[evolution/wip/webkit-composer] Bug 710571: [webkit-composer] Composer should honor the "Loading Images" mail preference

[Tomas Popela <tpopela src gnome org>]

commit 9cee8576f22c165293ff741836b4022da22cc26a
Author: Tomas Popela <tpopela redhat com>
Date:   Fri Mar 14 13:12:51 2014 +0100

    Bug 710571: [webkit-composer] Composer should honor the "Loading Images" mail preference
    
    EEditorWidget is now redirecting http(s) requests to evo-http(s) thus
    when they are going through EHttpRequest they are respecting "Loading
    Images" mail preferences. Right now it lacks support for forcing the
    images load.

 e-util/e-editor-widget.c |  148 +++++++++++++++++++++++++++++++++++-----------
 1 files changed, 113 insertions(+), 35 deletions(-)
---
diff --git a/e-util/e-editor-widget.c b/e-util/e-editor-widget.c
index acedc95..eb0ea60 100644
--- a/e-util/e-editor-widget.c
+++ b/e-util/e-editor-widget.c
@@ -106,6 +106,8 @@ enum {
 
 static guint signals[LAST_SIGNAL] = { 0 };
 
+static CamelDataCache *emd_global_http_cache = NULL;
+
 G_DEFINE_TYPE_WITH_CODE (
        EEditorWidget,
        e_editor_widget,
@@ -469,37 +471,6 @@ body_input_event_cb (WebKitDOMElement *element,
 }
 
 static void
-change_images_http_src_to_evo_http (EEditorWidget *widget,
-                                    gboolean to_evo_http)
-{
-       WebKitDOMDocument *document;
-       WebKitDOMNodeList *list;
-       gint length, ii;
-
-       document = webkit_web_view_get_dom_document (WEBKIT_WEB_VIEW (widget));
-       list = webkit_dom_document_query_selector_all (
-               document, to_evo_http ? "img[src^=http]" : "img[src^=evo-http]", NULL);
-       length = webkit_dom_node_list_get_length (list);
-
-       for (ii = 0; ii < length; ii++) {
-               WebKitDOMHTMLImageElement *img;
-               gchar *src;
-
-               img = WEBKIT_DOM_HTML_IMAGE_ELEMENT (webkit_dom_node_list_item (list, ii));
-               src = webkit_dom_html_image_element_get_src (img);
-
-               if (to_evo_http) {
-                       gchar *new_src = g_strconcat ("evo-http", src + 4, NULL);
-                       webkit_dom_html_image_element_set_src (img, new_src);
-                       g_free (new_src);
-               } else
-                       webkit_dom_html_image_element_set_src (img, src + 4);
-
-               g_free (src);
-       }
-}
-
-static void
 set_base64_to_element_attribute (EEditorWidget *widget,
                                  WebKitDOMElement *element,
                                  const gchar *attribute)
@@ -695,10 +666,8 @@ editor_widget_load_status_changed (EEditorWidget *widget)
                FALSE,
                widget);
 
-       if (widget->priv->html_mode) {
-               change_images_http_src_to_evo_http (widget, TRUE);
+       if (widget->priv->html_mode)
                change_cid_images_src_to_base64 (widget);
-       }
 }
 
 /* Based on original use_pictograms() from GtkHTML */
@@ -1931,6 +1900,101 @@ editor_widget_paste_clipboard_quoted (EEditorWidget *widget)
                widget);
 }
 
+static gboolean
+editor_widget_image_exists_in_cache (const gchar *image_uri)
+{
+       gchar *filename;
+       gchar *hash;
+       gboolean exists = FALSE;
+
+       g_return_val_if_fail (emd_global_http_cache != NULL, FALSE);
+
+       hash = g_compute_checksum_for_string (G_CHECKSUM_MD5, image_uri, -1);
+       filename = camel_data_cache_get_filename (
+               emd_global_http_cache, "http", hash);
+
+       if (filename != NULL) {
+               exists = g_file_test (filename, G_FILE_TEST_EXISTS);
+               g_free (filename);
+       }
+
+       g_free (hash);
+
+       return exists;
+}
+
+static gchar *
+editor_widget_redirect_uri (EEditorWidget *widget,
+                            const gchar *uri)
+{
+       EImageLoadingPolicy image_policy;
+       GSettings *settings;
+       gboolean uri_is_http;
+
+       uri_is_http =
+               g_str_has_prefix (uri, "http:") ||
+               g_str_has_prefix (uri, "https:") ||
+               g_str_has_prefix (uri, "evo-http:") ||
+               g_str_has_prefix (uri, "evo-https:");
+
+       /* Redirect http(s) request to evo-http(s) protocol.
+        * See EMailRequest for further details about this. */
+       if (uri_is_http) {
+               gchar *new_uri;
+               SoupURI *soup_uri;
+               gboolean image_exists;
+
+               /* Check Evolution's cache */
+               image_exists = editor_widget_image_exists_in_cache (uri);
+
+               settings = g_settings_new ("org.gnome.evolution.mail");
+               image_policy = g_settings_get_enum (settings, "image-loading-policy");
+               g_object_unref (settings);
+               /* If the URI is not cached and we are not allowed to load it
+                * then redirect to invalid URI, so that webkit would display
+                * a native placeholder for it. */
+               if (!image_exists && (image_policy == E_IMAGE_LOADING_POLICY_NEVER)) {
+                       return g_strdup ("about:blank");
+               }
+
+               new_uri = g_strconcat ("evo-", uri, NULL);
+               soup_uri = soup_uri_new (new_uri);
+               g_free (new_uri);
+
+               new_uri = soup_uri_to_string (soup_uri, FALSE);
+
+               soup_uri_free (soup_uri);
+
+               return new_uri;
+       }
+
+       return g_strdup (uri);
+}
+
+static void
+editor_widget_resource_requested (WebKitWebView *web_view,
+                                  WebKitWebFrame *frame,
+                                  WebKitWebResource *resource,
+                                  WebKitNetworkRequest *request,
+                                  WebKitNetworkResponse *response,
+                                  gpointer user_data)
+{
+       const gchar *original_uri;
+
+       original_uri = webkit_network_request_get_uri (request);
+
+       if (original_uri != NULL) {
+               gchar *redirected_uri;
+
+               redirected_uri = editor_widget_redirect_uri (
+                       E_EDITOR_WIDGET (web_view), original_uri);
+
+               webkit_network_request_set_uri (request, redirected_uri);
+
+               g_free (redirected_uri);
+       }
+}
+
 static void
 e_editor_widget_class_init (EEditorWidgetClass *class)
 {
@@ -2695,6 +2759,7 @@ e_editor_widget_init (EEditorWidget *editor)
        ESpellChecker *checker;
        gchar **languages;
        gchar *comma_separated;
+       const gchar *user_cache_dir;
 
        editor->priv = E_EDITOR_WIDGET_GET_PRIVATE (editor);
 
@@ -2734,6 +2799,9 @@ e_editor_widget_init (EEditorWidget *editor)
                editor, "should-show-delete-interface-for-element",
                G_CALLBACK (editor_widget_should_show_delete_interface_for_element), NULL);
        g_signal_connect (
+               editor, "resource-request-starting",
+               G_CALLBACK (editor_widget_resource_requested), NULL);
+       g_signal_connect (
                editor, "notify::load-status",
                G_CALLBACK (editor_widget_load_status_changed), NULL);
 
@@ -2804,6 +2872,17 @@ e_editor_widget_init (EEditorWidget *editor)
                WEBKIT_WEB_VIEW (editor), "", "text/html", "UTF-8", "file://");
 
        editor_widget_set_links_active (editor, FALSE);
+
+       if (emd_global_http_cache == NULL) {
+               user_cache_dir = e_get_user_cache_dir ();
+               emd_global_http_cache = camel_data_cache_new (user_cache_dir, NULL);
+
+               /* cache expiry - 2 hour access, 1 day max */
+               camel_data_cache_set_expire_age (
+                       emd_global_http_cache, 24 * 60 * 60);
+               camel_data_cache_set_expire_access (
+                       emd_global_http_cache, 2 * 60 * 60);
+       }
 }
 
 /**
@@ -4994,7 +5073,6 @@ e_editor_widget_get_spell_checker (EEditorWidget *widget)
 gchar *
 e_editor_widget_get_text_html (EEditorWidget *widget)
 {
-       change_images_http_src_to_evo_http (widget, FALSE);
        return process_content_for_html (widget);
 }