python data_error ai_generated true

aiohttp.multipart.MultipartError: Could not find boundary in multipart body

ID: python/aiohttp-multipart-parse-error

Also available as: JSON · Markdown · 中文
80%Fix Rate
80%Confidence
0Evidence
2025-04-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.7 active — — —
3.8 active — — —

Root Cause

The multipart request body is malformed or missing the boundary parameter.

generic

中文

多部分请求体格式错误或缺少边界参数。

Workarounds

  1. 95% success 
    writer = aiohttp.MultipartWriter(); part = payload; writer.append(part); await session.post(url, data=writer)
  2. 85% success 
    headers = {'Content-Type': 'multipart/form-data; boundary=myboundary'}; data = '--myboundary...'

Dead Ends

Common approaches that don't work:

  1. 70% fail

    If the server expects a specific boundary, it won't match.

  2. 90% fail

    The data cannot be parsed, leading to incomplete processing.