# -*- coding: utf-8 -*- """Built-in template filters used with the ``|`` operator.""" import math import random import re import warnings from collections import namedtuple from itertools import chain from itertools import groupby from markupsafe import escape from markupsafe import Markup from markupsafe import soft_unicode from ._compat import abc from ._compat import imap from ._compat import iteritems from ._compat import string_types from ._compat import text_type from .exceptions import FilterArgumentError from .runtime import Undefined from .utils import htmlsafe_json_dumps from .utils import pformat from .utils import unicode_urlencode from .utils import urlize _word_re = re.compile(r"\w+", re.UNICODE) _word_beginning_split_re = re.compile(r"([-\s\(\{\[\<]+)", re.UNICODE) def contextfilter(f): """Decorator for marking context dependent filters. The current :class:`Context` will be passed as first argument. """ f.contextfilter = True return f def evalcontextfilter(f): """Decorator for marking eval-context dependent filters. An eval context object is passed as first argument. For more information about the eval context, see :ref:`eval-context`. .. versionadded:: 2.4 """ f.evalcontextfilter = True return f def environmentfilter(f): """Decorator for marking environment dependent filters. The current :class:`Environment` is passed to the filter as first argument. """ f.environmentfilter = True return f def ignore_case(value): """For use as a postprocessor for :func:`make_attrgetter`. Converts strings to lowercase and returns other types as-is.""" return value.lower() if isinstance(value, string_types) else value def make_attrgetter(environment, attribute, postprocess=None, default=None): """Returns a callable that looks up the given attribute from a passed object with the rules of the environment. Dots are allowed to access attributes of attributes. Integer parts in paths are looked up as integers. """ attribute = _prepare_attribute_parts(attribute) def attrgetter(item): for part in attribute: item = environment.getitem(item, part) if default and isinstance(item, Undefined): item = default if postprocess is not None: item = postprocess(item) return item return attrgetter def make_multi_attrgetter(environment, attribute, postprocess=None): """Returns a callable that looks up the given comma separated attributes from a passed object with the rules of the environment. Dots are allowed to access attributes of each attribute. Integer parts in paths are looked up as integers. The value returned by the returned callable is a list of extracted attribute values. Examples of attribute: "attr1,attr2", "attr1.inner1.0,attr2.inner2.0", etc. """ attribute_parts = ( attribute.split(",") if isinstance(attribute, string_types) else [attribute] ) attribute = [ _prepare_attribute_parts(attribute_part) for attribute_part in attribute_parts ] def attrgetter(item): items = [None] * len(attribute) for i, attribute_part in enumerate(attribute): item_i = item for part in attribute_part: item_i = environment.getitem(item_i, part) if postprocess is not None: item_i = postprocess(item_i) items[i] = item_i return items return attrgetter def _prepare_attribute_parts(attr): if attr is None: return [] elif isinstance(attr, string_types): return [int(x) if x.isdigit() else x for x in attr.split(".")] else: return [attr] def do_forceescape(value): """Enforce HTML escaping. This will probably double escape variables.""" if hasattr(value, "__html__"): value = value.__html__() return escape(text_type(value)) def do_urlencode(value): """Quote data for use in a URL path or query using UTF-8. Basic wrapper around :func:`urllib.parse.quote` when given a string, or :func:`urllib.parse.urlencode` for a dict or iterable. :param value: Data to quote. A string will be quoted directly. A dict or iterable of ``(key, value)`` pairs will be joined as a query string. When given a string, "/" is not quoted. HTTP servers treat "/" and "%2F" equivalently in paths. If you need quoted slashes, use the ``|replace("/", "%2F")`` filter. .. versionadded:: 2.7 """ if isinstance(value, string_types) or not isinstance(value, abc.Iterable): return unicode_urlencode(value) if isinstance(value, dict): items = iteritems(value) else: items = iter(value) return u"&".join( "%s=%s" % (unicode_urlencode(k, for_qs=True), unicode_urlencode(v, for_qs=True)) for k, v in items ) @evalcontextfilter def do_replace(eval_ctx, s, old, new, count=None): """Return a copy of the value with all occurrences of a substring replaced with a new one. The first argument is the substring that should be replaced, the second is the replacement string. If the optional third argument ``count`` is given, only the first ``count`` occurrences are replaced: .. sourcecode:: jinja {{ "Hello World"|replace("Hello", "Goodbye") }} -> Goodbye World {{ "aaaaargh"|replace("a", "d'oh, ", 2) }} -> d'oh, d'oh, aaargh """ if count is None: count = -1 if not eval_ctx.autoescape: return text_type(s).replace(text_type(old), text_type(new), count) if ( hasattr(old, "__html__") or hasattr(new, "__html__") and not hasattr(s, "__html__") ): s = escape(s) else: s = soft_unicode(s) return s.replace(soft_unicode(old), soft_unicode(new), count) def do_upper(s): """Convert a value to uppercase.""" return soft_unicode(s).upper() def do_lower(s): """Convert a value to lowercase.""" return soft_unicode(s).lower() @evalcontextfilter def do_xmlattr(_eval_ctx, d, autospace=True): """Create an SGML/XML attribute string based on the items in a dict. All values that are neither `none` nor `undefined` are automatically escaped: .. sourcecode:: html+jinja ... Results in something like this: .. sourcecode:: html As you can see it automatically prepends a space in front of the item if the filter returned something unless the second parameter is false. """ rv = u" ".join( u'%s="%s"' % (escape(key), escape(value)) for key, value in iteritems(d) if value is not None and not isinstance(value, Undefined) ) if autospace and rv: rv = u" " + rv if _eval_ctx.autoescape: rv = Markup(rv) return rv def do_capitalize(s): """Capitalize a value. The first character will be uppercase, all others lowercase. """ return soft_unicode(s).capitalize() def do_title(s): """Return a titlecased version of the value. I.e. words will start with uppercase letters, all remaining characters are lowercase. """ return "".join( [ item[0].upper() + item[1:].lower() for item in _word_beginning_split_re.split(soft_unicode(s)) if item ] ) def do_dictsort(value, case_sensitive=False, by="key", reverse=False): """Sort a dict and yield (key, value) pairs. Because python dicts are unsorted you may want to use this function to order them by either key or value: .. sourcecode:: jinja {% for key, value in mydict|dictsort %} sort the dict by key, case insensitive {% for key, value in mydict|dictsort(reverse=true) %} sort the dict by key, case insensitive, reverse order {% for key, value in mydict|dictsort(true) %} sort the dict by key, case sensitive {% for key, value in mydict|dictsort(false, 'value') %} sort the dict by value, case insensitive """ if by == "key": pos = 0 elif by == "value": pos = 1 else: raise FilterArgumentError('You can only sort by either "key" or "value"') def sort_func(item): value = item[pos] if not case_sensitive: value = ignore_case(value) return value return sorted(value.items(), key=sort_func, reverse=reverse) @environmentfilter def do_sort(environment, value, reverse=False, case_sensitive=False, attribute=None): """Sort an iterable using Python's :func:`sorted`. .. sourcecode:: jinja {% for city in cities|sort %} ... {% endfor %} :param reverse: Sort descending instead of ascending. :param case_sensitive: When sorting strings, sort upper and lower case separately. :param attribute: When sorting objects or dicts, an attribute or key to sort by. Can use dot notation like ``"address.city"``. Can be a list of attributes like ``"age,name"``. The sort is stable, it does not change the relative order of elements that compare equal. This makes it is possible to chain sorts on different attributes and ordering. .. sourcecode:: jinja {% for user in users|sort(attribute="name") |sort(reverse=true, attribute="age") %} ... {% endfor %} As a shortcut to chaining when the direction is the same for all attributes, pass a comma separate list of attributes. .. sourcecode:: jinja {% for user users|sort(attribute="age,name") %} ... {% endfor %} .. versionchanged:: 2.11.0 The ``attribute`` parameter can be a comma separated list of attributes, e.g. ``"age,name"``. .. versionchanged:: 2.6 The ``attribute`` parameter was added. """ key_func = make_multi_attrgetter( environment, attribute, postprocess=ignore_case if not case_sensitive else None ) return sorted(value, key=key_func, reverse=reverse) @environmentfilter def do_unique(environment, value, case_sensitive=False, attribute=None): """Returns a list of unique items from the given iterable. .. sourcecode:: jinja {{ ['foo', 'bar', 'foobar', 'FooBar']|unique|list }} -> ['foo', 'bar', 'foobar'] The unique items are yielded in the same order as their first occurrence in the iterable passed to the filter. :param case_sensitive: Treat upper and lower case strings as distinct. :param attribute: Filter objects with unique values for this attribute. """ getter = make_attrgetter( environment, attribute, postprocess=ignore_case if not case_sensitive else None ) seen = set() for item in value: key = getter(item) if key not in seen: seen.add(key) yield item def _min_or_max(environment, value, func, case_sensitive, attribute): it = iter(value) try: first = next(it) except StopIteration: return environment.undefined("No aggregated item, sequence was empty.") key_func = make_attrgetter( environment, attribute, postprocess=ignore_case if not case_sensitive else None ) return func(chain([first], it), key=key_func) @environmentfilter def do_min(environment, value, case_sensitive=False, attribute=None): """Return the smallest item from the sequence. .. sourcecode:: jinja {{ [1, 2, 3]|min }} -> 1 :param case_sensitive: Treat upper and lower case strings as distinct. :param attribute: Get the object with the min value of this attribute. """ return _min_or_max(environment, value, min, case_sensitive, attribute) @environmentfilter def do_max(environment, value, case_sensitive=False, attribute=None): """Return the largest item from the sequence. .. sourcecode:: jinja {{ [1, 2, 3]|max }} -> 3 :param case_sensitive: Treat upper and lower case strings as distinct. :param attribute: Get the object with the max value of this attribute. """ return _min_or_max(environment, value, max, case_sensitive, attribute) def do_default(value, default_value=u"", boolean=False): """If the value is undefined it will return the passed default value, otherwise the value of the variable: .. sourcecode:: jinja {{ my_variable|default('my_variable is not defined') }} This will output the value of ``my_variable`` if the variable was defined, otherwise ``'my_variable is not defined'``. If you want to use default with variables that evaluate to false you have to set the second parameter to `true`: .. sourcecode:: jinja {{ ''|default('the string was empty', true) }} .. versionchanged:: 2.11 It's now possible to configure the :class:`~jinja2.Environment` with :class:`~jinja2.ChainableUndefined` to make the `default` filter work on nested elements and attributes that may contain undefined values in the chain without getting an :exc:`~jinja2.UndefinedError`. """ if isinstance(value, Undefined) or (boolean and not value): return default_value return value @evalcontextfilter def do_join(eval_ctx, value, d=u"", attribute=None): """Return a string which is the concatenation of the strings in the sequence. The separator between elements is an empty string per default, you can define it with the optional parameter: .. sourcecode:: jinja {{ [1, 2, 3]|join('|') }} -> 1|2|3 {{ [1, 2, 3]|join }} -> 123 It is also possible to join certain attributes of an object: .. sourcecode:: jinja {{ users|join(', ', attribute='username') }} .. versionadded:: 2.6 The `attribute` parameter was added. """ if attribute is not None: value = imap(make_attrgetter(eval_ctx.environment, attribute), value) # no automatic escaping? joining is a lot easier then if not eval_ctx.autoescape: return text_type(d).join(imap(text_type, value)) # if the delimiter doesn't have an html representation we check # if any of the items has. If yes we do a coercion to Markup if not hasattr(d, "__html__"): value = list(value) do_escape = False for idx, item in enumerate(value): if hasattr(item, "__html__"): do_escape = True else: value[idx] = text_type(item) if do_escape: d = escape(d) else: d = text_type(d) return d.join(value) # no html involved, to normal joining return soft_unicode(d).join(imap(soft_unicode, value)) def do_center(value, width=80): """Centers the value in a field of a given width.""" return text_type(value).center(width) @environmentfilter def do_first(environment, seq): """Return the first item of a sequence.""" try: return next(iter(seq)) except StopIteration: return environment.undefined("No first item, sequence was empty.") @environmentfilter def do_last(environment, seq): """ Return the last item of a sequence. Note: Does not work with generators. You may want to explicitly convert it to a list: .. sourcecode:: jinja {{ data | selectattr('name', '==', 'Jinja') | list | last }} """ try: return next(iter(reversed(seq))) except StopIteration: return environment.undefined("No last item, sequence was empty.") @contextfilter def do_random(context, seq): """Return a random item from the sequence.""" try: return random.choice(seq) except IndexError: return context.environment.undefined("No random item, sequence was empty.") def do_filesizeformat(value, binary=False): """Format the value like a 'human-readable' file size (i.e. 13 kB, 4.1 MB, 102 Bytes, etc). Per default decimal prefixes are used (Mega, Giga, etc.), if the second parameter is set to `True` the binary prefixes are used (Mebi, Gibi). """ bytes = float(value) base = binary and 1024 or 1000 prefixes = [ (binary and "KiB" or "kB"), (binary and "MiB" or "MB"), (binary and "GiB" or "GB"), (binary and "TiB" or "TB"), (binary and "PiB" or "PB"), (binary and "EiB" or "EB"), (binary and "ZiB" or "ZB"), (binary and "YiB" or "YB"), ] if bytes == 1: return "1 Byte" elif bytes < base: return "%d Bytes" % bytes else: for i, prefix in enumerate(prefixes): unit = base ** (i + 2) if bytes < unit: return "%.1f %s" % ((base * bytes / unit), prefix) return "%.1f %s" % ((base * bytes / unit), prefix) def do_pprint(value, verbose=False): """Pretty print a variable. Useful for debugging. With Jinja 1.2 onwards you can pass it a parameter. If this parameter is truthy the output will be more verbose (this requires `pretty`) """ return pformat(value, verbose=verbose) @evalcontextfilter def do_urlize( eval_ctx, value, trim_url_limit=None, nofollow=False, target=None, rel=None ): """Converts URLs in plain text into clickable links. If you pass the filter an additional integer it will shorten the urls to that number. Also a third argument exists that makes the urls "nofollow": .. sourcecode:: jinja {{ mytext|urlize(40, true) }} links are shortened to 40 chars and defined with rel="nofollow" If *target* is specified, the ``target`` attribute will be added to the ```` tag: .. sourcecode:: jinja {{ mytext|urlize(40, target='_blank') }} .. versionchanged:: 2.8+ The *target* parameter was added. """ policies = eval_ctx.environment.policies rel = set((rel or "").split() or []) if nofollow: rel.add("nofollow") rel.update((policies["urlize.rel"] or "").split()) if target is None: target = policies["urlize.target"] rel = " ".join(sorted(rel)) or None rv = urlize(value, trim_url_limit, rel=rel, target=target) if eval_ctx.autoescape: rv = Markup(rv) return rv def do_indent(s, width=4, first=False, blank=False, indentfirst=None): """Return a copy of the string with each line indented by 4 spaces. The first line and blank lines are not indented by default. :param width: Number of spaces to indent by. :param first: Don't skip indenting the first line. :param blank: Don't skip indenting empty lines. .. versionchanged:: 2.10 Blank lines are not indented by default. Rename the ``indentfirst`` argument to ``first``. """ if indentfirst is not None: warnings.warn( "The 'indentfirst' argument is renamed to 'first' and will" " be removed in version 3.0.", DeprecationWarning, stacklevel=2, ) first = indentfirst indention = u" " * width newline = u"\n" if isinstance(s, Markup): indention = Markup(indention) newline = Markup(newline) s += newline # this quirk is necessary for splitlines method if blank: rv = (newline + indention).join(s.splitlines()) else: lines = s.splitlines() rv = lines.pop(0) if lines: rv += newline + newline.join( indention + line if line else line for line in lines ) if first: rv = indention + rv return rv @environmentfilter def do_truncate(env, s, length=255, killwords=False, end="...", leeway=None): """Return a truncated copy of the string. The length is specified with the first parameter which defaults to ``255``. If the second parameter is ``true`` the filter will cut the text at length. Otherwise it will discard the last word. If the text was in fact truncated it will append an ellipsis sign (``"..."``). If you want a different ellipsis sign than ``"..."`` you can specify it using the third parameter. Strings that only exceed the length by the tolerance margin given in the fourth parameter will not be truncated. .. sourcecode:: jinja {{ "foo bar baz qux"|truncate(9) }} -> "foo..." {{ "foo bar baz qux"|truncate(9, True) }} -> "foo ba..." {{ "foo bar baz qux"|truncate(11) }} -> "foo bar baz qux" {{ "foo bar baz qux"|truncate(11, False, '...', 0) }} -> "foo bar..." The default leeway on newer Jinja versions is 5 and was 0 before but can be reconfigured globally. """ if leeway is None: leeway = env.policies["truncate.leeway"] assert length >= len(end), "expected length >= %s, got %s" % (len(end), length) assert leeway >= 0, "expected leeway >= 0, got %s" % leeway if len(s) <= length + leeway: return s if killwords: return s[: length - len(end)] + end result = s[: length - len(end)].rsplit(" ", 1)[0] return result + end @environmentfilter def do_wordwrap( environment, s, width=79, break_long_words=True, wrapstring=None, break_on_hyphens=True, ): """Wrap a string to the given width. Existing newlines are treated as paragraphs to be wrapped separately. :param s: Original text to wrap. :param width: Maximum length of wrapped lines. :param break_long_words: If a word is longer than ``width``, break it across lines. :param break_on_hyphens: If a word contains hyphens, it may be split across lines. :param wrapstring: String to join each wrapped line. Defaults to :attr:`Environment.newline_sequence`. .. versionchanged:: 2.11 Existing newlines are treated as paragraphs wrapped separately. .. versionchanged:: 2.11 Added the ``break_on_hyphens`` parameter. .. versionchanged:: 2.7 Added the ``wrapstring`` parameter. """ import textwrap if not wrapstring: wrapstring = environment.newline_sequence # textwrap.wrap doesn't consider existing newlines when wrapping. # If the string has a newline before width, wrap will still insert # a newline at width, resulting in a short line. Instead, split and # wrap each paragraph individually. return wrapstring.join( [ wrapstring.join( textwrap.wrap( line, width=width, expand_tabs=False, replace_whitespace=False, break_long_words=break_long_words, break_on_hyphens=break_on_hyphens, ) ) for line in s.splitlines() ] ) def do_wordcount(s): """Count the words in that string.""" return len(_word_re.findall(soft_unicode(s))) def do_int(value, default=0, base=10): """Convert the value into an integer. If the conversion doesn't work it will return ``0``. You can override this default using the first parameter. You can also override the default base (10) in the second parameter, which handles input with prefixes such as 0b, 0o and 0x for bases 2, 8 and 16 respectively. The base is ignored for decimal numbers and non-string values. """ try: if isinstance(value, string_types): return int(value, base) return int(value) except (TypeError, ValueError): # this quirk is necessary so that "42.23"|int gives 42. try: return int(float(value)) except (TypeError, ValueError): return default def do_float(value, default=0.0): """Convert the value into a floating point number. If the conversion doesn't work it will return ``0.0``. You can override this default using the first parameter. """ try: return float(value) except (TypeError, ValueError): return default def do_format(value, *args, **kwargs): """Apply the given values to a `printf-style`_ format string, like ``string % values``. .. sourcecode:: jinja {{ "%s, %s!"|format(greeting, name) }} Hello, World! In most cases it should be more convenient and efficient to use the ``%`` operator or :meth:`str.format`. .. code-block:: text {{ "%s, %s!" % (greeting, name) }} {{ "{}, {}!".format(greeting, name) }} .. _printf-style: https://docs.python.org/library/stdtypes.html #printf-style-string-formatting """ if args and kwargs: raise FilterArgumentError( "can't handle positional and keyword arguments at the same time" ) return soft_unicode(value) % (kwargs or args) def do_trim(value, chars=None): """Strip leading and trailing characters, by default whitespace.""" return soft_unicode(value).strip(chars) def do_striptags(value): """Strip SGML/XML tags and replace adjacent whitespace by one space.""" if hasattr(value, "__html__"): value = value.__html__() return Markup(text_type(value)).striptags() def do_slice(value, slices, fill_with=None): """Slice an iterator and return a list of lists containing those items. Useful if you want to create a div containing three ul tags that represent columns: .. sourcecode:: html+jinja
{%- for column in items|slice(3) %}
    {%- for item in column %}
  • {{ item }}
  • {%- endfor %}
{%- endfor %}
If you pass it a second argument it's used to fill missing values on the last iteration. """ seq = list(value) length = len(seq) items_per_slice = length // slices slices_with_extra = length % slices offset = 0 for slice_number in range(slices): start = offset + slice_number * items_per_slice if slice_number < slices_with_extra: offset += 1 end = offset + (slice_number + 1) * items_per_slice tmp = seq[start:end] if fill_with is not None and slice_number >= slices_with_extra: tmp.append(fill_with) yield tmp def do_batch(value, linecount, fill_with=None): """ A filter that batches items. It works pretty much like `slice` just the other way round. It returns a list of lists with the given number of items. If you provide a second parameter this is used to fill up missing items. See this example: .. sourcecode:: html+jinja {%- for row in items|batch(3, ' ') %} {%- for column in row %} {%- endfor %} {%- endfor %}
{{ column }}
""" tmp = [] for item in value: if len(tmp) == linecount: yield tmp tmp = [] tmp.append(item) if tmp: if fill_with is not None and len(tmp) < linecount: tmp += [fill_with] * (linecount - len(tmp)) yield tmp def do_round(value, precision=0, method="common"): """Round the number to a given precision. The first parameter specifies the precision (default is ``0``), the second the rounding method: - ``'common'`` rounds either up or down - ``'ceil'`` always rounds up - ``'floor'`` always rounds down If you don't specify a method ``'common'`` is used. .. sourcecode:: jinja {{ 42.55|round }} -> 43.0 {{ 42.55|round(1, 'floor') }} -> 42.5 Note that even if rounded to 0 precision, a float is returned. If you need a real integer, pipe it through `int`: .. sourcecode:: jinja {{ 42.55|round|int }} -> 43 """ if method not in {"common", "ceil", "floor"}: raise FilterArgumentError("method must be common, ceil or floor") if method == "common": return round(value, precision) func = getattr(math, method) return func(value * (10 ** precision)) / (10 ** precision) # Use a regular tuple repr here. This is what we did in the past and we # really want to hide this custom type as much as possible. In particular # we do not want to accidentally expose an auto generated repr in case # people start to print this out in comments or something similar for # debugging. _GroupTuple = namedtuple("_GroupTuple", ["grouper", "list"]) _GroupTuple.__repr__ = tuple.__repr__ _GroupTuple.__str__ = tuple.__str__ @environmentfilter def do_groupby(environment, value, attribute): """Group a sequence of objects by an attribute using Python's :func:`itertools.groupby`. The attribute can use dot notation for nested access, like ``"address.city"``. Unlike Python's ``groupby``, the values are sorted first so only one group is returned for each unique value. For example, a list of ``User`` objects with a ``city`` attribute can be rendered in groups. In this example, ``grouper`` refers to the ``city`` value of the group. .. sourcecode:: html+jinja ``groupby`` yields namedtuples of ``(grouper, list)``, which can be used instead of the tuple unpacking above. ``grouper`` is the value of the attribute, and ``list`` is the items with that value. .. sourcecode:: html+jinja .. versionchanged:: 2.6 The attribute supports dot notation for nested access. """ expr = make_attrgetter(environment, attribute) return [ _GroupTuple(key, list(values)) for key, values in groupby(sorted(value, key=expr), expr) ] @environmentfilter def do_sum(environment, iterable, attribute=None, start=0): """Returns the sum of a sequence of numbers plus the value of parameter 'start' (which defaults to 0). When the sequence is empty it returns start. It is also possible to sum up only certain attributes: .. sourcecode:: jinja Total: {{ items|sum(attribute='price') }} .. versionchanged:: 2.6 The `attribute` parameter was added to allow suming up over attributes. Also the `start` parameter was moved on to the right. """ if attribute is not None: iterable = imap(make_attrgetter(environment, attribute), iterable) return sum(iterable, start) def do_list(value): """Convert the value into a list. If it was a string the returned list will be a list of characters. """ return list(value) def do_mark_safe(value): """Mark the value as safe which means that in an environment with automatic escaping enabled this variable will not be escaped. """ return Markup(value) def do_mark_unsafe(value): """Mark a value as unsafe. This is the reverse operation for :func:`safe`.""" return text_type(value) def do_reverse(value): """Reverse the object or return an iterator that iterates over it the other way round. """ if isinstance(value, string_types): return value[::-1] try: return reversed(value) except TypeError: try: rv = list(value) rv.reverse() return rv except TypeError: raise FilterArgumentError("argument must be iterable") @environmentfilter def do_attr(environment, obj, name): """Get an attribute of an object. ``foo|attr("bar")`` works like ``foo.bar`` just that always an attribute is returned and items are not looked up. See :ref:`Notes on subscriptions ` for more details. """ try: name = str(name) except UnicodeError: pass else: try: value = getattr(obj, name) except AttributeError: pass else: if environment.sandboxed and not environment.is_safe_attribute( obj, name, value ): return environment.unsafe_undefined(obj, name) return value return environment.undefined(obj=obj, name=name) @contextfilter def do_map(*args, **kwargs): """Applies a filter on a sequence of objects or looks up an attribute. This is useful when dealing with lists of objects but you are really only interested in a certain value of it. The basic usage is mapping on an attribute. Imagine you have a list of users but you are only interested in a list of usernames: .. sourcecode:: jinja Users on this page: {{ users|map(attribute='username')|join(', ') }} You can specify a ``default`` value to use if an object in the list does not have the given attribute. .. sourcecode:: jinja {{ users|map(attribute="username", default="Anonymous")|join(", ") }} Alternatively you can let it invoke a filter by passing the name of the filter and the arguments afterwards. A good example would be applying a text conversion filter on a sequence: .. sourcecode:: jinja Users on this page: {{ titles|map('lower')|join(', ') }} Similar to a generator comprehension such as: .. code-block:: python (u.username for u in users) (u.username or "Anonymous" for u in users) (do_lower(x) for x in titles) .. versionchanged:: 2.11.0 Added the ``default`` parameter. .. versionadded:: 2.7 """ seq, func = prepare_map(args, kwargs) if seq: for item in seq: yield func(item) @contextfilter def do_select(*args, **kwargs): """Filters a sequence of objects by applying a test to each object, and only selecting the objects with the test succeeding. If no test is specified, each object will be evaluated as a boolean. Example usage: .. sourcecode:: jinja {{ numbers|select("odd") }} {{ numbers|select("odd") }} {{ numbers|select("divisibleby", 3) }} {{ numbers|select("lessthan", 42) }} {{ strings|select("equalto", "mystring") }} Similar to a generator comprehension such as: .. code-block:: python (n for n in numbers if test_odd(n)) (n for n in numbers if test_divisibleby(n, 3)) .. versionadded:: 2.7 """ return select_or_reject(args, kwargs, lambda x: x, False) @contextfilter def do_reject(*args, **kwargs): """Filters a sequence of objects by applying a test to each object, and rejecting the objects with the test succeeding. If no test is specified, each object will be evaluated as a boolean. Example usage: .. sourcecode:: jinja {{ numbers|reject("odd") }} Similar to a generator comprehension such as: .. code-block:: python (n for n in numbers if not test_odd(n)) .. versionadded:: 2.7 """ return select_or_reject(args, kwargs, lambda x: not x, False) @contextfilter def do_selectattr(*args, **kwargs): """Filters a sequence of objects by applying a test to the specified attribute of each object, and only selecting the objects with the test succeeding. If no test is specified, the attribute's value will be evaluated as a boolean. Example usage: .. sourcecode:: jinja {{ users|selectattr("is_active") }} {{ users|selectattr("email", "none") }} Similar to a generator comprehension such as: .. code-block:: python (u for user in users if user.is_active) (u for user in users if test_none(user.email)) .. versionadded:: 2.7 """ return select_or_reject(args, kwargs, lambda x: x, True) @contextfilter def do_rejectattr(*args, **kwargs): """Filters a sequence of objects by applying a test to the specified attribute of each object, and rejecting the objects with the test succeeding. If no test is specified, the attribute's value will be evaluated as a boolean. .. sourcecode:: jinja {{ users|rejectattr("is_active") }} {{ users|rejectattr("email", "none") }} Similar to a generator comprehension such as: .. code-block:: python (u for user in users if not user.is_active) (u for user in users if not test_none(user.email)) .. versionadded:: 2.7 """ return select_or_reject(args, kwargs, lambda x: not x, True) @evalcontextfilter def do_tojson(eval_ctx, value, indent=None): """Dumps a structure to JSON so that it's safe to use in ``