[Bug]: RAGFlow Hypercorn/h11 protocol bug — When an empty knowledge_id and query are received, it triggers build_error_result, but Hypercorn's h11 protocol state machine crashes, resulting in an empty response (0 bytes) instead of returning a JSON error. #17980

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RAGFlow workspace code commit ID

3e11914

RAGFlow image version

v0.26.4-707-g3e1191414

Other environment information

Actual behavior

用dify远程连接ragflow的知识库出现的错误，两个软件装在同一台主机上

Expected behavior

No response

Steps to reproduce

错误现象：错误标题：
Failed to save/update External API
错误详情：
failed to connect to the endpoint:
http://192.168.5.12:9380/api/v1/dify/retrieval
错误问题：SSRF 代理拒绝私有 IP ✅ 已在上一步修复
RAGFlow Hypercorn/h11 协议 Bug — 当收到空 knowledge_id + query 时触发 build_error_result，但 Hypercorn 的 h11 协议状态机崩溃导致空响应（0 字节），而非返回 JSON 错误
Squid 看到空响应 → 502 — Dify 收到 502 后报告 "failed to connect"

Additional information

No response