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Diffstat (limited to 'python/jinja2/utils.py')
| -rw-r--r-- | python/jinja2/utils.py | 647 |
1 files changed, 647 insertions, 0 deletions
diff --git a/python/jinja2/utils.py b/python/jinja2/utils.py new file mode 100644 index 0000000..502a311 --- /dev/null +++ b/python/jinja2/utils.py @@ -0,0 +1,647 @@ +# -*- coding: utf-8 -*- +""" + jinja2.utils + ~~~~~~~~~~~~ + + Utility functions. + + :copyright: (c) 2017 by the Jinja Team. + :license: BSD, see LICENSE for more details. +""" +import re +import json +import errno +from collections import deque +from threading import Lock +from jinja2._compat import text_type, string_types, implements_iterator, \ + url_quote + + +_word_split_re = re.compile(r'(\s+)') +_punctuation_re = re.compile( + '^(?P<lead>(?:%s)*)(?P<middle>.*?)(?P<trail>(?:%s)*)$' % ( + '|'.join(map(re.escape, ('(', '<', '<'))), + '|'.join(map(re.escape, ('.', ',', ')', '>', '\n', '>'))) + ) +) +_simple_email_re = re.compile(r'^\S+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+$') +_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(): + """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 + 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: + items = import_name.split('.') + module = '.'.join(items[:-1]) + obj = items[-1] + 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`. + """ + try: + return open(filename, mode) + except IOError as e: + if e.errno not in (errno.ENOENT, errno.EISDIR, errno.EINVAL): + raise + + +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): + """URL escapes a single bytestring or unicode string with the + given charset if applicable to URL safe quoting under all rules + that need to be considered under all supported Python versions. + + If non strings are provided they are converted to their unicode + representation first. + """ + if not isinstance(obj, string_types): + obj = text_type(obj) + if isinstance(obj, text_type): + obj = obj.encode(charset) + safe = not for_qs and b'/' or b'' + rv = text_type(url_quote(obj, safe)) + 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 = deque(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. + """ + self._wlock.acquire() + try: + try: + return self[key] + except KeyError: + self[key] = default + return default + finally: + self._wlock.release() + + 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: + # __getitem__ is not locked, it might happen + 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.""" + 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 +try: + from collections import MutableMapping + MutableMapping.register(LRUCache) +except ImportError: + pass + + +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) + + +@implements_iterator +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 + self.reset() + + def reset(self): + """Resets the cycle.""" + self.pos = 0 + + @property + 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 + + __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 argments.""" + + 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 |