Update app.py

app.py

@@ -779,6 +779,30 @@ else:
         st.session_state["recording_complete"] = False
         st.rerun()
 
+def get_ice_servers():
+    """Use Twilio's TURN server because Streamlit Community Cloud has changed
+    its infrastructure and WebRTC connection cannot be established without TURN server now.  # noqa: E501
+    We considered Open Relay Project (https://www.metered.ca/tools/openrelay/) too,
+    but it is not stable and hardly works as some people reported like https://github.com/aiortc/aiortc/issues/832#issuecomment-1482420656  # noqa: E501
+    See https://github.com/whitphx/streamlit-webrtc/issues/1213
+    """
+
+    # Ref: https://www.twilio.com/docs/stun-turn/api
+    try:
+        account_sid = os.environ["TWILIO_ACCOUNT_SID"]
+        auth_token = os.environ["TWILIO_AUTH_TOKEN"]
+    except KeyError:
+        logger.warning(
+            "Twilio credentials are not set. Fallback to a free STUN server from Google."  # noqa: E501
+        )
+        return [{"urls": ["stun:stun.l.google.com:19302"]}]
+
+    client = Client(account_sid, auth_token)
+
+    token = client.tokens.create()
+
+    return token.ice_servers
+
 # === Main QA Interface ===
 if st.session_state["generated_questions"]:
     idx = st.session_state["current_question_index"]
@@ -847,11 +871,7 @@ if st.session_state["generated_questions"]:
                     mode=WebRtcMode.SENDONLY,
                     audio_receiver_size=256,
                     media_stream_constraints={"audio": True, "video": False},
-                    rtc_configuration = {
-                        "iceServers": [
-                            {"urls": ["stun:stun.l.google.com:19302"] }
-                        ]
-                    }
+                    rtc_configuration={"iceServers": get_ice_servers()},
                 )
 
                 if webrtc_ctx.state.playing: