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# -*- coding: utf-8 -*-
Utility functions.
:copyright: (c) 2010 by the Jinja Team.
:license: BSD, see LICENSE for more details.
import re
import sys
import errno
from thread import allocate_lock
except ImportError:
from dummy_thread import allocate_lock
from collections import deque
from itertools import imap
_word_split_re = re.compile(r'(\s+)')
_punctuation_re = re.compile(
'^(?P<lead>(?:%s)*)(?P<middle>.*?)(?P<trail>(?:%s)*)$' % (
'|'.join(imap(re.escape, ('(', '<', '&lt;'))),
'|'.join(imap(re.escape, ('.', ',', ')', '>', '\n', '&gt;')))
_simple_email_re = re.compile(r'^\S+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+$')
_striptags_re = re.compile(r'(<!--.*?-->|<[^>]*>)')
_entity_re = re.compile(r'&([^;]+);')
_letters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
_digits = '0123456789'
# special singleton representing missing values for the runtime
missing = type('MissingType', (), {'__repr__': lambda x: 'missing'})()
# internal code
internal_code = set()
# concatenate a list of strings and convert them to unicode.
# unfortunately there is a bug in python 2.4 and lower that causes
# unicode.join trash the traceback.
_concat = u''.join
def _test_gen_bug():
raise TypeError(_test_gen_bug)
yield None
except TypeError, _error:
if not _error.args or _error.args[0] is not _test_gen_bug:
def concat(gen):
return _concat(list(gen))
# this hack is needed so that the current frame
# does not show up in the traceback.
exc_type, exc_value, tb = sys.exc_info()
raise exc_type, exc_value, tb.tb_next
concat = _concat
del _test_gen_bug, _error
# for python 2.x we create outselves a next() function that does the
# basics without exception catching.
next = next
except NameError:
def next(x):
# if this python version is unable to deal with unicode filenames
# when passed to encode we let this function encode it properly.
# This is used in a couple of places. As far as Jinja is concerned
# filenames are unicode *or* bytestrings in 2.x and unicode only in
# 3.x because compile cannot handle bytes
if sys.version_info < (3, 0):
def _encode_filename(filename):
if isinstance(filename, unicode):
return filename.encode('utf-8')
return filename
def _encode_filename(filename):
assert filename is None or isinstance(filename, str), \
'filenames must be strings'
return filename
from keyword import iskeyword as is_python_keyword
# common types. These do exist in the special types module too which however
# does not exist in IronPython out of the box. Also that way we don't have
# to deal with implementation specific stuff here
class _C(object):
def method(self): pass
def _func():
yield None
FunctionType = type(_func)
GeneratorType = type(_func())
MethodType = type(_C.method)
CodeType = type(_C.method.func_code)
raise TypeError()
except TypeError:
_tb = sys.exc_info()[2]
TracebackType = type(_tb)
FrameType = type(_tb.tb_frame)
del _C, _tb, _func
def contextfunction(f):
"""This decorator can be used to mark a function or method context callable.
A context callable is passed the active :class:`Context` as first argument when
called from the template. This is useful if a function wants to get access
to the context or functions provided on the context object. For example
a function that returns a sorted list of template variables the current
template exports could look like this::
def get_exported_names(context):
return sorted(context.exported_vars)
f.contextfunction = True
return f
def environmentfunction(f):
"""This decorator can be used to mark a function or method as environment
callable. This decorator works exactly like the :func:`contextfunction`
decorator just that the first argument is the active :class:`Environment`
and not context.
f.environmentfunction = True
return f
def internalcode(f):
"""Marks the function as internally used"""
return f
def is_undefined(obj):
"""Check if the object passed is undefined. This does nothing more than
performing an instance check against :class:`Undefined` but looks nicer.
This can be used for custom filters or tests that want to react to
undefined variables. For example a custom default filter can look like
def default(var, default=''):
if is_undefined(var):
return default
return var
from jinja2.runtime import Undefined
return isinstance(obj, Undefined)
def consume(iterable):
"""Consumes an iterable without doing anything with it."""
for event in iterable:
def clear_caches():
"""Jinja2 keeps internal caches for environments and lexers. These are
used so that Jinja2 doesn't have to recreate environments and lexers all
the time. Normally you don't have to care about that but if you are
messuring memory consumption you may want to clean the caches.
from jinja2.environment import _spontaneous_environments
from jinja2.lexer import _lexer_cache
def import_string(import_name, silent=False):
"""Imports an object based on a string. This use useful if you want to
use import paths as endpoints or something similar. An import path can
be specified either in dotted notation (``xml.sax.saxutils.escape``)
or with a colon as object delimiter (``xml.sax.saxutils:escape``).
If the `silent` is True the return value will be `None` if the import
:return: imported object
if ':' in import_name:
module, obj = import_name.split(':', 1)
elif '.' in import_name:
items = import_name.split('.')
module = '.'.join(items[:-1])
obj = items[-1]
return __import__(import_name)
return getattr(__import__(module, None, None, [obj]), obj)
except (ImportError, AttributeError):
if not silent:
def open_if_exists(filename, mode='rb'):
"""Returns a file descriptor for the filename if that file exists,
otherwise `None`.
return open(filename, mode)
except IOError, e:
if e.errno not in (errno.ENOENT, errno.EISDIR):
def pformat(obj, verbose=False):
"""Prettyprint an object. Either use the `pretty` library or the
builtin `pprint`.
from pretty import pretty
return pretty(obj, verbose=verbose)
except ImportError:
from pprint import pformat
return pformat(obj)
def urlize(text, trim_url_limit=None, nofollow=False):
"""Converts any URLs in text into clickable links. Works on http://,
https:// and www. links. Links can have trailing punctuation (periods,
commas, close-parens) and leading punctuation (opening parens) and
it'll still do the right thing.
If trim_url_limit is not None, the URLs in link text will be limited
to trim_url_limit characters.
If nofollow is True, the URLs in link text will get a rel="nofollow"
trim_url = lambda x, limit=trim_url_limit: limit is not None \
and (x[:limit] + (len(x) >=limit and '...'
or '')) or x
words = _word_split_re.split(unicode(escape(text)))
nofollow_attr = nofollow and ' rel="nofollow"' or ''
for i, word in enumerate(words):
match = _punctuation_re.match(word)
if match:
lead, middle, trail = match.groups()
if middle.startswith('www.') or (
'@' not in middle and
not middle.startswith('http://') and
len(middle) > 0 and
middle[0] in _letters + _digits and (
middle.endswith('.org') or
middle.endswith('.net') or
middle = '<a href="http://%s"%s>%s</a>' % (middle,
nofollow_attr, trim_url(middle))
if middle.startswith('http://') or \
middle = '<a href="%s"%s>%s</a>' % (middle,
nofollow_attr, trim_url(middle))
if '@' in middle and not middle.startswith('www.') and \
not ':' in middle and _simple_email_re.match(middle):
middle = '<a href="mailto:%s">%s</a>' % (middle, middle)
if lead + middle + trail != word:
words[i] = lead + middle + trail
return u''.join(words)
def generate_lorem_ipsum(n=5, html=True, min=20, max=100):
"""Generate some lorem impsum for the template."""
from jinja2.constants import LOREM_IPSUM_WORDS
from random import choice, randrange
words = LOREM_IPSUM_WORDS.split()
result = []
for _ in xrange(n):
next_capitalized = True
last_comma = last_fullstop = 0
word = None
last = None
p = []
# each paragraph contains out of 20 to 100 words.
for idx, _ in enumerate(xrange(randrange(min, max))):
while True:
word = choice(words)
if word != last:
last = word
if next_capitalized:
word = word.capitalize()
next_capitalized = False
# add commas
if idx - randrange(3, 8) > last_comma:
last_comma = idx
last_fullstop += 2
word += ','
# add end of sentences
if idx - randrange(10, 20) > last_fullstop:
last_comma = last_fullstop = idx
word += '.'
next_capitalized = True
# ensure that the paragraph ends with a dot.
p = u' '.join(p)
if p.endswith(','):
p = p[:-1] + '.'
elif not p.endswith('.'):
p += '.'
if not html:
return u'\n\n'.join(result)
return Markup(u'\n'.join(u'<p>%s</p>' % escape(x) for x in result))
class Markup(unicode):
r"""Marks a string as being safe for inclusion in HTML/XML output without
needing to be escaped. This implements the `__html__` interface a couple
of frameworks and web applications use. :class:`Markup` is a direct
subclass of `unicode` and provides all the methods of `unicode` just that
it escapes arguments passed and always returns `Markup`.
The `escape` function returns markup objects so that double escaping can't
happen. If you want to use autoescaping in Jinja just enable the
autoescaping feature in the environment.
The constructor of the :class:`Markup` class can be used for three
different things: When passed an unicode object it's assumed to be safe,
when passed an object with an HTML representation (has an `__html__`
method) that representation is used, otherwise the object passed is
converted into a unicode string and then assumed to be safe:
>>> Markup("Hello <em>World</em>!")
Markup(u'Hello <em>World</em>!')
>>> class Foo(object):
... def __html__(self):
... return '<a href="#">foo</a>'
>>> Markup(Foo())
Markup(u'<a href="#">foo</a>')
If you want object passed being always treated as unsafe you can use the
:meth:`escape` classmethod to create a :class:`Markup` object:
>>> Markup.escape("Hello <em>World</em>!")
Markup(u'Hello &lt;em&gt;World&lt;/em&gt;!')
Operations on a markup string are markup aware which means that all
arguments are passed through the :func:`escape` function:
>>> em = Markup("<em>%s</em>")
>>> em % "foo & bar"
Markup(u'<em>foo &amp; bar</em>')
>>> strong = Markup("<strong>%(text)s</strong>")
>>> strong % {'text': '<blink>hacker here</blink>'}
Markup(u'<strong>&lt;blink&gt;hacker here&lt;/blink&gt;</strong>')
>>> Markup("<em>Hello</em> ") + "<foo>"
Markup(u'<em>Hello</em> &lt;foo&gt;')
__slots__ = ()
def __new__(cls, base=u'', encoding=None, errors='strict'):
if hasattr(base, '__html__'):
base = base.__html__()
if encoding is None:
return unicode.__new__(cls, base)
return unicode.__new__(cls, base, encoding, errors)
def __html__(self):
return self
def __add__(self, other):
if hasattr(other, '__html__') or isinstance(other, basestring):
return self.__class__(unicode(self) + unicode(escape(other)))
return NotImplemented
def __radd__(self, other):
if hasattr(other, '__html__') or isinstance(other, basestring):
return self.__class__(unicode(escape(other)) + unicode(self))
return NotImplemented
def __mul__(self, num):
if isinstance(num, (int, long)):
return self.__class__(unicode.__mul__(self, num))
return NotImplemented
__rmul__ = __mul__
def __mod__(self, arg):
if isinstance(arg, tuple):
arg = tuple(imap(_MarkupEscapeHelper, arg))
arg = _MarkupEscapeHelper(arg)
return self.__class__(unicode.__mod__(self, arg))
def __repr__(self):
return '%s(%s)' % (
def join(self, seq):
return self.__class__(unicode.join(self, imap(escape, seq)))
join.__doc__ = unicode.join.__doc__
def split(self, *args, **kwargs):
return map(self.__class__, unicode.split(self, *args, **kwargs))
split.__doc__ = unicode.split.__doc__
def rsplit(self, *args, **kwargs):
return map(self.__class__, unicode.rsplit(self, *args, **kwargs))
rsplit.__doc__ = unicode.rsplit.__doc__
def splitlines(self, *args, **kwargs):
return map(self.__class__, unicode.splitlines(self, *args, **kwargs))
splitlines.__doc__ = unicode.splitlines.__doc__
def unescape(self):
r"""Unescape markup again into an unicode string. This also resolves
known HTML4 and XHTML entities:
>>> Markup("Main &raquo; <em>About</em>").unescape()
u'Main \xbb <em>About</em>'
from jinja2.constants import HTML_ENTITIES
def handle_match(m):
name =
if name in HTML_ENTITIES:
return unichr(HTML_ENTITIES[name])
if name[:2] in ('#x', '#X'):
return unichr(int(name[2:], 16))
elif name.startswith('#'):
return unichr(int(name[1:]))
except ValueError:
return u''
return _entity_re.sub(handle_match, unicode(self))
def striptags(self):
r"""Unescape markup into an unicode string and strip all tags. This
also resolves known HTML4 and XHTML entities. Whitespace is
normalized to one:
>>> Markup("Main &raquo; <em>About</em>").striptags()
u'Main \xbb About'
stripped = u' '.join(_striptags_re.sub('', self).split())
return Markup(stripped).unescape()
def escape(cls, s):
"""Escape the string. Works like :func:`escape` with the difference
that for subclasses of :class:`Markup` this function would return the
correct subclass.
rv = escape(s)
if rv.__class__ is not cls:
return cls(rv)
return rv
def make_wrapper(name):
orig = getattr(unicode, name)
def func(self, *args, **kwargs):
args = _escape_argspec(list(args), enumerate(args))
_escape_argspec(kwargs, kwargs.iteritems())
return self.__class__(orig(self, *args, **kwargs))
func.__name__ = orig.__name__
func.__doc__ = orig.__doc__
return func
for method in '__getitem__', 'capitalize', \
'title', 'lower', 'upper', 'replace', 'ljust', \
'rjust', 'lstrip', 'rstrip', 'center', 'strip', \
'translate', 'expandtabs', 'swapcase', 'zfill':
locals()[method] = make_wrapper(method)
# new in python 2.5
if hasattr(unicode, 'partition'):
partition = make_wrapper('partition'),
rpartition = make_wrapper('rpartition')
# new in python 2.6
if hasattr(unicode, 'format'):
format = make_wrapper('format')
# not in python 3
if hasattr(unicode, '__getslice__'):
__getslice__ = make_wrapper('__getslice__')
del method, make_wrapper
def _escape_argspec(obj, iterable):
"""Helper for various string-wrapped functions."""
for key, value in iterable:
if hasattr(value, '__html__') or isinstance(value, basestring):
obj[key] = escape(value)
return obj
class _MarkupEscapeHelper(object):
"""Helper for Markup.__mod__"""
def __init__(self, obj):
self.obj = obj
__getitem__ = lambda s, x: _MarkupEscapeHelper(s.obj[x])
__str__ = lambda s: str(escape(s.obj))
__unicode__ = lambda s: unicode(escape(s.obj))
__repr__ = lambda s: str(escape(repr(s.obj)))
__int__ = lambda s: int(s.obj)
__float__ = lambda s: float(s.obj)
class LRUCache(object):
"""A simple LRU Cache implementation."""
# this is fast for small capacities (something below 1000) but doesn't
# scale. But as long as it's only used as storage for templates this
# won't do any harm.
def __init__(self, capacity):
self.capacity = capacity
self._mapping = {}
self._queue = deque()
def _postinit(self):
# alias all queue methods for faster lookup
self._popleft = self._queue.popleft
self._pop = self._queue.pop
if hasattr(self._queue, 'remove'):
self._remove = self._queue.remove
self._wlock = allocate_lock()
self._append = self._queue.append
def _remove(self, obj):
"""Python 2.4 compatibility."""
for idx, item in enumerate(self._queue):
if item == obj:
del self._queue[idx]
def __getstate__(self):
return {
'capacity': self.capacity,
'_mapping': self._mapping,
'_queue': self._queue
def __setstate__(self, d):
def __getnewargs__(self):
return (self.capacity,)
def copy(self):
"""Return an shallow copy of the instance."""
rv = self.__class__(self.capacity)
rv._queue = deque(self._queue)
return rv
def get(self, key, default=None):
"""Return an item from the cache dict or `default`"""
return self[key]
except KeyError:
return default
def setdefault(self, key, default=None):
"""Set `default` if the key is not in the cache otherwise
leave unchanged. Return the value of this key.
return self[key]
except KeyError:
self[key] = default
return default
def clear(self):
"""Clear the cache."""
def __contains__(self, key):
"""Check if a key exists in this cache."""
return key in self._mapping
def __len__(self):
"""Return the current size of the cache."""
return len(self._mapping)
def __repr__(self):
return '<%s %r>' % (
def __getitem__(self, key):
"""Get an item from the cache. Moves the item up so that it has the
highest priority then.
Raise an `KeyError` if it does not exist.
rv = self._mapping[key]
if self._queue[-1] != key:
except ValueError:
# if something removed the key from the container
# when we read, ignore the ValueError that we would
# get otherwise.
return rv
def __setitem__(self, key, value):
"""Sets the value for an item. Moves the item up so that it
has the highest priority then.
if key in self._mapping:
except ValueError:
# __getitem__ is not locked, it might happen
elif len(self._mapping) == self.capacity:
del self._mapping[self._popleft()]
self._mapping[key] = value
def __delitem__(self, key):
"""Remove an item from the cache dict.
Raise an `KeyError` if it does not exist.
del self._mapping[key]
except ValueError:
# __getitem__ is not locked, it might happen
def items(self):
"""Return a list of items."""
result = [(key, self._mapping[key]) for key in list(self._queue)]
return result
def iteritems(self):
"""Iterate over all items."""
return iter(self.items())
def values(self):
"""Return a list of all values."""
return [x[1] for x in self.items()]
def itervalue(self):
"""Iterate over all values."""
return iter(self.values())
def keys(self):
"""Return a list of all keys ordered by most recent usage."""
return list(self)
def iterkeys(self):
"""Iterate over all keys in the cache dict, ordered by
the most recent usage.
return reversed(tuple(self._queue))
__iter__ = iterkeys
def __reversed__(self):
"""Iterate over the values in the cache dict, oldest items
coming first.
return iter(tuple(self._queue))
__copy__ = copy
# register the LRU cache as mutable mapping if possible
from collections import MutableMapping
except ImportError:
class Cycler(object):
"""A cycle helper for templates."""
def __init__(self, *items):
if not items:
raise RuntimeError('at least one item has to be provided')
self.items = items
def reset(self):
"""Resets the cycle."""
self.pos = 0
def current(self):
"""Returns the current item."""
return self.items[self.pos]
def next(self):
"""Goes one item ahead and returns it."""
rv = self.current
self.pos = (self.pos + 1) % len(self.items)
return rv
class Joiner(object):
"""A joining helper for templates."""
def __init__(self, sep=u', '):
self.sep = sep
self.used = False
def __call__(self):
if not self.used:
self.used = True
return u''
return self.sep
# we have to import it down here as the speedups module imports the
# markup type which is define above.
from jinja2._speedups import escape, soft_unicode
except ImportError:
def escape(s):
"""Convert the characters &, <, >, ' and " in string s to HTML-safe
sequences. Use this if you need to display text that might contain
such characters in HTML. Marks return value as markup string.
if hasattr(s, '__html__'):
return s.__html__()
return Markup(unicode(s)
.replace('&', '&amp;')
.replace('>', '&gt;')
.replace('<', '&lt;')
.replace("'", '&#39;')
.replace('"', '&#34;')
def soft_unicode(s):
"""Make a string unicode if it isn't already. That way a markup
string is not converted back to unicode.
if not isinstance(s, unicode):
s = unicode(s)
return s
# partials
from functools import partial
except ImportError:
class partial(object):
def __init__(self, _func, *args, **kwargs):
self._func = _func
self._args = args
self._kwargs = kwargs
def __call__(self, *args, **kwargs):
return self._func(*(self._args + args), **kwargs)
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