Don't allow to import the same post twice

boards/models/post/sync.py

@@ -102,24 +102,27 b' class SyncManager:'
                     print('Post with same ID already exists')
                 except GlobalId.DoesNotExist:
                     global_id = GlobalId.from_xml_element(tag_id)
-                    global_id.save()
+
+                    if not GlobalId.objects.global_id_exists(global_id):
+                        global_id.save()
 
-                    title = tag_content.find(TAG_TITLE).text
-                    text = tag_content.find(TAG_TEXT).text
-                    pub_time = tag_content.find(TAG_PUB_TIME).text
-                    # TODO Check that the replied posts are already present
-                    # before adding new ones
+                        title = tag_content.find(TAG_TITLE).text
+                        text = tag_content.find(TAG_TEXT).text
+                        pub_time = tag_content.find(TAG_PUB_TIME).text
+
+                        # TODO Check that the replied posts are already present
+                        # before adding new ones
 
-                    # TODO Pub time, thread, tags
+                        # TODO thread, tags
 
-                    # FIXME This prints are for testing purposes only, they must
-                    # be removed after sync is implemented
-                    print(title)
-                    print(text)
+                        # FIXME This prints are for testing purposes only, they must
+                        # be removed after sync is implemented
+                        print(title)
+                        print(text)
 
-                    post = Post.objects.import_post(title=title, text=text,
-                                                    pub_time=pub_time)
-                    post.global_id = global_id
+                        post = Post.objects.import_post(title=title, text=text,
+                                                        pub_time=pub_time)
+                        post.global_id = global_id
         else:
             # TODO Throw an exception?
             pass

boards/models/signature.py

@@ -37,6 +37,15 b' class GlobalIdManager(models.Manager):'
 
         return et.tostring(request, 'unicode')
 
+    def global_id_exists(self, global_id):
+        """
+        Checks if the same global id already exists in the system.
+        """
+
+        return self.filter(key=global_id.key,
+                           key_type=global_id.key_type,
+                           local_id=global_id.local_id).exists()
+
 
 class GlobalId(models.Model):
     class Meta:

boards/tests/test_sync.py

@@ -54,3 +54,7 b' class SyncTest(TestCase):'
         SyncManager().parse_response_get(response)
         self.assertEqual(1, Post.objects.count(),
                          'Post was not created from XML response.')
+
+        SyncManager().parse_response_get(response)
+        self.assertEqual(1, Post.objects.count(),
+                         'The same post was imported twice.')