Moved catalogue, chunks, compress, newtagging and pagination applications to apps...

[wolnelektury.git] / apps / chunks / templatetags / chunks.py

diff --git a/apps/chunks/templatetags/chunks.py b/apps/chunks/templatetags/chunks.py
new file mode 100644 (file)
index 0000000..f79d495
--- /dev/null
+++ b/apps/chunks/templatetags/chunks.py
@@ -0,0 +1,45 @@
+from django import template
+from django.db import models
+from django.core.cache import cache
+
+register = template.Library()
+
+Chunk = models.get_model('chunks', 'chunk')
+CACHE_PREFIX = "chunk_"
+
+def do_get_chunk(parser, token):
+    # split_contents() knows not to split quoted strings.
+    tokens = token.split_contents()
+    if len(tokens) < 2 or len(tokens) > 3:
+        raise template.TemplateSyntaxError, "%r tag should have either 2 or 3 arguments" % (tokens[0],)
+    if len(tokens) == 2:
+        tag_name, key = tokens
+        cache_time = 0
+    if len(tokens) == 3:
+        tag_name, key, cache_time = tokens
+    # Check to see if the key is properly double/single quoted
+    if not (key[0] == key[-1] and key[0] in ('"', "'")):
+        raise template.TemplateSyntaxError, "%r tag's argument should be in quotes" % tag_name
+    # Send key without quotes and caching time
+    return ChunkNode(key[1:-1], cache_time)
+
+class ChunkNode(template.Node):
+    def __init__(self, key, cache_time=0):
+       self.key = key
+       self.cache_time = cache_time
+    
+    def render(self, context):
+        try:
+            cache_key = CACHE_PREFIX + self.key
+            c = cache.get(cache_key)
+            if c is None:
+                c = Chunk.objects.get(key=self.key)
+                cache.set(cache_key, c, int(self.cache_time))
+            content = c.content
+        except Chunk.DoesNotExist:
+            n = Chunk(key=self.key)
+            n.save()
+            return ''
+        return content
+        
+register.tag('chunk', do_get_chunk)