How to log request inputstream with HttpModule, then reset InputStream position.

Question

I am trying to log the contents of an http request, using an IHttpModule like so:

public class LoggingModule : IHttpModule
{
    public void Init(HttpApplication context)
    {
        context.BeginRequest += ContextBeginRequest;
    }

    private void ContextBeginRequest(object sender, EventArgs e)
    {
        var request = ((HttpApplication)sender).Request;
        string content;

        using (var reader = new StreamReader(request.InputStream))
        {
            content = reader.ReadToEnd();
        }

        LogRequest(content)
    }
}

The problem is that after reading the input stream to the end, the InputStream seems to have either disappeared or more likely, the cursor is at the end of the stream.

I have tried doing this:

request.InputStream.Position = 0;

and this: request.InputStream.Seek(0, SeekOrigin.Begin);

but neither work.

Answer 1

You need to use a request filter. Write a class deriving from Stream and register it as a filter.

Answer 2

I've worked out the problem: I think that calling dispose on the StreamReader must be killing the InputStream too.

Instead of using the StreamReader I did the following:

        var bytes = new byte[request.InputStream.Length];
        request.InputStream.Read(bytes, 0, bytes.Length);
        request.InputStream.Position = 0;
        string content = Encoding.ASCII.GetString(bytes);

So the complete code:

public class LoggingModule : IHttpModule
{
    public void Init(HttpApplication context)
    {
        context.BeginRequest += ContextBeginRequest;
    }

    private void ContextBeginRequest(object sender, EventArgs e)
    {
        var request = ((HttpApplication)sender).Request;

        var bytes = new byte[request.InputStream.Length];
        request.InputStream.Read(bytes, 0, bytes.Length);
        request.InputStream.Position = 0;
        string content = Encoding.ASCII.GetString(bytes);

        LogRequest(content)
    }
}

Answer 3

this answer did not work. it returns an array that contains null values.

        var bytes = new byte[request.InputStream.Length];
        request.InputStream.Read(bytes, 0, bytes.Length);
        request.InputStream.Position = 0;
        string content = Encoding.ASCII.GetString(bytes);

because the input stream consumed.