Auto-upload stems to Gokapi on completion, save share link

- New helpers: parse_stems_urls, upload_to_gokapi, process_stems_to_gokapi
- Stems webhook handler now downloads stem files from MusicGPT CDN,
  zips them, uploads to Gokapi with 30-day expiry, saves the Gokapi
  download URL to stems_link in the DB
- Download Stems button uses stems_link (Gokapi URL) when available,
  falls back to the zip endpoint if not
- Config: GOKAPI_URL, GOKAPI_API_KEY, GOKAPI_EXPIRY_DAYS env vars
- docker-compose: GOKAPI_* environment variables added

helpers.py

@@ -34,6 +34,7 @@ from mutagen.easyid3 import EasyID3
 import requests
 
 from models import update_request
+from config import Config
 
 
 # ---------------------------------------------------------------------------
@@ -794,3 +795,116 @@ def get_musicgpt_cost_totals():
         "total_cost": rows["total_cost"] or 0,
         "stems_total": rows["stems_total"] or 0,
     }
+
+
+def parse_stems_urls(stems_url_field):
+    """
+    Parse the stems_url DB field into a list of (label, url) tuples.
+    The field can be:
+      - "label1: url1; label2: url2" (multiple individual stem files)
+      - A single bundle/zip URL
+      - A bare URL
+    """
+    if not stems_url_field:
+        return []
+    urls = []
+    if ';' in stems_url_field or ': ' in stems_url_field:
+        parts = stems_url_field.split(';')
+        for part in parts:
+            part = part.strip()
+            if not part:
+                continue
+            if ': ' in part:
+                label, url = part.split(': ', 1)
+                urls.append((label.strip(), url.strip()))
+            else:
+                urls.append(('stem', part))
+    else:
+        urls.append(('stems', stems_url_field.strip()))
+    return urls
+
+
+def upload_to_gokapi(file_bytes, filename, expiry_days=30):
+    """
+    Upload a file to Gokapi and return the download URL.
+    Returns (download_url, error_message).
+    """
+    gokapi_url = Config.GOKAPI_URL.rstrip('/')
+    api_key = Config.GOKAPI_API_KEY
+    if not gokapi_url or not api_key:
+        return None, 'Gokapi URL or API key not configured'
+    try:
+        resp = requests.post(
+            f"{gokapi_url}/api/files/add",
+            headers={"apikey": api_key},
+            files={"file": (filename, file_bytes, "application/octet-stream")},
+            data={
+                "allowedDownloads": "0",
+                "expiryDays": str(expiry_days),
+                "password": "",
+            },
+            timeout=120,
+        )
+        if resp.status_code != 200:
+            return None, f'Gokapi HTTP {resp.status_code}: {resp.text[:200]}'
+        data = resp.json()
+        if data.get('Result') != 'OK':
+            return None, f"Gokapi error: {data.get('Result')}"
+        file_info = data.get('FileInfo', {})
+        download_url = file_info.get('UrlDownload')
+        if not download_url:
+            return None, 'Gokapi returned no download URL'
+        return download_url, None
+    except Exception as e:
+        return None, str(e)
+
+
+def process_stems_to_gokapi(req):
+    """
+    Download stem files from MusicGPT CDN, zip them, upload the zip to Gokapi,
+    and return (gokapi_url, error_message).
+
+    Also updates the request row with the Gokapi download link in stems_link.
+    """
+    import io
+    import zipfile
+
+    stems_url = req.get('stems_url') or ''
+    urls = parse_stems_urls(stems_url)
+    if not urls:
+        return None, 'No stems URL to process'
+
+    # If there's only one URL and it's already a .zip, upload it directly.
+    if len(urls) == 1 and urls[0][1].endswith('.zip'):
+        try:
+            r = requests.get(urls[0][1], timeout=120)
+            r.raise_for_status()
+            zip_bytes = r.content
+        except Exception as e:
+            return None, f'Failed to download stems zip: {e}'
+    else:
+        # Download each stem file and bundle into a zip in memory.
+        buf = io.BytesIO()
+        with zipfile.ZipFile(buf, 'w', zipfile.ZIP_DEFLATED) as zf:
+            for label, url in urls:
+                try:
+                    r = requests.get(url, timeout=60)
+                    r.raise_for_status()
+                    filename = url.split('/')[-1] if '/' in url else f"{label}.mp3"
+                    if '.' not in filename:
+                        filename = f"{label}.mp3"
+                    zf.writestr(filename, r.content)
+                except Exception:
+                    pass
+        zip_bytes = buf.getvalue()
+
+    title = req.get('suno_title') or req.get('name') or f'request_{req["id"]}'
+    zip_filename = f"stems_{title}.zip"
+
+    download_url, error = upload_to_gokapi(zip_bytes, zip_filename, Config.GOKAPI_EXPIRY_DAYS)
+    if error:
+        return None, error
+
+    # Save the Gokapi link to stems_link in the database.
+    update_request(req['id'], stems_link=download_url)
+    return download_url, None