python network_error ai_generated partial

fastapi.exceptions.WebSocketRequestValidationError: 400 Bad WebSocket Request

ID: python/fastapi-websocket-validation-error

Also available as: JSON · Markdown · 中文
80%Fix Rate
80%Confidence
0Evidence
2025-04-02First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.x active — — —

Root Cause

The WebSocket connection request has invalid parameters or headers.

generic

中文

WebSocket 连接请求具有无效的参数或头部。

Workarounds

  1. 90% success 
    Ensure the WebSocket URL includes the correct subprotocols and headers: websocket.connect("ws://...", subprotocols=["chat"])
  2. 85% success 
    Handle the validation error in the endpoint: except WebSocketRequestValidationError as e: await websocket.close(code=1002)

Dead Ends

Common approaches that don't work:

  1. 70% fail

    This can lead to security vulnerabilities or broken connections.

  2. 90% fail

    This breaks the WebSocket functionality entirely.