from __future__ import unicode_literals import re from functools import partial from importlib import import_module from inspect import getargspec, getcallargs import warnings from django.apps import apps from django.conf import settings from django.template.context import (BaseContext, Context, RequestContext, # NOQA: imported for backwards compatibility ContextPopException) from django.utils.deprecation import RemovedInDjango20Warning from django.utils.itercompat import is_iterable from django.utils.text import (smart_split, unescape_string_literal, get_text_list) from django.utils.encoding import force_str, force_text from django.utils.translation import ugettext_lazy, pgettext_lazy from django.utils.safestring import (SafeData, EscapeData, mark_safe, mark_for_escaping) from django.utils.formats import localize from django.utils.html import escape from django.utils.module_loading import module_has_submodule from django.utils import six from django.utils.timezone import template_localtime from django.utils.encoding import python_2_unicode_compatible TOKEN_TEXT = 0 TOKEN_VAR = 1 TOKEN_BLOCK = 2 TOKEN_COMMENT = 3 TOKEN_MAPPING = { TOKEN_TEXT: 'Text', TOKEN_VAR: 'Var', TOKEN_BLOCK: 'Block', TOKEN_COMMENT: 'Comment', } # template syntax constants FILTER_SEPARATOR = '|' FILTER_ARGUMENT_SEPARATOR = ':' VARIABLE_ATTRIBUTE_SEPARATOR = '.' BLOCK_TAG_START = '{%' BLOCK_TAG_END = '%}' VARIABLE_TAG_START = '{{' VARIABLE_TAG_END = '}}' COMMENT_TAG_START = '{#' COMMENT_TAG_END = '#}' TRANSLATOR_COMMENT_MARK = 'Translators' SINGLE_BRACE_START = '{' SINGLE_BRACE_END = '}' ALLOWED_VARIABLE_CHARS = ('abcdefghijklmnopqrstuvwxyz' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.') # what to report as the origin for templates that come from non-loader sources # (e.g. strings) UNKNOWN_SOURCE = '' # match a variable or block tag and capture the entire tag, including start/end # delimiters tag_re = (re.compile('(%s.*?%s|%s.*?%s|%s.*?%s)' % (re.escape(BLOCK_TAG_START), re.escape(BLOCK_TAG_END), re.escape(VARIABLE_TAG_START), re.escape(VARIABLE_TAG_END), re.escape(COMMENT_TAG_START), re.escape(COMMENT_TAG_END)))) # global dictionary of libraries that have been loaded using get_library libraries = {} # global list of libraries to load by default for a new parser builtins = [] # True if TEMPLATE_STRING_IF_INVALID contains a format string (%s). None means # uninitialized. invalid_var_format_string = None class TemplateSyntaxError(Exception): pass class TemplateDoesNotExist(Exception): pass class TemplateEncodingError(Exception): pass @python_2_unicode_compatible class VariableDoesNotExist(Exception): def __init__(self, msg, params=()): self.msg = msg self.params = params def __str__(self): return self.msg % tuple(force_text(p, errors='replace') for p in self.params) class InvalidTemplateLibrary(Exception): pass class Origin(object): def __init__(self, name): self.name = name def reload(self): raise NotImplementedError('subclasses of Origin must provide a reload() method') def __str__(self): return self.name class StringOrigin(Origin): def __init__(self, source): super(StringOrigin, self).__init__(UNKNOWN_SOURCE) self.source = source def reload(self): return self.source class Template(object): def __init__(self, template_string, origin=None, name=None): try: template_string = force_text(template_string) except UnicodeDecodeError: raise TemplateEncodingError("Templates can only be constructed " "from unicode or UTF-8 strings.") if settings.TEMPLATE_DEBUG and origin is None: origin = StringOrigin(template_string) self.nodelist = compile_string(template_string, origin) self.name = name self.origin = origin def __iter__(self): for node in self.nodelist: for subnode in node: yield subnode def _render(self, context): return self.nodelist.render(context) def render(self, context): "Display stage -- can be called many times" context.render_context.push() try: return self._render(context) finally: context.render_context.pop() def compile_string(template_string, origin): "Compiles template_string into NodeList ready for rendering" if settings.TEMPLATE_DEBUG: from django.template.debug import DebugLexer, DebugParser lexer_class, parser_class = DebugLexer, DebugParser else: lexer_class, parser_class = Lexer, Parser lexer = lexer_class(template_string, origin) parser = parser_class(lexer.tokenize()) return parser.parse() class Token(object): def __init__(self, token_type, contents): # token_type must be TOKEN_TEXT, TOKEN_VAR, TOKEN_BLOCK or # TOKEN_COMMENT. self.token_type, self.contents = token_type, contents self.lineno = None def __str__(self): token_name = TOKEN_MAPPING[self.token_type] return ('<%s token: "%s...">' % (token_name, self.contents[:20].replace('\n', ''))) def split_contents(self): split = [] bits = iter(smart_split(self.contents)) for bit in bits: # Handle translation-marked template pieces if bit.startswith('_("') or bit.startswith("_('"): sentinal = bit[2] + ')' trans_bit = [bit] while not bit.endswith(sentinal): bit = next(bits) trans_bit.append(bit) bit = ' '.join(trans_bit) split.append(bit) return split class Lexer(object): def __init__(self, template_string, origin): self.template_string = template_string self.origin = origin self.lineno = 1 self.verbatim = False def tokenize(self): """ Return a list of tokens from a given template_string. """ in_tag = False result = [] for bit in tag_re.split(self.template_string): if bit: result.append(self.create_token(bit, in_tag)) in_tag = not in_tag return result def create_token(self, token_string, in_tag): """ Convert the given token string into a new Token object and return it. If in_tag is True, we are processing something that matched a tag, otherwise it should be treated as a literal string. """ if in_tag and token_string.startswith(BLOCK_TAG_START): # The [2:-2] ranges below strip off *_TAG_START and *_TAG_END. # We could do len(BLOCK_TAG_START) to be more "correct", but we've # hard-coded the 2s here for performance. And it's not like # the TAG_START values are going to change anytime, anyway. block_content = token_string[2:-2].strip() if self.verbatim and block_content == self.verbatim: self.verbatim = False if in_tag and not self.verbatim: if token_string.startswith(VARIABLE_TAG_START): token = Token(TOKEN_VAR, token_string[2:-2].strip()) elif token_string.startswith(BLOCK_TAG_START): if block_content[:9] in ('verbatim', 'verbatim '): self.verbatim = 'end%s' % block_content token = Token(TOKEN_BLOCK, block_content) elif token_string.startswith(COMMENT_TAG_START): content = '' if token_string.find(TRANSLATOR_COMMENT_MARK): content = token_string[2:-2].strip() token = Token(TOKEN_COMMENT, content) else: token = Token(TOKEN_TEXT, token_string) token.lineno = self.lineno self.lineno += token_string.count('\n') return token class Parser(object): def __init__(self, tokens): self.tokens = tokens self.tags = {} self.filters = {} for lib in builtins: self.add_library(lib) def parse(self, parse_until=None): if parse_until is None: parse_until = [] nodelist = self.create_nodelist() while self.tokens: token = self.next_token() # Use the raw values here for TOKEN_* for a tiny performance boost. if token.token_type == 0: # TOKEN_TEXT self.extend_nodelist(nodelist, TextNode(token.contents), token) elif token.token_type == 1: # TOKEN_VAR if not token.contents: self.empty_variable(token) try: filter_expression = self.compile_filter(token.contents) except TemplateSyntaxError as e: if not self.compile_filter_error(token, e): raise var_node = self.create_variable_node(filter_expression) self.extend_nodelist(nodelist, var_node, token) elif token.token_type == 2: # TOKEN_BLOCK try: command = token.contents.split()[0] except IndexError: self.empty_block_tag(token) if command in parse_until: # put token back on token list so calling # code knows why it terminated self.prepend_token(token) return nodelist # execute callback function for this tag and append # resulting node self.enter_command(command, token) try: compile_func = self.tags[command] except KeyError: self.invalid_block_tag(token, command, parse_until) try: compiled_result = compile_func(self, token) except TemplateSyntaxError as e: if not self.compile_function_error(token, e): raise self.extend_nodelist(nodelist, compiled_result, token) self.exit_command() if parse_until: self.unclosed_block_tag(parse_until) return nodelist def skip_past(self, endtag): while self.tokens: token = self.next_token() if token.token_type == TOKEN_BLOCK and token.contents == endtag: return self.unclosed_block_tag([endtag]) def create_variable_node(self, filter_expression): return VariableNode(filter_expression) def create_nodelist(self): return NodeList() def extend_nodelist(self, nodelist, node, token): if node.must_be_first and nodelist: try: if nodelist.contains_nontext: raise AttributeError except AttributeError: raise TemplateSyntaxError("%r must be the first tag " "in the template." % node) if isinstance(nodelist, NodeList) and not isinstance(node, TextNode): nodelist.contains_nontext = True nodelist.append(node) def enter_command(self, command, token): pass def exit_command(self): pass def error(self, token, msg): return TemplateSyntaxError(msg) def empty_variable(self, token): raise self.error(token, "Empty variable tag") def empty_block_tag(self, token): raise self.error(token, "Empty block tag") def invalid_block_tag(self, token, command, parse_until=None): if parse_until: raise self.error(token, "Invalid block tag: '%s', expected %s" % (command, get_text_list(["'%s'" % p for p in parse_until]))) raise self.error(token, "Invalid block tag: '%s'" % command) def unclosed_block_tag(self, parse_until): raise self.error(None, "Unclosed tags: %s " % ', '.join(parse_until)) def compile_filter_error(self, token, e): pass def compile_function_error(self, token, e): pass def next_token(self): return self.tokens.pop(0) def prepend_token(self, token): self.tokens.insert(0, token) def delete_first_token(self): del self.tokens[0] def add_library(self, lib): self.tags.update(lib.tags) self.filters.update(lib.filters) def compile_filter(self, token): """ Convenient wrapper for FilterExpression """ return FilterExpression(token, self) def find_filter(self, filter_name): if filter_name in self.filters: return self.filters[filter_name] else: raise TemplateSyntaxError("Invalid filter: '%s'" % filter_name) class TokenParser(object): """ Subclass this and implement the top() method to parse a template line. When instantiating the parser, pass in the line from the Django template parser. The parser's "tagname" instance-variable stores the name of the tag that the filter was called with. """ def __init__(self, subject): self.subject = subject self.pointer = 0 self.backout = [] self.tagname = self.tag() def top(self): """ Overload this method to do the actual parsing and return the result. """ raise NotImplementedError('subclasses of Tokenparser must provide a top() method') def more(self): """ Returns True if there is more stuff in the tag. """ return self.pointer < len(self.subject) def back(self): """ Undoes the last microparser. Use this for lookahead and backtracking. """ if not len(self.backout): raise TemplateSyntaxError("back called without some previous " "parsing") self.pointer = self.backout.pop() def tag(self): """ A microparser that just returns the next tag from the line. """ subject = self.subject i = self.pointer if i >= len(subject): raise TemplateSyntaxError("expected another tag, found " "end of string: %s" % subject) p = i while i < len(subject) and subject[i] not in (' ', '\t'): i += 1 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 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] i += 1 while i < len(subject) and subject[i] != c: i += 1 if i >= len(subject): raise TemplateSyntaxError("Searching for value. " "Unexpected end of string in column %d: %s" % (i, subject)) i += 1 return i if i >= len(subject): raise TemplateSyntaxError("Searching for value. Expected another " "value but found end of string: %s" % 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" % (i, subject)) 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)s)| ^(?P[%(var_chars)s]+|%(num)s)| (?:\s*%(filter_sep)s\s* (?P\w+) (?:%(arg_sep)s (?: (?P%(constant)s)| (?P[%(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 """ 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: if settings.TEMPLATE_STRING_IF_INVALID: global invalid_var_format_string if invalid_var_format_string is None: invalid_var_format_string = '%s' in settings.TEMPLATE_STRING_IF_INVALID if invalid_var_format_string: return settings.TEMPLATE_STRING_IF_INVALID % self.var return settings.TEMPLATE_STRING_IF_INVALID else: obj = settings.TEMPLATE_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 = settings.TEMPLATE_STRING_IF_INVALID else: try: # method call (assuming no args required) current = current() except TypeError: try: getcallargs(current) except TypeError: # arguments *were* required current = settings.TEMPLATE_STRING_IF_INVALID # invalid method call else: raise except Exception as e: if getattr(e, 'silent_variable_failure', False): current = settings.TEMPLATE_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("" % 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 escape(value) else: return value class VariableNode(Node): def __init__(self, filter_expression): self.filter_expression = filter_expression def __repr__(self): return "" % 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 = dict((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, context_class=Context, takes_context=False, name=None): def dec(func): params, varargs, varkw, defaults = getargspec(func) class InclusionNode(TagHelperNode): def render(self, context): resolved_args, resolved_kwargs = self.get_resolved_arguments(context) _dict = func(*resolved_args, **resolved_kwargs) if not getattr(self, 'nodelist', False): from django.template.loader import get_template, select_template if isinstance(file_name, Template): t = file_name elif not isinstance(file_name, six.string_types) and is_iterable(file_name): t = select_template(file_name) else: t = get_template(file_name) self.nodelist = t.nodelist new_context = context_class(_dict, **{ 'autoescape': context.autoescape, 'current_app': context.current_app, 'use_l10n': context.use_l10n, 'use_tz': context.use_tz, }) # 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 self.nodelist.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 /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) templatetags_modules = [] def get_templatetags_modules(): """ Return the list of all available template tag modules. Caches the result for faster access. """ global templatetags_modules if not templatetags_modules: _templatetags_modules = [] # Populate list once per process. Mutate the local list first, and # then assign it to the global name to ensure there are no cases where # two threads try to populate it simultaneously. templatetags_modules_candidates = ['django.templatetags'] templatetags_modules_candidates += ['%s.templatetags' % app_config.name for app_config in apps.get_app_configs()] for templatetag_module in templatetags_modules_candidates: try: import_module(templatetag_module) _templatetags_modules.append(templatetag_module) except ImportError: continue templatetags_modules = _templatetags_modules 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')