🐛 fix: reimplement caching code within the `search` function (#592)

- reduce resource usage &
- only cache search results which has not been cached before.

src/server/routes/search.rs

@@ -12,6 +12,7 @@ use crate::{
     results::aggregator::aggregate,
 };
 use actix_web::{get, http::header::ContentType, web, HttpRequest, HttpResponse};
+use itertools::Itertools;
 use regex::Regex;
 use std::borrow::Cow;
 use tokio::{
@@ -40,7 +41,6 @@ pub async fn search(
     config: web::Data<&'static Config>,
     cache: web::Data<&'static SharedCache>,
 ) -> Result<HttpResponse, Box<dyn std::error::Error>> {
-    use std::sync::Arc;
     let params = web::Query::<SearchParams>::from_query(req.query_string())?;
     match &params.q {
         Some(query) => {
@@ -83,44 +83,36 @@ pub async fn search(
             let previous_page = page.saturating_sub(1);
             let next_page = page + 1;
 
-            let mut results = Arc::new((SearchResults::default(), String::default()));
+            let results: (SearchResults, String, bool);
             if page != previous_page {
                 let (previous_results, current_results, next_results) = join!(
                     get_results(previous_page),
                     get_results(page),
                     get_results(next_page)
                 );
-                let (parsed_previous_results, parsed_next_results) =
-                    (previous_results?, next_results?);
 
-                let (cache_keys, results_list) = (
-                    [
-                        parsed_previous_results.1,
-                        results.1.clone(),
-                        parsed_next_results.1,
-                    ],
-                    [
-                        parsed_previous_results.0,
-                        results.0.clone(),
-                        parsed_next_results.0,
-                    ],
-                );
+                results = current_results?;
 
-                results = Arc::new(current_results?);
+                let (results_list, cache_keys): (Vec<SearchResults>, Vec<String>) =
+                    [previous_results?, results.clone(), next_results?]
+                        .into_iter()
+                        .filter_map(|(result, cache_key, flag)| {
+                            dbg!(flag).then_some((result, cache_key))
+                        })
+                        .multiunzip();
 
                 tokio::spawn(async move { cache.cache_results(&results_list, &cache_keys).await });
             } else {
                 let (current_results, next_results) =
                     join!(get_results(page), get_results(page + 1));
 
-                let parsed_next_results = next_results?;
-
-                results = Arc::new(current_results?);
+                results = current_results?;
 
-                let (cache_keys, results_list) = (
-                    [results.1.clone(), parsed_next_results.1.clone()],
-                    [results.0.clone(), parsed_next_results.0],
-                );
+                let (results_list, cache_keys): (Vec<SearchResults>, Vec<String>) =
+                    [results.clone(), next_results?]
+                        .into_iter()
+                        .filter_map(|(result, cache_key, flag)| flag.then_some((result, cache_key)))
+                        .multiunzip();
 
                 tokio::spawn(async move { cache.cache_results(&results_list, &cache_keys).await });
             }
@@ -163,7 +155,7 @@ async fn results(
     query: &str,
     page: u32,
     search_settings: &server_models::Cookie<'_>,
-) -> Result<(SearchResults, String), Box<dyn std::error::Error>> {
+) -> Result<(SearchResults, String, bool), Box<dyn std::error::Error>> {
     // eagerly parse cookie value to evaluate safe search level
     let safe_search_level = search_settings.safe_search_level;
 
@@ -182,7 +174,7 @@ async fn results(
     // check if fetched cache results was indeed fetched or it was an error and if so
     // handle the data accordingly.
     match cached_results {
-        Ok(results) => Ok((results, cache_key)),
+        Ok(results) => Ok((results, cache_key, false)),
         Err(_) => {
             if safe_search_level == 4 {
                 let mut results: SearchResults = SearchResults::default();
@@ -196,7 +188,7 @@ async fn results(
                         .cache_results(&[results.clone()], &[cache_key.clone()])
                         .await?;
                     results.set_safe_search_level(safe_search_level);
-                    return Ok((results, cache_key));
+                    return Ok((results, cache_key, true));
                 }
             }
 
@@ -235,7 +227,7 @@ async fn results(
                 .cache_results(&[results.clone()], &[cache_key.clone()])
                 .await?;
             results.set_safe_search_level(safe_search_level);
-            Ok((results, cache_key))
+            Ok((results, cache_key, true))
         }
     }
 }