Reject duplicate links

migrations/2025-04-30-120032_unique_magnet/down.sql

@@ -0,0 +1 @@
+DROP INDEX magnets_unique_link;

migrations/2025-04-30-120032_unique_magnet/up.sql

@@ -0,0 +1 @@
+CREATE UNIQUE INDEX magnets_unique_link ON magnets(link);

src/db.rs

@@ -69,6 +69,73 @@ mod tests {
             assert_eq!(magnet.published_at, expected_timestamp);
         }
     }
+
+    #[test]
+    fn test_prevent_duplicate_magnets() {
+        let temp_dir = tempdir().unwrap();
+        let db_path = temp_dir.path().join("test.db");
+
+        let mut db = Database::new(&db_path).unwrap();
+
+        // Create initial post with magnet links
+        let post_info = PostInfo {
+            title: "Test Title".to_string(),
+            submitter: "test_user".to_string(),
+            subreddit: "test_subreddit".to_string(),
+            magnet_links: vec![
+                "magnet:?xt=urn:btih:test1".to_string(),
+                "magnet:?xt=urn:btih:test2".to_string(),
+            ],
+            timestamp: Utc::now(),
+        };
+
+        // First insertion should succeed and insert 2 links
+        let result = db.store_magnets(&post_info);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), 2); // 2 links inserted
+
+        // Create a second post with some duplicate and some new links
+        let post_info2 = PostInfo {
+            title: "Test Title 2".to_string(),
+            submitter: "test_user2".to_string(),
+            subreddit: "test_subreddit2".to_string(),
+            magnet_links: vec![
+                "magnet:?xt=urn:btih:test1".to_string(), // Duplicate
+                "magnet:?xt=urn:btih:test3".to_string(), // New
+            ],
+            timestamp: Utc::now(),
+        };
+
+        // Second insertion should succeed but only insert the new link
+        let result2 = db.store_magnets(&post_info2);
+        assert!(result2.is_ok());
+        assert_eq!(result2.unwrap(), 1); // Only 1 new link inserted
+
+        // Verify we have 3 total links in the database
+        let magnets = db.get_all_magnets().unwrap();
+        assert_eq!(magnets.len(), 3);
+
+        // Try inserting only duplicates
+        let post_info3 = PostInfo {
+            title: "Test Title 3".to_string(),
+            submitter: "test_user3".to_string(),
+            subreddit: "test_subreddit3".to_string(),
+            magnet_links: vec![
+                "magnet:?xt=urn:btih:test1".to_string(), // Duplicate
+                "magnet:?xt=urn:btih:test2".to_string(), // Duplicate
+            ],
+            timestamp: Utc::now(),
+        };
+
+        // Third insertion should succeed but insert 0 links
+        let result3 = db.store_magnets(&post_info3);
+        assert!(result3.is_ok());
+        assert_eq!(result3.unwrap(), 0); // No new links inserted
+
+        // Verify we still have 3 total links in the database
+        let magnets = db.get_all_magnets().unwrap();
+        assert_eq!(magnets.len(), 3);
+    }
 }
 
 impl Database {
@@ -103,9 +170,18 @@ impl Database {
 
     pub fn store_magnets(&mut self, post: &PostInfo) -> Result<usize> {
         let published_at = post.timestamp.naive_utc();
+
+        // Filter out magnet links that already exist in the database
+        let existing_links: Vec<String> = magnets::table
+            .select(magnets::link)
+            .filter(magnets::link.eq_any(&post.magnet_links))
+            .load(&mut self.conn)
+            .wrap_err("Failed to query existing magnets")?;
+
         let links = post
             .magnet_links
             .iter()
+            .filter(|link| !existing_links.contains(link))
             .map(|m| NewMagnet {
                 title: post.title.as_str(),
                 submitter: post.submitter.as_str(),