EngineError::UnexpectedError => {
+                write!(f, "An unexpected error occurred while processing the data")
+            }
+        }
+    }
+}
+
+impl error_stack::Context for EngineError {}
+
+/// A trait to define common behavior for all search engines.
+#[async_trait::async_trait]
+pub trait SearchEngine: Sync + Send {
+    /// This helper function fetches/requests the search results from the upstream search engine in
+    /// an html form.
+    ///
+    /// # Arguments
+    ///
+    /// * `url` - It takes the url of the upstream search engine with the user requested search
+    /// query appended in the search parameters.
+    /// * `header_map` - It takes the http request headers to be sent to the upstream engine in
+    /// order to prevent being detected as a bot. It takes the header as a HeaderMap type.
+    /// * `request_timeout` - It takes the request timeout value as seconds which is used to limit
+    /// the amount of time for each request to remain connected when until the results can be provided
+    /// by the upstream engine.
+    ///
+    /// # Error
+    ///
+    /// It returns the html data as a string if the upstream engine provides the data as expected
+    /// otherwise it returns a custom `EngineError`.
+    async fn fetch_html_from_upstream(
+        &self,
+        url: &str,
+        header_map: reqwest::header::HeaderMap,
+        request_timeout: u8,
+    ) -> Result<String, EngineError> {
+        // fetch the html from upstream search engine
+        Ok(reqwest::Client::new()
+            .get(url)
+            .timeout(Duration::from_secs(request_timeout as u64)) // Add timeout to request to avoid DDOSing the server
+            .headers(header_map) // add spoofed headers to emulate human behavior
+            .send()
+            .await
+            .change_context(EngineError::RequestError)?
+            .text()
+            .await
+            .change_context(EngineError::RequestError)?)
+    }
+
+    /// This function scrapes results from the upstream engine and puts all the scraped results like
+    /// title, visiting_url (href in html),engine (from which engine it was fetched from) and description
+    /// in a RawSearchResult and then adds that to HashMap whose keys are url and values are RawSearchResult
+    /// struct and then returns it within a Result enum.
+    ///
+    /// # Arguments
+    ///
+    /// * `query` - Takes the user provided query to query to the upstream search engine with.
+    /// * `page` - Takes an u32 as an argument.
+    /// * `user_agent` - Takes a random user agent string as an argument.
+    /// * `request_timeout` - Takes a time (secs) as a value which controls the server request timeout.
+    ///
+    /// # Errors
+    ///
+    /// Returns an `EngineErrorKind` if the user is not connected to the internet or if their is failure to
+    /// reach the above `upstream search engine` page or if the `upstream search engine` is unable to
+    /// provide results for the requested search query and also returns error if the scraping selector
+    /// or HeaderMap fails to initialize.
+    async fn results(
+        &self,
+        query: &str,
+        page: u32,
+        user_agent: &str,
+        request_timeout: u8,
+        safe_search: u8,
+    ) -> Result<HashMap<String, SearchResult>, EngineError>;
+}
+
+/// A named struct which stores the engine struct with the name of the associated engine.
+pub struct EngineHandler {
+    /// It stores the engine struct wrapped in a box smart pointer as the engine struct implements
+    /// the `SearchEngine` trait.
+    engine: Box<dyn SearchEngine>,
+    /// It stores the name of the engine to which the struct is associated to.
+    name: &'static str,
+}
+
+impl Clone for EngineHandler {
+    fn clone(&self) -> Self {
+        Self::new(self.name).unwrap()
+    }
+}
+
+impl EngineHandler {
+    /// Parses an engine name into an engine handler.
+    ///
+    /// # Arguments
+    ///
+    /// * `engine_name` - It takes the name of the engine to which the struct was associated to.
+    ///
+    /// # Returns
+    ///
+    /// It returns an option either containing the value or a none if the engine is unknown
+    pub fn new(engine_name: &str) -> Option<Self> {
+        let engine: (&'static str, Box<dyn SearchEngine>) =
+            match engine_name.to_lowercase().as_str() {
+                "duckduckgo" => (
+                    "duckduckgo",
+                    Box::new(crate::engines::duckduckgo::DuckDuckGo),
+                ),
+                "searx" => ("searx", Box::new(crate::engines::searx::Searx)),
+                _ => return None,
+            };
+
+        Some(Self {
+            engine: engine.1,
+            name: engine.0,
+        })
+    }
+
+    /// This function converts the EngineHandler type into a tuple containing the engine name and
+    /// the associated engine struct.
+    pub fn into_name_engine(self) -> (&'static str, Box<dyn SearchEngine>) {
+        (self.name, self.engine)
+    }
+}

src/models/mod.rs

@@ -0,0 +1,8 @@
+//! This module provides modules which in turn provides various models for aggregrating search
+//! results, parsing config file, providing trait to standardize search engine handling code,
+//! custom engine error for the search engine, etc.
+
+pub mod aggregation_models;
+pub mod engine_models;
+pub mod parser_models;
+pub mod server_models;

src/models/parser_models.rs

@@ -12,15 +12,12 @@ use serde::{Deserialize, Serialize};
 /// order to allow the deserializing the json back to struct in aggregate function in
 /// aggregator.rs and create a new struct out of it and then serialize it back to json and pass
 /// it to the template files.
-///
+#[derive(Serialize, Deserialize, Clone, Default)]
-/// # Fields
-//
-/// * `theme` - It stores the parsed theme option used to set a theme for the website.
-/// * `colorscheme` - It stores the parsed colorscheme option used to set a colorscheme for the
-/// theme being used.
-#[derive(Serialize, Deserialize, Clone)]
 pub struct Style {
+    /// It stores the parsed theme option used to set a theme for the website.
     pub theme: String,
+    /// It stores the parsed colorscheme option used to set a colorscheme for the
+    /// theme being used.
     pub colorscheme: String,
 }
 
@@ -36,3 +33,20 @@ impl Style {
         Style { theme, colorscheme }
     }
 }
+
+/// Configuration options for the aggregator.
+#[derive(Clone)]
+pub struct AggregatorConfig {
+    /// It stores the option to whether enable or disable random delays between
+    /// requests.
+    pub random_delay: bool,
+}
+
+/// Configuration options for the rate limiter middleware.
+#[derive(Clone)]
+pub struct RateLimiter {
+    /// The number of request that are allowed within a provided time limit.
+    pub number_of_requests: u8,
+    /// The time limit in which the quantity of requests that should be accepted.
+    pub time_limit: u8,
+}

src/models/server_models.rs

@@ -0,0 +1,26 @@
+//! This module provides the models to parse cookies and search parameters from the search
+//! engine website.
+use serde::Deserialize;
+
+/// A named struct which deserializes all the user provided search parameters and stores them.
+#[derive(Deserialize)]
+pub struct SearchParams {
+    /// It stores the search parameter option `q` (or query in simple words)
+    /// of the search url.
+    pub q: Option<String>,
+    /// It stores the search parameter `page` (or pageno in simple words)
+    /// of the search url.
+    pub page: Option<u32>,
+}
+
+/// A named struct which is used to deserialize the cookies fetched from the client side.
+#[allow(dead_code)]
+#[derive(Deserialize)]
+pub struct Cookie {
+    /// It stores the theme name used in the website.
+    pub theme: String,
+    /// It stores the colorscheme name used for the website theme.
+    pub colorscheme: String,
+    /// It stores the user selected upstream search engines selected from the UI.
+    pub engines: Vec<String>,
+}

src/results/aggregation_models.rs

@@ -1,142 +0,0 @@
-//! This module provides public models for handling, storing and serializing of search results
-//! data scraped from the upstream search engines.
-
-use serde::{Deserialize, Serialize};
-
-use crate::{config::parser_models::Style, engines::engine_models::EngineError};
-
-/// A named struct to store the raw scraped search results scraped search results from the
-/// upstream search engines before aggregating it.It derives the Clone trait which is needed
-/// to write idiomatic rust using `Iterators`.
-///
-/// # Fields
-///
-/// * `title` - The title of the search result.
-/// * `url` - The url which is accessed when clicked on it
-/// (href url in html in simple words).
-/// * `description` - The description of the search result.
-/// * `engine` - The names of the upstream engines from which this results were provided.
-#[derive(Clone, Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-pub struct SearchResult {
-    pub title: String,
-    pub url: String,
-    pub description: String,
-    pub engine: Vec<String>,
-}
-
-impl SearchResult {
-    /// Constructs a new `RawSearchResult` with the given arguments needed for the struct.
-    ///
-    /// # Arguments
-    ///
-    /// * `title` - The title of the search result.
-    /// * `url` - The url which is accessed when clicked on it
-    /// (href url in html in simple words).
-    /// * `description` - The description of the search result.
-    /// * `engine` - The names of the upstream engines from which this results were provided.
-    pub fn new(title: String, url: String, description: String, engine: Vec<String>) -> Self {
-        SearchResult {
-            title,
-            url,
-            description,
-            engine,
-        }
-    }
-
-    /// A function which adds the engine name provided as a string into a vector of strings.
-    ///
-    /// # Arguments
-    ///
-    /// * `engine` - Takes an engine name provided as a String.
-    pub fn add_engines(&mut self, engine: String) {
-        self.engine.push(engine)
-    }
-
-    /// A function which returns the engine name stored from the struct as a string.
-    ///
-    /// # Returns
-    ///
-    /// An engine name stored as a string from the struct.
-    pub fn engine(self) -> String {
-        self.engine.get(0).unwrap().to_string()
-    }
-}
-
-///
-#[derive(Serialize, Deserialize)]
-pub struct EngineErrorInfo {
-    pub error: String,
-    pub engine: String,
-    pub severity_color: String,
-}
-
-impl EngineErrorInfo {
-    pub fn new(error: &EngineError, engine: String) -> Self {
-        Self {
-            error: match error {
-                EngineError::RequestError => String::from("RequestError"),
-                EngineError::EmptyResultSet => String::from("EmptyResultSet"),
-                EngineError::UnexpectedError => String::from("UnexpectedError"),
-            },
-            engine,
-            severity_color: match error {
-                EngineError::RequestError => String::from("green"),
-                EngineError::EmptyResultSet => String::from("blue"),
-                EngineError::UnexpectedError => String::from("red"),
-            },
-        }
-    }
-}
-
-/// A named struct to store, serialize, deserialize the all the search results scraped and
-/// aggregated from the upstream search engines.
-///
-/// # Fields
-///
-/// * `results` - Stores the individual serializable `SearchResult` struct into a vector of
-/// `SearchResult` structs.
-/// * `page_query` - Stores the current pages search query `q` provided in the search url.
-/// * `style` - Stores the theming options for the website.
-/// * `engine_errors_info` - Stores the information on which engines failed with their engine name
-/// and the type of error that caused it.
-/// * `empty_result_set` - Stores a boolean which indicates that no engines gave a result for the
-/// given search query.
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-pub struct SearchResults {
-    pub results: Vec<SearchResult>,
-    pub page_query: String,
-    pub style: Style,
-    pub engine_errors_info: Vec<EngineErrorInfo>,
-}
-
-impl SearchResults {
-    /// Constructs a new `SearchResult` with the given arguments needed for the struct.
-    ///
-    /// # Arguments
-    ///
-    /// * `results` - Takes an argument of individual serializable `SearchResult` struct
-    /// and stores it into a vector of `SearchResult` structs.
-    /// * `page_query` - Takes an argument of current page`s search query `q` provided in
-    /// the search url.
-    /// * `empty_result_set` - Takes a boolean which indicates that no engines gave a result for the
-    /// given search query.
-    pub fn new(
-        results: Vec<SearchResult>,
-        page_query: String,
-        engine_errors_info: Vec<EngineErrorInfo>,
-    ) -> Self {
-        SearchResults {
-            results,
-            page_query,
-            style: Style::new("".to_string(), "".to_string()),
-            engine_errors_info,
-        }
-    }
-
-    /// A setter function to add website style to the return search results.
-    pub fn add_style(&mut self, style: Style) {
-        self.style = style;
-    }
-}

src/results/aggregator.rs

@@ -1,27 +1,23 @@
 //! This module provides the functionality to scrape and gathers all the results from the upstream
 //! search engines and then removes duplicate results.
 
+use super::user_agent::random_user_agent;
+use crate::handler::paths::{file_path, FileType};
+use crate::models::{
+    aggregation_models::{EngineErrorInfo, SearchResult, SearchResults},
+    engine_models::{EngineError, EngineHandler},
+};
+use error_stack::Report;
+use rand::Rng;
+use regex::Regex;
 use std::{
     collections::HashMap,
     io::{BufReader, Read},
     time::Duration,
 };
-
-use super::{
-    aggregation_models::{EngineErrorInfo, SearchResult, SearchResults},
-    user_agent::random_user_agent,
-};
-use error_stack::Report;
-use rand::Rng;
-use regex::Regex;
 use std::{fs::File, io::BufRead};
 use tokio::task::JoinHandle;
 
-use crate::{
-    engines::engine_models::{EngineError, EngineHandler},
-    handler::paths::{file_path, FileType},
-};
-
 /// Aliases for long type annotations
 type FutureVec = Vec<JoinHandle<Result<HashMap<String, SearchResult>, Report<EngineError>>>>;
 
@@ -64,14 +60,15 @@ type FutureVec = Vec<JoinHandle<Result<HashMap<String, SearchResult>, Report<Eng
 /// function in either `searx` or `duckduckgo` or both otherwise returns a `SearchResults struct`
 /// containing appropriate values.
 pub async fn aggregate(
-    query: String,
+    query: &str,
     page: u32,
     random_delay: bool,
     debug: bool,
-    upstream_search_engines: Vec<EngineHandler>,
+    upstream_search_engines: &[EngineHandler],
     request_timeout: u8,
+    safe_search: u8,
 ) -> Result<SearchResults, Box<dyn std::error::Error>> {
-    let user_agent: String = random_user_agent();
+    let user_agent: &str = random_user_agent();
 
     // Add a random delay before making the request.
     if random_delay || !debug {
@@ -80,19 +77,24 @@ pub async fn aggregate(
         tokio::time::sleep(Duration::from_secs(delay_secs)).await;
     }
 
-    let mut names: Vec<&str> = vec![];
+    let mut names: Vec<&str> = Vec::with_capacity(0);
 
     // create tasks for upstream result fetching
     let mut tasks: FutureVec = FutureVec::new();
 
     for engine_handler in upstream_search_engines {
-        let (name, search_engine) = engine_handler.into_name_engine();
+        let (name, search_engine) = engine_handler.to_owned().into_name_engine();
         names.push(name);
-        let query: String = query.clone();
+        let query: String = query.to_owned();
-        let user_agent: String = user_agent.clone();
         tasks.push(tokio::spawn(async move {
             search_engine
-                .results(query, page, user_agent.clone(), request_timeout)
+                .results(
+                    &query,
+                    page,
+                    user_agent.clone(),
+                    request_timeout,
+                    safe_search,
+                )
                 .await
         }));
     }
@@ -110,7 +112,7 @@ pub async fn aggregate(
     let mut result_map: HashMap<String, SearchResult> = HashMap::new();
     let mut engine_errors_info: Vec<EngineErrorInfo> = Vec::new();
 
-    let mut handle_error = |error: Report<EngineError>, engine_name: String| {
+    let mut handle_error = |error: &Report<EngineError>, engine_name: &'static str| {
         log::error!("Engine Error: {:?}", error);
         engine_errors_info.push(EngineErrorInfo::new(
             error.downcast_ref::<EngineError>().unwrap(),
@@ -120,7 +122,7 @@ pub async fn aggregate(
 
     for _ in 0..responses.len() {
         let response = responses.pop().unwrap();
-        let engine = names.pop().unwrap().to_string();
+        let engine = names.pop().unwrap();
 
         if result_map.is_empty() {
             match response {
@@ -128,7 +130,7 @@ pub async fn aggregate(
                     result_map = results.clone();
                 }
                 Err(error) => {
-                    handle_error(error, engine);
+                    handle_error(&error, engine);
                 }
             }
             continue;
@@ -140,39 +142,37 @@ pub async fn aggregate(
                     result_map
                         .entry(key)
                         .and_modify(|result| {
-                            result.add_engines(engine.clone());
+                            result.add_engines(engine);
                         })
                         .or_insert_with(|| -> SearchResult { value });
                 });
             }
             Err(error) => {
-                handle_error(error, engine);
+                handle_error(&error, engine);
             }
         }
     }
 
-    let mut blacklist_map: HashMap<String, SearchResult> = HashMap::new();
+    if safe_search >= 3 {
-    filter_with_lists(
+        let mut blacklist_map: HashMap<String, SearchResult> = HashMap::new();
-        &mut result_map,
+        filter_with_lists(
-        &mut blacklist_map,
+            &mut result_map,
-        &file_path(FileType::BlockList)?,
+            &mut blacklist_map,
-    )?;
+            file_path(FileType::BlockList)?,
+        )?;
 
-    filter_with_lists(
+        filter_with_lists(
-        &mut blacklist_map,
+            &mut blacklist_map,
-        &mut result_map,
+            &mut result_map,
-        &file_path(FileType::AllowList)?,
+            file_path(FileType::AllowList)?,
-    )?;
+        )?;
 
-    drop(blacklist_map);
+        drop(blacklist_map);
+    }
 
     let results: Vec<SearchResult> = result_map.into_values().collect();
 
-    Ok(SearchResults::new(
+    Ok(SearchResults::new(results, query, &engine_errors_info))
-        results,
-        query.to_string(),
-        engine_errors_info,
-    ))
 }
 
 /// Filters a map of search results using a list of regex patterns.
@@ -194,7 +194,7 @@ pub fn filter_with_lists(
     let mut reader = BufReader::new(File::open(file_path)?);
 
     for line in reader.by_ref().lines() {
-        let re = Regex::new(&line?)?;
+        let re = Regex::new(line?.trim())?;
 
         // Iterate over each search result in the map and check if it matches the regex pattern
         for (url, search_result) in map_to_be_filtered.clone().into_iter() {
@@ -203,7 +203,10 @@ pub fn filter_with_lists(
                 || re.is_match(&search_result.description.to_lowercase())
             {
                 // If the search result matches the regex pattern, move it from the original map to the resultant map
-                resultant_map.insert(url.clone(), map_to_be_filtered.remove(&url).unwrap());
+                resultant_map.insert(
+                    url.to_owned(),
+                    map_to_be_filtered.remove(&url.to_owned()).unwrap(),
+                );
             }
         }
     }
@@ -214,6 +217,7 @@ pub fn filter_with_lists(
 #[cfg(test)]
 mod tests {
     use super::*;
+    use smallvec::smallvec;
     use std::collections::HashMap;
     use std::io::Write;
     use tempfile::NamedTempFile;
@@ -223,22 +227,22 @@ mod tests {
         // Create a map of search results to filter
         let mut map_to_be_filtered = HashMap::new();
         map_to_be_filtered.insert(
-            "https://www.example.com".to_string(),
+            "https://www.example.com".to_owned(),
             SearchResult {
-                title: "Example Domain".to_string(),
+                title: "Example Domain".to_owned(),
-                url: "https://www.example.com".to_string(),
+                url: "https://www.example.com".to_owned(),
                 description: "This domain is for use in illustrative examples in documents."
-                    .to_string(),
+                    .to_owned(),
-                engine: vec!["Google".to_string(), "Bing".to_string()],
+                engine: smallvec!["Google".to_owned(), "Bing".to_owned()],
             },
         );
         map_to_be_filtered.insert(
-            "https://www.rust-lang.org/".to_string(),
+            "https://www.rust-lang.org/".to_owned(),
             SearchResult {
-                title: "Rust Programming Language".to_string(),
+                title: "Rust Programming Language".to_owned(),
-                url: "https://www.rust-lang.org/".to_string(),
+                url: "https://www.rust-lang.org/".to_owned(),
-                description: "A systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.".to_string(),
+                description: "A systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.".to_owned(),
-                engine: vec!["Google".to_string(), "DuckDuckGo".to_string()],
+                engine: smallvec!["Google".to_owned(), "DuckDuckGo".to_owned()],
             },
         );
 
@@ -267,22 +271,22 @@ mod tests {
     fn test_filter_with_lists_wildcard() -> Result<(), Box<dyn std::error::Error>> {
         let mut map_to_be_filtered = HashMap::new();
         map_to_be_filtered.insert(
-            "https://www.example.com".to_string(),
+            "https://www.example.com".to_owned(),
             SearchResult {
-                title: "Example Domain".to_string(),
+                title: "Example Domain".to_owned(),
-                url: "https://www.example.com".to_string(),
+                url: "https://www.example.com".to_owned(),
                 description: "This domain is for use in illustrative examples in documents."
-                    .to_string(),
+                    .to_owned(),
-                engine: vec!["Google".to_string(), "Bing".to_string()],
+                engine: smallvec!["Google".to_owned(), "Bing".to_owned()],
             },
         );
         map_to_be_filtered.insert(
-            "https://www.rust-lang.org/".to_string(),
+            "https://www.rust-lang.org/".to_owned(),
             SearchResult {
-                title: "Rust Programming Language".to_string(),
+                title: "Rust Programming Language".to_owned(),
-                url: "https://www.rust-lang.org/".to_string(),
+                url: "https://www.rust-lang.org/".to_owned(),
-                description: "A systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.".to_string(),
+                description: "A systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.".to_owned(),
-                engine: vec!["Google".to_string(), "DuckDuckGo".to_string()],
+                engine: smallvec!["Google".to_owned(), "DuckDuckGo".to_owned()],
             },
         );
 
@@ -327,13 +331,13 @@ mod tests {
     fn test_filter_with_lists_invalid_regex() {
         let mut map_to_be_filtered = HashMap::new();
         map_to_be_filtered.insert(
-            "https://www.example.com".to_string(),
+            "https://www.example.com".to_owned(),
             SearchResult {
-                title: "Example Domain".to_string(),
+                title: "Example Domain".to_owned(),
-                url: "https://www.example.com".to_string(),
+                url: "https://www.example.com".to_owned(),
                 description: "This domain is for use in illustrative examples in documents."
-                    .to_string(),
+                    .to_owned(),
-                engine: vec!["Google".to_string(), "Bing".to_string()],
+                engine: smallvec!["Google".to_owned(), "Bing".to_owned()],
             },
         );
 

src/results/mod.rs

@@ -1,3 +1,6 @@
-pub mod aggregation_models;
+//! This module provides modules that handle the functionality to aggregate the fetched search
+//! results from the upstream search engines and filters it if safe search is set to 3 or 4. Also,
+//! provides various models to aggregate search results into a standardized form.
+
 pub mod aggregator;
 pub mod user_agent;

src/results/user_agent.rs

@@ -1,28 +1,34 @@
 //! This module provides the functionality to generate random user agent string.
 
+use std::sync::OnceLock;
+
 use fake_useragent::{Browsers, UserAgents, UserAgentsBuilder};
 
-static USER_AGENTS: once_cell::sync::Lazy<UserAgents> = once_cell::sync::Lazy::new(|| {
+/// A static variable which stores the initially build `UserAgents` struct. So as it can be resused
-    UserAgentsBuilder::new()
+/// again and again without the need of reinitializing the `UserAgents` struct.
-        .cache(false)
+static USER_AGENTS: OnceLock<UserAgents> = OnceLock::new();
-        .dir("/tmp")
-        .thread(1)
-        .set_browsers(
-            Browsers::new()
-                .set_chrome()
-                .set_safari()
-                .set_edge()
-                .set_firefox()
-                .set_mozilla(),
-        )
-        .build()
-});
 
 /// A function to generate random user agent to improve privacy of the user.
 ///
 /// # Returns
 ///
 /// A randomly generated user agent string.
-pub fn random_user_agent() -> String {
+pub fn random_user_agent() -> &'static str {
-    USER_AGENTS.random().to_string()
+    USER_AGENTS
+        .get_or_init(|| {
+            UserAgentsBuilder::new()
+                .cache(false)
+                .dir("/tmp")
+                .thread(1)
+                .set_browsers(
+                    Browsers::new()
+                        .set_chrome()
+                        .set_safari()
+                        .set_edge()
+                        .set_firefox()
+                        .set_mozilla(),
+                )
+                .build()
+        })
+        .random()
 }

src/server/mod.rs

@@ -1 +1,7 @@
+//! This module provides modules that handle the functionality of handling different routes/paths
+//! for the `websurfx` search engine website. Also it handles the parsing of search parameters in
+//! the search route. Also, caches the next, current and previous search results in the search
+//! routes with the help of the redis server.
+
+pub mod router;
 pub mod routes;

src/server/router.rs

@@ -0,0 +1,64 @@
+//! This module provides the functionality to handle different routes of the `websurfx`
+//! meta search engine website and provide appropriate response to each route/page
+//! when requested.
+
+use crate::{
+    config::parser::Config,
+    handler::paths::{file_path, FileType},
+};
+use actix_web::{get, web, HttpRequest, HttpResponse};
+use handlebars::Handlebars;
+use std::fs::read_to_string;
+
+/// Handles the route of index page or main page of the `websurfx` meta search engine website.
+#[get("/")]
+pub async fn index(
+    hbs: web::Data<Handlebars<'_>>,
+    config: web::Data<Config>,
+) -> Result<HttpResponse, Box<dyn std::error::Error>> {
+    let page_content: String = hbs.render("index", &config.style).unwrap();
+    Ok(HttpResponse::Ok().body(page_content))
+}
+
+/// Handles the route of any other accessed route/page which is not provided by the
+/// website essentially the 404 error page.
+pub async fn not_found(
+    hbs: web::Data<Handlebars<'_>>,
+    config: web::Data<Config>,
+) -> Result<HttpResponse, Box<dyn std::error::Error>> {
+    let page_content: String = hbs.render("404", &config.style)?;
+
+    Ok(HttpResponse::Ok()
+        .content_type("text/html; charset=utf-8")
+        .body(page_content))
+}
+
+/// Handles the route of robots.txt page of the `websurfx` meta search engine website.
+#[get("/robots.txt")]
+pub async fn robots_data(_req: HttpRequest) -> Result<HttpResponse, Box<dyn std::error::Error>> {
+    let page_content: String =
+        read_to_string(format!("{}/robots.txt", file_path(FileType::Theme)?))?;
+    Ok(HttpResponse::Ok()
+        .content_type("text/plain; charset=ascii")
+        .body(page_content))
+}
+
+/// Handles the route of about page of the `websurfx` meta search engine website.
+#[get("/about")]
+pub async fn about(
+    hbs: web::Data<Handlebars<'_>>,
+    config: web::Data<Config>,
+) -> Result<HttpResponse, Box<dyn std::error::Error>> {
+    let page_content: String = hbs.render("about", &config.style)?;
+    Ok(HttpResponse::Ok().body(page_content))
+}
+
+/// Handles the route of settings page of the `websurfx` meta search engine website.
+#[get("/settings")]
+pub async fn settings(
+    hbs: web::Data<Handlebars<'_>>,
+    config: web::Data<Config>,
+) -> Result<HttpResponse, Box<dyn std::error::Error>> {
+    let page_content: String = hbs.render("settings", &config.style)?;
+    Ok(HttpResponse::Ok().body(page_content))
+}

src/server/routes/mod.rs

@@ -0,0 +1,3 @@
+//! This module provides modules to handle various routes in the search engine website.
+
+pub mod search;

src/server/routes/search.rs

@@ -1,33 +1,38 @@
-//! This module provides the functionality to handle different routes of the `websurfx`
+//! This module handles the search route of the search engine website.
-//! meta search engine website and provide appropriate response to each route/page
-//! when requested.
-
-use std::fs::read_to_string;
 
 use crate::{
     cache::cacher::RedisCache,
     config::parser::Config,
-    engines::engine_models::EngineHandler,
     handler::paths::{file_path, FileType},
-    results::{aggregation_models::SearchResults, aggregator::aggregate},
+    models::{aggregation_models::SearchResults, engine_models::EngineHandler},
+    results::aggregator::aggregate,
 };
 use actix_web::{get, web, HttpRequest, HttpResponse};
 use handlebars::Handlebars;
+use regex::Regex;
 use serde::Deserialize;
+use std::{
+    fs::{read_to_string, File},
+    io::{BufRead, BufReader, Read},
+};
 use tokio::join;
 
+// ---- Constants ----
+/// Initialize redis cache connection once and store it on the heap.
+static REDIS_CACHE: async_once_cell::OnceCell<RedisCache> = async_once_cell::OnceCell::new();
+
 /// A named struct which deserializes all the user provided search parameters and stores them.
-///
-/// # Fields
-///
-/// * `q` - It stores the search parameter option `q` (or query in simple words)
-/// of the search url.
-/// * `page` - It stores the search parameter `page` (or pageno in simple words)
-/// of the search url.
 #[derive(Deserialize)]
-struct SearchParams {
+pub struct SearchParams {
+    /// It stores the search parameter option `q` (or query in simple words)
+    /// of the search url.
     q: Option<String>,
+    /// It stores the search parameter `page` (or pageno in simple words)
+    /// of the search url.
     page: Option<u32>,
+    /// It stores the search parameter `safesearch` (or safe search level in simple words) of the
+    /// search url.
+    safesearch: Option<u8>,
 }
 
 /// Handles the route of index page or main page of the `websurfx` meta search engine website.
@@ -54,18 +59,15 @@ pub async fn not_found(
 }
 
 /// A named struct which is used to deserialize the cookies fetched from the client side.
-///
-/// # Fields
-///
-/// * `theme` - It stores the theme name used in the website.
-/// * `colorscheme` - It stores the colorscheme name used for the website theme.
-/// * `engines` - It stores the user selected upstream search engines selected from the UI.
 #[allow(dead_code)]
 #[derive(Deserialize)]
-struct Cookie {
+struct Cookie<'a> {
-    theme: String,
+    /// It stores the theme name used in the website.
-    colorscheme: String,
+    theme: &'a str,
-    engines: Vec<String>,
+    /// It stores the colorscheme name used for the website theme.
+    colorscheme: &'a str,
+    /// It stores the user selected upstream search engines selected from the UI.
+    engines: Vec<&'a str>,
 }
 
 /// Handles the route of search page of the `websurfx` meta search engine website and it takes
@@ -101,42 +103,58 @@ pub async fn search(
                 None => 1,
             };
 
+            let safe_search: u8 = match config.safe_search {
+                3..=4 => config.safe_search,
+                _ => match &params.safesearch {
+                    Some(safesearch) => match safesearch {
+                        0..=2 => *safesearch,
+                        _ => 1,
+                    },
+                    None => config.safe_search,
+                },
+            };
+
             let (_, results, _) = join!(
                 results(
                     format!(
-                        "http://{}:{}/search?q={}&page={}",
+                        "http://{}:{}/search?q={}&page={}&safesearch={}",
                         config.binding_ip,
                         config.port,
                         query,
-                        page - 1
+                        page - 1,
+                        safe_search
                     ),
                     &config,
-                    query.to_string(),
+                    query,
                     page - 1,
                     req.clone(),
+                    safe_search
                 ),
                 results(
                     format!(
-                        "http://{}:{}/search?q={}&page={}",
+                        "http://{}:{}/search?q={}&page={}&safesearch={}",
-                        config.binding_ip, config.port, query, page
+                        config.binding_ip, config.port, query, page, safe_search
                     ),
                     &config,
-                    query.to_string(),
+                    query,
                     page,
                     req.clone(),
+                    safe_search
                 ),
                 results(
                     format!(
-                        "http://{}:{}/search?q={}&page={}",
+                        "http://{}:{}/search?q={}&page={}&safesearch={}",
                         config.binding_ip,
                         config.port,
                         query,
-                        page + 1
+                        page + 1,
+                        safe_search
                     ),
                     &config,
-                    query.to_string(),
+                    query,
                     page + 1,
                     req.clone(),
+                    safe_search
                 )
             );
 
@@ -149,35 +167,72 @@ pub async fn search(
     }
 }
 
-/// Fetches the results for a query and page.
+/// Fetches the results for a query and page. It First checks the redis cache, if that
-/// First checks the redis cache, if that fails it gets proper results
+/// fails it gets proper results by requesting from the upstream search engines.
+///
+/// # Arguments
+///
+/// * `url` - It takes the url of the current page that requested the search results for a
+/// particular search query.
+/// * `config` - It takes a parsed config struct.
+/// * `query` - It takes the page number as u32 value.
+/// * `req` - It takes the `HttpRequest` struct as a value.
+///
+/// # Error
+///
+/// It returns the `SearchResults` struct if the search results could be successfully fetched from
+/// the cache or from the upstream search engines otherwise it returns an appropriate error.
 async fn results(
     url: String,
     config: &Config,
-    query: String,
+    query: &str,
     page: u32,
     req: HttpRequest,
+    safe_search: u8,
 ) -> Result<SearchResults, Box<dyn std::error::Error>> {
-    //Initialize redis cache connection struct
+    // Initialize redis cache connection struct
-    let mut redis_cache = RedisCache::new(config.redis_url.clone())?;
+    let mut redis_cache: RedisCache = REDIS_CACHE
+        .get_or_init(async {
+            // Initialize redis cache connection pool only one and store it in the heap.
+            RedisCache::new(&config.redis_url, 5).await.unwrap()
+        })
+        .await
+        .clone();
     // fetch the cached results json.
-    let cached_results_json = redis_cache.cached_json(&url);
+    let cached_results_json: Result<String, error_stack::Report<crate::cache::error::PoolError>> =
+        redis_cache.clone().cached_json(&url).await;
     // check if fetched cache results was indeed fetched or it was an error and if so
     // handle the data accordingly.
     match cached_results_json {
-        Ok(results) => Ok(serde_json::from_str::<SearchResults>(&results).unwrap()),
+        Ok(results) => Ok(serde_json::from_str::<SearchResults>(&results)?),
         Err(_) => {
+            if safe_search == 4 {
+                let mut results: SearchResults = SearchResults::default();
+                let mut _flag: bool =
+                    is_match_from_filter_list(file_path(FileType::BlockList)?, query)?;
+                _flag = !is_match_from_filter_list(file_path(FileType::AllowList)?, query)?;
+
+                if _flag {
+                    results.set_disallowed();
+                    results.add_style(&config.style);
+                    results.set_page_query(query);
+                    redis_cache
+                        .cache_results(&serde_json::to_string(&results)?, &url)
+                        .await?;
+                    return Ok(results);
+                }
+            }
+
             // check if the cookie value is empty or not if it is empty then use the
             // default selected upstream search engines from the config file otherwise
             // parse the non-empty cookie and grab the user selected engines from the
             // UI and use that.
-            let mut results: crate::results::aggregation_models::SearchResults = match req
+            let mut results: SearchResults = match req.cookie("appCookie") {
-                .cookie("appCookie")
-            {
                 Some(cookie_value) => {
-                    let cookie_value: Cookie = serde_json::from_str(cookie_value.name_value().1)?;
+                    let cookie_value: Cookie<'_> =
+                        serde_json::from_str(cookie_value.name_value().1)?;
 
-                    let engines = cookie_value
+                    let engines: Vec<EngineHandler> = cookie_value
                         .engines
                         .iter()
                         .filter_map(|name| EngineHandler::new(name))
@@ -188,8 +243,9 @@ async fn results(
                         page,
                         config.aggregator.random_delay,
                         config.debug,
-                        engines,
+                        &engines,
                         config.request_timeout,
+                        safe_search,
                     )
                     .await?
                 }
@@ -199,19 +255,43 @@ async fn results(
                         page,
                         config.aggregator.random_delay,
                         config.debug,
-                        config.upstream_search_engines.clone(),
+                        &config.upstream_search_engines,
                         config.request_timeout,
+                        safe_search,
                     )
                     .await?
                 }
             };
-            results.add_style(config.style.clone());
+            if results.engine_errors_info().is_empty() && results.results().is_empty() {
-            redis_cache.cache_results(serde_json::to_string(&results)?, &url)?;
+                results.set_filtered();
+            }
+            results.add_style(&config.style);
+            redis_cache
+                .cache_results(&serde_json::to_string(&results)?, &url)
+                .await?;
             Ok(results)
         }
     }
 }
 
+/// A helper function which checks whether the search query contains any keywords which should be
+/// disallowed/allowed based on the regex based rules present in the blocklist and allowlist files.
+fn is_match_from_filter_list(
+    file_path: &str,
+    query: &str,
+) -> Result<bool, Box<dyn std::error::Error>> {
+    let mut flag = false;
+    let mut reader = BufReader::new(File::open(file_path)?);
+    for line in reader.by_ref().lines() {
+        let re = Regex::new(&line?)?;
+        if re.is_match(query) {
+            flag = true;
+            break;
+        }
+    }
+    Ok(flag)
+}
+
 /// Handles the route of robots.txt page of the `websurfx` meta search engine website.
 #[get("/robots.txt")]
 pub async fn robots_data(_req: HttpRequest) -> Result<HttpResponse, Box<dyn std::error::Error>> {

websurfx/config.lua

@@ -10,6 +10,21 @@ production_use = false -- whether to use production mode or not (in other words
 -- if production_use is set to true
 -- There will be a random delay before sending the request to the search engines, this is to prevent DDoSing the upstream search engines from a large number of simultaneous requests.
 request_timeout = 30 -- timeout for the search requests sent to the upstream search engines to be fetched (value in seconds).
+rate_limiter = {
+	number_of_requests = 20, -- The number of request that are allowed within a provided time limit.
+	time_limit = 3, -- The time limit in which the quantity of requests that should be accepted.
+}
+
+-- ### Search ###
+-- Filter results based on different levels. The levels provided are:
+-- {{
+-- 0 - None
+-- 1 - Low
+-- 2 - Moderate
+-- 3 - High
+-- 4 - Aggressive
+-- }}
+safe_search = 2
 
 -- ### Website ###
 -- The different colorschemes provided are:
@@ -34,4 +49,7 @@ theme = "simple" -- the theme name which should be used for the website
 redis_url = "redis://127.0.0.1:8082" -- redis connection url address on which the client should connect on.
 
 -- ### Search Engines ###
-upstream_search_engines = { DuckDuckGo = true, Searx = false } -- select the upstream search engines from which the results should be fetched.
+upstream_search_engines = {
+	DuckDuckGo = true,
+	Searx = false,
+} -- select the upstream search engines from which the results should be fetched.