How to read the HttpResponse Body?

Question

I have a .NET Core Web API project with a request and response logging middleware. I registered both middleware files in the Configure method in the Startup file

app.UseMiddleware<RequestLoggingMiddleware>();
app.UseMiddleware<ResponseLoggingMiddleware>();

For now I'm just trying to log the body, the request logging seems to work fine

public class RequestLoggingMiddleware
{
    private readonly RequestDelegate requestDelegate;

    public RequestLoggingMiddleware(RequestDelegate requestDelegate)
    {
        this.requestDelegate = requestDelegate;
    }

    public async Task InvokeAsync(HttpContext httpContext)
    {
        HttpRequest httpRequest = httpContext.Request;
        httpRequest.EnableBuffering();

        ReadResult bodyReadResult = await httpRequest.BodyReader.ReadAsync();
        ReadOnlySequence<byte> bodyBuffer = bodyReadResult.Buffer;

        if (bodyBuffer.Length > 0)
        {
            byte[] bodyBytes = bodyBuffer.ToArray();
            string bodyText = Encoding.UTF8.GetString(bodyBytes);

            Console.WriteLine(bodyText);
        }

        // Reset
        httpRequest.Body.Seek(0, SeekOrigin.Begin);

        await requestDelegate(httpContext);
    }
}

My response logging middleware does not have access to a BodyReader. I tried to go with this code

public class ResponseLoggingMiddleware
{
    private readonly RequestDelegate requestDelegate;

    public ResponseLoggingMiddleware(RequestDelegate requestDelegate)
    {
        this.requestDelegate = requestDelegate;
    }

    public async Task InvokeAsync(HttpContext httpContext)
    {
        await requestDelegate(httpContext);

        Stream responseBody = httpContext.Response.Body;

        using (StreamReader reader = new StreamReader(responseBody))
        {
            string bodyText = await reader.ReadToEndAsync();

            // Reset
            responseBody.Seek(0, SeekOrigin.Begin);

            Console.WriteLine(bodyText);
        }
    }
}

but unfortunately I get this exception

System.ArgumentException: Stream was not readable.

Does someone know how to fix it?

HttpResponseStream mentioned in your exception message is not readable, it's write only by design. Depending on why you are trying to do that - you might be able to use some hacks like https://stackoverflow.com/q/43403941/5311735 — Evk, Oct 19 '20 at 09:14
Are you sure, that your code is about [`System.IO.Pipelines`](https://devblogs.microsoft.com/dotnet/system-io-pipelines-high-performance-io-in-net/) APIs? — Pavel Anikhouski, Oct 19 '20 at 09:15
@PavelAnikhouski no I mean I'm just using some types from the namespace — , Oct 19 '20 at 09:18

Mahi · Answer 1 · 2022-05-25T06:54:55.097

7

You may use StreamReader to read the request body. Below code, you may follow.

            string body = string.Empty;
            Request.EnableRewind();
            using (var reader = new StreamReader(Request.Body))
            {
                Request.Body.Seek(0, SeekOrigin.Begin);
                body = reader.ReadToEnd();
            }

In the same way, you can get a response body.

            using (var reader = new StreamReader(Response.Body))
            {
                Response.Body.Seek(0, SeekOrigin.Begin);
                body = reader.ReadToEnd();
            }

Notes: Above code is based on .net core 2.2

Below is the code supported by .net core 5

string body = string.Empty; 
using (var reader = new StreamReader(Request.Body))
{
    //Request.Body.Seek(0, SeekOrigin.Begin);
    //body = reader.ReadToEnd();
    body = await reader.ReadToEndAsync();
}

Now, you have the response in the body property, do your kinds of stuff (JSON Deserilize).

edited May 25 '22 at 06:54

answered Oct 19 '20 at 09:05

Mahi

1,019
9
19

1

thanks for your reply. Unfortunately I don't have access to the `EnableRewind` method. But I imported the using `Microsoft.AspNetCore.Http`. But my package `Microsoft.AspNetCore.Http` does not know about the `Microsoft.AspNetCore.Http.Internal` namespace – Oct 19 '20 at 09:24
ah, in core 3.0 it's `EnableBuffering` – Oct 19 '20 at 09:27
Yeah, I was using .net core 2.2 – Mahi Oct 19 '20 at 09:30
2

sorry but I get this exception `System.ArgumentException: Stream was not readable.` – Oct 19 '20 at 09:31
@OlafSvenson, Can you please share your code? what you have tried?. – Mahi Oct 19 '20 at 10:12
yes sure. I updated my question. I took this code and modified the `InvokeAsync` methods to your suggested changes: https://pastebin.com/EgZk4TYJ – Oct 19 '20 at 11:44

score 1 · Answer 2 · answered Feb 13 '23 at 03:25

Anyone who is looking for the solution of .net standard can use the following snippet

For ApiController

string requestBody = string.Empty;
using (var reader = new StreamReader(HttpContext.Current.Request.InputStream))
{
  reader.BaseStream.Seek(0, SeekOrigin.Begin);
  requestBody = reader.ReadToEnd();
}
Console.WriteLine(requestBody);

For regular controller

string requestBody = string.Empty;
using (var reader = new StreamReader(HttpContext.Request.InputStream))
{
   reader.BaseStream.Seek(0, SeekOrigin.Begin);
   requestBody = reader.ReadToEnd();
}
Console.WriteLine(requestBody);

score -1 · Answer 3 · answered Jul 16 '22 at 20:38

-1

Stream is an Abstract class, you must tu use a MemoryStream, check this:

        using (var ms = new MemoryStream())
        {
            var cuerpoOriginalRespuesta = contexto.Response.Body;
            contexto.Response.Body = ms;

            await siguiente(contexto);  
            ms.Seek(0, SeekOrigin.Begin);
            string respuesta = new StreamReader(ms).ReadToEnd();
            ms.Seek(0, SeekOrigin.Begin);

            await ms.CopyToAsync(cuerpoOriginalRespuesta);
            contexto.Response.Body = cuerpoOriginalRespuesta;


        }

answered Jul 16 '22 at 20:38

Lauro Ramirez

1

You probably do not want t advice him set the response body, as the wish is to read ? – T. Nielsen Jul 20 '22 at 11:44
Yeah, you are right.. but you can deduce from it – Lauro Ramirez Aug 31 '22 at 13:39

How to read the HttpResponse Body?

3 Answers3