Azure Function中CreateLessonPlan API代理转发时出现“Stream was already consumed”错误

测试端点 #

POST http://localhost:7071/api/lessonplans

请求体 #

{
  "SubjectId": 1,
  "TeacherId": "628d0f85-6915-4df6-b769-c636e433abab",
  "School": "Trường THPT Kim Sơn B",
  "Class": "12A1",
  "LessonTitle": "Bài 1. Định nghĩa – Quy tắc tính đạo hàm",
  "Time": "1 tiết"
}

观察到的行为 #

• 函数主机调用Functions.CreateLessonPlan
• 请求认证成功，但userId和role为null
• 代理重试10次后失败
• 错误提示请求流已被消耗

日志摘录 #

System.Net.Http.HttpRequestException: An error occurred while sending the request.
 ---> System.InvalidOperationException: Stream was already consumed.
   at Yarp.ReverseProxy.Forwarder.StreamCopyHttpContent.SerializeToStreamAsync(...)

预期行为 #

该API应正常执行并返回生成的教案响应，与项目中其他端点表现一致。

附加信息 #

• 缺失小数精度的警告（如HasColumnType、HasPrecision相关）与当前崩溃无关
• 代理错误发生在认证完成后、EF Core写入数据之前
• 问题大概率是请求体流被重复使用，或自定义中间件两次读取流导致

内容的提问来源于stack exchange，提问作者Ngọc Hồng