✨ feat: rewrite code by implementing common engine trait `SearchEngine`

src/engines/duckduckgo.rs

@@ -9,7 +9,7 @@ use scraper::{Html, Selector};
 
 use crate::search_results_handler::aggregation_models::RawSearchResult;
 
-use super::engine_models::EngineError;
+use super::engine_models::{EngineError, SearchEngine};
 
 use error_stack::{IntoReport, Report, Result, ResultExt};
 
@@ -30,126 +30,121 @@ use error_stack::{IntoReport, Report, Result, ResultExt};
 /// 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.
-pub async fn results(
-    query: &str,
-    page: u32,
-    user_agent: &str,
-) -> Result<HashMap<String, RawSearchResult>, EngineError> {
-    // Page number can be missing or empty string and so appropriate handling is required
-    // so that upstream server recieves valid page number.
-    let url: String = match page {
-        1 => {
-            format!("https://html.duckduckgo.com/html/?q={query}&s=&dc=&v=1&o=json&api=/d.js")
-        }
-        _ => {
-            format!(
-                "https://duckduckgo.com/html/?q={}&s={}&dc={}&v=1&o=json&api=/d.js",
-                query,
-                (page / 2 + (page % 2)) * 30,
-                (page / 2 + (page % 2)) * 30 + 1
-            )
-        }
-    };
 
-    // initializing HeaderMap and adding appropriate headers.
-    let mut header_map = HeaderMap::new();
-    header_map.insert(
-        USER_AGENT,
-        user_agent
-            .parse()
-            .into_report()
-            .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,
-        "kl=wt-wt"
-            .parse()
-            .into_report()
-            .change_context(EngineError::UnexpectedError)?,
-    );
+pub struct DuckDuckGo;
 
-    // fetch the html from upstream duckduckgo engine
-    let results: String = reqwest::Client::new()
-        .get(url)
-        .timeout(Duration::from_secs(5))
-        .headers(header_map) // add spoofed headers to emulate human behaviour
-        .send()
-        .await
-        .into_report()
-        .change_context(EngineError::RequestError)?
-        .text()
-        .await
-        .into_report()
-        .change_context(EngineError::RequestError)?;
+#[async_trait::async_trait]
+impl SearchEngine for DuckDuckGo {
+    async fn results(
+        &self,
+        query: String,
+        page: u32,
+        user_agent: String,
+    ) -> Result<HashMap<String, RawSearchResult>, EngineError> {
+        // Page number can be missing or empty string and so appropriate handling is required
+        // so that upstream server recieves valid page number.
+        let url: String = match page {
+            1 => {
+                format!("https://html.duckduckgo.com/html/?q={query}&s=&dc=&v=1&o=json&api=/d.js")
+            }
+            _ => {
+                format!(
+                    "https://duckduckgo.com/html/?q={}&s={}&dc={}&v=1&o=json&api=/d.js",
+                    query,
+                    (page / 2 + (page % 2)) * 30,
+                    (page / 2 + (page % 2)) * 30 + 1
+                )
+            }
+        };
 
-    let document: Html = Html::parse_document(&results);
+        // initializing HeaderMap and adding appropriate headers.
+        let mut header_map = HeaderMap::new();
+        header_map.insert(
+            USER_AGENT,
+            user_agent
+                .parse()
+                .into_report()
+                .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,
+            "kl=wt-wt"
+                .parse()
+                .into_report()
+                .change_context(EngineError::UnexpectedError)?,
+        );
 
-    let no_result: Selector = Selector::parse(".no-results")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".no-results"))?;
+        let document: Html = Html::parse_document(
+            &DuckDuckGo::fetch_html_from_upstream(&self, url, header_map).await?,
+        );
 
-    if document.select(&no_result).next().is_some() {
-        return Err(Report::new(EngineError::EmptyResultSet));
-    }
+        let no_result: Selector = Selector::parse(".no-results")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".no-results"))?;
 
-    let results: Selector = Selector::parse(".result")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result"))?;
-    let result_title: Selector = Selector::parse(".result__a")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result__a"))?;
-    let result_url: Selector = Selector::parse(".result__url")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result__url"))?;
-    let result_desc: Selector = Selector::parse(".result__snippet")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result__snippet"))?;
+        if document.select(&no_result).next().is_some() {
+            return Err(Report::new(EngineError::EmptyResultSet));
+        }
 
-    // scrape all the results from the html
-    Ok(document
-        .select(&results)
-        .map(|result| {
-            RawSearchResult::new(
-                result
-                    .select(&result_title)
-                    .next()
-                    .unwrap()
-                    .inner_html()
-                    .trim()
-                    .to_string(),
-                format!(
-                    "https://{}",
+        let results: Selector = Selector::parse(".result")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result"))?;
+        let result_title: Selector = Selector::parse(".result__a")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result__a"))?;
+        let result_url: Selector = Selector::parse(".result__url")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result__url"))?;
+        let result_desc: Selector = Selector::parse(".result__snippet")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result__snippet"))?;
+
+        // scrape all the results from the html
+        Ok(document
+            .select(&results)
+            .map(|result| {
+                RawSearchResult::new(
                     result
-                        .select(&result_url)
+                        .select(&result_title)
                         .next()
                         .unwrap()
                         .inner_html()
                         .trim()
-                ),
-                result
-                    .select(&result_desc)
-                    .next()
-                    .unwrap()
-                    .inner_html()
-                    .trim()
-                    .to_string(),
-                vec!["duckduckgo".to_string()],
-            )
-        })
-        .map(|search_result| (search_result.visiting_url.clone(), search_result))
-        .collect())
+                        .to_string(),
+                    format!(
+                        "https://{}",
+                        result
+                            .select(&result_url)
+                            .next()
+                            .unwrap()
+                            .inner_html()
+                            .trim()
+                    ),
+                    result
+                        .select(&result_desc)
+                        .next()
+                        .unwrap()
+                        .inner_html()
+                        .trim()
+                        .to_string(),
+                    vec!["duckduckgo".to_string()],
+                )
+            })
+            .map(|search_result| (search_result.visiting_url.clone(), search_result))
+            .collect())
+    }
 }

src/engines/searx.rs

@@ -8,7 +8,7 @@ use std::collections::HashMap;
 
 use crate::search_results_handler::aggregation_models::RawSearchResult;
 
-use super::engine_models::EngineError;
+use super::engine_models::{EngineError, SearchEngine};
 use error_stack::{IntoReport, Report, Result, ResultExt};
 
 /// This function scrapes results from the upstream engine duckduckgo and puts all the scraped
@@ -28,111 +28,108 @@ use error_stack::{IntoReport, Report, Result, ResultExt};
 /// 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.
-pub async fn results(
-    query: &str,
-    page: u32,
-    user_agent: &str,
-) -> Result<HashMap<String, RawSearchResult>, EngineError> {
-    // Page number can be missing or empty string and so appropriate handling is required
-    // so that upstream server recieves valid page number.
-    let url: String = format!("https://searx.work/search?q={query}&pageno={page}");
 
-    // initializing headers and adding appropriate headers.
-    let mut header_map = HeaderMap::new();
-    header_map.insert(
-        USER_AGENT,
-        user_agent
-            .parse()
-            .into_report()
-            .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)?);
+pub struct Searx;
 
-    // fetch the html from upstream searx instance engine
-    let results: String = reqwest::Client::new()
-        .get(url)
-        .headers(header_map) // add spoofed headers to emulate human behaviours.
-        .send()
-        .await
-        .into_report()
-        .change_context(EngineError::RequestError)?
-        .text()
-        .await
-        .into_report()
-        .change_context(EngineError::RequestError)?;
+#[async_trait::async_trait]
+impl SearchEngine for Searx {
+    async fn results(
+        &self,
+        query: String,
+        page: u32,
+        user_agent: String,
+    ) -> Result<HashMap<String, RawSearchResult>, EngineError> {
+        // Page number can be missing or empty string and so appropriate handling is required
+        // so that upstream server recieves valid page number.
+        let url: String = format!("https://searx.work/search?q={query}&pageno={page}");
 
-    let document: Html = Html::parse_document(&results);
+        // initializing headers and adding appropriate headers.
+        let mut header_map = HeaderMap::new();
+        header_map.insert(
+            USER_AGENT,
+            user_agent
+                .parse()
+                .into_report()
+                .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 no_result: Selector = Selector::parse("#urls>.dialog-error>p")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", "#urls>.dialog-error>p"))?;
+        let document: Html =
+            Html::parse_document(&Searx::fetch_html_from_upstream(&self, url, header_map).await?);
 
-    if let Some(no_result_msg) = document.select(&no_result).nth(1) {
-        if no_result_msg.inner_html()
+        let no_result: Selector = Selector::parse("#urls>.dialog-error>p")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| {
+                format!("invalid CSS selector: {}", "#urls>.dialog-error>p")
+            })?;
+
+        if let Some(no_result_msg) = document.select(&no_result).nth(1) {
+            if no_result_msg.inner_html()
             == "we didn't find any results. Please use another query or search in more categories"
         {
             return Err(Report::new(EngineError::EmptyResultSet));
         }
-    }
+        }
 
-    let results: Selector = Selector::parse(".result")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result"))?;
-    let result_title: Selector = Selector::parse("h3>a")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", "h3>a"))?;
-    let result_url: Selector = Selector::parse("h3>a")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", "h3>a"))?;
+        let results: Selector = Selector::parse(".result")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".result"))?;
+        let result_title: Selector = Selector::parse("h3>a")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| format!("invalid CSS selector: {}", "h3>a"))?;
+        let result_url: Selector = Selector::parse("h3>a")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| format!("invalid CSS selector: {}", "h3>a"))?;
 
-    let result_desc: Selector = Selector::parse(".content")
-        .map_err(|_| Report::new(EngineError::UnexpectedError))
-        .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".content"))?;
+        let result_desc: Selector = Selector::parse(".content")
+            .map_err(|_| Report::new(EngineError::UnexpectedError))
+            .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".content"))?;
 
-    // scrape all the results from the html
-    Ok(document
-        .select(&results)
-        .map(|result| {
-            RawSearchResult::new(
-                result
-                    .select(&result_title)
-                    .next()
-                    .unwrap()
-                    .inner_html()
-                    .trim()
-                    .to_string(),
-                result
-                    .select(&result_url)
-                    .next()
-                    .unwrap()
-                    .value()
-                    .attr("href")
-                    .unwrap()
-                    .to_string(),
-                result
-                    .select(&result_desc)
-                    .next()
-                    .unwrap()
-                    .inner_html()
-                    .trim()
-                    .to_string(),
-                vec!["searx".to_string()],
-            )
-        })
-        .map(|search_result| (search_result.visiting_url.clone(), search_result))
-        .collect())
+        // scrape all the results from the html
+        Ok(document
+            .select(&results)
+            .map(|result| {
+                RawSearchResult::new(
+                    result
+                        .select(&result_title)
+                        .next()
+                        .unwrap()
+                        .inner_html()
+                        .trim()
+                        .to_string(),
+                    result
+                        .select(&result_url)
+                        .next()
+                        .unwrap()
+                        .value()
+                        .attr("href")
+                        .unwrap()
+                        .to_string(),
+                    result
+                        .select(&result_desc)
+                        .next()
+                        .unwrap()
+                        .inner_html()
+                        .trim()
+                        .to_string(),
+                    vec!["searx".to_string()],
+                )
+            })
+            .map(|search_result| (search_result.visiting_url.clone(), search_result))
+            .collect())
+    }
 }