mirror of
https://github.com/neon-mmd/websurfx.git
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77 lines
3.2 KiB
Rust
77 lines
3.2 KiB
Rust
//! This modules provides helper functionalities for parsing a html document into internal SearchResult.
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use std::collections::HashMap;
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use crate::models::{aggregation_models::SearchResult, engine_models::EngineError};
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use error_stack::{Report, Result};
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use scraper::{html::Select, ElementRef, Html, Selector};
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/// A html search result parser, based on a predefined CSS selectors.
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pub struct SearchResultParser {
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/// selector to locate the element which is displayed, if there were nothing found.
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no_result: Selector,
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/// selector to locate the element which contains one item from the search result.
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results: Selector,
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/// selector to locate the title relative to the search result item.
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result_title: Selector,
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/// selector to locate the url relative to the search result item.
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result_url: Selector,
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/// selector to locate the description relative to the search result item.
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result_desc: Selector,
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}
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impl SearchResultParser {
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/// Creates a new parser, if all the selectors are valid, otherwise it returns an EngineError
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pub fn new(
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no_result_selector: &str,
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results_selector: &str,
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result_title_selector: &str,
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result_url_selector: &str,
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result_desc_selector: &str,
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) -> Result<SearchResultParser, EngineError> {
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Ok(SearchResultParser {
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no_result: new_selector(no_result_selector)?,
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results: new_selector(results_selector)?,
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result_title: new_selector(result_title_selector)?,
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result_url: new_selector(result_url_selector)?,
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result_desc: new_selector(result_desc_selector)?,
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})
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}
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/// Parse the html and returns element representing the 'no result found' response.
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pub fn parse_for_no_results<'a>(&'a self, document: &'a Html) -> Select<'a, 'a> {
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document.select(&self.no_result)
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}
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/// Parse the html, and convert the results to SearchResult with the help of the builder function
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pub fn parse_for_results(
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&self,
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document: &Html,
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builder: impl Fn(&ElementRef<'_>, &ElementRef<'_>, &ElementRef<'_>) -> Option<SearchResult>,
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) -> Result<HashMap<String, SearchResult>, EngineError> {
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let res = document
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.select(&self.results)
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.filter_map(|result| {
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let title = result.select(&self.result_title).next();
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let url = result.select(&self.result_url).next();
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let desc = result.select(&self.result_desc).next();
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match (title, url, desc) {
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(Some(ref t), Some(ref u), Some(ref d)) => builder(t, u, d),
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_ => None,
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}
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})
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.map(|search_result| (search_result.url.clone(), search_result))
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.collect();
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Ok(res)
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}
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}
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/// Create a Selector struct, if the given parameter is a valid css expression, otherwise convert it into an EngineError.
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fn new_selector(selector: &str) -> Result<Selector, EngineError> {
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Selector::parse(selector).map_err(|err| {
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Report::new(EngineError::UnexpectedError).attach_printable(format!(
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"invalid CSS selector: {}, err: {:?}",
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selector, err
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))
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})
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}
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