django>template>defaultfilters.py

"""Default variable filters."""
import random as random_module
import re
import types
from decimal import ROUND_HALF_UP, Context, Decimal, InvalidOperation
from functools import wraps
from operator import itemgetter
from pprint import pformat
from urllib.parse import quote

from django.utils import formats
from django.utils.dateformat import format, time_format
from django.utils.encoding import iri_to_uri
from django.utils.html import (
    avoid_wrapping, conditional_escape, escape, escapejs,
    json_script as _json_script, linebreaks, strip_tags, urlize as _urlize,
)
from django.utils.safestring import SafeData, mark_safe
from django.utils.text import (
    Truncator, normalize_newlines, phone2numeric, slugify as _slugify, wrap,
)
from django.utils.timesince import timesince, timeuntil
from django.utils.translation import gettext, ngettext

from .base import Variable, VariableDoesNotExist
from .library import Library

register = Library()


#######################
# STRING DECORATOR    #
#######################

def stringfilter(func):
    """
    Decorator for filters which should only receive strings. The object
    passed as the first positional argument will be converted to a string.
    """
    def _dec(*args, **kwargs):
        args = list(args)
        args[0] = str(args[0])
        if (isinstance(args[0], SafeData) and
                getattr(_dec._decorated_function, 'is_safe', False)):
            return mark_safe(func(*args, **kwargs))
        return func(*args, **kwargs)

    # Include a reference to the real function (used to check original
    # arguments by the template parser, and to bear the 'is_safe' attribute
    # when multiple decorators are applied).
    _dec._decorated_function = getattr(func, '_decorated_function', func)

    return wraps(func)(_dec)


###################
# STRINGS         #
###################

@register.filter(is_safe=True)
@stringfilter
def addslashes(value):
    """
    Add slashes before quotes. Useful for escaping strings in CSV, for
    example. Less useful for escaping JavaScript; use the ``escapejs``
    filter instead.
    """
    return value.replace('\\', '\\\\').replace('"', '\\"').replace("'", "\\'")


@register.filter(is_safe=True)
@stringfilter
def capfirst(value):
    """Capitalize the first character of the value."""
    return value and value[0].upper() + value[1:]


@register.filter("escapejs")
@stringfilter
def escapejs_filter(value):
    """Hex encode characters for use in JavaScript strings."""
    return escapejs(value)


@register.filter(is_safe=True)
def json_script(value, element_id):
    """
    Output value JSON-encoded, wrapped in a