Better use of posts cache

generators/index.py

@@ -27,6 +27,8 @@ class Index(DynastieGenerator):
                       'tags' : self.createTags,
                       'replace' : self.createReplace}
 
+        self.first_try = True
+
     def createReplace(self, posts, dom, root, replace_elem):
         if not replace_elem.hasAttribute('div_name'):
             self.addError('No attribute div_name for a replace tag')
@@ -106,6 +108,11 @@ class Index(DynastieGenerator):
 
     def createPost(self, posts, dom, post_elem, root):
         post = self.cur_post_obj
+
+        if post.id in self.hash_posts and not self.first_try:
+            node = self.hash_posts[post.id]
+            return node.cloneNode(0)
+
         values = {}
         values['author'] = post.author.first_name + ' ' + post.author.last_name
         values['date'] = post.creation_date.strftime('%A, %d %B %Y %H:%m')
@@ -118,15 +125,11 @@ class Index(DynastieGenerator):
 
         if not os.path.exists(filename):
             self.addError('File does not exists ' + filename)
-            return
+            return None
 
-        if self.hash_posts is None or not filename in self.hash_posts:
         f = open(filename, 'rb')
         post_content = f.read()
         f.close()
-            self.hash_posts[filename] = post_content
-        else:
-            post_content = self.hash_posts[filename]
 
         while True:
             start = post_content.find('<dyn:code')
@@ -158,6 +161,36 @@ class Index(DynastieGenerator):
             new_node = dom.createTextNode(post_content)
             content_node.appendChild(new_node)
         
+        if post.id in self.hash_posts:
+            import hashlib
+
+            # Here, we are in first_try, check that computed
+            # post has the same result than the one in cache
+            self.first_try = False
+
+            writer = StrictUTF8Writer()
+            node = self.hash_posts[post.id]
+            node.writexml(writer)
+            content1 = writer.getvalue().encode('utf-8')
+
+            writer = StrictUTF8Writer()
+            post_elem.writexml(writer)
+            content2 = writer.getvalue().encode('utf-8')
+            
+            md5_1 = hashlib.md5()
+            md5_1.update(content1)
+
+            md5_2 = hashlib.md5()
+            md5_2.update(content2)
+
+            # If not, clear cache
+            if md5_1.digest() != md5_2.digest():
+                self.hash_posts = {}
+
+        self.hash_posts[post.id] = post_elem.cloneNode(0)
+
+        return post_elem
+
     def createPosts(self, posts, dom, root, node):
         posts_elem = self.createElement(dom, 'posts')
         create_link = (node.getAttribute('link') == '1')
@@ -165,10 +198,11 @@ class Index(DynastieGenerator):
             post_elem = self.createElement(dom, 'post')
             if len(posts) > self.cur_post:
                 self.cur_post_obj = posts[self.cur_post]
-                self.createPost(posts, dom, post_elem, node)
+                post_elem = self.createPost(posts, dom, post_elem, node)
             else:
                 post_elem = self.createElement(dom, '', '<b>No posts yet</b>')
                 self.cur_post_obj = None
+            if not post_elem is None:
                 posts_elem.appendChild(post_elem)
 
             # Parse inner HTML