[url_launcher_linux] Support file scheme

Author: jokerttu

packages/url_launcher/url_launcher_linux/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.0.3
+
+* Fix canLaunch detection for `file` scheme
+
 ## 2.0.2
 
 * Replaced reference to `shared_preferences` plugin with the `url_launcher` in the README.

packages/url_launcher/url_launcher_linux/linux/test/url_launcher_linux_test.cc

@@ -39,6 +39,31 @@ TEST(UrlLauncherPlugin, CanLaunchFailureUnhandled) {
                              expected));
 }
 
+TEST(UrlLauncherPlugin, CanLaunchFileSuccess) {
+  g_autoptr(FlValue) args = fl_value_new_map();
+  fl_value_set_string_take(args, "url", fl_value_new_string("file:/"));
+  FlMethodResponse* response = can_launch(nullptr, args);
+  ASSERT_NE(response, nullptr);
+  ASSERT_TRUE(FL_IS_METHOD_SUCCESS_RESPONSE(response));
+  g_autoptr(FlValue) expected = fl_value_new_bool(true);
+  EXPECT_TRUE(fl_value_equal(fl_method_success_response_get_result(
+                                 FL_METHOD_SUCCESS_RESPONSE(response)),
+                             expected));
+}
+
+TEST(UrlLauncherPlugin, CanLaunchFailureInvalidFileExtension) {
+  g_autoptr(FlValue) args = fl_value_new_map();
+  fl_value_set_string_take(
+      args, "url", fl_value_new_string("file:///madeup.madeupextension"));
+  FlMethodResponse* response = can_launch(nullptr, args);
+  ASSERT_NE(response, nullptr);
+  ASSERT_TRUE(FL_IS_METHOD_SUCCESS_RESPONSE(response));
+  g_autoptr(FlValue) expected = fl_value_new_bool(false);
+  EXPECT_TRUE(fl_value_equal(fl_method_success_response_get_result(
+                                 FL_METHOD_SUCCESS_RESPONSE(response)),
+                             expected));
+}
+
 // For consistency with the established mobile implementations,
 // an invalid URL should return false, not an error.
 TEST(UrlLauncherPlugin, CanLaunchFailureInvalidUrl) {

packages/url_launcher/url_launcher_linux/linux/url_launcher_plugin.cc

@@ -45,6 +45,21 @@ static gchar* get_url(FlValue* args, GError** error) {
   return g_strdup(fl_value_get_string(url_value));
 }
 
+// Called to check if URL with file scheme can be launched.
+static gboolean can_launch_url_with_file_scheme(FlUrlLauncherPlugin* self,
+                                                const gchar* url) {
+  g_autoptr(GError) error = nullptr;
+  GFile* file = g_file_new_for_uri(url);
+  GAppInfo* app_info = g_file_query_default_handler(file, NULL, &error);
+  g_object_unref(file);
+  gboolean is_launchable = FALSE;
+  if (app_info != nullptr) {
+    is_launchable = TRUE;
+    g_object_unref(app_info);
+  }
+  return is_launchable;
+}
+
 // Called to check if a URL can be launched.
 FlMethodResponse* can_launch(FlUrlLauncherPlugin* self, FlValue* args) {
   g_autoptr(GError) error = nullptr;
@@ -60,6 +75,10 @@ FlMethodResponse* can_launch(FlUrlLauncherPlugin* self, FlValue* args) {
     g_autoptr(GAppInfo) app_info =
         g_app_info_get_default_for_uri_scheme(scheme);
     is_launchable = app_info != nullptr;
+
+    if (!is_launchable) {
+      is_launchable = can_launch_url_with_file_scheme(self, url);
+    }
   }
 
   g_autoptr(FlValue) result = fl_value_new_bool(is_launchable);

packages/url_launcher/url_launcher_linux/pubspec.yaml

@@ -2,7 +2,7 @@ name: url_launcher_linux
 description: Linux implementation of the url_launcher plugin.
 repository: https://github.com/flutter/plugins/tree/master/packages/url_launcher/url_launcher_linux
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+url_launcher%22
-version: 2.0.2
+version: 2.0.3
 
 environment:
   sdk: ">=2.12.0 <3.0.0"