CODEWITHSUNDEEP
c#asp.net-coremiddleware
Stan
Stan

Reputation: 13

Get request body after exception in middleware. .NET Core 3.1

I need to get the request body after exception in my ExceptionHandlingMiddleware. Before Exception I get easy request body, but after I can't. Part of code from ExceptionHandlingMiddleware below.

    try
    {
      await _next.Invoke(context);
    }
    catch (Exception exception)
    {
      RequestBody = await FormatRequest(context.Request);
    }

    private async Task<string> FormatRequest(HttpRequest request)
    {
        request.EnableBuffering();

        var body = request.Body;

        var buffer = new byte[Convert.ToInt32(request.ContentLength)];

        await request.Body.ReadAsync(buffer, 0, buffer.Length);

        var bodyAsText = Encoding.UTF8.GetString(buffer);

        return $"{request.Scheme} {request.Host}{request.Path} {request.QueryString} 
        {bodyAsText}";
    }

In result, I get this

body

I tried to get the body in try by this way

    try
    {
     RequestBody = await FormatRequest(context.Request);
     await _next.Invoke(context);
    }

And it works, I get normal json data, but I have the exception that my model is not valid because it is empty.

I tried to do request.EnableBuffering(); before exception but it didn't help me.

So If I try to get body after exception, I can`t parse it. If I get it before exception my model in the controller is not valid.

How I can get my model after exception for logging in ExceptionHandlingMiddleware?

Upvotes: 1

Views: 3177

Answers (1)

Rena
Rena

Reputation: 36575

Usually Request.Body does not support rewinding, so it can only be read once. A temp workaround is to pull out the body right after the call to EnableBuffering and then rewinding the stream to 0 and not disposing it:

request.EnableBuffering();

var body = request.Body;

var buffer = new byte[Convert.ToInt32(request.ContentLength)];

await request.Body.ReadAsync(buffer, 0, buffer.Length);

var bodyAsText = Encoding.UTF8.GetString(buffer);

request.Body.Position = 0;  //rewinding the stream to 0

Upvotes: 3

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