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"""Default variable filters."""
from __future__ import unicode_literals
import random as random_module
import re
import warnings
from decimal import ROUND_HALF_UP, Context, Decimal, InvalidOperation
from functools import wraps
from pprint import pformat
from django.conf import settings
from django.utils import formats, six
from django.utils.dateformat import format, time_format
from django.utils.deprecation import RemovedInDjango110Warning
from django.utils.encoding import force_text, iri_to_uri
from django.utils.html import (
avoid_wrapping, conditional_escape, escape, escapejs, linebreaks,
remove_tags, strip_tags, urlize as _urlize,
)
from django.utils.http import urlquote
from django.utils.safestring import SafeData, mark_for_escaping, 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 ugettext, ungettext
from .base import Variable, VariableDoesNotExist
from .library import Library
register = Library()
#######################
# STRING DECORATOR #
#######################
def stringfilter(func):
"""
Decorator for filters which should only receive unicode objects. The object
passed as the first positional argument will be converted to a unicode
object.
"""
def _dec(*args, **kwargs):
if args:
args = list(args)
args[0] = force_text(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):
"""
Adds 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):
"""Capitalizes the first character of the value."""
return value and value[0].upper() + value[1:]
@register.filter("escapejs")
@stringfilter
def escapejs_filter(value):
"""Hex encodes characters for use in JavaScript strings."""
return escapejs(value)
# Values for testing floatformat input against infinity and NaN representations,
# which differ across platforms and Python versions. Some (i.e. old Windows
# ones) are not recognized by Decimal but we want to return them unchanged vs.
# returning an empty string as we do for completely invalid input. Note these
# need to be built up from values that are not inf/nan, since inf/nan values do
# not reload properly from .pyc files on Windows prior to some level of Python 2.5
# (see Python Issue757815 and Issue1080440).
pos_inf = 1e200 * 1e200
neg_inf = -1e200 * 1e200
nan = (1e200 * 1e200) // (1e200 * 1e200)
special_floats = [str(pos_inf), str(neg_inf), str(nan)]
@register.filter(is_safe=True)
def floatformat(text, arg=-1):
"""
Displays a float to a specified number of decimal places.
If called without an argument, it displays the floating point number with
one decimal place -- but only if there's a decimal place to be displayed:
* num1 = 34.23234
* num2 = 34.00000
* num3 = 34.26000
* {{ num1|floatformat }} displays "34.2"
* {{ num2|floatformat }} displays "34"
* {{ num3|floatformat }} displays "34.3"
If arg is positive, it will always display exactly arg number of decimal
places:
* {{ num1|floatformat:3 }} displays "34.232"
* {{ num2|floatformat:3 }} displays "34.000"
* {{ num3|floatformat:3 }} displays "34.260"
If arg is negative, it will display arg number of decimal places -- but
only if there are places to be displayed:
* {{ num1|floatformat:"-3" }} displays "34.232"
* {{ num2|floatformat:"-3" }} displays "34"
* {{ num3|floatformat:"-3" }} displays "34.260"
If the input float is infinity or NaN, the (platform-dependent) string
representation of that value will be displayed.
"""
try:
input_val = force_text(text)
d = Decimal(input_val)
except UnicodeEncodeError:
return ''
except InvalidOperation:
if input_val in special_floats:
return input_val
try:
d = Decimal(force_text(float(text)))
except (ValueError, InvalidOperation, TypeError, UnicodeEncodeError):
return ''
try:
p = int(arg)
except ValueError:
return input_val
try:
m = int(d) - d
except (ValueError, OverflowError, InvalidOperation):
return input_val
if not m and p < 0:
return mark_safe(formats.number_format('%d' % (int(d)), 0))
if p == 0:
exp = Decimal(1)
else:
exp = Decimal('1.0') / (Decimal(10) ** abs(p))
try:
# Set the precision high enough to avoid an exception, see #15789.
tupl = d.as_tuple()
units = len(tupl[1]) - tupl[2]
prec = abs(p) + units + 1
# Avoid conversion to scientific notation by accessing `sign`, `digits`
# and `exponent` from `Decimal.as_tuple()` directly.
sign, digits, exponent = d.quantize(exp, ROUND_HALF_UP,
Context(prec=prec)).as_tuple()
digits = [six.text_type(digit) for digit in reversed(digits)]
while len(digits) <= abs(exponent):
digits.append('0')
digits.insert(-exponent, '.')
if sign:
digits.append('-')
number = ''.join(reversed(digits))
return mark_safe(formats.number_format(number, abs(p)))
except InvalidOperation:
return input_val
@register.filter(is_safe=True)
@stringfilter
def iriencode(value):
"""Escapes an IRI value for use in a URL."""
return force_text(iri_to_uri(value))
@register.filter(is_safe=True, needs_autoescape=True)
@stringfilter
def linenumbers(value, autoescape=True):
"""Displays text with line numbers."""
lines = value.split('\n')
# Find the maximum width of the line count, for use with zero padding
# string format command
width = six.text_type(len(six.text_type(len(lines))))
if not autoescape or isinstance(value, SafeData):
for i, line in enumerate(lines):
lines[i] = ("%0" + width + "d. %s") % (i + 1, line)
else:
for i, line in enumerate(lines):
lines[i] = ("%0" + width + "d. %s") % (i + 1, escape(line))
return mark_safe('\n'.join(lines))
@register.filter(is_safe=True)
@stringfilter
def lower(value):
"""Converts a string into all lowercase."""
return value.lower()
@register.filter(is_safe=False)
@stringfilter
def make_list(value):
"""
Returns the value turned into a list.
For an integer, it's a list of digits.
For a string, it's a list of characters.
"""
return list(value)
@register.filter(is_safe=True)
@stringfilter
def slugify(value):
"""
Converts to ASCII. Converts spaces to hyphens. Removes characters that
aren't alphanumerics, underscores, or hyphens. Converts to lowercase.
Also strips leading and trailing whitespace.
"""
return _slugify(value)
@register.filter(is_safe=True)
def stringformat(value, arg):
"""
Formats the variable according to the arg, a string formatting specifier.
This specifier uses Python string formating syntax, with the exception that
the leading "%" is dropped.
See http://docs.python.org/lib/typesseq-strings.html for documentation
of Python string formatting
"""
try:
return ("%" + six.text_type(arg)) % value
except (ValueError, TypeError):
return ""
@register.filter(is_safe=True)
@stringfilter
def title(value):
"""Converts a string into titlecase."""
t = re.sub("([a-z])'([A-Z])", lambda m: m.group(0).lower(), value.title())
return re.sub("\d([A-Z])", lambda m: m.group(0).lower(), t)
@register.filter(is_safe=True)
@stringfilter
def truncatechars(value, arg):
"""
Truncates a string after a certain number of characters.
Argument: Number of characters to truncate after.
"""
try:
length = int(arg)
except ValueError: # Invalid literal for int().
return value # Fail silently.
return Truncator(value).chars(length)
@register.filter(is_safe=True)
@stringfilter
def truncatechars_html(value, arg):
"""
Truncates HTML after a certain number of chars.
Argument: Number of chars to truncate after.
Newlines in the HTML are preserved.
"""
try:
length = int(arg)
except ValueError: # invalid literal for int()
return value # Fail silently.
return Truncator(value).chars(length, html=True)
@register.filter(is_safe=True)
@stringfilter
def truncatewords(value, arg):
"""
Truncates a string after a certain number of words.
Argument: Number of words to truncate after.
Newlines within the string are removed.
"""
try:
length = int(arg)
except ValueError: # Invalid literal for int().
return value # Fail silently.
return Truncator(value).words(length, truncate=' ...')
@register.filter(is_safe=True)
@stringfilter
def truncatewords_html(value, arg):
"""
Truncates HTML after a certain number of words.
Argument: Number of words to truncate after.
Newlines in the HTML are preserved.
"""
try:
length = int(arg)
except ValueError: # invalid literal for int()
return value # Fail silently.
return Truncator(value).words(length, html=True, truncate=' ...')
@register.filter(is_safe=False)
@stringfilter
def upper(value):
"""Converts a string into all uppercase."""
return value.upper()
@register.filter(is_safe=False)
@stringfilter
def urlencode(value, safe=None):
"""
Escapes a value for use in a URL.
Takes an optional ``safe`` parameter used to determine the characters which
should not be escaped by Django's ``urlquote`` method. If not provided, the
default safe characters will be used (but an empty string can be provided
when *all* characters should be escaped).
"""
kwargs = {}
if safe is not None:
kwargs['safe'] = safe
return urlquote(value, **kwargs)
@register.filter(is_safe=True, needs_autoescape=True)
@stringfilter
def urlize(value, autoescape=True):
"""Converts URLs in plain text into clickable links."""
return mark_safe(_urlize(value, nofollow=True, autoescape=autoescape))
@register.filter(is_safe=True, needs_autoescape=True)
@stringfilter
def urlizetrunc(value, limit, autoescape=True):
"""
Converts URLs into clickable links, truncating URLs to the given character
limit, and adding 'rel=nofollow' attribute to discourage spamming.
Argument: Length to truncate URLs to.
"""
return mark_safe(_urlize(value, trim_url_limit=int(limit), nofollow=True,
autoescape=autoescape))
@register.filter(is_safe=False)
@stringfilter
def wordcount(value):
"""Returns the number of words."""
return len(value.split())
@register.filter(is_safe=True)
@stringfilter
def wordwrap(value, arg):
"""
Wraps words at specified line length.
Argument: number of characters to wrap the text at.
"""
return wrap(value, int(arg))
@register.filter(is_safe=True)
@stringfilter
def ljust(value, arg):
"""
Left-aligns the value in a field of a given width.
Argument: field size.
"""
return value.ljust(int(arg))
@register.filter(is_safe=True)
@stringfilter
def rjust(value, arg):
"""
Right-aligns the value in a field of a given width.
Argument: field size.
"""
return value.rjust(int(arg))
@register.filter(is_safe=True)
@stringfilter
def center(value, arg):
"""Centers the value in a field of a given width."""
return value.center(int(arg))
@register.filter
@stringfilter
def cut(value, arg):
"""
Removes all values of arg from the given string.
"""
safe = isinstance(value, SafeData)
value = value.replace(arg, '')
if safe and arg != ';':
return mark_safe(value)
return value
###################
# HTML STRINGS #
###################
@register.filter("escape", is_safe=True)
@stringfilter
def escape_filter(value):
"""
Marks the value as a string that should be auto-escaped.
"""
return mark_for_escaping(value)
@register.filter(is_safe=True)
@stringfilter
def force_escape(value):
"""
Escapes a string's HTML. This returns a new string containing the escaped
characters (as opposed to "escape", which marks the content for later
possible escaping).
"""
return escape(value)
@register.filter("linebreaks", is_safe=True, needs_autoescape=True)
@stringfilter
def linebreaks_filter(value, autoescape=True):
"""
Replaces line breaks in plain text with appropriate HTML; a single
newline becomes an HTML line break (``<br />``) and a new line
followed by a blank line becomes a paragraph break (``</p>``).
"""
autoescape = autoescape and not isinstance(value, SafeData)
return mark_safe(linebreaks(value, autoescape))
@register.filter(is_safe=True, needs_autoescape=True)
@stringfilter
def linebreaksbr(value, autoescape=True):
"""
Converts all newlines in a piece of plain text to HTML line breaks
(``<br />``).
"""
autoescape = autoescape and not isinstance(value, SafeData)
value = normalize_newlines(value)
if autoescape:
value = escape(value)
return mark_safe(value.replace('\n', '<br />'))
@register.filter(is_safe=True)
@stringfilter
def safe(value):
"""
Marks the value as a string that should not be auto-escaped.
"""
return mark_safe(value)
@register.filter(is_safe=True)
def safeseq(value):
"""
A "safe" filter for sequences. Marks each element in the sequence,
individually, as safe, after converting them to unicode. Returns a list
with the results.
"""
return [mark_safe(force_text(obj)) for obj in value]
@register.filter(is_safe=True)
@stringfilter
def removetags(value, tags):
"""Removes a space separated list of [X]HTML tags from the output."""
return remove_tags(value, tags)
@register.filter(is_safe=True)
@stringfilter
def striptags(value):
"""Strips all [X]HTML tags."""
return strip_tags(value)
###################
# LISTS #
###################
@register.filter(is_safe=False)
def dictsort(value, arg):
"""
Takes a list of dicts, returns that list sorted by the property given in
the argument.
"""
try:
return sorted(value, key=Variable(arg).resolve)
except (TypeError, VariableDoesNotExist):
return ''
@register.filter(is_safe=False)
def dictsortreversed(value, arg):
"""
Takes a list of dicts, returns that list sorted in reverse order by the
property given in the argument.
"""
try:
return sorted(value, key=Variable(arg).resolve, reverse=True)
except (TypeError, VariableDoesNotExist):
return ''
@register.filter(is_safe=False)
def first(value):
"""Returns the first item in a list."""
try:
return value[0]
except IndexError:
return ''
@register.filter(is_safe=True, needs_autoescape=True)
def join(value, arg, autoescape=True):
"""
Joins a list with a string, like Python's ``str.join(list)``.
"""
value = map(force_text, value)
if autoescape:
value = [conditional_escape(v) for v in value]
try:
data = conditional_escape(arg).join(value)
except AttributeError: # fail silently but nicely
return value
return mark_safe(data)
@register.filter(is_safe=True)
def last(value):
"Returns the last item in a list"
try:
return value[-1]
except IndexError:
return ''
@register.filter(is_safe=False)
def length(value):
"""Returns the length of the value - useful for lists."""
try:
return len(value)
except (ValueError, TypeError):
return 0
@register.filter(is_safe=False)
def length_is(value, arg):
"""Returns a boolean of whether the value's length is the argument."""
try:
return len(value) == int(arg)
except (ValueError, TypeError):
return ''
@register.filter(is_safe=True)
def random(value):
"""Returns a random item from the list."""
return random_module.choice(value)
@register.filter("slice", is_safe=True)
def slice_filter(value, arg):
"""
Returns a slice of the list.
Uses the same syntax as Python's list slicing; see
http://www.diveintopython3.net/native-datatypes.html#slicinglists
for an introduction.
"""
try:
bits = []
for x in arg.split(':'):
if len(x) == 0:
bits.append(None)
else:
bits.append(int(x))
return value[slice(*bits)]
except (ValueError, TypeError):
return value # Fail silently.
@register.filter(is_safe=True, needs_autoescape=True)
def unordered_list(value, autoescape=True):
"""
Recursively takes a self-nested list and returns an HTML unordered list --
WITHOUT opening and closing <ul> tags.
The list is assumed to be in the proper format. For example, if ``var``
contains: ``['States', ['Kansas', ['Lawrence', 'Topeka'], 'Illinois']]``,
then ``{{ var|unordered_list }}`` would return::
<li>States
<ul>
<li>Kansas
<ul>
<li>Lawrence</li>
<li>Topeka</li>
</ul>
</li>
<li>Illinois</li>
</ul>
</li>
"""
if autoescape:
escaper = conditional_escape
else:
escaper = lambda x: x
def convert_old_style_list(list_):
"""
Converts old style lists to the new easier to understand format.
The old list format looked like:
['Item 1', [['Item 1.1', []], ['Item 1.2', []]]
And it is converted to:
['Item 1', ['Item 1.1', 'Item 1.2]]
"""
if not isinstance(list_, (tuple, list)) or len(list_) != 2:
return list_, False
first_item, second_item = list_
if second_item == []:
return [first_item], True
try:
# see if second item is iterable
iter(second_item)
except TypeError:
return list_, False
old_style_list = True
new_second_item = []
for sublist in second_item:
item, old_style_list = convert_old_style_list(sublist)
if not old_style_list:
break
new_second_item.extend(item)
if old_style_list:
second_item = new_second_item
return [first_item, second_item], old_style_list
def walk_items(item_list):
item_iterator = iter(item_list)
try:
item = next(item_iterator)
while True:
try:
next_item = next(item_iterator)
except StopIteration:
yield item, None
break
if not isinstance(next_item, six.string_types):
try:
iter(next_item)
except TypeError:
pass
else:
yield item, next_item
item = next(item_iterator)
continue
yield item, None
item = next_item
except StopIteration:
pass
def list_formatter(item_list, tabs=1):
indent = '\t' * tabs
output = []
for item, children in walk_items(item_list):
sublist = ''
if children:
sublist = '\n%s<ul>\n%s\n%s</ul>\n%s' % (
indent, list_formatter(children, tabs + 1), indent, indent)
output.append('%s<li>%s%s</li>' % (
indent, escaper(force_text(item)), sublist))
return '\n'.join(output)
value, converted = convert_old_style_list(value)
if converted:
warnings.warn(
"The old style syntax in `unordered_list` is deprecated and will "
"be removed in Django 1.10. Use the the new format instead.",
RemovedInDjango110Warning)
return mark_safe(list_formatter(value))
###################
# INTEGERS #
###################
@register.filter(is_safe=False)
def add(value, arg):
"""Adds the arg to the value."""
try:
return int(value) + int(arg)
except (ValueError, TypeError):
try:
return value + arg
except Exception:
return ''
@register.filter(is_safe=False)
def get_digit(value, arg):
"""
Given a whole number, returns the requested digit of it, where 1 is the
right-most digit, 2 is the second-right-most digit, etc. Returns the
original value for invalid input (if input or argument is not an integer,
or if argument is less than 1). Otherwise, output is always an integer.
"""
try:
arg = int(arg)
value = int(value)
except ValueError:
return value # Fail silently for an invalid argument
if arg < 1:
return value
try:
return int(str(value)[-arg])
except IndexError:
return 0
###################
# DATES #
###################
@register.filter(expects_localtime=True, is_safe=False)
def date(value, arg=None):
"""Formats a date according to the given format."""
if value in (None, ''):
return ''
if arg is None:
arg = settings.DATE_FORMAT
try:
return formats.date_format(value, arg)
except AttributeError:
try:
return format(value, arg)
except AttributeError:
return ''
@register.filter(expects_localtime=True, is_safe=False)
def time(value, arg=None):
"""Formats a time according to the given format."""
if value in (None, ''):
return ''
if arg is None:
arg = settings.TIME_FORMAT
try:
return formats.time_format(value, arg)
except AttributeError:
try:
return time_format(value, arg)
except AttributeError:
return ''
@register.filter("timesince", is_safe=False)
def timesince_filter(value, arg=None):
"""Formats a date as the time since that date (i.e. "4 days, 6 hours")."""
if not value:
return ''
try:
if arg:
return timesince(value, arg)
return timesince(value)
except (ValueError, TypeError):
return ''
@register.filter("timeuntil", is_safe=False)
def timeuntil_filter(value, arg=None):
"""Formats a date as the time until that date (i.e. "4 days, 6 hours")."""
if not value:
return ''
try:
return timeuntil(value, arg)
except (ValueError, TypeError):
return ''
###################
# LOGIC #
###################
@register.filter(is_safe=False)
def default(value, arg):
"""If value is unavailable, use given default."""
return value or arg
@register.filter(is_safe=False)
def default_if_none(value, arg):
"""If value is None, use given default."""
if value is None:
return arg
return value
@register.filter(is_safe=False)
def divisibleby(value, arg):
"""Returns True if the value is devisible by the argument."""
return int(value) % int(arg) == 0
@register.filter(is_safe=False)
def yesno(value, arg=None):
"""
Given a string mapping values for true, false and (optionally) None,
returns one of those strings according to the value:
========== ====================== ==================================
Value Argument Outputs
========== ====================== ==================================
``True`` ``"yeah,no,maybe"`` ``yeah``
``False`` ``"yeah,no,maybe"`` ``no``
``None`` ``"yeah,no,maybe"`` ``maybe``
``None`` ``"yeah,no"`` ``"no"`` (converts None to False
if no mapping for None is given.
========== ====================== ==================================
"""
if arg is None:
arg = ugettext('yes,no,maybe')
bits = arg.split(',')
if len(bits) < 2:
return value # Invalid arg.
try:
yes, no, maybe = bits
except ValueError:
# Unpack list of wrong size (no "maybe" value provided).
yes, no, maybe = bits[0], bits[1], bits[1]
if value is None:
return maybe
if value:
return yes
return no
###################
# MISC #
###################
@register.filter(is_safe=True)
def filesizeformat(bytes):
"""
Formats the value like a 'human-readable' file size (i.e. 13 KB, 4.1 MB,
102 bytes, etc).
"""
try:
bytes = float(bytes)
except (TypeError, ValueError, UnicodeDecodeError):
value = ungettext("%(size)d byte", "%(size)d bytes", 0) % {'size': 0}
return avoid_wrapping(value)
filesize_number_format = lambda value: formats.number_format(round(value, 1), 1)
KB = 1 << 10
MB = 1 << 20
GB = 1 << 30
TB = 1 << 40
PB = 1 << 50
if bytes < KB:
value = ungettext("%(size)d byte", "%(size)d bytes", bytes) % {'size': bytes}
elif bytes < MB:
value = ugettext("%s KB") % filesize_number_format(bytes / KB)
elif bytes < GB:
value = ugettext("%s MB") % filesize_number_format(bytes / MB)
elif bytes < TB:
value = ugettext("%s GB") % filesize_number_format(bytes / GB)
elif bytes < PB:
value = ugettext("%s TB") % filesize_number_format(bytes / TB)
else:
value = ugettext("%s PB") % filesize_number_format(bytes / PB)
return avoid_wrapping(value)
@register.filter(is_safe=False)
def pluralize(value, arg='s'):
"""
Returns a plural suffix if the value is not 1. By default, 's' is used as
the suffix:
* If value is 0, vote{{ value|pluralize }} displays "0 votes".
* If value is 1, vote{{ value|pluralize }} displays "1 vote".
* If value is 2, vote{{ value|pluralize }} displays "2 votes".
If an argument is provided, that string is used instead:
* If value is 0, class{{ value|pluralize:"es" }} displays "0 classes".
* If value is 1, class{{ value|pluralize:"es" }} displays "1 class".
* If value is 2, class{{ value|pluralize:"es" }} displays "2 classes".
If the provided argument contains a comma, the text before the comma is
used for the singular case and the text after the comma is used for the
plural case:
* If value is 0, cand{{ value|pluralize:"y,ies" }} displays "0 candies".
* If value is 1, cand{{ value|pluralize:"y,ies" }} displays "1 candy".
* If value is 2, cand{{ value|pluralize:"y,ies" }} displays "2 candies".
"""
if ',' not in arg:
arg = ',' + arg
bits = arg.split(',')
if len(bits) > 2:
return ''
singular_suffix, plural_suffix = bits[:2]
try:
if float(value) != 1:
return plural_suffix
except ValueError: # Invalid string that's not a number.
pass
except TypeError: # Value isn't a string or a number; maybe it's a list?
try:
if len(value) != 1:
return plural_suffix
except TypeError: # len() of unsized object.
pass
return singular_suffix
@register.filter("phone2numeric", is_safe=True)
def phone2numeric_filter(value):
"""Takes a phone number and converts it in to its numerical equivalent."""
return phone2numeric(value)
@register.filter(is_safe=True)
def pprint(value):
"""A wrapper around pprint.pprint -- for debugging, really."""
try:
return pformat(value)
except Exception as e:
return "Error in formatting: %s: %s" % (e.__class__.__name__, force_text(e, errors="replace"))
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