1411 lines
51 KiB
Python
1411 lines
51 KiB
Python
"""
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This is the Django template system.
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How it works:
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The Lexer.tokenize() function converts a template string (i.e., a string containing
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markup with custom template tags) to tokens, which can be either plain text
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(TOKEN_TEXT), variables (TOKEN_VAR) or block statements (TOKEN_BLOCK).
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The Parser() class takes a list of tokens in its constructor, and its parse()
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method returns a compiled template -- which is, under the hood, a list of
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Node objects.
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Each Node is responsible for creating some sort of output -- e.g. simple text
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(TextNode), variable values in a given context (VariableNode), results of basic
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logic (IfNode), results of looping (ForNode), or anything else. The core Node
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types are TextNode, VariableNode, IfNode and ForNode, but plugin modules can
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define their own custom node types.
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Each Node has a render() method, which takes a Context and returns a string of
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the rendered node. For example, the render() method of a Variable Node returns
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the variable's value as a string. The render() method of a ForNode returns the
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rendered output of whatever was inside the loop, recursively.
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The Template class is a convenient wrapper that takes care of template
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compilation and rendering.
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Usage:
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The only thing you should ever use directly in this file is the Template class.
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Create a compiled template object with a template_string, then call render()
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with a context. In the compilation stage, the TemplateSyntaxError exception
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will be raised if the template doesn't have proper syntax.
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Sample code:
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>>> from django import template
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>>> s = u'<html>{% if test %}<h1>{{ varvalue }}</h1>{% endif %}</html>'
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>>> t = template.Template(s)
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(t is now a compiled template, and its render() method can be called multiple
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times with multiple contexts)
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>>> c = template.Context({'test':True, 'varvalue': 'Hello'})
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>>> t.render(c)
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u'<html><h1>Hello</h1></html>'
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>>> c = template.Context({'test':False, 'varvalue': 'Hello'})
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>>> t.render(c)
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u'<html></html>'
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"""
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from __future__ import unicode_literals
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import re
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import warnings
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from functools import partial
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from importlib import import_module
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from inspect import getargspec, getcallargs
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from django.apps import apps
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from django.template.context import ( # NOQA: imported for backwards compatibility
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BaseContext, Context, ContextPopException, RequestContext,
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)
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from django.utils import lru_cache, six
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from django.utils.deprecation import RemovedInDjango20Warning
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from django.utils.encoding import (
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force_str, force_text, python_2_unicode_compatible,
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)
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from django.utils.formats import localize
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from django.utils.html import conditional_escape
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from django.utils.itercompat import is_iterable
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from django.utils.module_loading import module_has_submodule
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from django.utils.safestring import (
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EscapeData, SafeData, mark_for_escaping, mark_safe,
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)
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from django.utils.text import (
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get_text_list, smart_split, unescape_string_literal,
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)
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from django.utils.timezone import template_localtime
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from django.utils.translation import pgettext_lazy, ugettext_lazy
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TOKEN_TEXT = 0
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TOKEN_VAR = 1
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TOKEN_BLOCK = 2
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TOKEN_COMMENT = 3
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TOKEN_MAPPING = {
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TOKEN_TEXT: 'Text',
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TOKEN_VAR: 'Var',
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TOKEN_BLOCK: 'Block',
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TOKEN_COMMENT: 'Comment',
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}
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# template syntax constants
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FILTER_SEPARATOR = '|'
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FILTER_ARGUMENT_SEPARATOR = ':'
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VARIABLE_ATTRIBUTE_SEPARATOR = '.'
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BLOCK_TAG_START = '{%'
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BLOCK_TAG_END = '%}'
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VARIABLE_TAG_START = '{{'
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VARIABLE_TAG_END = '}}'
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COMMENT_TAG_START = '{#'
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COMMENT_TAG_END = '#}'
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TRANSLATOR_COMMENT_MARK = 'Translators'
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SINGLE_BRACE_START = '{'
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SINGLE_BRACE_END = '}'
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ALLOWED_VARIABLE_CHARS = ('abcdefghijklmnopqrstuvwxyz'
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'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.')
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# what to report as the origin for templates that come from non-loader sources
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# (e.g. strings)
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UNKNOWN_SOURCE = '<unknown source>'
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# match a variable or block tag and capture the entire tag, including start/end
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# delimiters
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tag_re = (re.compile('(%s.*?%s|%s.*?%s|%s.*?%s)' %
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(re.escape(BLOCK_TAG_START), re.escape(BLOCK_TAG_END),
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re.escape(VARIABLE_TAG_START), re.escape(VARIABLE_TAG_END),
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re.escape(COMMENT_TAG_START), re.escape(COMMENT_TAG_END))))
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# global dictionary of libraries that have been loaded using get_library
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libraries = {}
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# global list of libraries to load by default for a new parser
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builtins = []
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class TemplateSyntaxError(Exception):
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pass
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class TemplateDoesNotExist(Exception):
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pass
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class TemplateEncodingError(Exception):
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pass
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@python_2_unicode_compatible
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class VariableDoesNotExist(Exception):
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def __init__(self, msg, params=()):
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self.msg = msg
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self.params = params
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def __str__(self):
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return self.msg % tuple(force_text(p, errors='replace') for p in self.params)
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class InvalidTemplateLibrary(Exception):
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pass
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class Origin(object):
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def __init__(self, name):
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self.name = name
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def reload(self):
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raise NotImplementedError('subclasses of Origin must provide a reload() method')
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def __str__(self):
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return self.name
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class StringOrigin(Origin):
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def __init__(self, source):
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super(StringOrigin, self).__init__(UNKNOWN_SOURCE)
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self.source = source
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def reload(self):
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return self.source
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class Template(object):
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def __init__(self, template_string, origin=None, name=None, engine=None):
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try:
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template_string = force_text(template_string)
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except UnicodeDecodeError:
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raise TemplateEncodingError("Templates can only be constructed "
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"from unicode or UTF-8 strings.")
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# If Template is instantiated directly rather than from an Engine and
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# exactly one Django template engine is configured, use that engine.
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# This is required to preserve backwards-compatibility for direct use
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# e.g. Template('...').render(Context({...}))
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if engine is None:
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from .engine import Engine
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engine = Engine.get_default()
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if engine.debug and origin is None:
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origin = StringOrigin(template_string)
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self.nodelist = engine.compile_string(template_string, origin)
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self.name = name
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self.origin = origin
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self.engine = engine
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def __iter__(self):
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for node in self.nodelist:
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for subnode in node:
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yield subnode
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def _render(self, context):
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return self.nodelist.render(context)
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def render(self, context):
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"Display stage -- can be called many times"
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context.render_context.push()
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try:
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if context.template is None:
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with context.bind_template(self):
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return self._render(context)
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else:
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return self._render(context)
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finally:
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context.render_context.pop()
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class Token(object):
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def __init__(self, token_type, contents):
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# token_type must be TOKEN_TEXT, TOKEN_VAR, TOKEN_BLOCK or
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# TOKEN_COMMENT.
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self.token_type, self.contents = token_type, contents
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self.lineno = None
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def __str__(self):
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token_name = TOKEN_MAPPING[self.token_type]
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return ('<%s token: "%s...">' %
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(token_name, self.contents[:20].replace('\n', '')))
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def split_contents(self):
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split = []
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bits = iter(smart_split(self.contents))
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for bit in bits:
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# Handle translation-marked template pieces
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if bit.startswith('_("') or bit.startswith("_('"):
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sentinal = bit[2] + ')'
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trans_bit = [bit]
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while not bit.endswith(sentinal):
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bit = next(bits)
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trans_bit.append(bit)
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bit = ' '.join(trans_bit)
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split.append(bit)
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return split
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class Lexer(object):
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def __init__(self, template_string, origin):
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self.template_string = template_string
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self.origin = origin
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self.lineno = 1
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self.verbatim = False
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def tokenize(self):
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"""
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Return a list of tokens from a given template_string.
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"""
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in_tag = False
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result = []
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for bit in tag_re.split(self.template_string):
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if bit:
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result.append(self.create_token(bit, in_tag))
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in_tag = not in_tag
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return result
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def create_token(self, token_string, in_tag):
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"""
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Convert the given token string into a new Token object and return it.
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If in_tag is True, we are processing something that matched a tag,
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otherwise it should be treated as a literal string.
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"""
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if in_tag and token_string.startswith(BLOCK_TAG_START):
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# The [2:-2] ranges below strip off *_TAG_START and *_TAG_END.
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# We could do len(BLOCK_TAG_START) to be more "correct", but we've
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# hard-coded the 2s here for performance. And it's not like
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# the TAG_START values are going to change anytime, anyway.
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block_content = token_string[2:-2].strip()
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if self.verbatim and block_content == self.verbatim:
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self.verbatim = False
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if in_tag and not self.verbatim:
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if token_string.startswith(VARIABLE_TAG_START):
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token = Token(TOKEN_VAR, token_string[2:-2].strip())
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elif token_string.startswith(BLOCK_TAG_START):
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if block_content[:9] in ('verbatim', 'verbatim '):
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self.verbatim = 'end%s' % block_content
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token = Token(TOKEN_BLOCK, block_content)
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elif token_string.startswith(COMMENT_TAG_START):
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content = ''
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if token_string.find(TRANSLATOR_COMMENT_MARK):
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content = token_string[2:-2].strip()
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token = Token(TOKEN_COMMENT, content)
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else:
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token = Token(TOKEN_TEXT, token_string)
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token.lineno = self.lineno
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self.lineno += token_string.count('\n')
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return token
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class Parser(object):
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def __init__(self, tokens):
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self.tokens = tokens
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self.tags = {}
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self.filters = {}
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for lib in builtins:
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self.add_library(lib)
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def parse(self, parse_until=None):
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if parse_until is None:
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parse_until = []
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nodelist = self.create_nodelist()
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while self.tokens:
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token = self.next_token()
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# Use the raw values here for TOKEN_* for a tiny performance boost.
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if token.token_type == 0: # TOKEN_TEXT
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self.extend_nodelist(nodelist, TextNode(token.contents), token)
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elif token.token_type == 1: # TOKEN_VAR
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if not token.contents:
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self.empty_variable(token)
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try:
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filter_expression = self.compile_filter(token.contents)
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except TemplateSyntaxError as e:
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if not self.compile_filter_error(token, e):
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raise
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var_node = self.create_variable_node(filter_expression)
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self.extend_nodelist(nodelist, var_node, token)
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elif token.token_type == 2: # TOKEN_BLOCK
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try:
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command = token.contents.split()[0]
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except IndexError:
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self.empty_block_tag(token)
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if command in parse_until:
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# put token back on token list so calling
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# code knows why it terminated
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self.prepend_token(token)
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return nodelist
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# execute callback function for this tag and append
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# resulting node
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self.enter_command(command, token)
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try:
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compile_func = self.tags[command]
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except KeyError:
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self.invalid_block_tag(token, command, parse_until)
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try:
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compiled_result = compile_func(self, token)
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except TemplateSyntaxError as e:
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if not self.compile_function_error(token, e):
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raise
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self.extend_nodelist(nodelist, compiled_result, token)
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self.exit_command()
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if parse_until:
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self.unclosed_block_tag(parse_until)
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return nodelist
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def skip_past(self, endtag):
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while self.tokens:
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token = self.next_token()
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if token.token_type == TOKEN_BLOCK and token.contents == endtag:
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return
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self.unclosed_block_tag([endtag])
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def create_variable_node(self, filter_expression):
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return VariableNode(filter_expression)
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def create_nodelist(self):
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return NodeList()
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def extend_nodelist(self, nodelist, node, token):
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if node.must_be_first and nodelist:
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try:
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if nodelist.contains_nontext:
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raise AttributeError
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except AttributeError:
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raise TemplateSyntaxError("%r must be the first tag "
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"in the template." % node)
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if isinstance(nodelist, NodeList) and not isinstance(node, TextNode):
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nodelist.contains_nontext = True
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nodelist.append(node)
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def enter_command(self, command, token):
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pass
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def exit_command(self):
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pass
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def error(self, token, msg):
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return TemplateSyntaxError(msg)
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def empty_variable(self, token):
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raise self.error(token, "Empty variable tag")
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def empty_block_tag(self, token):
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raise self.error(token, "Empty block tag")
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def invalid_block_tag(self, token, command, parse_until=None):
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if parse_until:
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raise self.error(token, "Invalid block tag: '%s', expected %s" %
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(command, get_text_list(["'%s'" % p for p in parse_until])))
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raise self.error(token, "Invalid block tag: '%s'" % command)
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def unclosed_block_tag(self, parse_until):
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raise self.error(None, "Unclosed tags: %s " % ', '.join(parse_until))
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def compile_filter_error(self, token, e):
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pass
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def compile_function_error(self, token, e):
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pass
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def next_token(self):
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return self.tokens.pop(0)
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def prepend_token(self, token):
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self.tokens.insert(0, token)
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def delete_first_token(self):
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del self.tokens[0]
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def add_library(self, lib):
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self.tags.update(lib.tags)
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self.filters.update(lib.filters)
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|
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def compile_filter(self, token):
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"""
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Convenient wrapper for FilterExpression
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"""
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return FilterExpression(token, self)
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|
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def find_filter(self, filter_name):
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if filter_name in self.filters:
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return self.filters[filter_name]
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else:
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raise TemplateSyntaxError("Invalid filter: '%s'" % filter_name)
|
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|
|
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class TokenParser(object):
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"""
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|
Subclass this and implement the top() method to parse a template line.
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When instantiating the parser, pass in the line from the Django template
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parser.
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The parser's "tagname" instance-variable stores the name of the tag that
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the filter was called with.
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"""
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def __init__(self, subject):
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self.subject = subject
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self.pointer = 0
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self.backout = []
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self.tagname = self.tag()
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|
|
def top(self):
|
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"""
|
|
Overload this method to do the actual parsing and return the result.
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|
"""
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raise NotImplementedError('subclasses of Tokenparser must provide a top() method')
|
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|
|
def more(self):
|
|
"""
|
|
Returns True if there is more stuff in the tag.
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|
"""
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return self.pointer < len(self.subject)
|
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|
|
def back(self):
|
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"""
|
|
Undoes the last microparser. Use this for lookahead and backtracking.
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|
"""
|
|
if not len(self.backout):
|
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raise TemplateSyntaxError("back called without some previous "
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"parsing")
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self.pointer = self.backout.pop()
|
|
|
|
def tag(self):
|
|
"""
|
|
A microparser that just returns the next tag from the line.
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|
"""
|
|
subject = self.subject
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i = self.pointer
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|
if i >= len(subject):
|
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raise TemplateSyntaxError("expected another tag, found "
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|
"end of string: %s" % subject)
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p = i
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while i < len(subject) and subject[i] not in (' ', '\t'):
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i += 1
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s = subject[p:i]
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while i < len(subject) and subject[i] in (' ', '\t'):
|
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i += 1
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self.backout.append(self.pointer)
|
|
self.pointer = i
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return s
|
|
|
|
def value(self):
|
|
"""
|
|
A microparser that parses for a value: some string constant or
|
|
variable name.
|
|
"""
|
|
subject = self.subject
|
|
i = self.pointer
|
|
|
|
def next_space_index(subject, i):
|
|
"""
|
|
Increment pointer until a real space (i.e. a space not within
|
|
quotes) is encountered
|
|
"""
|
|
while i < len(subject) and subject[i] not in (' ', '\t'):
|
|
if subject[i] in ('"', "'"):
|
|
c = subject[i]
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i += 1
|
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while i < len(subject) and subject[i] != c:
|
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i += 1
|
|
if i >= len(subject):
|
|
raise TemplateSyntaxError("Searching for value. "
|
|
"Unexpected end of string in column %d: %s" %
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(i, subject))
|
|
i += 1
|
|
return i
|
|
|
|
if i >= len(subject):
|
|
raise TemplateSyntaxError("Searching for value. Expected another "
|
|
"value but found end of string: %s" %
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subject)
|
|
if subject[i] in ('"', "'"):
|
|
p = i
|
|
i += 1
|
|
while i < len(subject) and subject[i] != subject[p]:
|
|
i += 1
|
|
if i >= len(subject):
|
|
raise TemplateSyntaxError("Searching for value. Unexpected "
|
|
"end of string in column %d: %s" %
|
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(i, subject))
|
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i += 1
|
|
|
|
# Continue parsing until next "real" space,
|
|
# so that filters are also included
|
|
i = next_space_index(subject, i)
|
|
|
|
res = subject[p:i]
|
|
while i < len(subject) and subject[i] in (' ', '\t'):
|
|
i += 1
|
|
self.backout.append(self.pointer)
|
|
self.pointer = i
|
|
return res
|
|
else:
|
|
p = i
|
|
i = next_space_index(subject, i)
|
|
s = subject[p:i]
|
|
while i < len(subject) and subject[i] in (' ', '\t'):
|
|
i += 1
|
|
self.backout.append(self.pointer)
|
|
self.pointer = i
|
|
return s
|
|
|
|
# This only matches constant *strings* (things in quotes or marked for
|
|
# translation). Numbers are treated as variables for implementation reasons
|
|
# (so that they retain their type when passed to filters).
|
|
constant_string = r"""
|
|
(?:%(i18n_open)s%(strdq)s%(i18n_close)s|
|
|
%(i18n_open)s%(strsq)s%(i18n_close)s|
|
|
%(strdq)s|
|
|
%(strsq)s)
|
|
""" % {
|
|
'strdq': r'"[^"\\]*(?:\\.[^"\\]*)*"', # double-quoted string
|
|
'strsq': r"'[^'\\]*(?:\\.[^'\\]*)*'", # single-quoted string
|
|
'i18n_open': re.escape("_("),
|
|
'i18n_close': re.escape(")"),
|
|
}
|
|
constant_string = constant_string.replace("\n", "")
|
|
|
|
filter_raw_string = r"""
|
|
^(?P<constant>%(constant)s)|
|
|
^(?P<var>[%(var_chars)s]+|%(num)s)|
|
|
(?:\s*%(filter_sep)s\s*
|
|
(?P<filter_name>\w+)
|
|
(?:%(arg_sep)s
|
|
(?:
|
|
(?P<constant_arg>%(constant)s)|
|
|
(?P<var_arg>[%(var_chars)s]+|%(num)s)
|
|
)
|
|
)?
|
|
)""" % {
|
|
'constant': constant_string,
|
|
'num': r'[-+\.]?\d[\d\.e]*',
|
|
'var_chars': "\w\.",
|
|
'filter_sep': re.escape(FILTER_SEPARATOR),
|
|
'arg_sep': re.escape(FILTER_ARGUMENT_SEPARATOR),
|
|
}
|
|
|
|
filter_re = re.compile(filter_raw_string, re.UNICODE | re.VERBOSE)
|
|
|
|
|
|
class FilterExpression(object):
|
|
"""
|
|
Parses a variable token and its optional filters (all as a single string),
|
|
and return a list of tuples of the filter name and arguments.
|
|
Sample::
|
|
|
|
>>> token = 'variable|default:"Default value"|date:"Y-m-d"'
|
|
>>> p = Parser('')
|
|
>>> fe = FilterExpression(token, p)
|
|
>>> len(fe.filters)
|
|
2
|
|
>>> fe.var
|
|
<Variable: 'variable'>
|
|
"""
|
|
def __init__(self, token, parser):
|
|
self.token = token
|
|
matches = filter_re.finditer(token)
|
|
var_obj = None
|
|
filters = []
|
|
upto = 0
|
|
for match in matches:
|
|
start = match.start()
|
|
if upto != start:
|
|
raise TemplateSyntaxError("Could not parse some characters: "
|
|
"%s|%s|%s" %
|
|
(token[:upto], token[upto:start],
|
|
token[start:]))
|
|
if var_obj is None:
|
|
var, constant = match.group("var", "constant")
|
|
if constant:
|
|
try:
|
|
var_obj = Variable(constant).resolve({})
|
|
except VariableDoesNotExist:
|
|
var_obj = None
|
|
elif var is None:
|
|
raise TemplateSyntaxError("Could not find variable at "
|
|
"start of %s." % token)
|
|
else:
|
|
var_obj = Variable(var)
|
|
else:
|
|
filter_name = match.group("filter_name")
|
|
args = []
|
|
constant_arg, var_arg = match.group("constant_arg", "var_arg")
|
|
if constant_arg:
|
|
args.append((False, Variable(constant_arg).resolve({})))
|
|
elif var_arg:
|
|
args.append((True, Variable(var_arg)))
|
|
filter_func = parser.find_filter(filter_name)
|
|
self.args_check(filter_name, filter_func, args)
|
|
filters.append((filter_func, args))
|
|
upto = match.end()
|
|
if upto != len(token):
|
|
raise TemplateSyntaxError("Could not parse the remainder: '%s' "
|
|
"from '%s'" % (token[upto:], token))
|
|
|
|
self.filters = filters
|
|
self.var = var_obj
|
|
|
|
def resolve(self, context, ignore_failures=False):
|
|
if isinstance(self.var, Variable):
|
|
try:
|
|
obj = self.var.resolve(context)
|
|
except VariableDoesNotExist:
|
|
if ignore_failures:
|
|
obj = None
|
|
else:
|
|
string_if_invalid = context.template.engine.string_if_invalid
|
|
if string_if_invalid:
|
|
if '%s' in string_if_invalid:
|
|
return string_if_invalid % self.var
|
|
else:
|
|
return string_if_invalid
|
|
else:
|
|
obj = string_if_invalid
|
|
else:
|
|
obj = self.var
|
|
for func, args in self.filters:
|
|
arg_vals = []
|
|
for lookup, arg in args:
|
|
if not lookup:
|
|
arg_vals.append(mark_safe(arg))
|
|
else:
|
|
arg_vals.append(arg.resolve(context))
|
|
if getattr(func, 'expects_localtime', False):
|
|
obj = template_localtime(obj, context.use_tz)
|
|
if getattr(func, 'needs_autoescape', False):
|
|
new_obj = func(obj, autoescape=context.autoescape, *arg_vals)
|
|
else:
|
|
new_obj = func(obj, *arg_vals)
|
|
if getattr(func, 'is_safe', False) and isinstance(obj, SafeData):
|
|
obj = mark_safe(new_obj)
|
|
elif isinstance(obj, EscapeData):
|
|
obj = mark_for_escaping(new_obj)
|
|
else:
|
|
obj = new_obj
|
|
return obj
|
|
|
|
def args_check(name, func, provided):
|
|
provided = list(provided)
|
|
# First argument, filter input, is implied.
|
|
plen = len(provided) + 1
|
|
# Check to see if a decorator is providing the real function.
|
|
func = getattr(func, '_decorated_function', func)
|
|
args, varargs, varkw, defaults = getargspec(func)
|
|
alen = len(args)
|
|
dlen = len(defaults or [])
|
|
# Not enough OR Too many
|
|
if plen < (alen - dlen) or plen > alen:
|
|
raise TemplateSyntaxError("%s requires %d arguments, %d provided" %
|
|
(name, alen - dlen, plen))
|
|
|
|
return True
|
|
args_check = staticmethod(args_check)
|
|
|
|
def __str__(self):
|
|
return self.token
|
|
|
|
|
|
def resolve_variable(path, context):
|
|
"""
|
|
Returns the resolved variable, which may contain attribute syntax, within
|
|
the given context.
|
|
|
|
Deprecated; use the Variable class instead.
|
|
"""
|
|
warnings.warn("resolve_variable() is deprecated. Use django.template."
|
|
"Variable(path).resolve(context) instead",
|
|
RemovedInDjango20Warning, stacklevel=2)
|
|
return Variable(path).resolve(context)
|
|
|
|
|
|
class Variable(object):
|
|
"""
|
|
A template variable, resolvable against a given context. The variable may
|
|
be a hard-coded string (if it begins and ends with single or double quote
|
|
marks)::
|
|
|
|
>>> c = {'article': {'section':u'News'}}
|
|
>>> Variable('article.section').resolve(c)
|
|
u'News'
|
|
>>> Variable('article').resolve(c)
|
|
{'section': u'News'}
|
|
>>> class AClass: pass
|
|
>>> c = AClass()
|
|
>>> c.article = AClass()
|
|
>>> c.article.section = u'News'
|
|
|
|
(The example assumes VARIABLE_ATTRIBUTE_SEPARATOR is '.')
|
|
"""
|
|
|
|
def __init__(self, var):
|
|
self.var = var
|
|
self.literal = None
|
|
self.lookups = None
|
|
self.translate = False
|
|
self.message_context = None
|
|
|
|
if not isinstance(var, six.string_types):
|
|
raise TypeError(
|
|
"Variable must be a string or number, got %s" % type(var))
|
|
try:
|
|
# First try to treat this variable as a number.
|
|
#
|
|
# Note that this could cause an OverflowError here that we're not
|
|
# catching. Since this should only happen at compile time, that's
|
|
# probably OK.
|
|
self.literal = float(var)
|
|
|
|
# So it's a float... is it an int? If the original value contained a
|
|
# dot or an "e" then it was a float, not an int.
|
|
if '.' not in var and 'e' not in var.lower():
|
|
self.literal = int(self.literal)
|
|
|
|
# "2." is invalid
|
|
if var.endswith('.'):
|
|
raise ValueError
|
|
|
|
except ValueError:
|
|
# A ValueError means that the variable isn't a number.
|
|
if var.startswith('_(') and var.endswith(')'):
|
|
# The result of the lookup should be translated at rendering
|
|
# time.
|
|
self.translate = True
|
|
var = var[2:-1]
|
|
# If it's wrapped with quotes (single or double), then
|
|
# we're also dealing with a literal.
|
|
try:
|
|
self.literal = mark_safe(unescape_string_literal(var))
|
|
except ValueError:
|
|
# Otherwise we'll set self.lookups so that resolve() knows we're
|
|
# dealing with a bonafide variable
|
|
if var.find(VARIABLE_ATTRIBUTE_SEPARATOR + '_') > -1 or var[0] == '_':
|
|
raise TemplateSyntaxError("Variables and attributes may "
|
|
"not begin with underscores: '%s'" %
|
|
var)
|
|
self.lookups = tuple(var.split(VARIABLE_ATTRIBUTE_SEPARATOR))
|
|
|
|
def resolve(self, context):
|
|
"""Resolve this variable against a given context."""
|
|
if self.lookups is not None:
|
|
# We're dealing with a variable that needs to be resolved
|
|
value = self._resolve_lookup(context)
|
|
else:
|
|
# We're dealing with a literal, so it's already been "resolved"
|
|
value = self.literal
|
|
if self.translate:
|
|
if self.message_context:
|
|
return pgettext_lazy(self.message_context, value)
|
|
else:
|
|
return ugettext_lazy(value)
|
|
return value
|
|
|
|
def __repr__(self):
|
|
return "<%s: %r>" % (self.__class__.__name__, self.var)
|
|
|
|
def __str__(self):
|
|
return self.var
|
|
|
|
def _resolve_lookup(self, context):
|
|
"""
|
|
Performs resolution of a real variable (i.e. not a literal) against the
|
|
given context.
|
|
|
|
As indicated by the method's name, this method is an implementation
|
|
detail and shouldn't be called by external code. Use Variable.resolve()
|
|
instead.
|
|
"""
|
|
current = context
|
|
try: # catch-all for silent variable failures
|
|
for bit in self.lookups:
|
|
try: # dictionary lookup
|
|
current = current[bit]
|
|
# ValueError/IndexError are for numpy.array lookup on
|
|
# numpy < 1.9 and 1.9+ respectively
|
|
except (TypeError, AttributeError, KeyError, ValueError, IndexError):
|
|
try: # attribute lookup
|
|
# Don't return class attributes if the class is the context:
|
|
if isinstance(current, BaseContext) and getattr(type(current), bit):
|
|
raise AttributeError
|
|
current = getattr(current, bit)
|
|
except (TypeError, AttributeError) as e:
|
|
# Reraise an AttributeError raised by a @property
|
|
if (isinstance(e, AttributeError) and
|
|
not isinstance(current, BaseContext) and bit in dir(current)):
|
|
raise
|
|
try: # list-index lookup
|
|
current = current[int(bit)]
|
|
except (IndexError, # list index out of range
|
|
ValueError, # invalid literal for int()
|
|
KeyError, # current is a dict without `int(bit)` key
|
|
TypeError): # unsubscriptable object
|
|
raise VariableDoesNotExist("Failed lookup for key "
|
|
"[%s] in %r",
|
|
(bit, current)) # missing attribute
|
|
if callable(current):
|
|
if getattr(current, 'do_not_call_in_templates', False):
|
|
pass
|
|
elif getattr(current, 'alters_data', False):
|
|
current = context.template.engine.string_if_invalid
|
|
else:
|
|
try: # method call (assuming no args required)
|
|
current = current()
|
|
except TypeError:
|
|
try:
|
|
getcallargs(current)
|
|
except TypeError: # arguments *were* required
|
|
current = context.template.engine.string_if_invalid # invalid method call
|
|
else:
|
|
raise
|
|
except Exception as e:
|
|
if getattr(e, 'silent_variable_failure', False):
|
|
current = context.template.engine.string_if_invalid
|
|
else:
|
|
raise
|
|
|
|
return current
|
|
|
|
|
|
class Node(object):
|
|
# Set this to True for nodes that must be first in the template (although
|
|
# they can be preceded by text nodes.
|
|
must_be_first = False
|
|
child_nodelists = ('nodelist',)
|
|
|
|
def render(self, context):
|
|
"""
|
|
Return the node rendered as a string.
|
|
"""
|
|
pass
|
|
|
|
def __iter__(self):
|
|
yield self
|
|
|
|
def get_nodes_by_type(self, nodetype):
|
|
"""
|
|
Return a list of all nodes (within this node and its nodelist)
|
|
of the given type
|
|
"""
|
|
nodes = []
|
|
if isinstance(self, nodetype):
|
|
nodes.append(self)
|
|
for attr in self.child_nodelists:
|
|
nodelist = getattr(self, attr, None)
|
|
if nodelist:
|
|
nodes.extend(nodelist.get_nodes_by_type(nodetype))
|
|
return nodes
|
|
|
|
|
|
class NodeList(list):
|
|
# Set to True the first time a non-TextNode is inserted by
|
|
# extend_nodelist().
|
|
contains_nontext = False
|
|
|
|
def render(self, context):
|
|
bits = []
|
|
for node in self:
|
|
if isinstance(node, Node):
|
|
bit = self.render_node(node, context)
|
|
else:
|
|
bit = node
|
|
bits.append(force_text(bit))
|
|
return mark_safe(''.join(bits))
|
|
|
|
def get_nodes_by_type(self, nodetype):
|
|
"Return a list of all nodes of the given type"
|
|
nodes = []
|
|
for node in self:
|
|
nodes.extend(node.get_nodes_by_type(nodetype))
|
|
return nodes
|
|
|
|
def render_node(self, node, context):
|
|
return node.render(context)
|
|
|
|
|
|
class TextNode(Node):
|
|
def __init__(self, s):
|
|
self.s = s
|
|
|
|
def __repr__(self):
|
|
return force_str("<Text Node: '%s'>" % self.s[:25], 'ascii',
|
|
errors='replace')
|
|
|
|
def render(self, context):
|
|
return self.s
|
|
|
|
|
|
def render_value_in_context(value, context):
|
|
"""
|
|
Converts any value to a string to become part of a rendered template. This
|
|
means escaping, if required, and conversion to a unicode object. If value
|
|
is a string, it is expected to have already been translated.
|
|
"""
|
|
value = template_localtime(value, use_tz=context.use_tz)
|
|
value = localize(value, use_l10n=context.use_l10n)
|
|
value = force_text(value)
|
|
if ((context.autoescape and not isinstance(value, SafeData)) or
|
|
isinstance(value, EscapeData)):
|
|
return conditional_escape(value)
|
|
else:
|
|
return value
|
|
|
|
|
|
class VariableNode(Node):
|
|
def __init__(self, filter_expression):
|
|
self.filter_expression = filter_expression
|
|
|
|
def __repr__(self):
|
|
return "<Variable Node: %s>" % self.filter_expression
|
|
|
|
def render(self, context):
|
|
try:
|
|
output = self.filter_expression.resolve(context)
|
|
except UnicodeDecodeError:
|
|
# Unicode conversion can fail sometimes for reasons out of our
|
|
# control (e.g. exception rendering). In that case, we fail
|
|
# quietly.
|
|
return ''
|
|
return render_value_in_context(output, context)
|
|
|
|
# Regex for token keyword arguments
|
|
kwarg_re = re.compile(r"(?:(\w+)=)?(.+)")
|
|
|
|
|
|
def token_kwargs(bits, parser, support_legacy=False):
|
|
"""
|
|
A utility method for parsing token keyword arguments.
|
|
|
|
:param bits: A list containing remainder of the token (split by spaces)
|
|
that is to be checked for arguments. Valid arguments will be removed
|
|
from this list.
|
|
|
|
:param support_legacy: If set to true ``True``, the legacy format
|
|
``1 as foo`` will be accepted. Otherwise, only the standard ``foo=1``
|
|
format is allowed.
|
|
|
|
:returns: A dictionary of the arguments retrieved from the ``bits`` token
|
|
list.
|
|
|
|
There is no requirement for all remaining token ``bits`` to be keyword
|
|
arguments, so the dictionary will be returned as soon as an invalid
|
|
argument format is reached.
|
|
"""
|
|
if not bits:
|
|
return {}
|
|
match = kwarg_re.match(bits[0])
|
|
kwarg_format = match and match.group(1)
|
|
if not kwarg_format:
|
|
if not support_legacy:
|
|
return {}
|
|
if len(bits) < 3 or bits[1] != 'as':
|
|
return {}
|
|
|
|
kwargs = {}
|
|
while bits:
|
|
if kwarg_format:
|
|
match = kwarg_re.match(bits[0])
|
|
if not match or not match.group(1):
|
|
return kwargs
|
|
key, value = match.groups()
|
|
del bits[:1]
|
|
else:
|
|
if len(bits) < 3 or bits[1] != 'as':
|
|
return kwargs
|
|
key, value = bits[2], bits[0]
|
|
del bits[:3]
|
|
kwargs[key] = parser.compile_filter(value)
|
|
if bits and not kwarg_format:
|
|
if bits[0] != 'and':
|
|
return kwargs
|
|
del bits[:1]
|
|
return kwargs
|
|
|
|
|
|
def parse_bits(parser, bits, params, varargs, varkw, defaults,
|
|
takes_context, name):
|
|
"""
|
|
Parses bits for template tag helpers (simple_tag, include_tag and
|
|
assignment_tag), in particular by detecting syntax errors and by
|
|
extracting positional and keyword arguments.
|
|
"""
|
|
if takes_context:
|
|
if params[0] == 'context':
|
|
params = params[1:]
|
|
else:
|
|
raise TemplateSyntaxError(
|
|
"'%s' is decorated with takes_context=True so it must "
|
|
"have a first argument of 'context'" % name)
|
|
args = []
|
|
kwargs = {}
|
|
unhandled_params = list(params)
|
|
for bit in bits:
|
|
# First we try to extract a potential kwarg from the bit
|
|
kwarg = token_kwargs([bit], parser)
|
|
if kwarg:
|
|
# The kwarg was successfully extracted
|
|
param, value = list(six.iteritems(kwarg))[0]
|
|
if param not in params and varkw is None:
|
|
# An unexpected keyword argument was supplied
|
|
raise TemplateSyntaxError(
|
|
"'%s' received unexpected keyword argument '%s'" %
|
|
(name, param))
|
|
elif param in kwargs:
|
|
# The keyword argument has already been supplied once
|
|
raise TemplateSyntaxError(
|
|
"'%s' received multiple values for keyword argument '%s'" %
|
|
(name, param))
|
|
else:
|
|
# All good, record the keyword argument
|
|
kwargs[str(param)] = value
|
|
if param in unhandled_params:
|
|
# If using the keyword syntax for a positional arg, then
|
|
# consume it.
|
|
unhandled_params.remove(param)
|
|
else:
|
|
if kwargs:
|
|
raise TemplateSyntaxError(
|
|
"'%s' received some positional argument(s) after some "
|
|
"keyword argument(s)" % name)
|
|
else:
|
|
# Record the positional argument
|
|
args.append(parser.compile_filter(bit))
|
|
try:
|
|
# Consume from the list of expected positional arguments
|
|
unhandled_params.pop(0)
|
|
except IndexError:
|
|
if varargs is None:
|
|
raise TemplateSyntaxError(
|
|
"'%s' received too many positional arguments" %
|
|
name)
|
|
if defaults is not None:
|
|
# Consider the last n params handled, where n is the
|
|
# number of defaults.
|
|
unhandled_params = unhandled_params[:-len(defaults)]
|
|
if unhandled_params:
|
|
# Some positional arguments were not supplied
|
|
raise TemplateSyntaxError(
|
|
"'%s' did not receive value(s) for the argument(s): %s" %
|
|
(name, ", ".join("'%s'" % p for p in unhandled_params)))
|
|
return args, kwargs
|
|
|
|
|
|
def generic_tag_compiler(parser, token, params, varargs, varkw, defaults,
|
|
name, takes_context, node_class):
|
|
"""
|
|
Returns a template.Node subclass.
|
|
"""
|
|
bits = token.split_contents()[1:]
|
|
args, kwargs = parse_bits(parser, bits, params, varargs, varkw,
|
|
defaults, takes_context, name)
|
|
return node_class(takes_context, args, kwargs)
|
|
|
|
|
|
class TagHelperNode(Node):
|
|
"""
|
|
Base class for tag helper nodes such as SimpleNode, InclusionNode and
|
|
AssignmentNode. Manages the positional and keyword arguments to be passed
|
|
to the decorated function.
|
|
"""
|
|
|
|
def __init__(self, takes_context, args, kwargs):
|
|
self.takes_context = takes_context
|
|
self.args = args
|
|
self.kwargs = kwargs
|
|
|
|
def get_resolved_arguments(self, context):
|
|
resolved_args = [var.resolve(context) for var in self.args]
|
|
if self.takes_context:
|
|
resolved_args = [context] + resolved_args
|
|
resolved_kwargs = {k: v.resolve(context) for k, v in self.kwargs.items()}
|
|
return resolved_args, resolved_kwargs
|
|
|
|
|
|
class Library(object):
|
|
def __init__(self):
|
|
self.filters = {}
|
|
self.tags = {}
|
|
|
|
def tag(self, name=None, compile_function=None):
|
|
if name is None and compile_function is None:
|
|
# @register.tag()
|
|
return self.tag_function
|
|
elif name is not None and compile_function is None:
|
|
if callable(name):
|
|
# @register.tag
|
|
return self.tag_function(name)
|
|
else:
|
|
# @register.tag('somename') or @register.tag(name='somename')
|
|
def dec(func):
|
|
return self.tag(name, func)
|
|
return dec
|
|
elif name is not None and compile_function is not None:
|
|
# register.tag('somename', somefunc)
|
|
self.tags[name] = compile_function
|
|
return compile_function
|
|
else:
|
|
raise InvalidTemplateLibrary("Unsupported arguments to "
|
|
"Library.tag: (%r, %r)", (name, compile_function))
|
|
|
|
def tag_function(self, func):
|
|
self.tags[getattr(func, "_decorated_function", func).__name__] = func
|
|
return func
|
|
|
|
def filter(self, name=None, filter_func=None, **flags):
|
|
if name is None and filter_func is None:
|
|
# @register.filter()
|
|
def dec(func):
|
|
return self.filter_function(func, **flags)
|
|
return dec
|
|
|
|
elif name is not None and filter_func is None:
|
|
if callable(name):
|
|
# @register.filter
|
|
return self.filter_function(name, **flags)
|
|
else:
|
|
# @register.filter('somename') or @register.filter(name='somename')
|
|
def dec(func):
|
|
return self.filter(name, func, **flags)
|
|
return dec
|
|
|
|
elif name is not None and filter_func is not None:
|
|
# register.filter('somename', somefunc)
|
|
self.filters[name] = filter_func
|
|
for attr in ('expects_localtime', 'is_safe', 'needs_autoescape'):
|
|
if attr in flags:
|
|
value = flags[attr]
|
|
# set the flag on the filter for FilterExpression.resolve
|
|
setattr(filter_func, attr, value)
|
|
# set the flag on the innermost decorated function
|
|
# for decorators that need it e.g. stringfilter
|
|
if hasattr(filter_func, "_decorated_function"):
|
|
setattr(filter_func._decorated_function, attr, value)
|
|
filter_func._filter_name = name
|
|
return filter_func
|
|
else:
|
|
raise InvalidTemplateLibrary("Unsupported arguments to "
|
|
"Library.filter: (%r, %r)", (name, filter_func))
|
|
|
|
def filter_function(self, func, **flags):
|
|
name = getattr(func, "_decorated_function", func).__name__
|
|
return self.filter(name, func, **flags)
|
|
|
|
def simple_tag(self, func=None, takes_context=None, name=None):
|
|
def dec(func):
|
|
params, varargs, varkw, defaults = getargspec(func)
|
|
|
|
class SimpleNode(TagHelperNode):
|
|
|
|
def render(self, context):
|
|
resolved_args, resolved_kwargs = self.get_resolved_arguments(context)
|
|
return func(*resolved_args, **resolved_kwargs)
|
|
|
|
function_name = (name or
|
|
getattr(func, '_decorated_function', func).__name__)
|
|
compile_func = partial(generic_tag_compiler,
|
|
params=params, varargs=varargs, varkw=varkw,
|
|
defaults=defaults, name=function_name,
|
|
takes_context=takes_context, node_class=SimpleNode)
|
|
compile_func.__doc__ = func.__doc__
|
|
self.tag(function_name, compile_func)
|
|
return func
|
|
|
|
if func is None:
|
|
# @register.simple_tag(...)
|
|
return dec
|
|
elif callable(func):
|
|
# @register.simple_tag
|
|
return dec(func)
|
|
else:
|
|
raise TemplateSyntaxError("Invalid arguments provided to simple_tag")
|
|
|
|
def assignment_tag(self, func=None, takes_context=None, name=None):
|
|
def dec(func):
|
|
params, varargs, varkw, defaults = getargspec(func)
|
|
|
|
class AssignmentNode(TagHelperNode):
|
|
def __init__(self, takes_context, args, kwargs, target_var):
|
|
super(AssignmentNode, self).__init__(takes_context, args, kwargs)
|
|
self.target_var = target_var
|
|
|
|
def render(self, context):
|
|
resolved_args, resolved_kwargs = self.get_resolved_arguments(context)
|
|
context[self.target_var] = func(*resolved_args, **resolved_kwargs)
|
|
return ''
|
|
|
|
function_name = (name or
|
|
getattr(func, '_decorated_function', func).__name__)
|
|
|
|
def compile_func(parser, token):
|
|
bits = token.split_contents()[1:]
|
|
if len(bits) < 2 or bits[-2] != 'as':
|
|
raise TemplateSyntaxError(
|
|
"'%s' tag takes at least 2 arguments and the "
|
|
"second last argument must be 'as'" % function_name)
|
|
target_var = bits[-1]
|
|
bits = bits[:-2]
|
|
args, kwargs = parse_bits(parser, bits, params,
|
|
varargs, varkw, defaults, takes_context, function_name)
|
|
return AssignmentNode(takes_context, args, kwargs, target_var)
|
|
|
|
compile_func.__doc__ = func.__doc__
|
|
self.tag(function_name, compile_func)
|
|
return func
|
|
|
|
if func is None:
|
|
# @register.assignment_tag(...)
|
|
return dec
|
|
elif callable(func):
|
|
# @register.assignment_tag
|
|
return dec(func)
|
|
else:
|
|
raise TemplateSyntaxError("Invalid arguments provided to assignment_tag")
|
|
|
|
def inclusion_tag(self, file_name, takes_context=False, name=None):
|
|
def dec(func):
|
|
params, varargs, varkw, defaults = getargspec(func)
|
|
|
|
class InclusionNode(TagHelperNode):
|
|
|
|
def render(self, context):
|
|
"""
|
|
Renders the specified template and context. Caches the
|
|
template object in render_context to avoid reparsing and
|
|
loading when used in a for loop.
|
|
"""
|
|
resolved_args, resolved_kwargs = self.get_resolved_arguments(context)
|
|
_dict = func(*resolved_args, **resolved_kwargs)
|
|
|
|
t = context.render_context.get(self)
|
|
if t is None:
|
|
if isinstance(file_name, Template):
|
|
t = file_name
|
|
elif isinstance(getattr(file_name, 'template', None), Template):
|
|
t = file_name.template
|
|
elif not isinstance(file_name, six.string_types) and is_iterable(file_name):
|
|
t = context.template.engine.select_template(file_name)
|
|
else:
|
|
t = context.template.engine.get_template(file_name)
|
|
context.render_context[self] = t
|
|
new_context = context.new(_dict)
|
|
# Copy across the CSRF token, if present, because
|
|
# inclusion tags are often used for forms, and we need
|
|
# instructions for using CSRF protection to be as simple
|
|
# as possible.
|
|
csrf_token = context.get('csrf_token', None)
|
|
if csrf_token is not None:
|
|
new_context['csrf_token'] = csrf_token
|
|
return t.render(new_context)
|
|
|
|
function_name = (name or
|
|
getattr(func, '_decorated_function', func).__name__)
|
|
compile_func = partial(generic_tag_compiler,
|
|
params=params, varargs=varargs, varkw=varkw,
|
|
defaults=defaults, name=function_name,
|
|
takes_context=takes_context, node_class=InclusionNode)
|
|
compile_func.__doc__ = func.__doc__
|
|
self.tag(function_name, compile_func)
|
|
return func
|
|
return dec
|
|
|
|
|
|
def is_library_missing(name):
|
|
"""Check if library that failed to load cannot be found under any
|
|
templatetags directory or does exist but fails to import.
|
|
|
|
Non-existing condition is checked recursively for each subpackage in cases
|
|
like <appdir>/templatetags/subpackage/package/module.py.
|
|
"""
|
|
# Don't bother to check if '.' is in name since any name will be prefixed
|
|
# with some template root.
|
|
path, module = name.rsplit('.', 1)
|
|
try:
|
|
package = import_module(path)
|
|
return not module_has_submodule(package, module)
|
|
except ImportError:
|
|
return is_library_missing(path)
|
|
|
|
|
|
def import_library(taglib_module):
|
|
"""
|
|
Load a template tag library module.
|
|
|
|
Verifies that the library contains a 'register' attribute, and
|
|
returns that attribute as the representation of the library
|
|
"""
|
|
try:
|
|
mod = import_module(taglib_module)
|
|
except ImportError as e:
|
|
# If the ImportError is because the taglib submodule does not exist,
|
|
# that's not an error that should be raised. If the submodule exists
|
|
# and raised an ImportError on the attempt to load it, that we want
|
|
# to raise.
|
|
if is_library_missing(taglib_module):
|
|
return None
|
|
else:
|
|
raise InvalidTemplateLibrary("ImportError raised loading %s: %s" %
|
|
(taglib_module, e))
|
|
try:
|
|
return mod.register
|
|
except AttributeError:
|
|
raise InvalidTemplateLibrary("Template library %s does not have "
|
|
"a variable named 'register'" %
|
|
taglib_module)
|
|
|
|
|
|
@lru_cache.lru_cache()
|
|
def get_templatetags_modules():
|
|
"""
|
|
Return the list of all available template tag modules.
|
|
|
|
Caches the result for faster access.
|
|
"""
|
|
templatetags_modules_candidates = ['django.templatetags']
|
|
templatetags_modules_candidates.extend(
|
|
'%s.templatetags' % app_config.name
|
|
for app_config in apps.get_app_configs())
|
|
|
|
templatetags_modules = []
|
|
for templatetag_module in templatetags_modules_candidates:
|
|
try:
|
|
import_module(templatetag_module)
|
|
except ImportError:
|
|
continue
|
|
else:
|
|
templatetags_modules.append(templatetag_module)
|
|
return templatetags_modules
|
|
|
|
|
|
def get_library(library_name):
|
|
"""
|
|
Load the template library module with the given name.
|
|
|
|
If library is not already loaded loop over all templatetags modules
|
|
to locate it.
|
|
|
|
{% load somelib %} and {% load someotherlib %} loops twice.
|
|
|
|
Subsequent loads eg. {% load somelib %} in the same process will grab
|
|
the cached module from libraries.
|
|
"""
|
|
lib = libraries.get(library_name, None)
|
|
if not lib:
|
|
templatetags_modules = get_templatetags_modules()
|
|
tried_modules = []
|
|
for module in templatetags_modules:
|
|
taglib_module = '%s.%s' % (module, library_name)
|
|
tried_modules.append(taglib_module)
|
|
lib = import_library(taglib_module)
|
|
if lib:
|
|
libraries[library_name] = lib
|
|
break
|
|
if not lib:
|
|
raise InvalidTemplateLibrary("Template library %s not found, "
|
|
"tried %s" %
|
|
(library_name,
|
|
','.join(tried_modules)))
|
|
return lib
|
|
|
|
|
|
def add_to_builtins(module):
|
|
builtins.append(import_library(module))
|
|
|
|
|
|
add_to_builtins('django.template.defaulttags')
|
|
add_to_builtins('django.template.defaultfilters')
|
|
add_to_builtins('django.template.loader_tags')
|