Authentication via GTK+ in windows applications

This guide describes how to use GTK+ to create a mini browser in a windows application to pass the OAuth 2.0 authentication flow without passing the web GUI flow in a browser:

1- Install and set up the required tools
To get started, you'll need to install the following tools on your development machine:

GTK+ library: This is a toolkit for creating graphical user interfaces. You can download it from the GTK+ website.
WebKitGTK+: This is a web browser engine that uses the GTK+ library. You can download it from the WebKitGTK+ website.
A text editor or integrated development environment (IDE) for writing your code. Some popular options include Visual Studio Code, Eclipse, and Atom.
Once you have these tools installed, you can start building your mini browser.
2- Create a new GTK+ project
Open your text editor or IDE and create a new GTK+ project. In your project, you'll need to create a new GTK+ window and add a WebKitGTK+ widget to it. You can do this using the following code:

#include <gtk/gtk.h>
#include <webkit2/webkit2.h>

static void destroyWindowCallback(GtkWidget* widget, gpointer data) {
    gtk_main_quit();
}

int main(int argc, char* argv[]) {
    gtk_init(&argc, &argv);

    GtkWidget* window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title(GTK_WINDOW(window), "Mini Browser");
    gtk_window_set_default_size(GTK_WINDOW(window), 800, 600);
    g_signal_connect(window, "destroy", G_CALLBACK(destroyWindowCallback), NULL);

    WebKitWebView* webView = WEBKIT_WEB_VIEW(webkit_web_view_new());
    gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(webView));
    webkit_web_view_load_uri(webView, "https://example.com/oauth2/auth");

    gtk_widget_show_all(window);

    gtk_main();
    return 0;
}

This code creates a new GTK+ window with a WebKitGTK+ widget that loads the OAuth 2.0 authorization URL when the window is created.

3- Handle the OAuth 2.0 authentication flow
Once the user has entered their credentials, the OAuth 2.0 authorization server will redirect the browser to a specified URL, which includes an authorization code that can be used to obtain an access token. To handle this redirect, you'll need to add a signal handler to the WebKitGTK+ widget. You can do this using the following code:

static void loadChangedCallback(WebKitWebView* webView, WebKitLoadEvent loadEvent, gpointer data) {
    const gchar* uri = webkit_web_view_get_uri(webView);
    if (g_str_has_prefix(uri, "https://example.com/oauth2/callback")) {
        // Extract the authorization code from the URL and use it to obtain an access token
        // ...
        // Close the browser window
        gtk_widget_destroy(GTK_WIDGET(gtk_widget_get_toplevel(GTK_WIDGET(webView))));
    }
}

// In the main function:
g_signal_connect(webView, "load-changed", G_CALLBACK(loadChangedCallback), NULL);

This code adds a signal handler to the WebKitGTK+ widget's "load-changed" signal, which is emitted when the page load status changes. When the URL changes to the callback URL specified by the OAuth 2.0 authorization server, the code extracts the authorization code from the URL and uses it to obtain an access token. It then closes the browser window.

4- Build and run the application
Finally, you can build and run the application using the following commands:

gcc -o mini-browser main.c `pkg-config --cflags --libs gtk+-