417 lines
13 KiB
Python
417 lines
13 KiB
Python
import html.entities
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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.functional import SimpleLazyObject, keep_lazy_text, lazy
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from django.utils.translation import gettext as _, gettext_lazy, pgettext
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@keep_lazy_text
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def capfirst(x):
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"""Capitalize the first letter of a string."""
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return x and str(x)[0].upper() + str(x)[1:]
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# Set up regular expressions
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re_words = re.compile(r'<.*?>|((?:\w[-\w]*|&.*?;)+)', re.S)
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re_chars = re.compile(r'<.*?>|(.)', re.S)
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re_tag = re.compile(r'<(/)?(\S+?)(?:(\s*/)|\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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Preserve all white space except added line breaks consume the space on
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which they break the line.
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Don't wrap long words, thus the output text may have lines longer than
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``width``.
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"""
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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().__init__(lambda: str(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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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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Return the text truncated to be no longer than the specified number
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of characters.
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`truncate` specifies what should be used to notify that the string has
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been truncated, defaulting to a translatable string of an 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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"""Truncate a string after a certain number of chars."""
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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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Truncate a string after a certain number of words. `truncate` specifies
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what should be used to notify that the string has been truncated,
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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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Truncate a string after a certain number of words.
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Strip newlines in the string.
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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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Truncate 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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Close opened tags if they were correctly closed in the given HTML.
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Preserve newlines in the HTML.
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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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Return the given string converted to a string that can be used for a clean
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filename. Remove leading and trailing spaces; convert other spaces to
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underscores; and remove anything that is not an alphanumeric, dash,
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underscore, or dot.
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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 = str(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=gettext_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 not list_:
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return ''
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if len(list_) == 1:
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return str(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(str(i) for i in list_[:-1]), str(last_word), str(list_[-1])
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)
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@keep_lazy_text
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def normalize_newlines(text):
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"""Normalize CRLF and CR newlines to just LF."""
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return re_newlines.sub('\n', str(text))
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@keep_lazy_text
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def phone2numeric(phone):
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"""Convert 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, mtime=0) as zfile:
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zfile.write(s)
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return zbuf.getvalue()
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class StreamingBuffer(BytesIO):
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def read(self):
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ret = self.getvalue()
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self.seek(0)
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self.truncate()
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return ret
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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, mtime=0) 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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for bit in smart_split_re.finditer(str(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 chr(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 chr(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, str(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_text
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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 = str(value)
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if allow_unicode:
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value = unicodedata.normalize('NFKC', value)
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else:
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value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore').decode('ascii')
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value = re.sub(r'[^\w\s-]', '', value).strip().lower()
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return re.sub(r'[-\s]+', '-', value)
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def camel_case_to_spaces(value):
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"""
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Split CamelCase and convert to lowercase. Strip surrounding 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, str)
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