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