[webkit-help] [WebKitGTK] Issue with web process extensions

[Alain Bareille]

Hello,

I'm on Ubuntu Linux 24.04 Noble Numbat, with the following packages installed:

- libwebkitgtk-6.0-4 2.46.1-0ubuntu0.24.04.1 amd64
- libwebkitgtk-6.0-dev 2.46.1-0ubuntu0.24.04.1 amd64

I'm trying to enable web process extensions in a mostly C++ written application. I've spent some hours going through the documentation and searching over the internet for a solution, but I don't find any issue with my code (although, I may be overlooking a small detail).

Below, there's a minimal reproducing sample. Is anything wrong with my code? If not, how should I proceed to figure out where the issue is?

Based on the code below, here's a few things I've tried already:
- moving the libextension.so file to another path than ./ or specifying an absolute path to webkit_web_context_set_web_process_extensions_directory.
- writing a tool using GModule that loads libextension.so and checks webkit_web_process_extension_initialize symbol can be reached with g_module_symbol().
- running inside gdb and placing a breakpoint on WebKit::WebProcessExtensionManager::initialize from Source/WebKit/WebProcess/InjectedBundle/API/glib/WebProcessExtensionManager.cpp. That breakpoint is never triggered.

=========== CMakeLists.txt

cmake_minimum_required(VERSION 3.28.3)

project(
        IssueSample
        VERSION 1.0.0
        LANGUAGES C CXX)

find_package(PkgConfig REQUIRED)
pkg_check_modules(WebkitGTK REQUIRED IMPORTED_TARGET glib-2.0>=2.74 gtk4>=4.14.2 webkitgtk-6.0)

add_executable(browser main.cpp)
target_link_libraries(browser PkgConfig::WebkitGTK)

add_library(extension MODULE extension.c)
target_link_libraries(extension PkgConfig::WebkitGTK)

=========== extension.c

#include <gtk/gtk.h>
#include <webkit/webkit-web-process-extension.h>

#ifdef __cplusplus
#error Must be compiled as C
#endif

static void web_page_created_cb(WebKitWebProcessExtension *extension, WebKitWebPage *web_page, gpointer /* unused */)
{
        g_print("Page %ld created for %s with table\n", webkit_web_page_get_id(web_page),
                webkit_web_page_get_uri(web_page));
}

G_MODULE_EXPORT void webkit_web_process_extension_initialize(WebKitWebProcessExtension *extension)
{
        g_print("Inside webkit_web_extension_initialize %p\n", extension);
        g_signal_connect(extension, "page-created", G_CALLBACK(web_page_created_cb), NULL);
}

=========== main.cpp

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

void initialize_web_extensions(WebKitWebContext *context, gpointer /*unused*/)
{
        webkit_web_context_set_web_process_extensions_directory(context, "./");
}

int main()
{
        gtk_init();

        g_signal_connect(webkit_web_context_get_default(), "initialize-web-process-extensions",
                G_CALLBACK(initialize_web_extensions), NULL);

        GtkWindow * window = GTK_WINDOW(gtk_window_new());

        WebKitWebView * web_view = WEBKIT_WEB_VIEW(webkit_web_view_new());

        webkit_web_view_load_uri(web_view, "https://linux.org/");

        gtk_window_set_child(window, GTK_WIDGET(web_view));

        gtk_window_present(window);

        while (g_list_model_get_n_items(gtk_window_get_toplevels()) > 0)
        {
                g_main_context_iteration(NULL, TRUE);
        }
}

===========




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