def autoescape(parser, token):
"""
Force autoescape behaviour for this block.
"""
args = token.contents.split()
if len(args) != 2:
raise TemplateSyntaxError("'autoescape' tag requires exactly one argument.")
arg = args[1]
if arg not in (u'on', u'off'):
raise TemplateSyntaxError("'autoescape' argument should be 'on' or 'off'")
nodelist = parser.parse(('endautoescape',))
parser.delete_first_token()
return AutoEscapeControlNode((arg == 'on'), nodelist)
def do_include(parser, token):
"""
Loads a template and renders it with the current context. You can pass
additional context using keyword arguments.
Example::
{% include "foo/some_include" %}
{% include "foo/some_include" with bar="BAZZ!" baz="BING!" %}
Use the ``only`` argument to exclude the current context when rendering
the included template::
{% include "foo/some_include" only %}
{% include "foo/some_include" with bar="1" only %}
"""
bits = token.split_contents()
if len(bits) < 2:
raise TemplateSyntaxError(
"%r tag takes at least one argument: the name of the template to be included."
% bits[0])
options = {}
remaining_bits = bits[2:]
while remaining_bits:
option = remaining_bits.pop(0)
if option in options:
raise TemplateSyntaxError('The %r option was specified more '
'than once.' % option)
if option == 'with':
value = token_kwargs(remaining_bits, parser, support_legacy=False)
if not value:
raise TemplateSyntaxError('"with" in %r tag needs at least '
'one keyword argument.' % bits[0])
elif option == 'only':
value = True
else:
raise TemplateSyntaxError('Unknown argument for %r tag: %r.' %
(bits[0], option))
options[option] = value
isolated_context = options.get('only', False)
namemap = options.get('with', {})
path = bits[1]
if path[0] in ('"', "'") and path[-1] == path[0]:
return ConstantIncludeNode(path[1:-1],
extra_context=namemap,
isolated_context=isolated_context)
return IncludeNode(parser.compile_filter(bits[1]),
extra_context=namemap,
isolated_context=isolated_context)
def do_block(parser, token):
"""
Define a block that can be overridden by child templates.
"""
bits = token.contents.split()
if len(bits) != 2:
raise TemplateSyntaxError("'%s' tag takes only one argument" % bits[0])
block_name = bits[1]
# Keep track of the names of BlockNodes found in this template, so we can
# check for duplication.
try:
if block_name in parser.__loaded_blocks:
raise TemplateSyntaxError(
"'%s' tag with name '%s' appears more than once" %
(bits[0], block_name))
parser.__loaded_blocks.append(block_name)
except AttributeError: # parser.__loaded_blocks isn't a list yet
parser.__loaded_blocks = [block_name]
nodelist = parser.parse(('endblock', 'endblock %s' % block_name))
parser.delete_first_token()
return BlockNode(block_name, nodelist)
def get_parent(self, context):
if self.parent_name_expr:
self.parent_name = self.parent_name_expr.resolve(context)
parent = self.parent_name
if not parent:
error_msg = "Invalid template name in 'extends' tag: %r." % parent
if self.parent_name_expr:
error_msg += " Got this from the '%s' variable." % self.parent_name_expr.token
raise TemplateSyntaxError(error_msg)
if hasattr(parent, 'render'):
return parent # parent is a Template object
return get_template(parent)
def do_extends(parser, token):
"""
Signal that this template extends a parent template.
This tag may be used in two ways: ``{% extends "base" %}`` (with quotes)
uses the literal value "base" as the name of the parent template to extend,
or ``{% extends variable %}`` uses the value of ``variable`` as either the
name of the parent template to extend (if it evaluates to a string) or as
the parent tempate itelf (if it evaluates to a Template object).
"""
bits = token.split_contents()
if len(bits) != 2:
raise TemplateSyntaxError("'%s' takes one argument" % bits[0])
parent_name, parent_name_expr = None, None
if bits[1][0] in ('"', "'") and bits[1][-1] == bits[1][0]:
parent_name = bits[1][1:-1]
else:
parent_name_expr = parser.compile_filter(bits[1])
nodelist = parser.parse()
if nodelist.get_nodes_by_type(ExtendsNode):
raise TemplateSyntaxError(
"'%s' cannot appear more than once in the same template" % bits[0])
return ExtendsNode(nodelist, parent_name, parent_name_expr)
def do_filter(parser, token):
"""
Filters the contents of the block through variable filters.
Filters can also be piped through each other, and they can have
arguments -- just like in variable syntax.
Sample usage::
{% filter force_escape|lower %}
This text will be HTML-escaped, and will appear in lowercase.
{% endfilter %}
"""
_, rest = token.contents.split(None, 1)
filter_expr = parser.compile_filter("var|%s" % (rest))
for func, unused in filter_expr.filters:
if getattr(func, '_decorated_function', func).__name__ in ('escape', 'safe'):
raise TemplateSyntaxError('"filter %s" is not permitted. Use the "autoescape" tag instead.' % func.__name__)
nodelist = parser.parse(('endfilter',))
parser.delete_first_token()
return FilterNode(filter_expr, nodelist)
def do_for(parser, token):
"""
Loops over each item in an array.
For example, to display a list of athletes given ``athlete_list``::
<ul>
{% for athlete in athlete_list %}
<li>{{ athlete.name }}</li>
{% endfor %}
</ul>
You can loop over a list in reverse by using
``{% for obj in list reversed %}``.
You can also unpack multiple values from a two-dimensional array::
{% for key,value in dict.items %}
{{ key }}: {{ value }}
{% endfor %}
The ``for`` tag can take an optional ``{% empty %}`` clause that will
be displayed if the given array is empty or could not be found::
<ul>
{% for athlete in athlete_list %}
<li>{{ athlete.name }}</li>
{% empty %}
<li>Sorry, no athletes in this list.</li>
{% endfor %}
<ul>
The above is equivalent to -- but shorter, cleaner, and possibly faster
than -- the following::
<ul>
{% if althete_list %}
{% for athlete in athlete_list %}
<li>{{ athlete.name }}</li>
{% endfor %}
{% else %}
<li>Sorry, no athletes in this list.</li>
{% endif %}
</ul>
The for loop sets a number of variables available within the loop:
========================== ================================================
Variable Description
========================== ================================================
``forloop.counter`` The current iteration of the loop (1-indexed)
``forloop.counter0`` The current iteration of the loop (0-indexed)
``forloop.revcounter`` The number of iterations from the end of the
loop (1-indexed)
``forloop.revcounter0`` The number of iterations from the end of the
loop (0-indexed)
``forloop.first`` True if this is the first time through the loop
``forloop.last`` True if this is the last time through the loop
``forloop.parentloop`` For nested loops, this is the loop "above" the
current one
========================== ================================================
"""
bits = token.contents.split()
if len(bits) < 4:
raise TemplateSyntaxError("'for' statements should have at least four"
" words: %s" % token.contents)
is_reversed = bits[-1] == 'reversed'
in_index = is_reversed and -3 or -2
if bits[in_index] != 'in':
raise TemplateSyntaxError("'for' statements should use the format"
" 'for x in y': %s" % token.contents)
loopvars = re.split(r' *, *', ' '.join(bits[1:in_index]))
for var in loopvars:
if not var or ' ' in var:
raise TemplateSyntaxError("'for' tag received an invalid argument:"
" %s" % token.contents)
sequence = parser.compile_filter(bits[in_index+1])
nodelist_loop = parser.parse(('empty', 'endfor',))
token = parser.next_token()
if token.contents == 'empty':
nodelist_empty = parser.parse(('endfor',))
parser.delete_first_token()
else:
nodelist_empty = None
return ForNode(loopvars, sequence, is_reversed, nodelist_loop, nodelist_empty)
def cycle(parser, token):
"""
Cycles among the given strings each time this tag is encountered.
Within a loop, cycles among the given strings each time through
the loop::
{% for o in some_list %}
<tr class="{% cycle 'row1' 'row2' %}">
...
</tr>
{% endfor %}
Outside of a loop, give the values a unique name the first time you call
it, then use that name each sucessive time through::
<tr class="{% cycle 'row1' 'row2' 'row3' as rowcolors %}">...</tr>
<tr class="{% cycle rowcolors %}">...</tr>
<tr class="{% cycle rowcolors %}">...</tr>
You can use any number of values, separated by spaces. Commas can also
be used to separate values; if a comma is used, the cycle values are
interpreted as literal strings.
The optional flag "silent" can be used to prevent the cycle declaration
from returning any value::
{% cycle 'row1' 'row2' as rowcolors silent %}{# no value here #}
{% for o in some_list %}
<tr class="{% cycle rowcolors %}">{# first value will be "row1" #}
...
</tr>
{% endfor %}
"""
# Note: This returns the exact same node on each {% cycle name %} call;
# that is, the node object returned from {% cycle a b c as name %} and the
# one returned from {% cycle name %} are the exact same object. This
# shouldn't cause problems (heh), but if it does, now you know.
#
# Ugly hack warning: This stuffs the named template dict into parser so
# that names are only unique within each template (as opposed to using
# a global variable, which would make cycle names have to be unique across
# *all* templates.
args = token.split_contents()
if len(args) < 2:
raise TemplateSyntaxError("'cycle' tag requires at least two arguments")
if ',' in args[1]:
# Backwards compatibility: {% cycle a,b %} or {% cycle a,b as foo %}
# case.
args[1:2] = ['"%s"' % arg for arg in args[1].split(",")]
if len(args) == 2:
# {% cycle foo %} case.
name = args[1]
if not hasattr(parser, '_namedCycleNodes'):
raise TemplateSyntaxError("No named cycles in template. '%s' is not defined" % name)
if not name in parser._namedCycleNodes:
raise TemplateSyntaxError("Named cycle '%s' does not exist" % name)
return parser._namedCycleNodes[name]
as_form = False
if len(args) > 4:
# {% cycle ... as foo [silent] %} case.
if args[-3] == "as":
if args[-1] != "silent":
raise TemplateSyntaxError("Only 'silent' flag is allowed after cycle's name, not '%s'." % args[-1])
as_form = True
silent = True
args = args[:-1]
elif args[-2] == "as":
as_form = True
silent = False
if as_form:
name = args[-1]
values = [parser.compile_filter(arg) for arg in args[1:-2]]
node = CycleNode(values, name, silent=silent)
if not hasattr(parser, '_namedCycleNodes'):
parser._namedCycleNodes = {}
parser._namedCycleNodes[name] = node
else:
values = [parser.compile_filter(arg) for arg in args[1:]]
node = CycleNode(values)
return node