Titanium

A light weight HTTP(S) proxy server written in C#

Kindly report only issues/bugs here . For programming help or questions use StackOverflow with the tag Titanium-Web-Proxy.

(Wiki & Contribution guidelines)

Console example application screenshot

GUI example application screenshot

Features

Supports HTTP(S) and most features of HTTP 1.1
Support redirect/block/update requests
Supports updating response
Safely relays Web Socket requests over HTTP
Support mutual SSL authentication
Fully asynchronous proxy
Supports proxy authentication & automatic proxy detection
Kerberos/NTLM authentication over HTTP protocols for windows domain

Usage

Refer the HTTP Proxy Server library in your project, look up Test project to learn usage.

Install by nuget

For beta releases on beta branch

Install-Package Titanium.Web.Proxy -Pre

For stable releases on stable branch

Install-Package Titanium.Web.Proxy

Supports

.Net Standard 2.0 or above
.Net Framework 4.5 or above

Setup HTTP proxy:

var proxyServer = new ProxyServer();

//locally trust root certificate used by this proxy 
proxyServer.TrustRootCertificate = true;

//optionally set the Certificate Engine
//Under Mono only BouncyCastle will be supported
//proxyServer.CertificateEngine = Network.CertificateEngine.BouncyCastle;

proxyServer.BeforeRequest += OnRequest;
proxyServer.BeforeResponse += OnResponse;
proxyServer.ServerCertificateValidationCallback += OnCertificateValidation;
proxyServer.ClientCertificateSelectionCallback += OnCertificateSelection;


var explicitEndPoint = new ExplicitProxyEndPoint(IPAddress.Any, 8000, true)
{
//Exclude HTTPS addresses you don't want to proxy
//Useful for clients that use certificate pinning
//for example dropbox.com
// ExcludedHttpsHostNameRegex = new List<string>() { "google.com", "dropbox.com" }

//Use self-issued generic certificate on all HTTPS requests
//Optimizes performance by not creating a certificate for each HTTPS-enabled domain
//Useful when certificate trust is not required by proxy clients
// GenericCertificate = new X509Certificate2(Path.Combine(System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location), "genericcert.pfx"), "password")
};

//An explicit endpoint is where the client knows about the existence of a proxy
//So client sends request in a proxy friendly manner
proxyServer.AddEndPoint(explicitEndPoint);
proxyServer.Start();

//Transparent endpoint is useful for reverse proxy (client is not aware of the existence of proxy)
//A transparent endpoint usually requires a network router port forwarding HTTP(S) packets or DNS
//to send data to this endPoint
var transparentEndPoint = new TransparentProxyEndPoint(IPAddress.Any, 8001, true)
{
	//Generic Certificate hostname to use
	//when SNI is disabled by client
	GenericCertificateName = "google.com"
};

proxyServer.AddEndPoint(transparentEndPoint);

//proxyServer.UpStreamHttpProxy = new ExternalProxy() { HostName = "localhost", Port = 8888 };
//proxyServer.UpStreamHttpsProxy = new ExternalProxy() { HostName = "localhost", Port = 8888 };

foreach (var endPoint in proxyServer.ProxyEndPoints)
Console.WriteLine("Listening on '{0}' endpoint at Ip {1} and port: {2} ",
    endPoint.GetType().Name, endPoint.IpAddress, endPoint.Port);

//Only explicit proxies can be set as system proxy!
proxyServer.SetAsSystemHttpProxy(explicitEndPoint);
proxyServer.SetAsSystemHttpsProxy(explicitEndPoint);

//wait here (You can use something else as a wait function, I am using this as a demo)
Console.Read();

//Unsubscribe & Quit
proxyServer.BeforeRequest -= OnRequest;
proxyServer.BeforeResponse -= OnResponse;
proxyServer.ServerCertificateValidationCallback -= OnCertificateValidation;
proxyServer.ClientCertificateSelectionCallback -= OnCertificateSelection;

proxyServer.Stop();

Sample request and response event handlers

//To access requestBody from OnResponse handler
private IDictionary<Guid, string> requestBodyHistory 
        = new ConcurrentDictionary<Guid, string>();

public async Task OnRequest(object sender, SessionEventArgs e)
{
    Console.WriteLine(e.WebSession.Request.Url);

    ////read request headers
    var requestHeaders = e.WebSession.Request.RequestHeaders;

    var method = e.WebSession.Request.Method.ToUpper();
    if ((method == "POST" || method == "PUT" || method == "PATCH"))
    {
	//Get/Set request body bytes
	byte[] bodyBytes = await e.GetRequestBody();
	await e.SetRequestBody(bodyBytes);

	//Get/Set request body as string
	string bodyString = await e.GetRequestBodyAsString();
	await e.SetRequestBodyString(bodyString);
	
	//store request Body/request headers etc with request Id as key
	//so that you can find it from response handler using request Id
  	requestBodyHistory[e.Id] = bodyString;
    }

    //To cancel a request with a custom HTML content
    //Filter URL
    if (e.WebSession.Request.RequestUri.AbsoluteUri.Contains("google.com"))
    {
	await e.Ok("<!DOCTYPE html>" +
	      "<html><body><h1>" +
	      "Website Blocked" +
	      "</h1>" +
	      "<p>Blocked by titanium web proxy.</p>" +
	      "</body>" +
	      "</html>");
    }
    //Redirect example
    if (e.WebSession.Request.RequestUri.AbsoluteUri.Contains("wikipedia.org"))
    {
	await e.Redirect("https://www.paypal.com");
    }
}

//Modify response
public async Task OnResponse(object sender, SessionEventArgs e)
{
    //read response headers
    var responseHeaders = e.WebSession.Response.ResponseHeaders;

    //if (!e.ProxySession.Request.Host.Equals("medeczane.sgk.gov.tr")) return;
    if (e.WebSession.Request.Method == "GET" || e.WebSession.Request.Method == "POST")
    {
	if (e.WebSession.Response.ResponseStatusCode == "200")
	{
	    if (e.WebSession.Response.ContentType!=null && e.WebSession.Response.ContentType.Trim().ToLower().Contains("text/html"))
	    {
		byte[] bodyBytes = await e.GetResponseBody();
		await e.SetResponseBody(bodyBytes);

		string body = await e.GetResponseBodyAsString();
		await e.SetResponseBodyString(body);
	    }
	}
    }
    
    //access request body/request headers etc by looking up using requestId
    if(requestBodyHistory.ContainsKey(e.Id))
    {
	var requestBody = requestBodyHistory[e.Id];
    }
}

/// Allows overriding default certificate validation logic
public Task OnCertificateValidation(object sender, CertificateValidationEventArgs e)
{
    //set IsValid to true/false based on Certificate Errors
    if (e.SslPolicyErrors == System.Net.Security.SslPolicyErrors.None)
	e.IsValid = true;

    return Task.FromResult(0);
}

/// Allows overriding default client certificate selection logic during mutual authentication
public Task OnCertificateSelection(object sender, CertificateSelectionEventArgs e)
{
    //set e.clientCertificate to override
    return Task.FromResult(0);
}

Future road map (Pull requests are welcome!)

Support HTTP 2.0
Support SOCKS protocol

dfzone/Titanium-Web-Proxy

Titanium

Features

Usage

Future road map (Pull requests are welcome!)