fix: [torrust#488] torrent without tracker keys for open tracker

Tracker HTTP URL: http://localhost:7070

- announce: "http://localhost:7070".
- announce_list: "http://localhost:7070" and keeps the original URLs in the uploaded torrent.

Tracker UDP URL: udp://localhost:6969

- announce: "udp://localhost:7070".
- announce_list: "udp://localhost:7070" and keeps the original URLs in the uploaded torrent.

Tracker HTTP URL: http://localhost:7070

- announce: "http://localhost:7070/**KEY**".
- announce_list: "http://localhost:7070/**KEY**" and keeps the original URLs in the uploaded torrent.

Tracker UDP URL: udp://localhost:6969

- announce: "udp://localhost:7070/**KEY**".
- announce_list: "udp://localhost:7070/**KEY**" and keeps the original URLs in the uploaded torrent.

It returns an 505 error if it can't get the user's tracker keys.

TODO:

- The application should not start with close tracker and UDP url in the
  configuration.
- THe API should return 503 instead of 500 when it can't connect to the
  tracker.

src/config.rs

@@ -144,6 +144,13 @@ impl Default for TrackerMode {
     }
 }
 
+impl TrackerMode {
+    #[must_use]
+    pub fn is_open(&self) -> bool {
+        matches!(self, TrackerMode::Public | TrackerMode::Whitelisted)
+    }
+}
+
 /// Configuration for the associated tracker.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Tracker {

src/models/torrent_file.rs

@@ -93,11 +93,37 @@ impl Torrent {
         }
     }
 
+    /// Includes the tracker URL a the main tracker in the torrent.
+    ///
+    /// It will be the URL in the `announce` field and also the first URL in the
+    /// `announce_list`.
+    ///
+    /// In practice, it's common for the `announce_list` to include the URL from 
+    /// the `announce` field as one of its entries, often in the first tier, 
+    /// to ensure that this primary tracker is always used. However, this is not 
+    /// a strict requirement of the `BitTorrent` protocol; it's more of a 
+    /// convention followed by some torrent creators for redundancy and to 
+    /// ensure better availability of trackers.
+    pub fn include_url_as_main_tracker(&mut self, tracker_url: &str) {
+        self.set_announce_to(tracker_url);
+        self.add_url_to_announce_list(tracker_url);
+    }
+
     /// Sets the announce url to the tracker url.
     pub fn set_announce_to(&mut self, tracker_url: &str) {
         self.announce = Some(tracker_url.to_owned());
     }
 
+    /// Adds a new tracker URL to the `announce_list` if it doesn't exist.
+    pub fn add_url_to_announce_list(&mut self, tracker_url: &str) {
+        if let Some(list) = &mut self.announce_list {
+            if !list.iter().any(|inner_list| inner_list.contains(&tracker_url.to_owned())) {
+                let vec = vec![tracker_url.to_owned()];
+                list.insert(0, vec);
+            }
+        }
+    }
+
     /// Removes all other trackers if the torrent is private.
     pub fn reset_announce_list_if_private(&mut self) {
         if self.is_private() {

src/services/torrent.rs

@@ -6,7 +6,7 @@ use serde_derive::{Deserialize, Serialize};
 
 use super::category::DbCategoryRepository;
 use super::user::DbUserRepository;
-use crate::config::Configuration;
+use crate::config::{Configuration, TrackerMode};
 use crate::databases::database::{Database, Error, Sorting};
 use crate::errors::ServiceError;
 use crate::models::category::CategoryId;
@@ -257,24 +257,18 @@ impl Index {
         let mut torrent = self.torrent_repository.get_by_info_hash(info_hash).await?;
 
         let tracker_url = self.get_tracker_url().await;
+        let tracker_mode = self.get_tracker_mode().await;
 
-        // Add personal tracker url or default tracker url
-        match opt_user_id {
-            Some(user_id) => {
-                let personal_announce_url = self
-                    .tracker_service
-                    .get_personal_announce_url(user_id)
-                    .await
-                    .unwrap_or(tracker_url);
-                torrent.announce = Some(personal_announce_url.clone());
-                if let Some(list) = &mut torrent.announce_list {
-                    let vec = vec![personal_announce_url];
-                    list.insert(0, vec);
-                }
-            }
-            None => {
-                torrent.announce = Some(tracker_url);
-            }
+        // code-review: should we remove all tracker URLs in the `announce_list`
+        // when the tracker is not open?
+
+        if tracker_mode.is_open() {
+            torrent.include_url_as_main_tracker(&tracker_url);
+        } else if let Some(authenticated_user_id) = opt_user_id {
+            let personal_announce_url = self.tracker_service.get_personal_announce_url(authenticated_user_id).await?;
+            torrent.include_url_as_main_tracker(&personal_announce_url);
+        } else {
+            torrent.include_url_as_main_tracker(&tracker_url);
         }
 
         Ok(torrent)
@@ -362,6 +356,9 @@ impl Index {
 
         let tracker_url = self.get_tracker_url().await;
 
+        // todo: duplicate logic. We have to check the same when we download
+        // the torrent file.
+
         // add tracker url
         match opt_user_id {
             Some(user_id) => {
@@ -513,6 +510,11 @@ impl Index {
         let settings = self.configuration.settings.read().await;
         settings.tracker.url.clone()
     }
+
+    async fn get_tracker_mode(&self) -> TrackerMode {
+        let settings = self.configuration.settings.read().await;
+        settings.tracker.mode.clone()
+    }
 }
 
 pub struct DbTorrentRepository {

tests/e2e/web/api/v1/contexts/torrent/contract.rs

@@ -473,15 +473,6 @@ mod for_guests {
 
 mod for_authenticated_users {
 
-    use torrust_index::utils::parse_torrent::decode_torrent;
-    use torrust_index::web::api;
-
-    use crate::common::client::Client;
-    use crate::e2e::environment::TestEnv;
-    use crate::e2e::web::api::v1::contexts::torrent::asserts::{build_announce_url, get_user_tracker_key};
-    use crate::e2e::web::api::v1::contexts::torrent::steps::upload_random_torrent_to_index;
-    use crate::e2e::web::api::v1::contexts::user::steps::new_logged_in_user;
-
     mod uploading_a_torrent {
 
         use torrust_index::web::api;
@@ -779,42 +770,6 @@ mod for_authenticated_users {
         }
     }
 
-    #[tokio::test]
-    async fn it_should_allow_authenticated_users_to_download_a_torrent_with_a_personal_announce_url() {
-        let mut env = TestEnv::new();
-        env.start(api::Version::V1).await;
-
-        if !env.provides_a_tracker() {
-            println!("test skipped. It requires a tracker to be running.");
-            return;
-        }
-
-        // Given a previously uploaded torrent
-        let uploader = new_logged_in_user(&env).await;
-        let (test_torrent, _torrent_listed_in_index) = upload_random_torrent_to_index(&uploader, &env).await;
-
-        // And a logged in user who is going to download the torrent
-        let downloader = new_logged_in_user(&env).await;
-        let client = Client::authenticated(&env.server_socket_addr().unwrap(), &downloader.token);
-
-        // When the user downloads the torrent
-        let response = client.download_torrent(&test_torrent.file_info_hash()).await;
-
-        let torrent = decode_torrent(&response.bytes).expect("could not decode downloaded torrent");
-
-        // Then the torrent should have the personal announce URL
-        let tracker_key = get_user_tracker_key(&downloader, &env)
-            .await
-            .expect("uploader should have a valid tracker key");
-
-        let tracker_url = env.server_settings().unwrap().tracker.url;
-
-        assert_eq!(
-            torrent.announce.unwrap(),
-            build_announce_url(&tracker_url, &Some(tracker_key))
-        );
-    }
-
     mod and_non_admins {
 
         use torrust_index::web::api;