318 lines
12 KiB
Python
318 lines
12 KiB
Python
import posixpath
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from collections import defaultdict
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from django.utils.safestring import mark_safe
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from .base import (
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Node, Template, TemplateSyntaxError, TextNode, Variable, token_kwargs,
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)
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from .library import Library
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register = Library()
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BLOCK_CONTEXT_KEY = 'block_context'
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class BlockContext:
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def __init__(self):
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# Dictionary of FIFO queues.
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self.blocks = defaultdict(list)
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def add_blocks(self, blocks):
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for name, block in blocks.items():
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self.blocks[name].insert(0, block)
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def pop(self, name):
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try:
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return self.blocks[name].pop()
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except IndexError:
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return None
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def push(self, name, block):
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self.blocks[name].append(block)
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def get_block(self, name):
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try:
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return self.blocks[name][-1]
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except IndexError:
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return None
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class BlockNode(Node):
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def __init__(self, name, nodelist, parent=None):
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self.name, self.nodelist, self.parent = name, nodelist, parent
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def __repr__(self):
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return "<Block Node: %s. Contents: %r>" % (self.name, self.nodelist)
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def render(self, context):
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block_context = context.render_context.get(BLOCK_CONTEXT_KEY)
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with context.push():
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if block_context is None:
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context['block'] = self
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result = self.nodelist.render(context)
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else:
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push = block = block_context.pop(self.name)
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if block is None:
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block = self
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# Create new block so we can store context without thread-safety issues.
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block = type(self)(block.name, block.nodelist)
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block.context = context
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context['block'] = block
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result = block.nodelist.render(context)
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if push is not None:
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block_context.push(self.name, push)
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return result
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def super(self):
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if not hasattr(self, 'context'):
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raise TemplateSyntaxError(
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"'%s' object has no attribute 'context'. Did you use "
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"{{ block.super }} in a base template?" % self.__class__.__name__
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)
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render_context = self.context.render_context
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if (BLOCK_CONTEXT_KEY in render_context and
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render_context[BLOCK_CONTEXT_KEY].get_block(self.name) is not None):
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return mark_safe(self.render(self.context))
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return ''
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class ExtendsNode(Node):
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must_be_first = True
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context_key = 'extends_context'
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def __init__(self, nodelist, parent_name, template_dirs=None):
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self.nodelist = nodelist
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self.parent_name = parent_name
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self.template_dirs = template_dirs
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self.blocks = {n.name: n for n in nodelist.get_nodes_by_type(BlockNode)}
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def __repr__(self):
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return '<%s: extends %s>' % (self.__class__.__name__, self.parent_name.token)
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def find_template(self, template_name, context):
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"""
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This is a wrapper around engine.find_template(). A history is kept in
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the render_context attribute between successive extends calls and
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passed as the skip argument. This enables extends to work recursively
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without extending the same template twice.
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"""
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history = context.render_context.setdefault(
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self.context_key, [self.origin],
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)
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template, origin = context.template.engine.find_template(
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template_name, skip=history,
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)
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history.append(origin)
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return template
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def get_parent(self, context):
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parent = self.parent_name.resolve(context)
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if not parent:
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error_msg = "Invalid template name in 'extends' tag: %r." % parent
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if self.parent_name.filters or\
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isinstance(self.parent_name.var, Variable):
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error_msg += " Got this from the '%s' variable." %\
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self.parent_name.token
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raise TemplateSyntaxError(error_msg)
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if isinstance(parent, Template):
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# parent is a django.template.Template
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return parent
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if isinstance(getattr(parent, 'template', None), Template):
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# parent is a django.template.backends.django.Template
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return parent.template
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return self.find_template(parent, context)
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def render(self, context):
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compiled_parent = self.get_parent(context)
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if BLOCK_CONTEXT_KEY not in context.render_context:
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context.render_context[BLOCK_CONTEXT_KEY] = BlockContext()
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block_context = context.render_context[BLOCK_CONTEXT_KEY]
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# Add the block nodes from this node to the block context
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block_context.add_blocks(self.blocks)
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# If this block's parent doesn't have an extends node it is the root,
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# and its block nodes also need to be added to the block context.
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for node in compiled_parent.nodelist:
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# The ExtendsNode has to be the first non-text node.
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if not isinstance(node, TextNode):
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if not isinstance(node, ExtendsNode):
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blocks = {n.name: n for n in
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compiled_parent.nodelist.get_nodes_by_type(BlockNode)}
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block_context.add_blocks(blocks)
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break
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# Call Template._render explicitly so the parser context stays
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# the same.
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with context.render_context.push_state(compiled_parent, isolated_context=False):
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return compiled_parent._render(context)
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class IncludeNode(Node):
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context_key = '__include_context'
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def __init__(self, template, *args, extra_context=None, isolated_context=False, **kwargs):
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self.template = template
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self.extra_context = extra_context or {}
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self.isolated_context = isolated_context
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super().__init__(*args, **kwargs)
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def render(self, context):
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"""
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Render the specified template and context. Cache the template object
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in render_context to avoid reparsing and loading when used in a for
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loop.
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"""
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template = self.template.resolve(context)
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# Does this quack like a Template?
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if not callable(getattr(template, 'render', None)):
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# If not, try the cache and get_template().
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template_name = template
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cache = context.render_context.dicts[0].setdefault(self, {})
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template = cache.get(template_name)
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if template is None:
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template = context.template.engine.get_template(template_name)
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cache[template_name] = template
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# Use the base.Template of a backends.django.Template.
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elif hasattr(template, 'template'):
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template = template.template
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values = {
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name: var.resolve(context)
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for name, var in self.extra_context.items()
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}
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if self.isolated_context:
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return template.render(context.new(values))
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with context.push(**values):
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return template.render(context)
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@register.tag('block')
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def do_block(parser, token):
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"""
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Define a block that can be overridden by child templates.
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"""
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# token.split_contents() isn't useful here because this tag doesn't accept variable as arguments
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bits = token.contents.split()
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if len(bits) != 2:
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raise TemplateSyntaxError("'%s' tag takes only one argument" % bits[0])
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block_name = bits[1]
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# Keep track of the names of BlockNodes found in this template, so we can
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# check for duplication.
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try:
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if block_name in parser.__loaded_blocks:
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raise TemplateSyntaxError("'%s' tag with name '%s' appears more than once" % (bits[0], block_name))
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parser.__loaded_blocks.append(block_name)
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except AttributeError: # parser.__loaded_blocks isn't a list yet
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parser.__loaded_blocks = [block_name]
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nodelist = parser.parse(('endblock',))
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# This check is kept for backwards-compatibility. See #3100.
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endblock = parser.next_token()
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acceptable_endblocks = ('endblock', 'endblock %s' % block_name)
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if endblock.contents not in acceptable_endblocks:
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parser.invalid_block_tag(endblock, 'endblock', acceptable_endblocks)
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return BlockNode(block_name, nodelist)
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def construct_relative_path(current_template_name, relative_name):
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"""
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Convert a relative path (starting with './' or '../') to the full template
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name based on the current_template_name.
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"""
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if not relative_name.startswith(("'./", "'../", '"./', '"../')):
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# relative_name is a variable or a literal that doesn't contain a
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# relative path.
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return relative_name
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new_name = posixpath.normpath(
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posixpath.join(
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posixpath.dirname(current_template_name.lstrip('/')),
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relative_name.strip('\'"')
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)
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)
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if new_name.startswith('../'):
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raise TemplateSyntaxError(
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"The relative path '%s' points outside the file hierarchy that "
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"template '%s' is in." % (relative_name, current_template_name)
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)
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if current_template_name.lstrip('/') == new_name:
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raise TemplateSyntaxError(
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"The relative path '%s' was translated to template name '%s', the "
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"same template in which the tag appears."
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% (relative_name, current_template_name)
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)
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return '"%s"' % new_name
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@register.tag('extends')
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def do_extends(parser, token):
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"""
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Signal that this template extends a parent template.
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This tag may be used in two ways: ``{% extends "base" %}`` (with quotes)
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uses the literal value "base" as the name of the parent template to extend,
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or ``{% extends variable %}`` uses the value of ``variable`` as either the
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name of the parent template to extend (if it evaluates to a string) or as
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the parent template itself (if it evaluates to a Template object).
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"""
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bits = token.split_contents()
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if len(bits) != 2:
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raise TemplateSyntaxError("'%s' takes one argument" % bits[0])
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bits[1] = construct_relative_path(parser.origin.template_name, bits[1])
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parent_name = parser.compile_filter(bits[1])
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nodelist = parser.parse()
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if nodelist.get_nodes_by_type(ExtendsNode):
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raise TemplateSyntaxError("'%s' cannot appear more than once in the same template" % bits[0])
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return ExtendsNode(nodelist, parent_name)
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@register.tag('include')
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def do_include(parser, token):
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"""
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Load a template and render it with the current context. You can pass
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additional context using keyword arguments.
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Example::
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{% include "foo/some_include" %}
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{% include "foo/some_include" with bar="BAZZ!" baz="BING!" %}
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Use the ``only`` argument to exclude the current context when rendering
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the included template::
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{% include "foo/some_include" only %}
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{% include "foo/some_include" with bar="1" only %}
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"""
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bits = token.split_contents()
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if len(bits) < 2:
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raise TemplateSyntaxError(
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"%r tag takes at least one argument: the name of the template to "
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"be included." % bits[0]
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)
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options = {}
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remaining_bits = bits[2:]
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while remaining_bits:
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option = remaining_bits.pop(0)
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if option in options:
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raise TemplateSyntaxError('The %r option was specified more '
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'than once.' % option)
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if option == 'with':
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value = token_kwargs(remaining_bits, parser, support_legacy=False)
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if not value:
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raise TemplateSyntaxError('"with" in %r tag needs at least '
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'one keyword argument.' % bits[0])
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elif option == 'only':
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value = True
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else:
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raise TemplateSyntaxError('Unknown argument for %r tag: %r.' %
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(bits[0], option))
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options[option] = value
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isolated_context = options.get('only', False)
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namemap = options.get('with', {})
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bits[1] = construct_relative_path(parser.origin.template_name, bits[1])
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return IncludeNode(parser.compile_filter(bits[1]), extra_context=namemap,
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isolated_context=isolated_context)
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