From 3264286f7f360eae18f1d4ef01b1aa3302e36961 Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Thu, 1 Jan 2026 13:21:07 +0700
Subject: [PATCH] Fix: Force IPv4 and add Retry logic for stream 403s

---
 backend/api/endpoints/stream.py | 36 +++++++++++++++++++++++++++++----
 backend/services/youtube.py     | 10 +++++++++
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/backend/api/endpoints/stream.py b/backend/api/endpoints/stream.py
index 1da80be..86f8c5d 100644
--- a/backend/api/endpoints/stream.py
+++ b/backend/api/endpoints/stream.py
@@ -22,18 +22,46 @@ async def stream_audio(id: str, yt: YouTubeService = Depends(get_youtube_service
                 "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36"
             }
         
-        def iterfile():
-            with requests.get(stream_url, headers=headers, stream=True, timeout=10) as r:
+        # Helper function to get stream
+        def get_stream(url, headers):
+            return requests.get(url, headers=headers, stream=True, timeout=10)
+
+        try:
+            r = get_stream(stream_url, headers)
+            r.raise_for_status()
+        except requests.exceptions.HTTPError as e:
+            if e.response.status_code == 403:
+                print("Got 403 Forbidden. Invalidating cache and retrying...")
+                yt.invalidate_stream_cache(id)
+                # Fetch fresh
+                data = yt.get_stream_url(id)
+                if isinstance(data, dict):
+                    stream_url = data.get("url")
+                    headers = data.get("headers", {})
+                else:
+                    stream_url = data
+                
+                # Retry request
+                r = get_stream(stream_url, headers)
                 r.raise_for_status()
+            else:
+                raise e
+
+        def iterfile():
+            # Already opened request 'r'
+            try:
                 for chunk in r.iter_content(chunk_size=64*1024): 
                     yield chunk
+            except Exception as e:
+                print(f"Chunk Error: {e}")
+            finally:
+                r.close()
 
         return StreamingResponse(iterfile(), media_type="audio/mpeg")
     except Exception as e:
         print(f"Stream Error: {e}")
-        # Return detail if it's a request error
         if isinstance(e, requests.exceptions.HTTPError):
-            print(f"Upstream Status: {e.response.status_code}")
+             print(f"Upstream Status: {e.response.status_code}")
         raise HTTPException(status_code=500, detail=str(e))
 
 @router.get("/download")
diff --git a/backend/services/youtube.py b/backend/services/youtube.py
index b2186b8..252ac91 100644
--- a/backend/services/youtube.py
+++ b/backend/services/youtube.py
@@ -165,6 +165,7 @@ class YouTubeService:
                 'format': 'bestaudio[ext=m4a]/best[ext=mp4]/best',
                 'quiet': True,
                 'noplaylist': True,
+                'force_ipv4': True, # Force IPv4 to avoid cloud range blocks
             }
             with yt_dlp.YoutubeDL(ydl_opts) as ydl:
                 info = ydl.extract_info(url, download=False)
@@ -183,6 +184,15 @@ class YouTubeService:
         except Exception as e:
             raise ExternalAPIError(str(e))
 
+    def invalidate_stream_cache(self, id: str):
+        cache_key = f"stream:{id}"
+        path = self.cache._get_path(cache_key)
+        if path.exists():
+            try:
+                path.unlink()
+            except:
+                pass
+
     def get_recommendations(self, seed_id: str):
         if not seed_id: return []
         cache_key = f"rec:{seed_id}"