WebKitWebExtension: WebKitGTK Reference Manual

WebKitWebExtension

WebKitWebExtension — Represents a WebExtension of the WebProcess

Functions

void	(*WebKitWebExtensionInitializeFunction) ()
void	(*WebKitWebExtensionInitializeWithUserDataFunction) ()
WebKitWebPage *	webkit_web_extension_get_page ()
void	webkit_web_extension_send_message_to_context ()
WebKitUserMessage *	webkit_web_extension_send_message_to_context_finish ()

Signals

void	page-created	Run Last
void	user-message-received	Run Last

Types and Values

struct

WebKitWebExtension

Object Hierarchy

    GObject
    ╰── WebKitWebExtension

Description

WebKitWebExtension is a loadable module for the WebProcess. It allows you to execute code in the WebProcess and being able to use the DOM API, to change any request or to inject custom JavaScript code, for example.

To create a WebKitWebExtension you should write a module with an initialization function that could be either webkit_web_extension_initialize() with prototype WebKitWebExtensionInitializeFunction or webkit_web_extension_initialize_with_user_data() with prototype WebKitWebExtensionInitializeWithUserDataFunction. This function has to be public and it has to use the G_MODULE_EXPORT macro. It is called when the web process is initialized.

static void
web_page_created_callback (WebKitWebExtension *extension,
                           WebKitWebPage      *web_page,
                           gpointer            user_data)
{
    g_print ("Page %d created for %s\n",
             webkit_web_page_get_id (web_page),
             webkit_web_page_get_uri (web_page));
}

G_MODULE_EXPORT void
webkit_web_extension_initialize (WebKitWebExtension *extension)
{
    g_signal_connect (extension, "page-created",
                      G_CALLBACK (web_page_created_callback),
                      NULL);
}

The previous piece of code shows a trivial example of an extension that notifies when a WebKitWebPage is created.

WebKit has to know where it can find the created WebKitWebExtension. To do so you should use the webkit_web_context_set_web_extensions_directory() function. The signal “initialize-web-extensions” is the recommended place to call it.

To provide the initialization data used by the webkit_web_extension_initialize_with_user_data() function, you have to call webkit_web_context_set_web_extensions_initialization_user_data() with the desired data as parameter. You can see an example of this in the following piece of code:

#define WEB_EXTENSIONS_DIRECTORY /* ... */

static void
initialize_web_extensions (WebKitWebContext *context,
                           gpointer          user_data)
{
  /* Web Extensions get a different ID for each Web Process */
  static guint32 unique_id = 0;

  webkit_web_context_set_web_extensions_directory (
     context, WEB_EXTENSIONS_DIRECTORY);
  webkit_web_context_set_web_extensions_initialization_user_data (
     context, g_variant_new_uint32 (unique_id++));
}

int main (int argc, char **argv)
{
  g_signal_connect (webkit_web_context_get_default (),
                   "initialize-web-extensions",
                    G_CALLBACK (initialize_web_extensions),
                    NULL);

  GtkWidget *view = webkit_web_view_new ();

  /* ... */
}

Functions

WebKitWebExtensionInitializeFunction ()

void
(*WebKitWebExtensionInitializeFunction)
                               (WebKitWebExtension *extension);

Type definition for a function that will be called to initialize the web extension when the web process starts.

Parameters

extension

a WebKitWebExtension

WebKitWebExtensionInitializeWithUserDataFunction ()

void
(*WebKitWebExtensionInitializeWithUserDataFunction)
                               (WebKitWebExtension *extension,
                                const GVariant *user_data);

Type definition for a function that will be called to initialize the web extensions when the web process starts, and which receives as additional argument the user data set with webkit_web_context_set_web_extensions_initialization_user_data().

Parameters

extension	a WebKitWebExtension
user_data	a GVariant

Since: 2.4

webkit_web_extension_get_page ()

WebKitWebPage *
webkit_web_extension_get_page (WebKitWebExtension *extension,
                               guint64 page_id);

Get the web page of the given page_id .

Parameters

extension	a WebKitWebExtension
page_id	the identifier of the WebKitWebPage to get

Returns

the WebKitWebPage for the given page_id , or NULL if the identifier doesn't correspond to an existing web page.

[transfer none]

webkit_web_extension_send_message_to_context ()

void
webkit_web_extension_send_message_to_context
                               (WebKitWebExtension *extension,
                                WebKitUserMessage *message,
                                GCancellable *cancellable,
                                GAsyncReadyCallback callback,
                                gpointer user_data);

Send message to the WebKitWebContext corresponding to extension . If message is floating, it's consumed.

If you don't expect any reply, or you simply want to ignore it, you can pass NULL as calback . When the operation is finished, callback will be called. You can then call webkit_web_extension_send_message_to_context_finish() to get the message reply.

Parameters

extension	a WebKitWebExtension
message	a WebKitUserMessage
cancellable	a GCancellable or `NULL` to ignore.	[nullable]
callback	(nullable): A GAsyncReadyCallback to call when the request is satisfied or `NULL`.	[scope async]
user_data	the data to pass to callback function.	[closure]

Since: 2.28

webkit_web_extension_send_message_to_context_finish ()

WebKitUserMessage *
webkit_web_extension_send_message_to_context_finish
                               (WebKitWebExtension *extension,
                                GAsyncResult *result,
                                GError **error);

Finish an asynchronous operation started with webkit_web_extension_send_message_to_context().

Parameters

extension	a WebKitWebExtension
result	a GAsyncResult
error	return location for error or `NULL` to ignor

Returns

a WebKitUserMessage with the reply or NULL in case of error.

[transfer full]

Since: 2.28

Types and Values

struct WebKitWebExtension

struct WebKitWebExtension;

Signal Details

The `“page-created”` signal

void
user_function (WebKitWebExtension *extension,
               WebKitWebPage      *web_page,
               gpointer            user_data)

This signal is emitted when a new WebKitWebPage is created in the Web Process.

Parameters

extension	the WebKitWebExtension on which the signal is emitted
web_page	the WebKitWebPage created
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“user-message-received”` signal

void
user_function (WebKitWebExtension *extension,
               WebKitUserMessage  *message,
               gpointer            user_data)

This signal is emitted when a WebKitUserMessage is received from the WebKitWebContext corresponding to extension . Messages sent by WebKitWebContext are always broadcasted to all WebKitWebExtensions and they can't be replied to. Calling webkit_user_message_send_reply() will do nothing.

Parameters

extension	the WebKitWebExtension on which the signal is emitted
message	the WebKitUserMessage received
user_data	user data set when the signal handler was connected.

Flags: Run Last

Since: 2.28