Fixed #20945 -- Allowed cache tag to use a specific cache. (8688f03e) · Commits · Dom Sekotill / django

django/templatetags/cache.py

+31 −3

Original line number	Diff line number	Diff line
		from __future__ import unicode_literals

		from django.core.cache import get_cache, InvalidCacheBackendError
		from django.core.cache.utils import make_template_fragment_key
		from django.template import Library, Node, TemplateSyntaxError, VariableDoesNotExist
		from django.core.cache import cache

		register = Library()

		try:
		default_cache = get_cache('template_fragments')
		except InvalidCacheBackendError:
		from django.core.cache import cache as default_cache


		class CacheNode(Node):
		def __init__(self, nodelist, expire_time_var, fragment_name, vary_on):
		def __init__(self, nodelist, expire_time_var, fragment_name, vary_on, cache_name):
		self.nodelist = nodelist
		self.expire_time_var = expire_time_var
		self.fragment_name = fragment_name
		self.vary_on = vary_on
		self.cache_name = cache_name

		def render(self, context):
		try:
		@@ -22,6 +29,17 @@ class CacheNode(Node):
		expire_time = int(expire_time)
		except (ValueError, TypeError):
		raise TemplateSyntaxError('"cache" tag got a non-integer timeout value: %r' % expire_time)
		if self.cache_name:
		try:
		cache_name = self.cache_name.resolve(context)
		except VariableDoesNotExist:
		raise TemplateSyntaxError('"cache" tag got an unknown variable: %r' % self.cache_name.var)
		try:
		cache = get_cache(cache_name)
		except InvalidCacheBackendError:
		raise TemplateSyntaxError('Invalid cache name specified for cache tag: %r' % cache_name)
		else:
		cache = default_cache
		vary_on = [var.resolve(context) for var in self.vary_on]
		cache_key = make_template_fragment_key(self.fragment_name, vary_on)
		value = cache.get(cache_key)
		@@ -50,6 +68,9 @@ def do_cache(parser, token):
		.. some expensive processing ..
		{% endcache %}

		Optionally the cache to use may be specified thus::

		{% cache .... using="cachename" %}
		Each unique set of arguments will result in a unique cache entry.
		"""
		nodelist = parser.parse(('endcache',))
		@@ -57,7 +78,14 @@ def do_cache(parser, token):
		tokens = token.split_contents()
		if len(tokens) < 3:
		raise TemplateSyntaxError("'%r' tag requires at least 2 arguments." % tokens[0])
		if len(tokens) > 3 and tokens[-1].startswith('using='):
		cache_name = parser.compile_filter(tokens[-1][len('using='):])
		tokens = tokens[:-1]
		else:
		cache_name = None
		return CacheNode(nodelist,
		parser.compile_filter(tokens[1]),
		tokens[2], # fragment_name can't be a variable.
		[parser.compile_filter(t) for t in tokens[3:]])
		[parser.compile_filter(t) for t in tokens[3:]],
		cache_name,
		)

docs/releases/1.7.txt

+5 −0

Original line number	Diff line number	Diff line
		@@ -396,6 +396,11 @@ Templates
		<naive_vs_aware_datetimes>` ``datetime`` instances performing the expected
		rendering.

		* The :ttag:`cache` tag will now try to use the cache called
		"template_fragments" if it exists and fall back to using the default cache
		otherwise. It also now accepts an optional ``using`` keyword argument to
		control which cache it uses.

		Requests
		^^^^^^^^

docs/topics/cache.txt

+13 −0

Original line number	Diff line number	Diff line
		@@ -652,6 +652,19 @@ equivalent:
		This feature is useful in avoiding repetition in templates. You can set the
		timeout in a variable, in one place, and just reuse that value.

		.. versionadded:: 1.7

		By default, the cache tag will try to use the cache called
		"template_fragments". If no such cache exists, it will fall back to using
		the default cache. You may select an alternate cache backend to use with
		the ``using`` keyword argument, which must be the last argument to the tag.

		.. code-block:: html+django

		{% cache 300 local-thing ... using="localcache" %}

		It is considered an error to specify a cache name that is not configured.

		.. function:: django.core.cache.utils.make_template_fragment_key(fragment_name, vary_on=None)

		If you want to obtain the cache key used for a cached fragment, you can use

tests/template_tests/tests.py

+36 −1

Original line number	Diff line number	Diff line
		@@ -478,6 +478,42 @@ class TemplateRegressionTests(TestCase):
		cachenode = t.nodelist[1]
		self.assertEqual(cachenode.fragment_name, 'regression_20130')

		@override_settings(CACHES={
		'default': {
		'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
		'LOCATION': 'default',
		},
		'template_fragments': {
		'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
		'LOCATION': 'fragments',
		},
		})
		def test_cache_fragment_cache(self):
		"""
		When a cache called "template_fragments" is present, the cache tag
		will use it in preference to 'default'
		"""
		t1 = Template('{% load cache %}{% cache 1 fragment %}foo{% endcache %}')
		t2 = Template('{% load cache %}{% cache 1 fragment using="default" %}bar{% endcache %}')

		ctx = Context()
		o1 = t1.render(ctx)
		o2 = t2.render(ctx)

		self.assertEqual(o1, 'foo')
		self.assertNotEqual(o1, o2)

		def test_cache_missing_backend(self):
		"""
		When a cache that doesn't exist is specified, the cache tag will
		raise a TemplateSyntaxError
		'"""
		t = Template('{% load cache %}{% cache 1 backend using="unknown" %}bar{% endcache %}')

		ctx = Context()
		with self.assertRaises(TemplateSyntaxError):
		t.render(ctx)

		def test_ifchanged_render_once(self):
		""" Test for ticket #19890. The content of ifchanged template tag was
		rendered twice."""
		@@ -1736,7 +1772,6 @@ class TemplateTests(TransRealMixin, TestCase):
		# Test whitespace in filter arguments
		'cache18': ('{% load cache custom %}{% cache 2\|noop:"x y" cache18 %}cache18{% endcache %}', {}, 'cache18'),


		### AUTOESCAPE TAG ##############################################
		'autoescape-tag01': ("{% autoescape off %}hello{% endautoescape %}", {}, "hello"),
		'autoescape-tag02': ("{% autoescape off %}{{ first }}{% endautoescape %}", {"first": "<b>hello</b>"}, "<b>hello</b>"),