『已解决』Synchronous operations are disallowed. Call ReadAsync or set AllowSynchronousIO to true instead

一、背景

• 环境：.Net Core 3.1
• 项目：WebApi
• 操作：读取Request.body的stream流
• 异常：Synchronous operations are disallowed. Call ReadAsync or set AllowSynchronousIO to true instead.

二、问题代码

var request = context.HttpContext.Request;
if (request.Method == "POST")
{request.Body.Seek(0, SeekOrigin.Begin);using (var reader = new StreamReader(request.Body, Encoding.UTF8)){var data = reader.ReadToEnd();}
}

三、问题处理

1. 原因

• 默认同步读取请求流为异步方式
• 默认不支持同步读取

2. 解决方法

解决方法1——配置支持同步读流

public void ConfigureServices(IServiceCollection services)
{services.Configure<KestrelServerOptions>(x => x.AllowSynchronousIO = true).Configure<IISServerOptions>(x => x.AllowSynchronousIO = true);
}

解决方法2——改为异步读流

var request = context.HttpContext.Request;
if (request.Method == "POST")
{request.Body.Seek(0, SeekOrigin.Begin);using (var reader = new StreamReader(request.Body, Encoding.UTF8)){//改为Async异步读流var data = await reader.ReadToEndAsync();}
}