getting the request body inside HttpContext from a Middleware in asp.net core 2.0

问题

I am having a simple middleware which fetches the body of the request and store it in a string. It is reading fine the stream, but the issue is it wont call my controller which called just after I read the stream and throw the error

A non-empty request body is required

. Below is my code.

  public async Task Invoke(HttpContext httpContext)
            {
                var timer = Stopwatch.StartNew();
                ReadBodyFromHttpContext(httpContext);
                await _next(httpContext);
                timer.Stop();
            }

   private string ReadBodyFromHttpContext(HttpContext httpContext)
        {
           return await new StreamReader(httpContext.Request.Body).ReadToEndAsync();
        }

回答1:

You need to convert HttpContext.Request.Body from a forward only memory stream to a seekable stream, shown below.

//  Enable seeking
context.Request.EnableBuffering();
//  Read the stream as text
var bodyAsText = await new System.IO.StreamReader(context.Request.Body).ReadToEndAsync();
//  Set the position of the stream to 0 to enable rereading
context.Request.Body.Position = 0;

回答2:

when it comes to capturing the body of an HTTP request and/or response, this is no trivial effort. In ASP .NET Core, the body is a stream – once you consume it (for logging, in this case), it’s gone, rendering the rest of the pipeline useless.

Ref:http://www.palador.com/2017/05/24/logging-the-body-of-http-request-and-response-in-asp-net-core/

public async Task Invoke(HttpContext httpContext)
    {
        var timer = Stopwatch.StartNew();
        string bodyAsText = await new StreamReader(httpContext.Request.Body).ReadToEndAsync();
        var injectedRequestStream = new MemoryStream();
        var bytesToWrite = Encoding.UTF8.GetBytes(bodyAsText);
        injectedRequestStream.Write(bytesToWrite, 0, bytesToWrite.Length);
        injectedRequestStream.Seek(0, SeekOrigin.Begin);
        httpContext.Request.Body = injectedRequestStream;
        await _next(httpContext);

        timer.Stop();
    }

回答3:

Few things are crucial here:

enable buffering
last flag leaveOpen in StreamReader
reset request body stream position

public void UseMyMiddleware(IApplicationBuilder app)
{
    app.Use(async (context, next) =>
    {
        context.Request.EnableBuffering();

        using (var reader = new StreamReader(context.Request.Body, Encoding.UTF8, false, 1024, true))
        {
            var body = await reader.ReadToEndAsync();

            context.Request.Body.Seek(0, SeekOrigin.Begin);
        }

        await next.Invoke();
    });
}

回答4:

using (var mem = new MemoryStream())
            using (var reader = new StreamReader(mem))
            {
                Request.Body.CopyTo(mem);
                var body = reader.ReadToEnd();

//and this you can reset the position of the stream.

                mem.Seek(0, SeekOrigin.Begin);
                body = reader.ReadToEnd();
            }

Here you are can read how it works. https://gunnarpeipman.com/aspnet-core-request-body/

来源：https://stackoverflow.com/questions/47624938/getting-the-request-body-inside-httpcontext-from-a-middleware-in-asp-net-core-2

标签

asp.net-core-2.0