def do_include_maybe(parser, token):
"""
A template helper to optionally include a template partial, and catch the
exception if it fails.
Source: http://stackoverflow.com/a/18951166/15690
"""
bits = token.split_contents()
if len(bits) < 2:
raise template.TemplateSyntaxError(
"%r tag takes at least one argument: "
"the name of the template to be included." % bits[0])
try:
silent_node = do_include(parser, token)
except template.TemplateDoesNotExist:
# Django < 1.7
return CommentNode()
_orig_render = silent_node.render
def wrapped_render(*args, **kwargs):
try:
return _orig_render(*args, **kwargs)
except template.TemplateDoesNotExist:
return CommentNode()
silent_node.render = wrapped_render
return silent_node
def if_has_tag(parser, token):
"""
The logic for both ``{% if_has_tag %}`` and ``{% if not_has_tag %}``.
Checks if all the given tags exist (or not exist if ``negate`` is ``True``)
and then only parses the branch that will not error due to non-existing
tags.
This means that the following is essentially the same as a
``{% comment %}`` tag::
{% if_has_tag non_existing_tag %}
{% non_existing_tag %}
{% endif_has_tag %}
Another example is checking a built-in tag. This will alway render the
current year and never FAIL::
{% if_has_tag now %}
{% now \"Y\" %}
{% else %}
FAIL
{% endif_has_tag %}
"""
bits = list(token.split_contents())
if len(bits) < 2:
raise TemplateSyntaxError("%r takes at least one arguments" % bits[0])
end_tag = 'end%s' % bits[0]
has_tag = all([tag in parser.tags for tag in bits[1:]])
nodelist_true = nodelist_false = CommentNode()
if has_tag:
nodelist_true = parser.parse(('else', end_tag))
token = parser.next_token()
if token.contents == 'else':
parser.skip_past(end_tag)
else:
while parser.tokens:
token = parser.next_token()
if token.token_type == TOKEN_BLOCK and token.contents == end_tag:
try:
return IfNode([(Literal(has_tag), nodelist_true),
(None, nodelist_false)])
except TypeError: # < 1.4
return IfNode(Literal(has_tag), nodelist_true,
nodelist_false)
elif token.token_type == TOKEN_BLOCK and token.contents == 'else':
break
nodelist_false = parser.parse((end_tag, ))
token = parser.next_token()
try:
return IfNode([(Literal(has_tag), nodelist_true),
(None, nodelist_false)])
except TypeError: # < 1.4
return IfNode(Literal(has_tag), nodelist_true, nodelist_false)
def wrapped_render(*args, **kwargs):
try:
return _orig_render(*args, **kwargs)
except template.TemplateDoesNotExist:
return CommentNode()
def do_include_maybe(parser, token):
try:
return do_include(parser, token)
except template.TemplateDoesNotExist:
return CommentNode()