python runtime_error ai_generated true

RuntimeError: No response returned.

ID: python/starlette-runtime-error-no-response-returned

Also available as: JSON · Markdown · 中文
80%Fix Rate
88%Confidence
0Evidence
2024-08-22First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.x active — — —

Root Cause

An async view function does not return a valid response object.

generic

中文

异步视图函数未返回有效的响应对象。

Workarounds

  1. 95% success Return a Response object 
    from starlette.responses import JSONResponse
async def handle(request):
    return JSONResponse({'message': 'OK'})
  2. 90% success Use PlainTextResponse for simple text 
    from starlette.responses import PlainTextResponse
async def handle(request):
    return PlainTextResponse('Hello')

Dead Ends

Common approaches that don't work:

  1. Returning a string directly 80% fail

    Starlette expects a Response object, not a string.

  2. Forgetting return statement entirely 90% fail

    Function returns None.