Don't allow to import the same post twice

boards/models/post/sync.py

@@ -1,125 +1,128 b''
 import xml.etree.ElementTree as et
 from django.db import transaction
 from boards.models import KeyPair, GlobalId, Signature, Post
 
 ENCODING_UNICODE = 'unicode'
 
 TAG_MODEL = 'model'
 TAG_REQUEST = 'request'
 TAG_RESPONSE = 'response'
 TAG_ID = 'id'
 TAG_STATUS = 'status'
 TAG_MODELS = 'models'
 TAG_TITLE = 'title'
 TAG_TEXT = 'text'
 TAG_THREAD = 'thread'
 TAG_PUB_TIME = 'pub-time'
 TAG_SIGNATURES = 'signatures'
 TAG_SIGNATURE = 'signature'
 TAG_CONTENT = 'content'
 TAG_ATTACHMENTS = 'attachments'
 TAG_ATTACHMENT = 'attachment'
 
 TYPE_GET = 'get'
 
 ATTR_VERSION = 'version'
 ATTR_TYPE = 'type'
 ATTR_NAME = 'name'
 ATTR_VALUE = 'value'
 ATTR_MIMETYPE = 'mimetype'
 
 STATUS_SUCCESS = 'success'
 
 
 # TODO Make this fully static
 class SyncManager:
     def generate_response_get(self, model_list: list):
         response = et.Element(TAG_RESPONSE)
 
         status = et.SubElement(response, TAG_STATUS)
         status.text = STATUS_SUCCESS
 
         models = et.SubElement(response, TAG_MODELS)
 
         for post in model_list:
             model = et.SubElement(models, TAG_MODEL)
             model.set(ATTR_NAME, 'post')
 
             content_tag = et.SubElement(model, TAG_CONTENT)
 
             tag_id = et.SubElement(content_tag, TAG_ID)
             post.global_id.to_xml_element(tag_id)
 
             title = et.SubElement(content_tag, TAG_TITLE)
             title.text = post.title
 
             text = et.SubElement(content_tag, TAG_TEXT)
             text.text = post.get_sync_text()
 
             if not post.is_opening():
                 thread = et.SubElement(content_tag, TAG_THREAD)
                 thread_id = et.SubElement(thread, TAG_ID)
                 post.get_thread().get_opening_post().global_id.to_xml_element(thread_id)
             else:
                 # TODO Output tags here
                 pass
 
             pub_time = et.SubElement(content_tag, TAG_PUB_TIME)
             pub_time.text = str(post.get_pub_time_str())
 
             signatures_tag = et.SubElement(model, TAG_SIGNATURES)
             post_signatures = post.signature.all()
             if post_signatures:
                 signatures = post.signatures
             else:
                 # TODO Maybe the signature can be computed only once after
                 # the post is added? Need to add some on_save signal queue
                 # and add this there.
                 key = KeyPair.objects.get(public_key=post.global_id.key)
                 signatures = [Signature(
                     key_type=key.key_type,
                     key=key.public_key,
                     signature=key.sign(et.tostring(model, ENCODING_UNICODE)),
                 )]
             for signature in signatures:
                 signature_tag = et.SubElement(signatures_tag, TAG_SIGNATURE)
                 signature_tag.set(ATTR_TYPE, signature.key_type)
                 signature_tag.set(ATTR_VALUE, signature.signature)
 
         return et.tostring(response, ENCODING_UNICODE)
 
     @transaction.atomic
     def parse_response_get(self, response_xml):
         tag_root = et.fromstring(response_xml)
         tag_status = tag_root.find(TAG_STATUS)
         if STATUS_SUCCESS == tag_status.text:
             tag_models = tag_root.find(TAG_MODELS)
             for tag_model in tag_models:
                 tag_content = tag_model.find(TAG_CONTENT)
                 tag_id = tag_content.find(TAG_ID)
                 try:
                     GlobalId.from_xml_element(tag_id, existing=True)
                     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

@@ -1,108 +1,117 b''
 import xml.etree.ElementTree as et
 from django.db import models
 
 
 TAG_MODEL = 'model'
 TAG_REQUEST = 'request'
 TAG_ID = 'id'
 
 TYPE_GET = 'get'
 
 ATTR_VERSION = 'version'
 ATTR_TYPE = 'type'
 ATTR_NAME = 'name'
 
 ATTR_KEY = 'key'
 ATTR_KEY_TYPE = 'type'
 ATTR_LOCAL_ID = 'local-id'
 
 
 class GlobalIdManager(models.Manager):
     def generate_request_get(self, global_id_list: list):
         """
         Form a get request from a list of ModelId objects.
         """
 
         request = et.Element(TAG_REQUEST)
         request.set(ATTR_TYPE, TYPE_GET)
         request.set(ATTR_VERSION, '1.0')
 
         model = et.SubElement(request, TAG_MODEL)
         model.set(ATTR_VERSION, '1.0')
         model.set(ATTR_NAME, 'post')
 
         for global_id in global_id_list:
             tag_id = et.SubElement(model, TAG_ID)
             global_id.to_xml_element(tag_id)
 
         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:
         app_label = 'boards'
 
     objects = GlobalIdManager()
 
     def __init__(self, *args, **kwargs):
         models.Model.__init__(self, *args, **kwargs)
 
         if 'key' in kwargs and 'key_type' in kwargs and 'local_id' in kwargs:
             self.key = kwargs['key']
             self.key_type = kwargs['key_type']
             self.local_id = kwargs['local_id']
 
     key = models.TextField()
     key_type = models.TextField()
     local_id = models.IntegerField()
 
     def __str__(self):
         return '%s::%s::%d' % (self.key_type, self.key, self.local_id)
 
     def to_xml_element(self, element: et.Element):
         """
         Exports global id to an XML element.
         """
 
         element.set(ATTR_KEY, self.key)
         element.set(ATTR_KEY_TYPE, self.key_type)
         element.set(ATTR_LOCAL_ID, str(self.local_id))
 
     @staticmethod
     def from_xml_element(element: et.Element, existing=False):
         """
         Parses XML id tag and gets global id from it.
 
         Arguments:
         element -- the XML 'id' element
         existing -- if this is False, a new instance of GlobalId will be
          created. Otherwise, we will search for an existing GlobalId instance
          and throw DoesNotExist if there isn't one.
         """
 
         if existing:
             return GlobalId.objects.get(key=element.get(ATTR_KEY),
                                         key_type=element.get(ATTR_KEY_TYPE),
                                         local_id=int(element.get(
                                             ATTR_LOCAL_ID)))
         else:
             return GlobalId(key=element.get(ATTR_KEY),
                             key_type=element.get(ATTR_KEY_TYPE),
                             local_id=int(element.get(ATTR_LOCAL_ID)))
 
 
 class Signature(models.Model):
     class Meta:
         app_label = 'boards'
 
     def __init__(self, *args, **kwargs):
         models.Model.__init__(self, *args, **kwargs)
 
         if 'key' in kwargs and 'key_type' in kwargs and 'signature' in kwargs:
             self.key_type = kwargs['key_type']
             self.key = kwargs['key']
             self.signature = kwargs['signature']
 
     key_type = models.TextField()
     key = models.TextField()
     signature = models.TextField()

boards/tests/test_sync.py

@@ -1,56 +1,60 b''
 from boards.models import KeyPair, Post
 from boards.models.post.sync import SyncManager
 from boards.tests.mocks import MockRequest
 from boards.views.sync import response_get
 
 __author__ = 'neko259'
 
 
 from django.test import TestCase
 
 
 class SyncTest(TestCase):
     def test_get(self):
         """
         Forms a GET request of a post and checks the response.
         """
 
         KeyPair.objects.generate_key(primary=True)
         post = Post.objects.create_post(title='test_title', text='test_text')
 
         request = MockRequest()
         request.body = (
             '<request type="get" version="1.0">'
             '<model name="post" version="1.0">'
             '<id key="%s" local-id="%d" type="%s" />'
             '</model>'
             '</request>' % (post.global_id.key,
                             post.id,
                             post.global_id.key_type)
         )
 
         response = response_get(request).content.decode()
         self.assertTrue(
             '<status>success</status>'
             '<models>'
             '<model name="post">'
             '<content>'
             '<id key="%s" local-id="%d" type="%s" />'
             '<title>%s</title>'
             '<text>%s</text>'
             '<pub-time>%s</pub-time>'
             '</content>' % (
                 post.global_id.key,
                 post.id,
                 post.global_id.key_type,
                 post.title,
                 post.get_raw_text(),
                 post.get_pub_time_str(),
             ) in response_get(request).content.decode(),
             'Wrong response generated for the GET request.')
 
         post.delete()
 
         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.')