1 # -*- coding: utf-8 -*-
6 Provides a class that holds runtime and parsing time options.
8 :copyright: 2008 by Armin Ronacher.
9 :license: BSD, see LICENSE for more details.
12 from jinja2.defaults import *
13 from jinja2.lexer import get_lexer, TokenStream
14 from jinja2.parser import Parser
15 from jinja2.optimizer import optimize
16 from jinja2.compiler import generate
17 from jinja2.runtime import Undefined, Context
18 from jinja2.exceptions import TemplateSyntaxError
19 from jinja2.utils import import_string, LRUCache, Markup, missing, concat
22 # for direct template usage we have up to ten living environments
23 _spontaneous_environments = LRUCache(10)
26 def get_spontaneous_environment(*args):
27 """Return a new spontaneus environment. A spontaneus environment is an
28 unnamed and unaccessable (in theory) environment that is used for
29 template generated from a string and not from the file system.
32 env = _spontaneous_environments.get(args)
34 return Environment(*args)
37 _spontaneous_environments[args] = env = Environment(*args)
42 def create_cache(size):
43 """Return the cache class for the given size."""
51 def load_extensions(environment, extensions):
52 """Load the extensions from the list and bind it to the environment.
53 Returns a dict of instanciated environments.
56 for extension in extensions:
57 if isinstance(extension, basestring):
58 extension = import_string(extension)
59 result[extension.identifier] = extension(environment)
63 def _environment_sanity_check(environment):
64 """Perform a sanity check on the environment."""
65 assert issubclass(environment.undefined, Undefined), 'undefined must ' \
66 'be a subclass of undefined because filters depend on it.'
67 assert environment.block_start_string != \
68 environment.variable_start_string != \
69 environment.comment_start_string, 'block, variable and comment ' \
70 'start strings must be different'
71 assert environment.newline_sequence in ('\r', '\r\n', '\n'), \
72 'newline_sequence set to unknown line ending string.'
76 class Environment(object):
77 r"""The core component of Jinja is the `Environment`. It contains
78 important shared variables like configuration, filters, tests,
79 globals and others. Instances of this class may be modified if
80 they are not shared and if no template was loaded so far.
81 Modifications on environments after the first template was loaded
82 will lead to surprising effects and undefined behavior.
84 Here the possible initialization parameters:
87 The string marking the begin of a block. Defaults to ``'{%'``.
90 The string marking the end of a block. Defaults to ``'%}'``.
92 `variable_start_string`
93 The string marking the begin of a print statement.
97 The string marking the end of a print statement. Defaults to
100 `comment_start_string`
101 The string marking the begin of a comment. Defaults to ``'{#'``.
104 The string marking the end of a comment. Defaults to ``'#}'``.
106 `line_statement_prefix`
107 If given and a string, this will be used as prefix for line based
108 statements. See also :ref:`line-statements`.
111 If this is set to ``True`` the first newline after a block is
112 removed (block, not variable tag!). Defaults to `False`.
115 The sequence that starts a newline. Must be one of ``'\r'``,
116 ``'\n'`` or ``'\r\n'``. The default is ``'\n'`` which is a
117 useful default for Linux and OS X systems as well as web
121 List of Jinja extensions to use. This can either be import paths
122 as strings or extension classes. For more information have a
123 look at :ref:`the extensions documentation <jinja-extensions>`.
126 should the optimizer be enabled? Default is `True`.
129 :class:`Undefined` or a subclass of it that is used to represent
130 undefined values in the template.
133 A callable that finalizes the variable. Per default no finalizing
137 If set to true the XML/HTML autoescaping feature is enabled.
140 The template loader for this environment.
143 The size of the cache. Per default this is ``50`` which means
144 that if more than 50 templates are loaded the loader will clean
145 out the least recently used template. If the cache size is set to
146 ``0`` templates are recompiled all the time, if the cache size is
147 ``-1`` the cache will not be cleaned.
150 Some loaders load templates from locations where the template
151 sources may change (ie: file system or database). If
152 `auto_reload` is set to `True` (default) every time a template is
153 requested the loader checks if the source changed and if yes, it
154 will reload the template. For higher performance it's possible to
158 #: if this environment is sandboxed. Modifying this variable won't make
159 #: the environment sandboxed though. For a real sandboxed environment
160 #: have a look at jinja2.sandbox
163 #: True if the environment is just an overlay
166 #: the environment this environment is linked to if it is an overlay
169 #: shared environments have this set to `True`. A shared environment
170 #: must not be modified
174 block_start_string=BLOCK_START_STRING,
175 block_end_string=BLOCK_END_STRING,
176 variable_start_string=VARIABLE_START_STRING,
177 variable_end_string=VARIABLE_END_STRING,
178 comment_start_string=COMMENT_START_STRING,
179 comment_end_string=COMMENT_END_STRING,
180 line_statement_prefix=LINE_STATEMENT_PREFIX,
181 trim_blocks=TRIM_BLOCKS,
182 newline_sequence=NEWLINE_SEQUENCE,
191 # !!Important notice!!
192 # The constructor accepts quite a few arguments that should be
193 # passed by keyword rather than position. However it's important to
194 # not change the order of arguments because it's used at least
195 # internally in those cases:
196 # - spontaneus environments (i18n extension and Template)
198 # If parameter changes are required only add parameters at the end
199 # and don't change the arguments (or the defaults!) of the arguments
202 # lexer / parser information
203 self.block_start_string = block_start_string
204 self.block_end_string = block_end_string
205 self.variable_start_string = variable_start_string
206 self.variable_end_string = variable_end_string
207 self.comment_start_string = comment_start_string
208 self.comment_end_string = comment_end_string
209 self.line_statement_prefix = line_statement_prefix
210 self.trim_blocks = trim_blocks
211 self.newline_sequence = newline_sequence
213 # runtime information
214 self.undefined = undefined
215 self.optimized = optimized
216 self.finalize = finalize
217 self.autoescape = autoescape
220 self.filters = DEFAULT_FILTERS.copy()
221 self.tests = DEFAULT_TESTS.copy()
222 self.globals = DEFAULT_NAMESPACE.copy()
224 # set the loader provided
226 self.cache = create_cache(cache_size)
227 self.auto_reload = auto_reload
230 self.extensions = load_extensions(self, extensions)
232 _environment_sanity_check(self)
234 def extend(self, **attributes):
235 """Add the items to the instance of the environment if they do not exist
236 yet. This is used by :ref:`extensions <writing-extensions>` to register
237 callbacks and configuration values without breaking inheritance.
239 for key, value in attributes.iteritems():
240 if not hasattr(self, key):
241 setattr(self, key, value)
243 def overlay(self, block_start_string=missing, block_end_string=missing,
244 variable_start_string=missing, variable_end_string=missing,
245 comment_start_string=missing, comment_end_string=missing,
246 line_statement_prefix=missing, trim_blocks=missing,
247 extensions=missing, optimized=missing, undefined=missing,
248 finalize=missing, autoescape=missing, loader=missing,
249 cache_size=missing, auto_reload=missing):
250 """Create a new overlay environment that shares all the data with the
251 current environment except of cache and the overriden attributes.
252 Extensions cannot be removed for a overlayed environment. A overlayed
253 environment automatically gets all the extensions of the environment it
254 is linked to plus optional extra extensions.
256 Creating overlays should happen after the initial environment was set
257 up completely. Not all attributes are truly linked, some are just
258 copied over so modifications on the original environment may not shine
261 args = dict(locals())
262 del args['self'], args['cache_size'], args['extensions']
264 rv = object.__new__(self.__class__)
265 rv.__dict__.update(self.__dict__)
269 for key, value in args.iteritems():
270 if value is not missing:
271 setattr(rv, key, value)
273 if cache_size is not missing:
274 rv.cache = create_cache(cache_size)
277 for key, value in self.extensions.iteritems():
278 rv.extensions[key] = value.bind(rv)
279 if extensions is not missing:
280 rv.extensions.update(load_extensions(extensions))
282 return _environment_sanity_check(rv)
284 lexer = property(get_lexer, doc="The lexer for this environment.")
286 def getitem(self, obj, argument):
287 """Get an item or attribute of an object but prefer the item."""
290 except (TypeError, LookupError):
291 if isinstance(argument, basestring):
298 return getattr(obj, attr)
299 except AttributeError:
301 return self.undefined(obj=obj, name=argument)
303 def getattr(self, obj, attribute):
304 """Get an item or attribute of an object but prefer the attribute.
305 Unlike :meth:`getitem` the attribute *must* be a bytestring.
308 return getattr(obj, attribute)
309 except AttributeError:
312 return obj[attribute]
313 except (TypeError, LookupError, AttributeError):
314 return self.undefined(obj=obj, name=attribute)
316 def parse(self, source, name=None, filename=None):
317 """Parse the sourcecode and return the abstract syntax tree. This
318 tree of nodes is used by the compiler to convert the template into
319 executable source- or bytecode. This is useful for debugging or to
320 extract information from templates.
322 If you are :ref:`developing Jinja2 extensions <writing-extensions>`
323 this gives you a good overview of the node tree generated.
325 if isinstance(filename, unicode):
326 filename = filename.encode('utf-8')
328 return Parser(self, source, name, filename).parse()
329 except TemplateSyntaxError, e:
330 from jinja2.debug import translate_syntax_error
331 exc_type, exc_value, tb = translate_syntax_error(e)
332 raise exc_type, exc_value, tb
334 def lex(self, source, name=None, filename=None):
335 """Lex the given sourcecode and return a generator that yields
336 tokens as tuples in the form ``(lineno, token_type, value)``.
337 This can be useful for :ref:`extension development <writing-extensions>`
338 and debugging templates.
340 This does not perform preprocessing. If you want the preprocessing
341 of the extensions to be applied you have to filter source through
342 the :meth:`preprocess` method.
344 return self.lexer.tokeniter(unicode(source), name, filename)
346 def preprocess(self, source, name=None, filename=None):
347 """Preprocesses the source with all extensions. This is automatically
348 called for all parsing and compiling methods but *not* for :meth:`lex`
349 because there you usually only want the actual source tokenized.
351 return reduce(lambda s, e: e.preprocess(s, name, filename),
352 self.extensions.itervalues(), unicode(source))
354 def _tokenize(self, source, name, filename=None):
355 """Called by the parser to do the preprocessing and filtering
356 for all the extensions. Returns a :class:`~jinja2.lexer.TokenStream`.
358 source = self.preprocess(source, name, filename)
359 stream = self.lexer.tokenize(source, name, filename)
360 for ext in self.extensions.itervalues():
361 stream = ext.filter_stream(stream)
362 if not isinstance(stream, TokenStream):
363 stream = TokenStream(stream, name, filename)
366 def compile(self, source, name=None, filename=None, raw=False):
367 """Compile a node or template source code. The `name` parameter is
368 the load name of the template after it was joined using
369 :meth:`join_path` if necessary, not the filename on the file system.
370 the `filename` parameter is the estimated filename of the template on
371 the file system. If the template came from a database or memory this
374 The return value of this method is a python code object. If the `raw`
375 parameter is `True` the return value will be a string with python
376 code equivalent to the bytecode returned otherwise. This method is
377 mainly used internally.
379 if isinstance(source, basestring):
380 source = self.parse(source, name, filename)
382 node = optimize(source, self)
383 source = generate(node, self, name, filename)
387 filename = '<template>'
388 elif isinstance(filename, unicode):
389 filename = filename.encode('utf-8')
390 return compile(source, filename, 'exec')
392 def join_path(self, template, parent):
393 """Join a template with the parent. By default all the lookups are
394 relative to the loader root so this method returns the `template`
395 parameter unchanged, but if the paths should be relative to the
396 parent template, this function can be used to calculate the real
399 Subclasses may override this method and implement template path
404 def get_template(self, name, parent=None, globals=None):
405 """Load a template from the loader. If a loader is configured this
406 method ask the loader for the template and returns a :class:`Template`.
407 If the `parent` parameter is not `None`, :meth:`join_path` is called
408 to get the real template name before loading.
410 The `globals` parameter can be used to provide template wide globals.
411 These variables are available in the context at render time.
413 If the template does not exist a :exc:`TemplateNotFound` exception is
416 if self.loader is None:
417 raise TypeError('no loader for this environment specified')
418 if parent is not None:
419 name = self.join_path(name, parent)
421 if self.cache is not None:
422 template = self.cache.get(name)
423 if template is not None and (not self.auto_reload or \
424 template.is_up_to_date):
427 template = self.loader.load(self, name, self.make_globals(globals))
428 if self.cache is not None:
429 self.cache[name] = template
432 def from_string(self, source, globals=None, template_class=None):
433 """Load a template from a string. This parses the source given and
434 returns a :class:`Template` object.
436 globals = self.make_globals(globals)
437 cls = template_class or self.template_class
438 return cls.from_code(self, self.compile(source), globals, None)
440 def make_globals(self, d):
441 """Return a dict for the globals."""
444 return dict(self.globals, **d)
447 class Template(object):
448 """The central template object. This class represents a compiled template
449 and is used to evaluate it.
451 Normally the template object is generated from an :class:`Environment` but
452 it also has a constructor that makes it possible to create a template
453 instance directly using the constructor. It takes the same arguments as
454 the environment constructor but it's not possible to specify a loader.
456 Every template object has a few methods and members that are guaranteed
457 to exist. However it's important that a template object should be
458 considered immutable. Modifications on the object are not supported.
460 Template objects created from the constructor rather than an environment
461 do have an `environment` attribute that points to a temporary environment
462 that is probably shared with other templates created with the constructor
463 and compatible settings.
465 >>> template = Template('Hello {{ name }}!')
466 >>> template.render(name='John Doe')
469 >>> stream = template.stream(name='John Doe')
473 Traceback (most recent call last):
478 def __new__(cls, source,
479 block_start_string=BLOCK_START_STRING,
480 block_end_string=BLOCK_END_STRING,
481 variable_start_string=VARIABLE_START_STRING,
482 variable_end_string=VARIABLE_END_STRING,
483 comment_start_string=COMMENT_START_STRING,
484 comment_end_string=COMMENT_END_STRING,
485 line_statement_prefix=LINE_STATEMENT_PREFIX,
486 trim_blocks=TRIM_BLOCKS,
487 newline_sequence=NEWLINE_SEQUENCE,
493 env = get_spontaneous_environment(
494 block_start_string, block_end_string, variable_start_string,
495 variable_end_string, comment_start_string, comment_end_string,
496 line_statement_prefix, trim_blocks, newline_sequence,
497 frozenset(extensions), optimized, undefined, finalize,
498 autoescape, None, 0, False)
499 return env.from_string(source, template_class=cls)
502 def from_code(cls, environment, code, globals, uptodate=None):
503 """Creates a template object from compiled code and the globals. This
504 is used by the loaders and environment to create a template object.
506 t = object.__new__(cls)
508 'environment': environment,
509 '__jinja_template__': t
511 exec code in namespace
512 t.environment = environment
514 t.name = namespace['name']
515 t.filename = code.co_filename
516 t.blocks = namespace['blocks']
518 # render function and module
519 t.root_render_func = namespace['root']
522 # debug and loader helpers
523 t._debug_info = namespace['debug_info']
524 t._uptodate = uptodate
528 def render(self, *args, **kwargs):
529 """This method accepts the same arguments as the `dict` constructor:
530 A dict, a dict subclass or some keyword arguments. If no arguments
531 are given the context will be empty. These two calls do the same::
533 template.render(knights='that say nih')
534 template.render({'knights': 'that say nih'})
536 This will return the rendered template as unicode string.
538 vars = dict(*args, **kwargs)
540 return concat(self.root_render_func(self.new_context(vars)))
542 from jinja2.debug import translate_exception
543 exc_type, exc_value, tb = translate_exception(sys.exc_info())
544 raise exc_type, exc_value, tb
546 def stream(self, *args, **kwargs):
547 """Works exactly like :meth:`generate` but returns a
548 :class:`TemplateStream`.
550 return TemplateStream(self.generate(*args, **kwargs))
552 def generate(self, *args, **kwargs):
553 """For very large templates it can be useful to not render the whole
554 template at once but evaluate each statement after another and yield
555 piece for piece. This method basically does exactly that and returns
556 a generator that yields one item after another as unicode strings.
558 It accepts the same arguments as :meth:`render`.
560 vars = dict(*args, **kwargs)
562 for event in self.root_render_func(self.new_context(vars)):
565 from jinja2.debug import translate_exception
566 exc_type, exc_value, tb = translate_exception(sys.exc_info())
567 raise exc_type, exc_value, tb
569 def new_context(self, vars=None, shared=False):
570 """Create a new :class:`Context` for this template. The vars
571 provided will be passed to the template. Per default the globals
572 are added to the context, if shared is set to `True` the data
573 provided is used as parent namespace. This is used to share the
574 same globals in multiple contexts without consuming more memory.
575 (This works because the context does not modify the parent dict)
582 parent = dict(self.globals, **vars)
583 return Context(self.environment, parent, self.name, self.blocks)
585 def make_module(self, vars=None, shared=False):
586 """This method works like the :attr:`module` attribute when called
587 without arguments but it will evaluate the template every call
588 rather then caching the template. It's also possible to provide
589 a dict which is then used as context. The arguments are the same
590 as for the :meth:`new_context` method.
592 return TemplateModule(self, self.new_context(vars, shared))
596 """The template as module. This is used for imports in the
597 template runtime but is also useful if one wants to access
598 exported template variables from the Python layer:
600 >>> t = Template('{% macro foo() %}42{% endmacro %}23')
601 >>> unicode(t.module)
606 if self._module is not None:
608 self._module = rv = self.make_module()
611 def get_corresponding_lineno(self, lineno):
612 """Return the source line number of a line number in the
613 generated bytecode as they are not in sync.
615 for template_line, code_line in reversed(self.debug_info):
616 if code_line <= lineno:
621 def is_up_to_date(self):
622 """If this variable is `False` there is a newer version available."""
623 if self._uptodate is None:
625 return self._uptodate()
628 def debug_info(self):
629 """The debug info mapping."""
630 return [tuple(map(int, x.split('='))) for x in
631 self._debug_info.split('&')]
634 if self.name is None:
635 name = 'memory:%x' % id(self)
637 name = repr(self.name)
638 return '<%s %s>' % (self.__class__.__name__, name)
641 class TemplateModule(object):
642 """Represents an imported template. All the exported names of the
643 template are available as attributes on this object. Additionally
644 converting it into an unicode- or bytestrings renders the contents.
647 def __init__(self, template, context):
648 self._body_stream = list(template.root_render_func(context))
649 self.__dict__.update(context.get_exported())
650 self.__name__ = template.name
652 __unicode__ = lambda x: concat(x._body_stream)
653 __html__ = lambda x: Markup(concat(x._body_stream))
656 return unicode(self).encode('utf-8')
659 if self.__name__ is None:
660 name = 'memory:%x' % id(self)
662 name = repr(self.__name__)
663 return '<%s %s>' % (self.__class__.__name__, name)
666 class TemplateStream(object):
667 """A template stream works pretty much like an ordinary python generator
668 but it can buffer multiple items to reduce the number of total iterations.
669 Per default the output is unbuffered which means that for every unbuffered
670 instruction in the template one unicode string is yielded.
672 If buffering is enabled with a buffer size of 5, five items are combined
673 into a new unicode string. This is mainly useful if you are streaming
674 big templates to a client via WSGI which flushes after each iteration.
677 def __init__(self, gen):
679 self.disable_buffering()
681 def dump(self, fp, encoding=None, errors='strict'):
682 """Dump the complete stream into a file or file-like object.
683 Per default unicode strings are written, if you want to encode
684 before writing specifiy an `encoding`.
688 Template('Hello {{ name }}!').stream(name='foo').dump('hello.html')
691 if isinstance(fp, basestring):
695 if encoding is not None:
696 iterable = (x.encode(encoding, errors) for x in self)
699 if hasattr(fp, 'writelines'):
700 fp.writelines(iterable)
702 for item in iterable:
708 def disable_buffering(self):
709 """Disable the output buffering."""
710 self._next = self._gen.next
711 self.buffered = False
713 def enable_buffering(self, size=5):
714 """Enable buffering. Buffer `size` items before yielding them."""
716 raise ValueError('buffer size too small')
730 except StopIteration:
738 self._next = generator(self._gen.next).next
747 # hook in default template class. if anyone reads this comment: ignore that
748 # it's possible to use custom templates ;-)
749 Environment.template_class = Template