Create separate search_result_parser

src/config/parser.rs

@@ -111,7 +111,7 @@ impl Config {
                 .get::<_, HashMap<String, bool>>("upstream_search_engines")?
                 .into_iter()
                 .filter_map(|(key, value)| value.then_some(key))
-                .filter_map(|engine| crate::models::engine_models::EngineHandler::new(&engine))
+                .filter_map(|engine| crate::models::engine_models::EngineHandler::new(&engine).ok())
                 .collect(),
             request_timeout: globals.get::<_, u8>("request_timeout")?,
             threads,

src/engines/duckduckgo.rs

@@ -5,7 +5,7 @@
 use std::collections::HashMap;
 
 use reqwest::header::HeaderMap;
-use scraper::{Html, Selector};
+use scraper::Html;
 
 use crate::models::aggregation_models::SearchResult;
 
@@ -13,9 +13,27 @@ use crate::models::engine_models::{EngineError, SearchEngine};
 
 use error_stack::{Report, Result, ResultExt};
 
+use super::search_result_parser::SearchResultParser;
+
 /// 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.
-pub struct DuckDuckGo;
+pub struct DuckDuckGo {
+    parser: SearchResultParser,
+}
+
+impl DuckDuckGo {
+    pub fn new() -> Result<Self, EngineError> {
+        Ok(Self {
+            parser: SearchResultParser::new(
+                ".no-results",
+                ".result",
+                ".result__a",
+                ".result__url",
+                ".result__snippet",
+            )?,
+        })
+    }
+}
 
 #[async_trait::async_trait]
 impl SearchEngine for DuckDuckGo {
@@ -59,34 +77,17 @@ impl SearchEngine for DuckDuckGo {
             &DuckDuckGo::fetch_html_from_upstream(self, &url, header_map, request_timeout).await?,
         );
 
-        let no_result: Selector = Selector::parse(".no-results")
-            .map_err(|_| Report::new(EngineError::UnexpectedError))
-            .attach_printable_lazy(|| format!("invalid CSS selector: {}", ".no-results"))?;
-
-        if document.select(&no_result).next().is_some() {
+        if document.select(&self.parser.no_result).next().is_some() {
             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(".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)
+            .select(&self.parser.results)
             .map(|result| {
                 SearchResult::new(
                     result
-                        .select(&result_title)
+                        .select(&self.parser.result_title)
                         .next()
                         .unwrap()
                         .inner_html()
@@ -94,7 +95,7 @@ impl SearchEngine for DuckDuckGo {
                     format!(
                         "https://{}",
                         result
-                            .select(&result_url)
+                            .select(&self.parser.result_url)
                             .next()
                             .unwrap()
                             .inner_html()
@@ -102,7 +103,7 @@ impl SearchEngine for DuckDuckGo {
                     )
                     .as_str(),
                     result
-                        .select(&result_desc)
+                        .select(&self.parser.result_desc)
                         .next()
                         .unwrap()
                         .inner_html()

src/engines/mod.rs

@@ -4,4 +4,5 @@
 //! code. Moreover, it also provides a custom error for the upstream search engine handling code.
 
 pub mod duckduckgo;
+pub mod search_result_parser;
 pub mod searx;

src/engines/search_result_parser.rs

@@ -0,0 +1,38 @@
+use crate::models::engine_models::EngineError;
+use error_stack::{Report, Result, ResultExt};
+use scraper::{Html, Selector};
+
+pub struct SearchResultParser {
+    pub no_result: Selector,
+    pub results: Selector,
+    pub result_title: Selector,
+    pub result_url: Selector,
+    pub result_desc: Selector,
+}
+
+impl SearchResultParser {
+    pub fn new(
+        no_result_selector: &str,
+        results_selector: &str,
+        result_title_selector: &str,
+        result_url_selector: &str,
+        result_desc_selector: &str,
+    ) -> Result<SearchResultParser, EngineError> {
+        Ok(SearchResultParser {
+            no_result: new_selector(no_result_selector)?,
+            results: new_selector(results_selector)?,
+            result_title: new_selector(result_title_selector)?,
+            result_url: new_selector(result_url_selector)?,
+            result_desc: new_selector(result_desc_selector)?,
+        })
+    }
+}
+
+fn new_selector(selector: &str) -> Result<Selector, EngineError> {
+    Selector::parse(selector).map_err(|err| {
+        Report::new(EngineError::UnexpectedError).attach_printable(format!(
+            "invalid CSS selector: {}, err: {:?}",
+            selector, err
+        ))
+    })
+}

src/engines/searx.rs

@@ -3,16 +3,34 @@
 //! number if provided.
 
 use reqwest::header::HeaderMap;
-use scraper::{Html, Selector};
+use scraper::Html;
 use std::collections::HashMap;
 
+use super::search_result_parser::SearchResultParser;
 use crate::models::aggregation_models::SearchResult;
 use crate::models::engine_models::{EngineError, SearchEngine};
 use error_stack::{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.
-pub struct Searx;
+pub struct Searx {
+    parser: SearchResultParser,
+}
+
+impl Searx {
+    // new Searchx engine
+    pub fn new() -> Result<Searx, EngineError> {
+        Ok(Self {
+            parser: SearchResultParser::new(
+                "#urls>.dialog-error>p",
+                ".result",
+                "h3>a",
+                "h3>a",
+                ".content",
+            )?,
+        })
+    }
+}
 
 #[async_trait::async_trait]
 impl SearchEngine for Searx {
@@ -52,13 +70,7 @@ impl SearchEngine for Searx {
             &Searx::fetch_html_from_upstream(self, &url, header_map, request_timeout).await?,
         );
 
-        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 let Some(no_result_msg) = document.select(&self.parser.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"
         {
@@ -66,40 +78,26 @@ impl SearchEngine for Searx {
         }
         }
 
-        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"))?;
-
         // scrape all the results from the html
         Ok(document
-            .select(&results)
+            .select(&self.parser.results)
             .map(|result| {
                 SearchResult::new(
                     result
-                        .select(&result_title)
+                        .select(&self.parser.result_title)
                         .next()
                         .unwrap()
                         .inner_html()
                         .trim(),
                     result
-                        .select(&result_url)
+                        .select(&self.parser.result_url)
                         .next()
                         .unwrap()
                         .value()
                         .attr("href")
                         .unwrap(),
                     result
-                        .select(&result_desc)
+                        .select(&self.parser.result_desc)
                         .next()
                         .unwrap()
                         .inner_html()

src/models/aggregation_models.rs

@@ -85,12 +85,14 @@ impl EngineErrorInfo {
     pub fn new(error: &EngineError, engine: &str) -> Self {
         Self {
             error: match error {
+                EngineError::EngineNotFound => "EngineNotFound".to_owned(),
                 EngineError::RequestError => "RequestError".to_owned(),
                 EngineError::EmptyResultSet => "EmptyResultSet".to_owned(),
                 EngineError::UnexpectedError => "UnexpectedError".to_owned(),
             },
             engine: engine.to_owned(),
             severity_color: match error {
+                EngineError::EngineNotFound => "red".to_owned(),
                 EngineError::RequestError => "green".to_owned(),
                 EngineError::EmptyResultSet => "blue".to_owned(),
                 EngineError::UnexpectedError => "red".to_owned(),

src/models/engine_models.rs

@@ -2,12 +2,14 @@
 //! the upstream search engines with the search query provided by the user.
 
 use super::aggregation_models::SearchResult;
-use error_stack::{Result, ResultExt};
+use error_stack::{Report, Result, ResultExt};
 use std::{collections::HashMap, fmt, time::Duration};
 
 /// A custom error type used for handle engine associated errors.
 #[derive(Debug)]
 pub enum EngineError {
+    // No matching engine found
+    EngineNotFound,
     /// This variant handles all request related errors like forbidden, not found,
     /// etc.
     EmptyResultSet,
@@ -24,6 +26,9 @@ pub enum EngineError {
 impl fmt::Display for EngineError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
+            EngineError::EngineNotFound => {
+                write!(f, "Search engine not found")
+            }
             EngineError::EmptyResultSet => {
                 write!(f, "The upstream search engine returned an empty result set")
             }
@@ -134,18 +139,21 @@ impl EngineHandler {
     /// # 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> {
+    pub fn new(engine_name: &str) -> Result<Self, EngineError> {
         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,
+                "duckduckgo" => {
+                    let engine = crate::engines::duckduckgo::DuckDuckGo::new()?;
+                    ("duckduckgo", Box::new(engine))
+                }
+                "searx" => {
+                    let engine = crate::engines::searx::Searx::new()?;
+                    ("searx", Box::new(engine))
+                }
+                _ => return Err(Report::from(EngineError::EngineNotFound)),
             };
 
-        Some(Self {
+        Ok(Self {
             engine: engine.1,
             name: engine.0,
         })

src/server/routes/search.rs

@@ -191,7 +191,7 @@ async fn results(
                     let engines: Vec<EngineHandler> = cookie_value
                         .engines
                         .iter()
-                        .filter_map(|name| EngineHandler::new(name))
+                        .filter_map(|name| EngineHandler::new(name).ok())
                         .collect();
 
                     safe_search_level = match config.safe_search {