import imp import re from functools import partial from inspect import getargspec from django.conf import settings from django.template.context import Context, RequestContext, ContextPopException from django.utils.importlib import import_module from django.utils.itercompat import is_iterable from django.utils.functional import Promise from django.utils.text import smart_split, unescape_string_literal, get_text_list from django.utils.encoding import smart_unicode, force_unicode, smart_str from django.utils.translation import ugettext_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 TOKEN_TEXT = 0 TOKEN_VAR = 1 TOKEN_BLOCK = 2 TOKEN_COMMENT = 3 # 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 = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.' # 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 # uninitialised. invalid_var_format_string = None class TemplateSyntaxError(Exception): pass class TemplateDoesNotExist(Exception): pass class TemplateEncodingError(Exception): pass class VariableDoesNotExist(Exception): def __init__(self, msg, params=()): self.msg = msg self.params = params def __str__(self): return unicode(self).encode('utf-8') def __unicode__(self): return self.msg % tuple([force_unicode(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 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=''): try: template_string = smart_unicode(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 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 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): return '<%s token: "%s...">' % \ ({TOKEN_TEXT: 'Text', TOKEN_VAR: 'Var', TOKEN_BLOCK: 'Block', TOKEN_COMMENT: 'Comment'}[self.token_type], 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 = bits.next() 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 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: if token_string.startswith(VARIABLE_TAG_START): token = Token(TOKEN_VAR, token_string[len(VARIABLE_TAG_START):-len(VARIABLE_TAG_END)].strip()) elif token_string.startswith(BLOCK_TAG_START): token = Token(TOKEN_BLOCK, token_string[len(BLOCK_TAG_START):-len(BLOCK_TAG_END)].strip()) elif token_string.startswith(COMMENT_TAG_START): content = '' if token_string.find(TRANSLATOR_COMMENT_MARK): content = token_string[len(COMMENT_TAG_START):-len(COMMENT_TAG_END)].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() if token.token_type == TOKEN_TEXT: self.extend_nodelist(nodelist, TextNode(token.contents), token) elif token.token_type == TOKEN_VAR: if not token.contents: self.empty_variable(token) filter_expression = self.compile_filter(token.contents) var_node = self.create_variable_node(filter_expression) self.extend_nodelist(nodelist, var_node,token) elif token.token_type == TOKEN_BLOCK: if token.contents in parse_until: # put token back on token list so calling code knows why it terminated self.prepend_token(token) return nodelist try: command = token.contents.split()[0] except IndexError: self.empty_block_tag(token) # 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, 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_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() 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)| (?:%(filter_sep)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): r""" 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 This class should never be instantiated outside of the get_filters_from_token helper function. """ 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, '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) plen = len(provided) # Check to see if a decorator is providing the real function. func = getattr(func, '_decorated_function', func) args, varargs, varkw, defaults = getargspec(func) # First argument is filter input. args.pop(0) if defaults: nondefs = args[:-len(defaults)] else: nondefs = args # Args without defaults must be provided. try: for arg in nondefs: provided.pop(0) except IndexError: # Not enough raise TemplateSyntaxError("%s requires %d arguments, %d provided" % (name, len(nondefs), plen)) # Defaults can be overridden. defaults = defaults and list(defaults) or [] try: for parg in provided: defaults.pop(0) except IndexError: # Too many. raise TemplateSyntaxError("%s requires %d arguments, %d provided" % (name, len(nondefs), 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. """ return Variable(path).resolve(context) class Variable(object): r""" 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 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: 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] except (TypeError, AttributeError, KeyError): try: # attribute lookup current = getattr(current, bit) except (TypeError, AttributeError): 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: # arguments *were* required # GOTCHA: This will also catch any TypeError # raised in the function itself. current = settings.TEMPLATE_STRING_IF_INVALID # invalid method call except Exception, 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): bits.append(self.render_node(node, context)) else: bits.append(node) return mark_safe(''.join([force_unicode(b) for b in 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 "" % smart_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 = localize(value, use_l10n=context.use_l10n) value = force_unicode(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) def generic_tag_compiler(params, defaults, name, node_class, parser, token): "Returns a template.Node subclass." bits = token.split_contents()[1:] bmax = len(params) def_len = defaults and len(defaults) or 0 bmin = bmax - def_len if(len(bits) < bmin or len(bits) > bmax): if bmin == bmax: message = "%s takes %s arguments" % (name, bmin) else: message = "%s takes between %s and %s arguments" % (name, bmin, bmax) raise TemplateSyntaxError(message) return node_class(bits) class Library(object): def __init__(self): self.filters = {} self.tags = {} def tag(self, name=None, compile_function=None): if name == None and compile_function == None: # @register.tag() return self.tag_function elif name != None and compile_function == 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 != None and compile_function != 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): if name == None and filter_func == None: # @register.filter() return self.filter_function elif filter_func == None: if callable(name): # @register.filter return self.filter_function(name) else: # @register.filter('somename') or @register.filter(name='somename') def dec(func): return self.filter(name, func) return dec elif name != None and filter_func != None: # register.filter('somename', somefunc) self.filters[name] = filter_func return filter_func else: raise InvalidTemplateLibrary("Unsupported arguments to Library.filter: (%r, %r)", (name, filter_func)) def filter_function(self, func): self.filters[getattr(func, "_decorated_function", func).__name__] = func return func def simple_tag(self, func=None, takes_context=None): def dec(func): params, xx, xxx, defaults = getargspec(func) if takes_context: if params[0] == 'context': params = params[1:] else: raise TemplateSyntaxError("Any tag function decorated with takes_context=True must have a first argument of 'context'") class SimpleNode(Node): def __init__(self, vars_to_resolve): self.vars_to_resolve = map(Variable, vars_to_resolve) def render(self, context): resolved_vars = [var.resolve(context) for var in self.vars_to_resolve] if takes_context: func_args = [context] + resolved_vars else: func_args = resolved_vars return func(*func_args) compile_func = partial(generic_tag_compiler, params, defaults, getattr(func, "_decorated_function", func).__name__, SimpleNode) compile_func.__doc__ = func.__doc__ self.tag(getattr(func, "_decorated_function", func).__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): def dec(func): params, xx, xxx, defaults = getargspec(func) if takes_context: if params[0] == 'context': params = params[1:] else: raise TemplateSyntaxError("Any tag function decorated with takes_context=True must have a first argument of 'context'") class AssignmentNode(Node): def __init__(self, params_vars, target_var): self.params_vars = map(Variable, params_vars) self.target_var = target_var def render(self, context): resolved_vars = [var.resolve(context) for var in self.params_vars] if takes_context: func_args = [context] + resolved_vars else: func_args = resolved_vars context[self.target_var] = func(*func_args) return '' def compile_func(parser, token): bits = token.split_contents() tag_name = bits[0] bits = bits[1:] params_max = len(params) defaults_length = defaults and len(defaults) or 0 params_min = params_max - defaults_length 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'" % tag_name) params_vars = bits[:-2] target_var = bits[-1] if (len(params_vars) < params_min or len(params_vars) > params_max): if params_min == params_max: raise TemplateSyntaxError( "%s takes %s arguments" % (tag_name, params_min)) else: raise TemplateSyntaxError( "%s takes between %s and %s arguments" % (tag_name, params_min, params_max)) return AssignmentNode(params_vars, target_var) compile_func.__doc__ = func.__doc__ self.tag(getattr(func, "_decorated_function", func).__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): def dec(func): params, xx, xxx, defaults = getargspec(func) if takes_context: if params[0] == 'context': params = params[1:] else: raise TemplateSyntaxError("Any tag function decorated with takes_context=True must have a first argument of 'context'") class InclusionNode(Node): def __init__(self, vars_to_resolve): self.vars_to_resolve = map(Variable, vars_to_resolve) def render(self, context): resolved_vars = [var.resolve(context) for var in self.vars_to_resolve] if takes_context: args = [context] + resolved_vars else: args = resolved_vars dict = func(*args) if not getattr(self, 'nodelist', False): from django.template.loader import get_template, select_template if not isinstance(file_name, basestring) 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, }) # 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) compile_func = partial(generic_tag_compiler, params, defaults, getattr(func, "_decorated_function", func).__name__, InclusionNode) compile_func.__doc__ = func.__doc__ self.tag(getattr(func, "_decorated_function", func).__name__, compile_func) return func return dec 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 """ app_path, taglib = taglib_module.rsplit('.',1) app_module = import_module(app_path) try: mod = import_module(taglib_module) except ImportError, 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 not module_has_submodule(app_module, taglib): 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 thread. for app_module in ['django'] + list(settings.INSTALLED_APPS): try: templatetag_module = '%s.templatetags' % app_module 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')