CODEWITHSUNDEEP
c#.nethttphttplistener
ispiro
ispiro

Reputation: 27673

Listen to Browser's requests

Using the following code:

HttpListener listener = new HttpListener();
//listener.Prefixes.Add("http://*:80/");
listener.Prefixes.Add("http://*:8080/");
listener.Prefixes.Add("http://*:8081/");
listener.Prefixes.Add("http://*:8082/");
listener.Start();
HttpListenerContext context = listener.GetContext();
HttpListenerRequest request = context.Request;

The program hangs on the GetContext(); despite loading http (not https) pages in IE and Firefox.

When I uncomment the first line I get the error:

Failed to listen on prefix 'http://*:80/' because it conflicts with an existing registration on the machine.

So how do I listen to a browser's requests?

Upvotes: 0

Views: 5608

Answers (6)

MadDev
MadDev

Reputation: 1150

Replace * in your prefixes with +

listener.Prefixes.Add("http://+:8080/");

Upvotes: 0

MiguelCldn
MiguelCldn

Reputation: 527

It hangs because GetContext() is waiting for a request to be received, as said in its documentation:

This method blocks while waiting for an incoming request. If you want incoming requests to be processed asynchronously (on separate threads) so that your application does not block, use the BeginGetContext method.

For more info see: https://msdn.microsoft.com/en-us/library/system.net.httplistener.getcontext(v=vs.110).aspx

Using Asynchronous model tends to be complex, another alternative is running all that code in a different Thread but it depends on your goals.

Upvotes: 0

Darrel Miller
Darrel Miller

Reputation: 142044

I would consider looking into this package http://www.nuget.org/packages/Microsoft.AspNet.WebApi.OwinSelfHost/ It uses HttpListener under the covers and with the WebApi HttpMessageHandler it is very easy to create a proxy.

Upvotes: 0

L.B
L.B

Reputation: 116118

@L.B I want to write a "proxy"

Don't reinvent the wheel and just use the FiddlerCore

public class HttpProxy : IDisposable
{
    public HttpProxy()
    {
        Fiddler.FiddlerApplication.BeforeRequest += FiddlerApplication_BeforeRequest;
        Fiddler.FiddlerApplication.Startup(8764, true, true);
    }

    void FiddlerApplication_BeforeRequest(Fiddler.Session oSession)
    {
        Console.WriteLine(String.Format("REQ: {0}", oSession.url));
    }

    public void Dispose()
    {
        Fiddler.FiddlerApplication.Shutdown();
    }
}

EDIT

You can start with this rectangular wheel :)

void SniffPort80()
{
    byte[] input = new byte[] { 1 };
    Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.IP);
    socket.Bind(new IPEndPoint(IPAddress.Broadcast, 80));
    socket.IOControl(IOControlCode.ReceiveAll, input, null);

    byte[] buffer = new byte[0x10000];

    Task.Factory.StartNew(() =>
        {
            while (true)
            {
                int len = socket.Receive(buffer);
                if (len <= 40) continue; //Poor man's check for TCP payload
                string bin = Encoding.UTF8.GetString(buffer, 0, len); //Don't trust to this line. Encoding may be different :) even it can contain binary data like images, videos etc.
                Console.WriteLine(bin);
            }
        });
}

Upvotes: 5

Tal
Tal

Reputation: 700

this port is probably being used... run netstat -ano on the command line, youll see list of the ports that are being used and the their process ids.

Upvotes: 1

Eddynand Fuchs
Eddynand Fuchs

Reputation: 354

I dont know, why the GetContext(); hangs, because there is too less information about what happens with the listerner variable, but the problem with port 80 usually is caused by Skype, because it uses port 80 by default. To fix that, open Skype's preferences, go to advanced->connection and uncheck "Use Port 80 and 443 as an alternative for incoming Connections".

Upvotes: 0

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