fix: use threading+httpx proxy instead of WSGIMiddleware mount

app.py

@@ -655,14 +655,29 @@ def verify_claim():
 init_db()      # Ensure DB exists before accepting requests
 load_models()
 
-# ─── Optional Gradio Interface (only when Gradio SDK is available) ────────────
-# In Docker mode (our HF deployment), Gradio is NOT installed and we serve
-# Flask directly via gunicorn. This block is kept for legacy compatibility.
+# ─── Gradio + Flask Integration via Thread Proxy ──────────────────────────────
+# Flask runs on internal port 7861. Gradio exposes it via a FastAPI proxy route
+# at /backend/{path}, which forwards to http://127.0.0.1:7861/{path}.
+# This avoids all WSGIMiddleware path-stripping conflicts with HF's Gradio proxy.
 try:
+    import threading
+    import httpx
     import gradio as gr
     import spaces
-    from fastapi.middleware.wsgi import WSGIMiddleware
+    from fastapi import Request as _FastAPIRequest
+    from fastapi.responses import Response as _FastAPIResponse
 
+    # ── 1. Start Flask on internal port 7861 ─────────────────────────────────
+    _FLASK_PORT = 7861
+
+    def _run_flask_internal():
+        logger.info(f"Starting internal Flask server on port {_FLASK_PORT}...")
+        app.run(host='127.0.0.1', port=_FLASK_PORT, debug=False, use_reloader=False)
+
+    _flask_thread = threading.Thread(target=_run_flask_internal, daemon=True)
+    _flask_thread.start()
+
+    # ── 2. Gradio UI ─────────────────────────────────────────────────────────
     @spaces.GPU
     def predict_gradio(statement, model_type):
         if not statement or len(statement) < 5:
@@ -700,13 +715,55 @@ try:
         ],
         outputs="text",
         title="Truth Detector API & Interactive Demo",
-        description="Backend API for Fake News Detection. REST API endpoints available at /api/*"
+        description="Backend API for Fake News Detection. REST API available at /backend/api/*"
+    )
+
+    # ── 3. FastAPI proxy: /backend/{path} → Flask on 127.0.0.1:7861/{path} ──
+    _SKIP_HEADERS = {'host', 'content-length', 'transfer-encoding', 'content-encoding'}
+
+    @demo.app.api_route(
+        "/backend/{path:path}",
+        methods=["GET", "POST", "PUT", "DELETE", "OPTIONS", "HEAD", "PATCH"]
     )
-    demo.app.mount("/flask", WSGIMiddleware(app))
+    async def flask_proxy(request: _FastAPIRequest, path: str):
+        """Transparent proxy forwarding /backend/* → internal Flask server."""
+        target_url = f"http://127.0.0.1:{_FLASK_PORT}/{path}"
+        fwd_headers = {
+            k: v for k, v in request.headers.items()
+            if k.lower() not in _SKIP_HEADERS
+        }
+        try:
+            async with httpx.AsyncClient(timeout=60) as client:
+                resp = await client.request(
+                    method=request.method,
+                    url=target_url,
+                    headers=fwd_headers,
+                    content=await request.body(),
+                    params=dict(request.query_params),
+                    follow_redirects=True,
+                )
+            resp_headers = {
+                k: v for k, v in resp.headers.items()
+                if k.lower() not in _SKIP_HEADERS
+            }
+            return _FastAPIResponse(
+                content=resp.content,
+                status_code=resp.status_code,
+                headers=resp_headers,
+            )
+        except Exception as proxy_err:
+            logger.error(f"Proxy error for /{path}: {proxy_err}")
+            return _FastAPIResponse(
+                content=b'{"error":"Backend proxy error","detail":"' + str(proxy_err).encode() + b'"}',
+                status_code=502,
+                headers={"Content-Type": "application/json"},
+            )
+
     _GRADIO_AVAILABLE = True
-except ImportError:
+
+except ImportError as _ie:
     _GRADIO_AVAILABLE = False
-    logger.info("Gradio not available — running in Flask-only (Docker) mode.")
+    logger.info(f"Gradio not available ({_ie}) — running in Flask-only (Docker) mode.")
 
 if __name__ == '__main__':
     port = int(os.environ.get('PORT', 7860))
@@ -715,4 +772,3 @@ if __name__ == '__main__':
     else:
         app.run(host='0.0.0.0', port=port, debug=False)
 
-