1 # -*- coding: utf-8 -*-
6 Jinja extensions allow to add custom tags similar to the way django custom
7 tags work. By default two example extensions exist: an i18n and a cache
10 :copyright: Copyright 2008 by Armin Ronacher.
13 from collections import deque
14 from jinja2 import nodes
15 from jinja2.environment import get_spontaneous_environment
16 from jinja2.runtime import Undefined, concat
17 from jinja2.exceptions import TemplateAssertionError, TemplateSyntaxError
18 from jinja2.utils import contextfunction, import_string, Markup
21 # the only real useful gettext functions for a Jinja template. Note
22 # that ugettext must be assigned to gettext as Jinja doesn't support
23 # non unicode strings.
24 GETTEXT_FUNCTIONS = ('_', 'gettext', 'ngettext')
27 class ExtensionRegistry(type):
28 """Gives the extension an unique identifier."""
30 def __new__(cls, name, bases, d):
31 rv = type.__new__(cls, name, bases, d)
32 rv.identifier = rv.__module__ + '.' + rv.__name__
36 class Extension(object):
37 """Extensions can be used to add extra functionality to the Jinja template
38 system at the parser level. Custom extensions are bound to an environment
39 but may not store environment specific data on `self`. The reason for
40 this is that an extension can be bound to another environment (for
41 overlays) by creating a copy and reassigning the `environment` attribute.
43 As extensions are created by the environment they cannot accept any
44 arguments for configuration. One may want to work around that by using
45 a factory function, but that is not possible as extensions are identified
46 by their import name. The correct way to configure the extension is
47 storing the configuration values on the environment. Because this way the
48 environment ends up acting as central configuration storage the
49 attributes may clash which is why extensions have to ensure that the names
50 they choose for configuration are not too generic. ``prefix`` for example
51 is a terrible name, ``fragment_cache_prefix`` on the other hand is a good
52 name as includes the name of the extension (fragment cache).
54 __metaclass__ = ExtensionRegistry
56 #: if this extension parses this is the list of tags it's listening to.
59 def __init__(self, environment):
60 self.environment = environment
62 def bind(self, environment):
63 """Create a copy of this extension bound to another environment."""
64 rv = object.__new__(self.__class__)
65 rv.__dict__.update(self.__dict__)
66 rv.environment = environment
69 def parse(self, parser):
70 """If any of the :attr:`tags` matched this method is called with the
71 parser as first argument. The token the parser stream is pointing at
72 is the name token that matched. This method has to return one or a
73 list of multiple nodes.
75 raise NotImplementedError()
77 def attr(self, name, lineno=None):
78 """Return an attribute node for the current extension. This is useful
79 to pass constants on extensions to generated template code::
81 self.attr('_my_attribute', lineno=lineno)
83 return nodes.ExtensionAttribute(self.identifier, name, lineno=lineno)
85 def call_method(self, name, args=None, kwargs=None, dyn_args=None,
86 dyn_kwargs=None, lineno=None):
87 """Call a method of the extension. This is a shortcut for
88 :meth:`attr` + :class:`jinja2.nodes.Call`.
94 return nodes.Call(self.attr(name, lineno=lineno), args, kwargs,
95 dyn_args, dyn_kwargs, lineno=lineno)
99 def _gettext_alias(context, string):
100 return context.resolve('gettext')(string)
103 class InternationalizationExtension(Extension):
104 """This extension adds gettext support to Jinja2."""
105 tags = set(['trans'])
107 def __init__(self, environment):
108 Extension.__init__(self, environment)
109 environment.globals['_'] = _gettext_alias
111 install_gettext_translations=self._install,
112 install_null_translations=self._install_null,
113 uninstall_gettext_translations=self._uninstall,
114 extract_translations=self._extract
117 def _install(self, translations):
118 self.environment.globals.update(
119 gettext=translations.ugettext,
120 ngettext=translations.ungettext
123 def _install_null(self):
124 self.environment.globals.update(
126 ngettext=lambda s, p, n: (n != 1 and (p,) or (s,))[0]
129 def _uninstall(self, translations):
130 for key in 'gettext', 'ngettext':
131 self.environment.globals.pop(key, None)
133 def _extract(self, source, gettext_functions=GETTEXT_FUNCTIONS):
134 if isinstance(source, basestring):
135 source = self.environment.parse(source)
136 return extract_from_ast(source, gettext_functions)
138 def parse(self, parser):
139 """Parse a translatable tag."""
140 lineno = parser.stream.next().lineno
142 # find all the variables referenced. Additionally a variable can be
143 # defined in the body of the trans block too, but this is checked at
147 while parser.stream.current.type is not 'block_end':
149 parser.stream.expect('comma')
151 # skip colon for python compatibility
152 if parser.stream.skip_if('colon'):
155 name = parser.stream.expect('name')
156 if name.value in variables:
157 parser.fail('translatable variable %r defined twice.' %
158 name.value, name.lineno,
159 exc=TemplateAssertionError)
162 if parser.stream.current.type is 'assign':
164 variables[name.value] = var = parser.parse_expression()
166 variables[name.value] = var = nodes.Name(name.value, 'load')
167 if plural_expr is None:
170 parser.stream.expect('block_end')
172 plural = plural_names = None
176 # now parse until endtrans or pluralize
177 singular_names, singular = self._parse_block(parser, True)
179 referenced.update(singular_names)
180 if plural_expr is None:
181 plural_expr = nodes.Name(singular_names[0], 'load')
183 # if we have a pluralize block, we parse that too
184 if parser.stream.current.test('name:pluralize'):
187 if parser.stream.current.type is not 'block_end':
188 plural_expr = parser.parse_expression()
189 parser.stream.expect('block_end')
190 plural_names, plural = self._parse_block(parser, False)
192 referenced.update(plural_names)
196 # register free names as simple name expressions
197 for var in referenced:
198 if var not in variables:
199 variables[var] = nodes.Name(var, 'load')
201 # no variables referenced? no need to escape
203 singular = singular.replace('%%', '%')
205 plural = plural.replace('%%', '%')
209 elif plural_expr is None:
210 parser.fail('pluralize without variables', lineno)
213 variables = nodes.Dict([nodes.Pair(nodes.Const(x, lineno=lineno), y)
214 for x, y in variables.items()])
218 node = self._make_node(singular, plural, variables, plural_expr)
219 node.set_lineno(lineno)
222 def _parse_block(self, parser, allow_pluralize):
223 """Parse until the next block tag with a given name."""
227 if parser.stream.current.type is 'data':
228 buf.append(parser.stream.current.value.replace('%', '%%'))
230 elif parser.stream.current.type is 'variable_begin':
232 name = parser.stream.expect('name').value
233 referenced.append(name)
234 buf.append('%%(%s)s' % name)
235 parser.stream.expect('variable_end')
236 elif parser.stream.current.type is 'block_begin':
238 if parser.stream.current.test('name:endtrans'):
240 elif parser.stream.current.test('name:pluralize'):
243 parser.fail('a translatable section can have only one '
245 parser.fail('control structures in translatable sections are '
248 assert False, 'internal parser error'
250 return referenced, concat(buf)
252 def _make_node(self, singular, plural, variables, plural_expr):
253 """Generates a useful node from the data provided."""
255 if plural_expr is None:
256 gettext = nodes.Name('gettext', 'load')
257 node = nodes.Call(gettext, [nodes.Const(singular)],
260 # singular and plural
262 ngettext = nodes.Name('ngettext', 'load')
263 node = nodes.Call(ngettext, [
264 nodes.Const(singular),
269 # mark the return value as safe if we are in an
270 # environment with autoescaping turned on
271 if self.environment.autoescape:
272 node = nodes.MarkSafe(node)
275 node = nodes.Mod(node, variables)
276 return nodes.Output([node])
279 class ExprStmtExtension(Extension):
280 """Adds a `do` tag to Jinja2 that works like the print statement just
281 that it doesn't print the return value.
285 def parse(self, parser):
286 node = nodes.ExprStmt(lineno=parser.stream.next().lineno)
287 node.node = parser.parse_tuple()
291 class LoopControlExtension(Extension):
292 """Adds break and continue to the template engine."""
293 tags = set(['break', 'continue'])
295 def parse(self, parser):
296 token = parser.stream.next()
297 if token.value == 'break':
298 return nodes.Break(lineno=token.lineno)
299 return nodes.Continue(lineno=token.lineno)
302 def extract_from_ast(node, gettext_functions=GETTEXT_FUNCTIONS):
303 """Extract localizable strings from the given template node.
305 For every string found this function yields a ``(lineno, function,
306 message)`` tuple, where:
308 * ``lineno`` is the number of the line on which the string was found,
309 * ``function`` is the name of the ``gettext`` function used (if the
310 string was extracted from embedded Python code), and
311 * ``message`` is the string itself (a ``unicode`` object, or a tuple
312 of ``unicode`` objects for functions with multiple string arguments).
314 for node in node.find_all(nodes.Call):
315 if not isinstance(node.node, nodes.Name) or \
316 node.node.name not in gettext_functions:
320 for arg in node.args:
321 if isinstance(arg, nodes.Const) and \
322 isinstance(arg.value, basestring):
323 strings.append(arg.value)
327 if len(strings) == 1:
330 strings = tuple(strings)
331 yield node.lineno, node.node.name, strings
334 def babel_extract(fileobj, keywords, comment_tags, options):
335 """Babel extraction method for Jinja templates.
337 :param fileobj: the file-like object the messages should be extracted from
338 :param keywords: a list of keywords (i.e. function names) that should be
339 recognized as translation functions
340 :param comment_tags: a list of translator tags to search for and include
341 in the results. (Unused)
342 :param options: a dictionary of additional options (optional)
343 :return: an iterator over ``(lineno, funcname, message, comments)`` tuples.
344 (comments will be empty currently)
346 encoding = options.get('encoding', 'utf-8')
348 have_trans_extension = False
350 for extension in options.get('extensions', '').split(','):
351 extension = extension.strip()
354 extension = import_string(extension)
355 if extension is InternationalizationExtension:
356 have_trans_extension = True
357 extensions.append(extension)
358 if not have_trans_extension:
359 extensions.append(InternationalizationExtension)
361 environment = get_spontaneous_environment(
362 options.get('block_start_string', '{%'),
363 options.get('block_end_string', '%}'),
364 options.get('variable_start_string', '{{'),
365 options.get('variable_end_string', '}}'),
366 options.get('comment_start_string', '{#'),
367 options.get('comment_end_string', '#}'),
368 options.get('line_statement_prefix') or None,
369 options.get('trim_blocks', '').lower() in ('1', 'on', 'yes', 'true'),
371 # fill with defaults so that environments are shared
372 # with other spontaneus environments. The rest of the
373 # arguments are optimizer, undefined, finalize, autoescape,
374 # loader, cache size and auto reloading setting
375 True, Undefined, None, False, None, 0, False
378 node = environment.parse(fileobj.read().decode(encoding))
379 for lineno, func, message in extract_from_ast(node, keywords):
380 yield lineno, func, message, []
383 #: nicer import names
384 i18n = InternationalizationExtension
385 do = ExprStmtExtension
386 loopcontrols = LoopControlExtension