c# - 如何使用 ReadAsync 将 http 正文变成 dot net core 2.0 中的字符串

Question

我正在接收带有原始正文的 http post 请求，我正在尝试将 http 正文流读入字符串。

我正在使用由 dotnet web 命令生成的基本 Hello World Web 项目。根据documentation :

In the .NET Framework 4 and earlier versions, you have to use methods such as BeginRead and EndRead to implement asynchronous I/O operations. These methods are still available in the .NET Framework 4.5 to support legacy code; however, the new async methods, such as ReadAsync, WriteAsync, CopyToAsync, and FlushAsync, help you implement asynchronous I/O operations more easily.

所以我尝试使用 ReadAsync方法是这样的:

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    // _controller = controller;
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }

    app.Run(async (context) =>
    {

        using (Stream Body = context.Request.Body) {
            byte[] result;
            result = new byte[context.Request.Body.Length];
            await context.Request.Body.ReadAsync(result, 0, (int)context.Request.Body.Length);

            String body = System.Text.Encoding.UTF8.GetString(result).TrimEnd('\0');

            _log.LogInformation($"Body: {body}");
        }
        await context.Response.WriteAsync("Hello World!");
    });
}

但我收到以下错误:

info: Microsoft.AspNetCore.Hosting.Internal.WebHost1 Request starting HTTP/1.1 POST http://localhost:5000/json/testing?id=2342&name=sas application/json 82 fail: Microsoft.AspNetCore.Server.Kestrel[13] Connection id "0HL7ISBH941G6", Request id "0HL7ISBH941G6:00000001": An unhandled exception was thrown by the application. System.NotSupportedException: Specified method is not supported. at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.FrameRequestStream.get_Length() at mtss.ws.Startup.<b__4_0>d.MoveNext() in /home/inspiron/devel/apps/dotnet/mtss-ws/Startup.cs:line 47

-- 更新

我可以将缓冲区的大小设置为 Int16.MaxValue，但这样我就无法读取大于 32k 的正文。

Answer 1

我找到了 this question在 SO 帮助我找到以下解决方案:

app.Run(async (context) =>
{

    string body = new StreamReader(context.Request.Body).ReadToEnd();
    _log.LogInformation($"Body: {body}");
    _log.LogInformation($"Body.Length: {body.Length}");

    await context.Response.WriteAsync("Hello World!");
});

异步版本非常相似:

    string body = await new StreamReader(context.Request.Body).ReadToEndAsync();

不确定这是否是最好的方法...