Merge pull request #13 from neon-mmd/optimise-code-for-server-use

optimise code for large scale server use and closes #7

src/engines/duckduckgo.rs

@@ -2,9 +2,8 @@
 //! by querying the upstream duckduckgo search engine with user provided query and with a page
 //! number if provided.
 
-use std::{collections::HashMap, time::Duration};
+use std::collections::HashMap;
 
-use rand::Rng;
 use reqwest::header::{HeaderMap, CONTENT_TYPE, REFERER, USER_AGENT};
 use scraper::{Html, Selector};
 
@@ -47,11 +46,6 @@ pub async fn results(
         }
     };
 
-    // Add a random delay before making the request.
-    let mut rng = rand::thread_rng();
-    let delay_secs = rng.gen_range(1, 10);
-    std::thread::sleep(Duration::from_secs(delay_secs));
-
     // initializing HeaderMap and adding appropriate headers.
     let mut header_map = HeaderMap::new();
     header_map.insert(USER_AGENT, user_agent.parse()?);

src/engines/searx.rs

@@ -2,10 +2,9 @@
 //! by querying the upstream searx search engine instance with user provided query and with a page
 //! number if provided.
 
-use rand::Rng;
 use reqwest::header::{HeaderMap, CONTENT_TYPE, REFERER, USER_AGENT};
 use scraper::{Html, Selector};
-use std::{collections::HashMap, time::Duration};
+use std::collections::HashMap;
 
 use crate::search_results_handler::aggregation_models::RawSearchResult;
 
@@ -34,11 +33,6 @@ pub async fn results(
     // so that upstream server recieves valid page number.
     let url: String = format!("https://searx.work/search?q={query}&pageno={page}");
 
-    // Add random delay before making the request.
-    let mut rng = rand::thread_rng();
-    let delay_secs = rng.gen_range(1, 10);
-    std::thread::sleep(Duration::from_secs(delay_secs));
-
     // initializing headers and adding appropriate headers.
     let mut header_map = HeaderMap::new();
     header_map.insert(USER_AGENT, user_agent.parse()?);

src/search_results_handler/aggregator.rs

@@ -1,7 +1,10 @@
 //! This module provides the functionality to scrape and gathers all the results from the upstream
 //! search engines and then removes duplicate results.
 
-use std::collections::HashMap;
+use std::{collections::HashMap, time::Duration};
+
+use rand::Rng;
+use tokio::join;
 
 use super::{
     aggregation_models::{RawSearchResult, SearchResult, SearchResults},
@@ -14,14 +17,14 @@ use crate::engines::{duckduckgo, searx};
 /// then removes duplicate results and if two results are found to be from two or more engines
 /// then puts their names together to show the results are fetched from these upstream engines
 /// and then removes all data from the HashMap and puts into a struct of all results aggregated
-/// into a vector and also adds the query used into the struct this is neccessory because 
+/// into a vector and also adds the query used into the struct this is neccessory because
 /// otherwise the search bar in search remains empty if searched from the query url
 ///
 /// # Example:
 ///
 /// If you search from the url like `https://127.0.0.1/search?q=huston` then the search bar should
 /// contain the word huston and not remain empty.
-/// 
+///
 /// # Arguments
 ///
 /// * `query` - Accepts a string to query with the above upstream search engines.
@@ -29,7 +32,7 @@ use crate::engines::{duckduckgo, searx};
 ///
 /// # Error
 ///
-/// Returns an error a reqwest and scraping selector errors if any error occurs in the results 
+/// Returns an error a reqwest and scraping selector errors if any error occurs in the results
 /// function in either `searx` or `duckduckgo` or both otherwise returns a `SearchResults struct`
 /// containing appropriate values.
 pub async fn aggregate(
@@ -39,10 +42,19 @@ pub async fn aggregate(
     let user_agent: String = random_user_agent();
     let mut result_map: HashMap<String, RawSearchResult> = HashMap::new();
 
-    let ddg_map_results: HashMap<String, RawSearchResult> =
+    // Add a random delay before making the request.
-        duckduckgo::results(query, page, &user_agent).await?;
+    let mut rng = rand::thread_rng();
-    let searx_map_results: HashMap<String, RawSearchResult> =
+    let delay_secs = rng.gen_range(1, 10);
-        searx::results(query, page, &user_agent).await?;
+    std::thread::sleep(Duration::from_secs(delay_secs));
+
+    // fetch results from upstream search engines simultaneously/concurrently.
+    let (ddg_map_results, searx_map_results) = join!(
+        duckduckgo::results(query, page, &user_agent),
+        searx::results(query, page, &user_agent)
+    );
+
+    let ddg_map_results: HashMap<String, RawSearchResult> = ddg_map_results?;
+    let searx_map_results: HashMap<String, RawSearchResult> = searx_map_results?;
 
     result_map.extend(ddg_map_results);