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authorDavid Lord <davidism@gmail.com>2020-01-09 10:38:52 -0800
committerDavid Lord <davidism@gmail.com>2020-01-09 10:38:52 -0800
commite1e1e7d18b0badcd982b0bbde4ed1ee8d8c19eb3 (patch)
tree7c8812b050ea757947a3c94871895953bde41de0 /src/jinja2/utils.py
parent8342180f3913daea28fcd6644a0ba4c69391b189 (diff)
downloadjinja2-e1e1e7d18b0badcd982b0bbde4ed1ee8d8c19eb3.tar.gz
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+# -*- coding: utf-8 -*-
+"""
+ jinja2.utils
+ ~~~~~~~~~~~~
+
+ Utility functions.
+
+ :copyright: (c) 2017 by the Jinja Team.
+ :license: BSD, see LICENSE for more details.
+"""
+import os
+import re
+import json
+import warnings
+from collections import deque
+from threading import Lock
+from jinja2._compat import text_type, string_types, url_quote, abc
+
+
+_word_split_re = re.compile(r'(\s+)')
+_punctuation_re = re.compile(
+ '^(?P<lead>(?:%s)*)(?P<middle>.*?)(?P<trail>(?:%s)*)$' % (
+ '|'.join(map(re.escape, ('(', '<', '&lt;'))),
+ '|'.join(map(re.escape, ('.', ',', ')', '>', '\n', '&gt;')))
+ )
+)
+_simple_email_re = re.compile(r'^\S+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+$')
+_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()
+
+concat = u''.join
+
+_slash_escape = '\\/' not in json.dumps('/')
+
+
+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::
+
+ @contextfunction
+ def get_exported_names(context):
+ return sorted(context.exported_vars)
+ """
+ f.contextfunction = True
+ return f
+
+
+def evalcontextfunction(f):
+ """This decorator can be used to mark a function or method as an eval
+ context callable. This is similar to the :func:`contextfunction`
+ but instead of passing the context, an evaluation context object is
+ passed. For more information about the eval context, see
+ :ref:`eval-context`.
+
+ .. versionadded:: 2.4
+ """
+ f.evalcontextfunction = 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"""
+ internal_code.add(f.__code__)
+ 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
+ this::
+
+ 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:
+ pass
+
+
+def clear_caches():
+ """Jinja keeps internal caches for environments and lexers. These are
+ used so that Jinja doesn't have to recreate environments and lexers all
+ the time. Normally you don't have to care about that but if you are
+ measuring memory consumption you may want to clean the caches.
+ """
+ from jinja2.environment import _spontaneous_environments
+ from jinja2.lexer import _lexer_cache
+ _spontaneous_environments.clear()
+ _lexer_cache.clear()
+
+
+def import_string(import_name, silent=False):
+ """Imports an object based on a string. This is 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
+ fails.
+
+ :return: imported object
+ """
+ try:
+ if ':' in import_name:
+ module, obj = import_name.split(':', 1)
+ elif '.' in import_name:
+ module, _, obj = import_name.rpartition('.')
+ else:
+ return __import__(import_name)
+ return getattr(__import__(module, None, None, [obj]), obj)
+ except (ImportError, AttributeError):
+ if not silent:
+ raise
+
+
+def open_if_exists(filename, mode='rb'):
+ """Returns a file descriptor for the filename if that file exists,
+ otherwise ``None``.
+ """
+ if not os.path.isfile(filename):
+ return None
+
+ return open(filename, mode)
+
+
+def object_type_repr(obj):
+ """Returns the name of the object's type. For some recognized
+ singletons the name of the object is returned instead. (For
+ example for `None` and `Ellipsis`).
+ """
+ if obj is None:
+ return 'None'
+ elif obj is Ellipsis:
+ return 'Ellipsis'
+ # __builtin__ in 2.x, builtins in 3.x
+ if obj.__class__.__module__ in ('__builtin__', 'builtins'):
+ name = obj.__class__.__name__
+ else:
+ name = obj.__class__.__module__ + '.' + obj.__class__.__name__
+ return '%s object' % name
+
+
+def pformat(obj, verbose=False):
+ """Prettyprint an object. Either use the `pretty` library or the
+ builtin `pprint`.
+ """
+ try:
+ 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, rel=None, target=None):
+ """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"
+ attribute.
+
+ If target is not None, a target attribute will be added to the link.
+ """
+ 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(text_type(escape(text)))
+ rel_attr = rel and ' rel="%s"' % text_type(escape(rel)) or ''
+ target_attr = target and ' target="%s"' % escape(target) 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
+ not middle.startswith('https://') and
+ len(middle) > 0 and
+ middle[0] in _letters + _digits and (
+ middle.endswith('.org') or
+ middle.endswith('.net') or
+ middle.endswith('.com')
+ )):
+ middle = '<a href="http://%s"%s%s>%s</a>' % (middle,
+ rel_attr, target_attr, trim_url(middle))
+ if middle.startswith('http://') or \
+ middle.startswith('https://'):
+ middle = '<a href="%s"%s%s>%s</a>' % (middle,
+ rel_attr, target_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 ipsum for the template."""
+ from jinja2.constants import LOREM_IPSUM_WORDS
+ from random import choice, randrange
+ words = LOREM_IPSUM_WORDS.split()
+ result = []
+
+ for _ in range(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(range(randrange(min, max))):
+ while True:
+ word = choice(words)
+ if word != last:
+ last = word
+ break
+ 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
+ p.append(word)
+
+ # ensure that the paragraph ends with a dot.
+ p = u' '.join(p)
+ if p.endswith(','):
+ p = p[:-1] + '.'
+ elif not p.endswith('.'):
+ p += '.'
+ result.append(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))
+
+
+def unicode_urlencode(obj, charset="utf-8", for_qs=False):
+ """Quote a string for use in a URL using the given charset.
+
+ This function is misnamed, it is a wrapper around
+ :func:`urllib.parse.quote`.
+
+ :param obj: String or bytes to quote. Other types are converted to
+ string then encoded to bytes using the given charset.
+ :param charset: Encode text to bytes using this charset.
+ :param for_qs: Quote "/" and use "+" for spaces.
+ """
+ if not isinstance(obj, string_types):
+ obj = text_type(obj)
+
+ if isinstance(obj, text_type):
+ obj = obj.encode(charset)
+
+ safe = b"" if for_qs else b"/"
+ rv = url_quote(obj, safe)
+
+ if not isinstance(rv, text_type):
+ rv = rv.decode("utf-8")
+
+ if for_qs:
+ rv = rv.replace("%20", "+")
+
+ return rv
+
+
+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()
+ self._postinit()
+
+ def _postinit(self):
+ # alias all queue methods for faster lookup
+ self._popleft = self._queue.popleft
+ self._pop = self._queue.pop
+ self._remove = self._queue.remove
+ self._wlock = Lock()
+ self._append = self._queue.append
+
+ def __getstate__(self):
+ return {
+ 'capacity': self.capacity,
+ '_mapping': self._mapping,
+ '_queue': self._queue
+ }
+
+ def __setstate__(self, d):
+ self.__dict__.update(d)
+ self._postinit()
+
+ def __getnewargs__(self):
+ return (self.capacity,)
+
+ def copy(self):
+ """Return a shallow copy of the instance."""
+ rv = self.__class__(self.capacity)
+ rv._mapping.update(self._mapping)
+ rv._queue.extend(self._queue)
+ return rv
+
+ def get(self, key, default=None):
+ """Return an item from the cache dict or `default`"""
+ try:
+ 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.
+ """
+ try:
+ return self[key]
+ except KeyError:
+ self[key] = default
+ return default
+
+ def clear(self):
+ """Clear the cache."""
+ self._wlock.acquire()
+ try:
+ self._mapping.clear()
+ self._queue.clear()
+ finally:
+ self._wlock.release()
+
+ 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>' % (
+ self.__class__.__name__,
+ self._mapping
+ )
+
+ def __getitem__(self, key):
+ """Get an item from the cache. Moves the item up so that it has the
+ highest priority then.
+
+ Raise a `KeyError` if it does not exist.
+ """
+ self._wlock.acquire()
+ try:
+ rv = self._mapping[key]
+ if self._queue[-1] != key:
+ try:
+ self._remove(key)
+ except ValueError:
+ # if something removed the key from the container
+ # when we read, ignore the ValueError that we would
+ # get otherwise.
+ pass
+ self._append(key)
+ return rv
+ finally:
+ self._wlock.release()
+
+ def __setitem__(self, key, value):
+ """Sets the value for an item. Moves the item up so that it
+ has the highest priority then.
+ """
+ self._wlock.acquire()
+ try:
+ if key in self._mapping:
+ self._remove(key)
+ elif len(self._mapping) == self.capacity:
+ del self._mapping[self._popleft()]
+ self._append(key)
+ self._mapping[key] = value
+ finally:
+ self._wlock.release()
+
+ def __delitem__(self, key):
+ """Remove an item from the cache dict.
+ Raise a `KeyError` if it does not exist.
+ """
+ self._wlock.acquire()
+ try:
+ del self._mapping[key]
+ try:
+ self._remove(key)
+ except ValueError:
+ pass
+ finally:
+ self._wlock.release()
+
+ def items(self):
+ """Return a list of items."""
+ result = [(key, self._mapping[key]) for key in list(self._queue)]
+ result.reverse()
+ 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."""
+ warnings.warn(DeprecationWarning(
+ '"itervalue()" is deprecated and will be removed in version 2.12.'
+ + ' Use "itervalues()" instead.'
+ ), stacklevel=2)
+ return self.itervalues()
+
+ def itervalues(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 keys in the cache dict, oldest items
+ coming first.
+ """
+ return iter(tuple(self._queue))
+
+ __copy__ = copy
+
+
+abc.MutableMapping.register(LRUCache)
+
+
+def select_autoescape(enabled_extensions=('html', 'htm', 'xml'),
+ disabled_extensions=(),
+ default_for_string=True,
+ default=False):
+ """Intelligently sets the initial value of autoescaping based on the
+ filename of the template. This is the recommended way to configure
+ autoescaping if you do not want to write a custom function yourself.
+
+ If you want to enable it for all templates created from strings or
+ for all templates with `.html` and `.xml` extensions::
+
+ from jinja2 import Environment, select_autoescape
+ env = Environment(autoescape=select_autoescape(
+ enabled_extensions=('html', 'xml'),
+ default_for_string=True,
+ ))
+
+ Example configuration to turn it on at all times except if the template
+ ends with `.txt`::
+
+ from jinja2 import Environment, select_autoescape
+ env = Environment(autoescape=select_autoescape(
+ disabled_extensions=('txt',),
+ default_for_string=True,
+ default=True,
+ ))
+
+ The `enabled_extensions` is an iterable of all the extensions that
+ autoescaping should be enabled for. Likewise `disabled_extensions` is
+ a list of all templates it should be disabled for. If a template is
+ loaded from a string then the default from `default_for_string` is used.
+ If nothing matches then the initial value of autoescaping is set to the
+ value of `default`.
+
+ For security reasons this function operates case insensitive.
+
+ .. versionadded:: 2.9
+ """
+ enabled_patterns = tuple('.' + x.lstrip('.').lower()
+ for x in enabled_extensions)
+ disabled_patterns = tuple('.' + x.lstrip('.').lower()
+ for x in disabled_extensions)
+ def autoescape(template_name):
+ if template_name is None:
+ return default_for_string
+ template_name = template_name.lower()
+ if template_name.endswith(enabled_patterns):
+ return True
+ if template_name.endswith(disabled_patterns):
+ return False
+ return default
+ return autoescape
+
+
+def htmlsafe_json_dumps(obj, dumper=None, **kwargs):
+ """Works exactly like :func:`dumps` but is safe for use in ``<script>``
+ tags. It accepts the same arguments and returns a JSON string. Note that
+ this is available in templates through the ``|tojson`` filter which will
+ also mark the result as safe. Due to how this function escapes certain
+ characters this is safe even if used outside of ``<script>`` tags.
+
+ The following characters are escaped in strings:
+
+ - ``<``
+ - ``>``
+ - ``&``
+ - ``'``
+
+ This makes it safe to embed such strings in any place in HTML with the
+ notable exception of double quoted attributes. In that case single
+ quote your attributes or HTML escape it in addition.
+ """
+ if dumper is None:
+ dumper = json.dumps
+ rv = dumper(obj, **kwargs) \
+ .replace(u'<', u'\\u003c') \
+ .replace(u'>', u'\\u003e') \
+ .replace(u'&', u'\\u0026') \
+ .replace(u"'", u'\\u0027')
+ return Markup(rv)
+
+
+class Cycler(object):
+ """Cycle through values by yield them one at a time, then restarting
+ once the end is reached. Available as ``cycler`` in templates.
+
+ Similar to ``loop.cycle``, but can be used outside loops or across
+ multiple loops. For example, render a list of folders and files in a
+ list, alternating giving them "odd" and "even" classes.
+
+ .. code-block:: html+jinja
+
+ {% set row_class = cycler("odd", "even") %}
+ <ul class="browser">
+ {% for folder in folders %}
+ <li class="folder {{ row_class.next() }}">{{ folder }}
+ {% endfor %}
+ {% for file in files %}
+ <li class="file {{ row_class.next() }}">{{ file }}
+ {% endfor %}
+ </ul>
+
+ :param items: Each positional argument will be yielded in the order
+ given for each cycle.
+
+ .. versionadded:: 2.1
+ """
+
+ def __init__(self, *items):
+ if not items:
+ raise RuntimeError('at least one item has to be provided')
+ self.items = items
+ self.pos = 0
+
+ def reset(self):
+ """Resets the current item to the first item."""
+ self.pos = 0
+
+ @property
+ def current(self):
+ """Return the current item. Equivalent to the item that will be
+ returned next time :meth:`next` is called.
+ """
+ return self.items[self.pos]
+
+ def next(self):
+ """Return the current item, then advance :attr:`current` to the
+ next item.
+ """
+ rv = self.current
+ self.pos = (self.pos + 1) % len(self.items)
+ return rv
+
+ __next__ = next
+
+
+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
+
+
+class Namespace(object):
+ """A namespace object that can hold arbitrary attributes. It may be
+ initialized from a dictionary or with keyword arguments."""
+
+ def __init__(*args, **kwargs):
+ self, args = args[0], args[1:]
+ self.__attrs = dict(*args, **kwargs)
+
+ def __getattribute__(self, name):
+ if name == '_Namespace__attrs':
+ return object.__getattribute__(self, name)
+ try:
+ return self.__attrs[name]
+ except KeyError:
+ raise AttributeError(name)
+
+ def __setitem__(self, name, value):
+ self.__attrs[name] = value
+
+ def __repr__(self):
+ return '<Namespace %r>' % self.__attrs
+
+
+# does this python version support async for in and async generators?
+try:
+ exec('async def _():\n async for _ in ():\n yield _')
+ have_async_gen = True
+except SyntaxError:
+ have_async_gen = False
+
+
+# Imported here because that's where it was in the past
+from markupsafe import Markup, escape, soft_unicode