mirror of
https://github.com/django/django.git
synced 2025-09-21 09:49:53 +00:00
9aaeec337e
Added format_lazy function to django.utils.text module. Useful when dealing with relative complex lazy string concatenations (e.g. in urls.py when translating urls in regular expressions).
447 lines
15 KiB
Python
447 lines
15 KiB
Python
from __future__ import unicode_literals
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import re
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import unicodedata
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from gzip import GzipFile
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from io import BytesIO
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from django.utils import six
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from django.utils.encoding import force_text
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from django.utils.functional import (
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SimpleLazyObject, keep_lazy, keep_lazy_text, lazy,
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)
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from django.utils.safestring import SafeText, mark_safe
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from django.utils.six.moves import html_entities
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from django.utils.translation import pgettext, ugettext as _, ugettext_lazy
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if six.PY2:
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# Import force_unicode even though this module doesn't use it, because some
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# people rely on it being here.
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from django.utils.encoding import force_unicode # NOQA
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# Capitalizes the first letter of a string.
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def capfirst(x):
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return x and force_text(x)[0].upper() + force_text(x)[1:]
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capfirst = keep_lazy_text(capfirst)
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# Set up regular expressions
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re_words = re.compile(r'<.*?>|((?:\w[-\w]*|&.*?;)+)', re.U | re.S)
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re_chars = re.compile(r'<.*?>|(.)', re.U | re.S)
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re_tag = re.compile(r'<(/)?([^ ]+?)(?:(\s*/)| .*?)?>', re.S)
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re_newlines = re.compile(r'\r\n|\r') # Used in normalize_newlines
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re_camel_case = re.compile(r'(((?<=[a-z])[A-Z])|([A-Z](?![A-Z]|$)))')
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@keep_lazy_text
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def wrap(text, width):
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"""
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A word-wrap function that preserves existing line breaks. Expects that
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existing line breaks are posix newlines.
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All white space is preserved except added line breaks consume the space on
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which they break the line.
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Long words are not wrapped, so the output text may have lines longer than
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``width``.
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"""
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text = force_text(text)
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def _generator():
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for line in text.splitlines(True): # True keeps trailing linebreaks
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max_width = min((line.endswith('\n') and width + 1 or width), width)
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while len(line) > max_width:
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space = line[:max_width + 1].rfind(' ') + 1
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if space == 0:
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space = line.find(' ') + 1
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if space == 0:
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yield line
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line = ''
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break
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yield '%s\n' % line[:space - 1]
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line = line[space:]
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max_width = min((line.endswith('\n') and width + 1 or width), width)
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if line:
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yield line
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return ''.join(_generator())
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class Truncator(SimpleLazyObject):
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"""
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An object used to truncate text, either by characters or words.
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"""
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def __init__(self, text):
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super(Truncator, self).__init__(lambda: force_text(text))
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def add_truncation_text(self, text, truncate=None):
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if truncate is None:
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truncate = pgettext(
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'String to return when truncating text',
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'%(truncated_text)s...')
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truncate = force_text(truncate)
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if '%(truncated_text)s' in truncate:
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return truncate % {'truncated_text': text}
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# The truncation text didn't contain the %(truncated_text)s string
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# replacement argument so just append it to the text.
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if text.endswith(truncate):
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# But don't append the truncation text if the current text already
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# ends in this.
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return text
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return '%s%s' % (text, truncate)
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def chars(self, num, truncate=None, html=False):
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"""
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Returns the text truncated to be no longer than the specified number
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of characters.
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Takes an optional argument of what should be used to notify that the
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string has been truncated, defaulting to a translatable string of an
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ellipsis (...).
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"""
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self._setup()
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length = int(num)
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text = unicodedata.normalize('NFC', self._wrapped)
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# Calculate the length to truncate to (max length - end_text length)
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truncate_len = length
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for char in self.add_truncation_text('', truncate):
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if not unicodedata.combining(char):
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truncate_len -= 1
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if truncate_len == 0:
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break
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if html:
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return self._truncate_html(length, truncate, text, truncate_len, False)
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return self._text_chars(length, truncate, text, truncate_len)
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def _text_chars(self, length, truncate, text, truncate_len):
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"""
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Truncates a string after a certain number of chars.
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"""
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s_len = 0
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end_index = None
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for i, char in enumerate(text):
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if unicodedata.combining(char):
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# Don't consider combining characters
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# as adding to the string length
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continue
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s_len += 1
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if end_index is None and s_len > truncate_len:
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end_index = i
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if s_len > length:
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# Return the truncated string
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return self.add_truncation_text(text[:end_index or 0],
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truncate)
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# Return the original string since no truncation was necessary
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return text
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def words(self, num, truncate=None, html=False):
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"""
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Truncates a string after a certain number of words. Takes an optional
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argument of what should be used to notify that the string has been
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truncated, defaulting to ellipsis (...).
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"""
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self._setup()
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length = int(num)
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if html:
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return self._truncate_html(length, truncate, self._wrapped, length, True)
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return self._text_words(length, truncate)
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def _text_words(self, length, truncate):
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"""
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Truncates a string after a certain number of words.
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Newlines in the string will be stripped.
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"""
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words = self._wrapped.split()
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if len(words) > length:
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words = words[:length]
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return self.add_truncation_text(' '.join(words), truncate)
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return ' '.join(words)
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def _truncate_html(self, length, truncate, text, truncate_len, words):
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"""
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Truncates HTML to a certain number of chars (not counting tags and
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comments), or, if words is True, then to a certain number of words.
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Closes opened tags if they were correctly closed in the given HTML.
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Newlines in the HTML are preserved.
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"""
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if words and length <= 0:
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return ''
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html4_singlets = (
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'br', 'col', 'link', 'base', 'img',
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'param', 'area', 'hr', 'input'
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)
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# Count non-HTML chars/words and keep note of open tags
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pos = 0
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end_text_pos = 0
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current_len = 0
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open_tags = []
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regex = re_words if words else re_chars
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while current_len <= length:
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m = regex.search(text, pos)
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if not m:
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# Checked through whole string
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break
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pos = m.end(0)
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if m.group(1):
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# It's an actual non-HTML word or char
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current_len += 1
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if current_len == truncate_len:
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end_text_pos = pos
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continue
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# Check for tag
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tag = re_tag.match(m.group(0))
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if not tag or current_len >= truncate_len:
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# Don't worry about non tags or tags after our truncate point
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continue
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closing_tag, tagname, self_closing = tag.groups()
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# Element names are always case-insensitive
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tagname = tagname.lower()
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if self_closing or tagname in html4_singlets:
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pass
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elif closing_tag:
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# Check for match in open tags list
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try:
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i = open_tags.index(tagname)
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except ValueError:
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pass
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else:
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# SGML: An end tag closes, back to the matching start tag,
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# all unclosed intervening start tags with omitted end tags
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open_tags = open_tags[i + 1:]
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else:
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# Add it to the start of the open tags list
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open_tags.insert(0, tagname)
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if current_len <= length:
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return text
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out = text[:end_text_pos]
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truncate_text = self.add_truncation_text('', truncate)
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if truncate_text:
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out += truncate_text
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# Close any tags still open
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for tag in open_tags:
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out += '</%s>' % tag
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# Return string
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return out
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@keep_lazy_text
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def get_valid_filename(s):
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"""
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Returns the given string converted to a string that can be used for a clean
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filename. Specifically, leading and trailing spaces are removed; other
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spaces are converted to underscores; and anything that is not a unicode
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alphanumeric, dash, underscore, or dot, is removed.
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>>> get_valid_filename("john's portrait in 2004.jpg")
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'johns_portrait_in_2004.jpg'
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"""
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s = force_text(s).strip().replace(' ', '_')
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return re.sub(r'(?u)[^-\w.]', '', s)
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@keep_lazy_text
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def get_text_list(list_, last_word=ugettext_lazy('or')):
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"""
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>>> get_text_list(['a', 'b', 'c', 'd'])
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'a, b, c or d'
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>>> get_text_list(['a', 'b', 'c'], 'and')
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'a, b and c'
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>>> get_text_list(['a', 'b'], 'and')
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'a and b'
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>>> get_text_list(['a'])
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'a'
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>>> get_text_list([])
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''
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"""
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if len(list_) == 0:
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return ''
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if len(list_) == 1:
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return force_text(list_[0])
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return '%s %s %s' % (
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# Translators: This string is used as a separator between list elements
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_(', ').join(force_text(i) for i in list_[:-1]),
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force_text(last_word), force_text(list_[-1]))
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@keep_lazy_text
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def normalize_newlines(text):
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"""Normalizes CRLF and CR newlines to just LF."""
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text = force_text(text)
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return re_newlines.sub('\n', text)
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@keep_lazy_text
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def phone2numeric(phone):
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"""Converts a phone number with letters into its numeric equivalent."""
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char2number = {
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'a': '2', 'b': '2', 'c': '2', 'd': '3', 'e': '3', 'f': '3', 'g': '4',
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'h': '4', 'i': '4', 'j': '5', 'k': '5', 'l': '5', 'm': '6', 'n': '6',
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'o': '6', 'p': '7', 'q': '7', 'r': '7', 's': '7', 't': '8', 'u': '8',
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'v': '8', 'w': '9', 'x': '9', 'y': '9', 'z': '9',
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}
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return ''.join(char2number.get(c, c) for c in phone.lower())
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# From http://www.xhaus.com/alan/python/httpcomp.html#gzip
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# Used with permission.
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def compress_string(s):
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zbuf = BytesIO()
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with GzipFile(mode='wb', compresslevel=6, fileobj=zbuf) as zfile:
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zfile.write(s)
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return zbuf.getvalue()
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class StreamingBuffer(object):
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def __init__(self):
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self.vals = []
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def write(self, val):
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self.vals.append(val)
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def read(self):
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if not self.vals:
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return b''
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ret = b''.join(self.vals)
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self.vals = []
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return ret
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def flush(self):
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return
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def close(self):
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return
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# Like compress_string, but for iterators of strings.
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def compress_sequence(sequence):
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buf = StreamingBuffer()
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with GzipFile(mode='wb', compresslevel=6, fileobj=buf) as zfile:
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# Output headers...
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yield buf.read()
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for item in sequence:
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zfile.write(item)
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data = buf.read()
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if data:
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yield data
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yield buf.read()
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# Expression to match some_token and some_token="with spaces" (and similarly
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# for single-quoted strings).
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smart_split_re = re.compile(r"""
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((?:
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[^\s'"]*
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(?:
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(?:"(?:[^"\\]|\\.)*" | '(?:[^'\\]|\\.)*')
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[^\s'"]*
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)+
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) | \S+)
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""", re.VERBOSE)
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def smart_split(text):
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r"""
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Generator that splits a string by spaces, leaving quoted phrases together.
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Supports both single and double quotes, and supports escaping quotes with
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backslashes. In the output, strings will keep their initial and trailing
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quote marks and escaped quotes will remain escaped (the results can then
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be further processed with unescape_string_literal()).
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>>> list(smart_split(r'This is "a person\'s" test.'))
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['This', 'is', '"a person\\\'s"', 'test.']
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>>> list(smart_split(r"Another 'person\'s' test."))
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['Another', "'person\\'s'", 'test.']
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>>> list(smart_split(r'A "\"funky\" style" test.'))
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['A', '"\\"funky\\" style"', 'test.']
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"""
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text = force_text(text)
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for bit in smart_split_re.finditer(text):
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yield bit.group(0)
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def _replace_entity(match):
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text = match.group(1)
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if text[0] == '#':
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text = text[1:]
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try:
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if text[0] in 'xX':
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c = int(text[1:], 16)
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else:
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c = int(text)
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return six.unichr(c)
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except ValueError:
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return match.group(0)
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else:
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try:
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return six.unichr(html_entities.name2codepoint[text])
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except (ValueError, KeyError):
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return match.group(0)
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_entity_re = re.compile(r"&(#?[xX]?(?:[0-9a-fA-F]+|\w{1,8}));")
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@keep_lazy_text
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def unescape_entities(text):
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return _entity_re.sub(_replace_entity, force_text(text))
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@keep_lazy_text
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def unescape_string_literal(s):
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r"""
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Convert quoted string literals to unquoted strings with escaped quotes and
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backslashes unquoted::
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>>> unescape_string_literal('"abc"')
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'abc'
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>>> unescape_string_literal("'abc'")
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'abc'
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>>> unescape_string_literal('"a \"bc\""')
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'a "bc"'
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>>> unescape_string_literal("'\'ab\' c'")
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"'ab' c"
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"""
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if s[0] not in "\"'" or s[-1] != s[0]:
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raise ValueError("Not a string literal: %r" % s)
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quote = s[0]
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return s[1:-1].replace(r'\%s' % quote, quote).replace(r'\\', '\\')
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@keep_lazy(six.text_type, SafeText)
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def slugify(value, allow_unicode=False):
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"""
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Convert to ASCII if 'allow_unicode' is False. Convert spaces to hyphens.
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Remove characters that aren't alphanumerics, underscores, or hyphens.
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Convert to lowercase. Also strip leading and trailing whitespace.
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"""
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value = force_text(value)
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if allow_unicode:
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value = unicodedata.normalize('NFKC', value)
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value = re.sub('[^\w\s-]', '', value, flags=re.U).strip().lower()
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return mark_safe(re.sub('[-\s]+', '-', value, flags=re.U))
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value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore').decode('ascii')
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value = re.sub('[^\w\s-]', '', value).strip().lower()
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return mark_safe(re.sub('[-\s]+', '-', value))
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def camel_case_to_spaces(value):
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"""
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Splits CamelCase and converts to lower case. Also strips leading and
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trailing whitespace.
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"""
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return re_camel_case.sub(r' \1', value).strip().lower()
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def _format_lazy(format_string, *args, **kwargs):
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"""
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Apply str.format() on 'format_string' where format_string, args,
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and/or kwargs might be lazy.
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"""
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return format_string.format(*args, **kwargs)
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format_lazy = lazy(_format_lazy, six.text_type)
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