christoffersch/googleAuth.cs

## googleAuth.cs
using Godot;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Windows;
using System.Security.Cryptography;
using System.Threading;
using System.Threading.Tasks;

public class googleAuth : Node
{
	const string clientID = "xxx";
	const string clientSecret = "xxx";
  	const string authorizationEndpoint = "https://accounts.google.com/o/oauth2/v2/auth";
  	const string tokenEndpoint = "https://www.googleapis.com/oauth2/v4/token";
   	const string userInfoEndpoint = "https://www.googleapis.com/oauth2/v3/userinfo";

    // Called when the node enters the scene tree for the first time.
    public override void _Ready()
    {

    }

	private async void _on_googleSignInButton_pressed()
    {

        // Set loading
		GetNode("../googleAuthVisualBehavior").Call("startLoadingIcon");

		// Generates state and PKCE values.
        string state = randomDataBase64url(32);
        string code_verifier = randomDataBase64url(32);
        string code_challenge = base64urlencodeNoPadding(sha256(code_verifier));
        const string code_challenge_method = "S256";

		// Creates a redirect URI using an available port on the loopback address.
        string redirectURI = string.Format("http://{0}:{1}/", IPAddress.Loopback, GetRandomUnusedPort());
        output("redirect URI: " + redirectURI);

        // Creates an HttpListener to listen for requests on that redirect URI.
        var http = new HttpListener();
        http.Prefixes.Add(redirectURI);
        output("Listening...");
        http.Start();

		// Creates the OAuth 2.0 authorization request.
        string authorizationRequest = string.Format("{0}?response_type=code&scope=openid%20profile&redirect_uri={1}&client_id={2}&state={3}&code_challenge={4}&code_challenge_method={5}",
            authorizationEndpoint,
            System.Uri.EscapeDataString(redirectURI),
            clientID,
            state,
            code_challenge,
            code_challenge_method);

		// Opens request in the browser.
		Godot.OS.ShellOpen(authorizationRequest);

		// Waits for the OAuth authorization response.
        var context = await http.GetContextAsync();

		// Brings this app back to the foreground.
		Godot.OS.MoveWindowToForeground();

		// Sends an HTTP response to the browser.
        var response = context.Response;
        string responseString = string.Format("<html><head><meta http-equiv='refresh' content='10;url=https://google.com'></head><body>Please return to the game.</body></html>");
        var buffer = System.Text.Encoding.UTF8.GetBytes(responseString);
        response.ContentLength64 = buffer.Length;
        var responseOutput = response.OutputStream;
        Task responseTask = responseOutput.WriteAsync(buffer, 0, buffer.Length).ContinueWith((task) =>
        {
            responseOutput.Close();
            http.Stop();
            Console.WriteLine("HTTP server stopped.");
        });

        // Checks for errors.
        if (context.Request.QueryString.Get("error") != null)
        {
            output(String.Format("OAuth authorization error: {0}.", context.Request.QueryString.Get("error")));
            return;
        }
        if (context.Request.QueryString.Get("code") == null
            || context.Request.QueryString.Get("state") == null)
        {
            output("Malformed authorization response. " + context.Request.QueryString);
            return;
        }

        // extracts the code
        var code = context.Request.QueryString.Get("code");
        var incoming_state = context.Request.QueryString.Get("state");

        // Compares the receieved state to the expected value, to ensure that
        // this app made the request which resulted in authorization.
        if (incoming_state != state)
        {
            output(String.Format("Received request with invalid state ({0})", incoming_state));
            return;
        }
        output("Authorization code: " + code);

        // Starts the code exchange at the Token Endpoint.
        performCodeExchange(code, code_verifier, redirectURI);
    }

	public async void performCodeExchange(string code, string code_verifier, string redirectURI)
    {
        output("Exchanging code for tokens...");

        // builds the  request
        string tokenRequestURI = "https://www.googleapis.com/oauth2/v4/token";
        string tokenRequestBody = string.Format("code={0}&redirect_uri={1}&client_id={2}&code_verifier={3}&client_secret={4}&scope=&grant_type=authorization_code",
            code,
            System.Uri.EscapeDataString(redirectURI),
            clientID,
            code_verifier,
            clientSecret
            );

        // sends the request
        HttpWebRequest tokenRequest = (HttpWebRequest)WebRequest.Create(tokenRequestURI);
        tokenRequest.Method = "POST";
        tokenRequest.ContentType = "application/x-www-form-urlencoded";
        tokenRequest.Accept = "Accept=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
        byte[] _byteVersion = Encoding.ASCII.GetBytes(tokenRequestBody);
        tokenRequest.ContentLength = _byteVersion.Length;
        Stream stream = tokenRequest.GetRequestStream();
        await stream.WriteAsync(_byteVersion, 0, _byteVersion.Length);
        stream.Close();

        try
        {
            // gets the response
            WebResponse tokenResponse = await tokenRequest.GetResponseAsync();
            using (StreamReader reader = new StreamReader(tokenResponse.GetResponseStream()))
            {
                // reads response body
                string responseText = await reader.ReadToEndAsync();
                output(responseText);

                // converts to dictionary
                Dictionary<string, string> tokenEndpointDecoded = JsonConvert.DeserializeObject<Dictionary<string, string>>(responseText);

                string access_token = tokenEndpointDecoded["access_token"];
                userinfoCall(access_token);
            }
        }
        catch (WebException ex)
        {
            if (ex.Status == WebExceptionStatus.ProtocolError)
            {
                var response = ex.Response as HttpWebResponse;
                if (response != null)
                {
                    output("HTTP: " + response.StatusCode);
                    using (StreamReader reader = new StreamReader(response.GetResponseStream()))
                    {
                        // reads response body
                        string responseText = await reader.ReadToEndAsync();
                        output(responseText);
                    }
                }

            }
        }
    }

	public async void userinfoCall(string access_token)
    {
        output("Making API Call to Userinfo...");

        // builds the  request
        string userinfoRequestURI = "https://www.googleapis.com/oauth2/v3/userinfo";

        // sends the request
        HttpWebRequest userinfoRequest = (HttpWebRequest)WebRequest.Create(userinfoRequestURI);
        userinfoRequest.Method = "GET";
        userinfoRequest.Headers.Add(string.Format("Authorization: Bearer {0}", access_token));
        userinfoRequest.ContentType = "application/x-www-form-urlencoded";
        userinfoRequest.Accept = "Accept=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";

        // gets the response
        WebResponse userinfoResponse = await userinfoRequest.GetResponseAsync();
        using (StreamReader userinfoResponseReader = new StreamReader(userinfoResponse.GetResponseStream()))
        {
            // reads response body
            var userinfoResponseText = await userinfoResponseReader.ReadToEndAsync();
			outputData(userinfoResponseText);
        }
    }

    // GETTING A RANDOM PORT

	public static int GetRandomUnusedPort()
    {
        var listener = new TcpListener(IPAddress.Loopback, 0);
        listener.Start();
        var port = ((IPEndPoint)listener.LocalEndpoint).Port;
        listener.Stop();
        return port;
    }

    // ------------ SECURITY ------------------

	public static byte[] sha256(string inputStirng)
    {
        byte[] bytes = Encoding.ASCII.GetBytes(inputStirng);
        SHA256Managed sha256 = new SHA256Managed();
        return sha256.ComputeHash(bytes);
    }

	public static string randomDataBase64url(uint length)
    {
        RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
        byte[] bytes = new byte[length];
        rng.GetBytes(bytes);
        return base64urlencodeNoPadding(bytes);
    }

	public static string base64urlencodeNoPadding(byte[] buffer)
    {
        string base64 = Convert.ToBase64String(buffer);

        // Converts base64 to base64url.
        base64 = base64.Replace("+", "-");
        base64 = base64.Replace("/", "_");
        // Strips padding.
        base64 = base64.Replace("=", "");

        return base64;
    }

    // ----------- OUTPUT ------------------

	public void output(string output)
    {
		GD.Print(output);
    }

	public void outputData(string output)
    {
		JObject data = JObject.Parse(output);
		string name = (string)data["given_name"];
		string sub = (string)data["sub"];
		string profile_picture = (string)data["picture"];

		GetNode("../googleAuthVisualBehavior").Call("updateInformation", sub, name, profile_picture);

    }

}
	using Godot;
	using Newtonsoft.Json;
	using Newtonsoft.Json.Linq;
	using System;
	using System.Collections.Generic;
	using System.IO;
	using System.Net;
	using System.Net.Sockets;
	using System.Text;
	using System.Windows;
	using System.Security.Cryptography;
	using System.Threading;
	using System.Threading.Tasks;

	public class googleAuth : Node
	{
	const string clientID = "xxx";
	const string clientSecret = "xxx";
	const string authorizationEndpoint = "https://accounts.google.com/o/oauth2/v2/auth";
	const string tokenEndpoint = "https://www.googleapis.com/oauth2/v4/token";
	const string userInfoEndpoint = "https://www.googleapis.com/oauth2/v3/userinfo";

	// Called when the node enters the scene tree for the first time.
	public override void _Ready()
	{

	}

	private async void _on_googleSignInButton_pressed()
	{

	// Set loading
	GetNode("../googleAuthVisualBehavior").Call("startLoadingIcon");

	// Generates state and PKCE values.
	string state = randomDataBase64url(32);
	string code_verifier = randomDataBase64url(32);
	string code_challenge = base64urlencodeNoPadding(sha256(code_verifier));
	const string code_challenge_method = "S256";

	// Creates a redirect URI using an available port on the loopback address.
	string redirectURI = string.Format("http://{0}:{1}/", IPAddress.Loopback, GetRandomUnusedPort());
	output("redirect URI: " + redirectURI);

	// Creates an HttpListener to listen for requests on that redirect URI.
	var http = new HttpListener();
	http.Prefixes.Add(redirectURI);
	output("Listening...");
	http.Start();

	// Creates the OAuth 2.0 authorization request.
	string authorizationRequest = string.Format("{0}?response_type=code&scope=openid%20profile&redirect_uri={1}&client_id={2}&state={3}&code_challenge={4}&code_challenge_method={5}",
	authorizationEndpoint,
	System.Uri.EscapeDataString(redirectURI),
	clientID,
	state,
	code_challenge,
	code_challenge_method);

	// Opens request in the browser.
	Godot.OS.ShellOpen(authorizationRequest);

	// Waits for the OAuth authorization response.
	var context = await http.GetContextAsync();

	// Brings this app back to the foreground.
	Godot.OS.MoveWindowToForeground();

	// Sends an HTTP response to the browser.
	var response = context.Response;
	string responseString = string.Format("<html><head><meta http-equiv='refresh' content='10;url=https://google.com'></head><body>Please return to the game.</body></html>");
	var buffer = System.Text.Encoding.UTF8.GetBytes(responseString);
	response.ContentLength64 = buffer.Length;
	var responseOutput = response.OutputStream;
	Task responseTask = responseOutput.WriteAsync(buffer, 0, buffer.Length).ContinueWith((task) =>
	{
	responseOutput.Close();
	http.Stop();
	Console.WriteLine("HTTP server stopped.");
	});

	// Checks for errors.
	if (context.Request.QueryString.Get("error") != null)
	{
	output(String.Format("OAuth authorization error: {0}.", context.Request.QueryString.Get("error")));
	return;
	}
	if (context.Request.QueryString.Get("code") == null
	\|\| context.Request.QueryString.Get("state") == null)
	{
	output("Malformed authorization response. " + context.Request.QueryString);
	return;
	}

	// extracts the code
	var code = context.Request.QueryString.Get("code");
	var incoming_state = context.Request.QueryString.Get("state");

	// Compares the receieved state to the expected value, to ensure that
	// this app made the request which resulted in authorization.
	if (incoming_state != state)
	{
	output(String.Format("Received request with invalid state ({0})", incoming_state));
	return;
	}
	output("Authorization code: " + code);

	// Starts the code exchange at the Token Endpoint.
	performCodeExchange(code, code_verifier, redirectURI);
	}

	public async void performCodeExchange(string code, string code_verifier, string redirectURI)
	{
	output("Exchanging code for tokens...");

	// builds the request
	string tokenRequestURI = "https://www.googleapis.com/oauth2/v4/token";
	string tokenRequestBody = string.Format("code={0}&redirect_uri={1}&client_id={2}&code_verifier={3}&client_secret={4}&scope=&grant_type=authorization_code",
	code,
	System.Uri.EscapeDataString(redirectURI),
	clientID,
	code_verifier,
	clientSecret
	);

	// sends the request
	HttpWebRequest tokenRequest = (HttpWebRequest)WebRequest.Create(tokenRequestURI);
	tokenRequest.Method = "POST";
	tokenRequest.ContentType = "application/x-www-form-urlencoded";
	tokenRequest.Accept = "Accept=text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8";
	byte[] _byteVersion = Encoding.ASCII.GetBytes(tokenRequestBody);
	tokenRequest.ContentLength = _byteVersion.Length;
	Stream stream = tokenRequest.GetRequestStream();
	await stream.WriteAsync(_byteVersion, 0, _byteVersion.Length);
	stream.Close();

	try
	{
	// gets the response
	WebResponse tokenResponse = await tokenRequest.GetResponseAsync();
	using (StreamReader reader = new StreamReader(tokenResponse.GetResponseStream()))
	{
	// reads response body
	string responseText = await reader.ReadToEndAsync();
	output(responseText);

	// converts to dictionary
	Dictionary<string, string> tokenEndpointDecoded = JsonConvert.DeserializeObject<Dictionary<string, string>>(responseText);

	string access_token = tokenEndpointDecoded["access_token"];
	userinfoCall(access_token);
	}
	}
	catch (WebException ex)
	{
	if (ex.Status == WebExceptionStatus.ProtocolError)
	{
	var response = ex.Response as HttpWebResponse;
	if (response != null)
	{
	output("HTTP: " + response.StatusCode);
	using (StreamReader reader = new StreamReader(response.GetResponseStream()))
	{
	// reads response body
	string responseText = await reader.ReadToEndAsync();
	output(responseText);
	}
	}

	}
	}
	}

	public async void userinfoCall(string access_token)
	{
	output("Making API Call to Userinfo...");

	// builds the request
	string userinfoRequestURI = "https://www.googleapis.com/oauth2/v3/userinfo";

	// sends the request
	HttpWebRequest userinfoRequest = (HttpWebRequest)WebRequest.Create(userinfoRequestURI);
	userinfoRequest.Method = "GET";
	userinfoRequest.Headers.Add(string.Format("Authorization: Bearer {0}", access_token));
	userinfoRequest.ContentType = "application/x-www-form-urlencoded";
	userinfoRequest.Accept = "Accept=text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8";

	// gets the response
	WebResponse userinfoResponse = await userinfoRequest.GetResponseAsync();
	using (StreamReader userinfoResponseReader = new StreamReader(userinfoResponse.GetResponseStream()))
	{
	// reads response body
	var userinfoResponseText = await userinfoResponseReader.ReadToEndAsync();
	outputData(userinfoResponseText);
	}
	}

	// GETTING A RANDOM PORT

	public static int GetRandomUnusedPort()
	{
	var listener = new TcpListener(IPAddress.Loopback, 0);
	listener.Start();
	var port = ((IPEndPoint)listener.LocalEndpoint).Port;
	listener.Stop();
	return port;
	}

	// ------------ SECURITY ------------------

	public static byte[] sha256(string inputStirng)
	{
	byte[] bytes = Encoding.ASCII.GetBytes(inputStirng);
	SHA256Managed sha256 = new SHA256Managed();
	return sha256.ComputeHash(bytes);
	}

	public static string randomDataBase64url(uint length)
	{
	RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
	byte[] bytes = new byte[length];
	rng.GetBytes(bytes);
	return base64urlencodeNoPadding(bytes);
	}

	public static string base64urlencodeNoPadding(byte[] buffer)
	{
	string base64 = Convert.ToBase64String(buffer);

	// Converts base64 to base64url.
	base64 = base64.Replace("+", "-");
	base64 = base64.Replace("/", "_");
	// Strips padding.
	base64 = base64.Replace("=", "");

	return base64;
	}

	// ----------- OUTPUT ------------------

	public void output(string output)
	{
	GD.Print(output);
	}

	public void outputData(string output)
	{
	JObject data = JObject.Parse(output);
	string name = (string)data["given_name"];
	string sub = (string)data["sub"];
	string profile_picture = (string)data["picture"];

	GetNode("../googleAuthVisualBehavior").Call("updateInformation", sub, name, profile_picture);

	}

	}