100 lines
3.8 KiB
Rust
100 lines
3.8 KiB
Rust
//! The `duckduckgo` module handles the scraping of results from the duckduckgo search engine
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//! by querying the upstream duckduckgo search engine with user provided query and with a page
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//! number if provided.
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use std::collections::HashMap;
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use reqwest::header::USER_AGENT;
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use scraper::{Html, Selector};
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use crate::search_results_handler::aggregation_models::RawSearchResult;
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/// This function scrapes results from the upstream engine duckduckgo and puts all the scraped
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/// results like title, visiting_url (href in html),engine (from which engine it was fetched from)
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/// and description in a RawSearchResult and then adds that to HashMap whose keys are url and
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/// values are RawSearchResult struct and then returns it within a Result enum.
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///
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/// # Arguments
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///
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/// * `query` - Takes the user provided query to query to the upstream search engine with.
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/// * `page` - Takes an Option<u32> as argument which can be either None or a valid page number.
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/// * `user_agent` - Takes a random user agent string as an argument.
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///
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/// # Errors
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///
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/// Returns a reqwest error if the user is not connected to the internet or if their is failure to
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/// reach the above `upstream search engine` page and also returns error if the scraping
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/// selector fails to initialize"
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pub async fn results(
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query: &str,
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page: Option<u32>,
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user_agent: &str,
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) -> Result<HashMap<String, RawSearchResult>, Box<dyn std::error::Error>> {
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// Page number can be missing or empty string and so appropriate handling is required
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// so that upstream server recieves valid page number.
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let url: String = match page {
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Some(page_number) => {
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if page_number <= 1 {
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format!("https://html.duckduckgo.com/html/?q={query}&s=&dc=&v=1&o=json&api=/d.js")
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} else {
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format!(
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"https://duckduckgo.com/html/?q={}&s={}&dc={}&v=1&o=json&api=/d.js",
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query,
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page_number / 2 * 30,
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page_number / 2 * 30 + 1
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)
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}
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}
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None => format!("https://html.duckduckgo.com/html/?q={query}&s=&dc=&v=1&o=json&api=/d.js"),
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};
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// fetch the html from upstream duckduckgo engine
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// TODO: Write better error handling code to handle no results case.
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let results: String = reqwest::Client::new()
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.get(url)
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.header(USER_AGENT, user_agent)
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.send()
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.await?
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.text()
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.await?;
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let document: Html = Html::parse_document(&results);
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let results: Selector = Selector::parse(".result")?;
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let result_title: Selector = Selector::parse(".result__a")?;
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let result_url: Selector = Selector::parse(".result__url")?;
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let result_desc: Selector = Selector::parse(".result__snippet")?;
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// scrape all the results from the html
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Ok(document
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.select(&results)
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.map(|result| {
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RawSearchResult::new(
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result
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.select(&result_title)
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.next()
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.unwrap()
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.inner_html()
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.trim()
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.to_string(),
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format!(
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"https://{}",
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result
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.select(&result_url)
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.next()
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.unwrap()
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.inner_html()
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.trim()
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),
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result
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.select(&result_desc)
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.next()
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.unwrap()
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.inner_html()
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.trim()
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.to_string(),
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vec!["duckduckgo".to_string()],
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)
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})
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.map(|search_result| (search_result.visiting_url.clone(), search_result))
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.collect())
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}
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