Question

我一直试图用python编写flatpak应用程序，该应用程序使用freedesktop门户获取屏幕截图。我正在改编用c语言编写的Gimp的freedesktop屏幕截图插件，在获取并与我的应用程序共享后访问屏幕截图时遇到了麻烦。我得到一个格式为'/ org / freedesktop / portal / desktop / request / 1_326 / t'的uri，freedesktop门户文档指出该uri指向安装在run / user / $ UID / doc /上的融合文件系统我可以确认屏幕截图已保存在此处。但是，我似乎无法为他们获取有用的标识符，这样我就可以通过我的应用将其附加到电子邮件中。

我已经在freedesktop Documents门户中尝试了所有方法，但在那里没有成功。调用返回uri并将其保存在opath变量中的uri的dbus代理后，Gimp实现会在此处设置另一个dbus代理，然后将该代理连接到回调函数：我在其中复制这些摘要的完整文件位于此处<{ {3}}>

if (opath)
    {
      GDBusProxy *proxy2 = NULL;

      proxy2 = g_dbus_proxy_new_for_bus_sync (G_BUS_TYPE_SESSION,
                                              G_DBUS_PROXY_FLAGS_DO_NOT_AUTO_START,
                                              NULL,
                                              "org.freedesktop.portal.Desktop",
                                              opath,
                                              "org.freedesktop.portal.Request",
                                              NULL, NULL);
      *image_ID = 0;
      g_signal_connect (proxy2, "g-signal",
                        G_CALLBACK (screenshot_freedesktop_dbus_signal),
                        image_ID);

      gtk_main ();
      g_object_unref (proxy2);
      g_free (opath);

并且screenshot_freedesktop_dbus_signal函数如下所示：

static void
screenshot_freedesktop_dbus_signal (GDBusProxy *proxy,
                                    gchar      *sender_name,
                                    gchar      *signal_name,
                                    GVariant   *parameters,
                                    gint32     *image_ID)
{
  if (g_strcmp0 (signal_name, "Response") == 0)
    {
      GVariant *results;
      guint32   response;

      g_variant_get (parameters, "(u@a{sv})",
                     &response,
                     &results);

      /* Possible values:
       * 0: Success, the request is carried out
       * 1: The user cancelled the interaction
       * 2: The user interaction was ended in some other way
       * Cf. https://github.com/flatpak/xdg-desktop-portal/blob/master/data/org.freedesktop.portal.Request.xml
       */
      if (response == 0)
        {
          gchar *uri;

          if (g_variant_lookup (results, "uri", "s", &uri))
            {
              GFile *file = g_file_new_for_uri (uri);
              gchar *path = g_file_get_path (file);

              *image_ID = gimp_file_load (GIMP_RUN_NONINTERACTIVE,
                                          path, path);
              gimp_image_set_filename (*image_ID, "screenshot.png");

              /* Delete the actual file. */
              g_file_delete (file, NULL, NULL);

              g_object_unref (file);
              g_free (path);
              g_free (uri);
            }
        }

      g_variant_unref (results);
      gtk_main_quit ();
    }
}

直到回调函数，我的代码都以相同的方式工作。我找不到g_signal_connect函数的pythonic等效项。我已经尝试将回调添加到新代理的初始化中，例如

proxy2 = Gio.DBusProxy.new_for_bus(Gio.BusType.SESSION,
                                            Gio.DBusProxyFlags.NONE,
                                            None,
                                            "org.freedesktop.portal.Desktop",
                                            returned_uri[0],
                                            "org.freedesktop.portal.Request",
                                            None,
                                            G_CALLBACK(self.receive_screenshot_signal),
                                            None)

但是我的receive_screenshot_signal函数没有传递任何值，传递的任务对象说它们还没有完成。

我不确定从这里要去哪里，所以请提供任何有关如何更有效地使用dbusproxy库和/或freedesktop门户的建议或见解。谢谢！

Answer 1

我通过在请求句柄的路径上订阅来自总线的信号来解决了这个问题。

        args = GLib.Variant('(sa{sv})', (filename, {}))
        result = self.proxy.call_sync('Screenshot',
                                      args,
                                      Gio.DBusCallFlags.NONE,
                                      -1,
                                      None)
        request_handle = result.unpack()[0]
        self.bus.signal_subscribe("org.freedesktop.portal.Desktop",
                                  "org.freedesktop.portal.Request",
                                  "Response",
                                  request_handle,
                                  None,
                                  Gio.DBusSignalFlags.NO_MATCH_RULE,
                                  self.receive_screenshot_signal)

我在Gio.bus.signal_subscribe上找不到任何特定的文档，但这是回调函数处理返回的方式：

  def receive_screenshot_signal(self,
                                  connection,
                                  sender,
                                  path,
                                  interface,
                                  signal,
                                  params):
        if not isinstance(params, GLib.Variant):
            print("It's not a variant")
            return
        response_code, results = params.unpack()
        # Response code 0 signifies success
        if response_code != 0 or 'uri' not in results:
            print("Error taking screenshot")
            return
        parsed_uri = urlparse(results['uri'])
        assert parsed_uri.scheme == "file"
        self.screenshot = unquote(parsed_uri.path)

使用freedesktop门户使用Python截屏

1 个答案: