425 lines
14 KiB
Python
425 lines
14 KiB
Python
"""Parse (absolute and relative) URLs.
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See RFC 1808: "Relative Uniform Resource Locators", by R. Fielding,
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UC Irvine, June 1995.
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"""
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__all__ = ["urlparse", "urlunparse", "urljoin", "urldefrag",
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"urlsplit", "urlunsplit", "parse_qs", "parse_qsl"]
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# A classification of schemes ('' means apply by default)
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uses_relative = ['ftp', 'http', 'gopher', 'nntp', 'imap',
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'wais', 'file', 'https', 'shttp', 'mms',
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'prospero', 'rtsp', 'rtspu', '', 'sftp']
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uses_netloc = ['ftp', 'http', 'gopher', 'nntp', 'telnet',
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'imap', 'wais', 'file', 'mms', 'https', 'shttp',
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'snews', 'prospero', 'rtsp', 'rtspu', 'rsync', '',
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'svn', 'svn+ssh', 'sftp','nfs']
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non_hierarchical = ['gopher', 'hdl', 'mailto', 'news',
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'telnet', 'wais', 'imap', 'snews', 'sip', 'sips']
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uses_params = ['ftp', 'hdl', 'prospero', 'http', 'imap',
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'https', 'shttp', 'rtsp', 'rtspu', 'sip', 'sips',
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'mms', '', 'sftp']
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uses_query = ['http', 'wais', 'imap', 'https', 'shttp', 'mms',
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'gopher', 'rtsp', 'rtspu', 'sip', 'sips', '']
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uses_fragment = ['ftp', 'hdl', 'http', 'gopher', 'news',
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'nntp', 'wais', 'https', 'shttp', 'snews',
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'file', 'prospero', '']
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# Characters valid in scheme names
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scheme_chars = ('abcdefghijklmnopqrstuvwxyz'
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'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
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'0123456789'
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'+-.')
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MAX_CACHE_SIZE = 20
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_parse_cache = {}
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def clear_cache():
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"""Clear the parse cache."""
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_parse_cache.clear()
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class ResultMixin(object):
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"""Shared methods for the parsed result objects."""
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@property
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def username(self):
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netloc = self.netloc
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if "@" in netloc:
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userinfo = netloc.rsplit("@", 1)[0]
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if ":" in userinfo:
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userinfo = userinfo.split(":", 1)[0]
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return userinfo
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return None
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@property
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def password(self):
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netloc = self.netloc
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if "@" in netloc:
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userinfo = netloc.rsplit("@", 1)[0]
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if ":" in userinfo:
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return userinfo.split(":", 1)[1]
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return None
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@property
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def hostname(self):
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netloc = self.netloc
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if "@" in netloc:
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netloc = netloc.rsplit("@", 1)[1]
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if ":" in netloc:
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netloc = netloc.split(":", 1)[0]
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return netloc.lower() or None
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@property
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def port(self):
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netloc = self.netloc
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if "@" in netloc:
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netloc = netloc.rsplit("@", 1)[1]
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if ":" in netloc:
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port = netloc.split(":", 1)[1]
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return int(port, 10)
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return None
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from collections import namedtuple
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class SplitResult(namedtuple('SplitResult', 'scheme netloc path query fragment'), ResultMixin):
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__slots__ = ()
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def geturl(self):
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return urlunsplit(self)
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class ParseResult(namedtuple('ParseResult', 'scheme netloc path params query fragment'), ResultMixin):
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__slots__ = ()
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def geturl(self):
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return urlunparse(self)
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def urlparse(url, scheme='', allow_fragments=True):
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"""Parse a URL into 6 components:
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<scheme>://<netloc>/<path>;<params>?<query>#<fragment>
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Return a 6-tuple: (scheme, netloc, path, params, query, fragment).
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Note that we don't break the components up in smaller bits
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(e.g. netloc is a single string) and we don't expand % escapes."""
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tuple = urlsplit(url, scheme, allow_fragments)
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scheme, netloc, url, query, fragment = tuple
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if scheme in uses_params and ';' in url:
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url, params = _splitparams(url)
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else:
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params = ''
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return ParseResult(scheme, netloc, url, params, query, fragment)
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def _splitparams(url):
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if '/' in url:
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i = url.find(';', url.rfind('/'))
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if i < 0:
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return url, ''
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else:
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i = url.find(';')
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return url[:i], url[i+1:]
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def _splitnetloc(url, start=0):
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delim = len(url) # position of end of domain part of url, default is end
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for c in '/?#': # look for delimiters; the order is NOT important
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wdelim = url.find(c, start) # find first of this delim
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if wdelim >= 0: # if found
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delim = min(delim, wdelim) # use earliest delim position
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return url[start:delim], url[delim:] # return (domain, rest)
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def urlsplit(url, scheme='', allow_fragments=True):
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"""Parse a URL into 5 components:
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<scheme>://<netloc>/<path>?<query>#<fragment>
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Return a 5-tuple: (scheme, netloc, path, query, fragment).
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Note that we don't break the components up in smaller bits
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(e.g. netloc is a single string) and we don't expand % escapes."""
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allow_fragments = bool(allow_fragments)
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key = url, scheme, allow_fragments, type(url), type(scheme)
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cached = _parse_cache.get(key, None)
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if cached:
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return cached
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if len(_parse_cache) >= MAX_CACHE_SIZE: # avoid runaway growth
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clear_cache()
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netloc = query = fragment = ''
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i = url.find(':')
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if i > 0:
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if url[:i] == 'http': # optimize the common case
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scheme = url[:i].lower()
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url = url[i+1:]
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if url[:2] == '//':
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netloc, url = _splitnetloc(url, 2)
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if allow_fragments and '#' in url:
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url, fragment = url.split('#', 1)
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if '?' in url:
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url, query = url.split('?', 1)
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v = SplitResult(scheme, netloc, url, query, fragment)
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_parse_cache[key] = v
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return v
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for c in url[:i]:
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if c not in scheme_chars:
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break
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else:
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scheme, url = url[:i].lower(), url[i+1:]
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if url[:2] == '//':
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netloc, url = _splitnetloc(url, 2)
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if allow_fragments and scheme in uses_fragment and '#' in url:
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url, fragment = url.split('#', 1)
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if scheme in uses_query and '?' in url:
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url, query = url.split('?', 1)
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v = SplitResult(scheme, netloc, url, query, fragment)
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_parse_cache[key] = v
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return v
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def urlunparse(data):
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"""Put a parsed URL back together again. This may result in a
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slightly different, but equivalent URL, if the URL that was parsed
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originally had redundant delimiters, e.g. a ? with an empty query
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(the draft states that these are equivalent)."""
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scheme, netloc, url, params, query, fragment = data
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if params:
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url = "%s;%s" % (url, params)
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return urlunsplit((scheme, netloc, url, query, fragment))
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def urlunsplit(data):
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scheme, netloc, url, query, fragment = data
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if netloc or (scheme and scheme in uses_netloc and url[:2] != '//'):
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if url and url[:1] != '/': url = '/' + url
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url = '//' + (netloc or '') + url
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if scheme:
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url = scheme + ':' + url
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if query:
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url = url + '?' + query
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if fragment:
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url = url + '#' + fragment
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return url
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def urljoin(base, url, allow_fragments=True):
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"""Join a base URL and a possibly relative URL to form an absolute
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interpretation of the latter."""
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if not base:
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return url
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if not url:
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return base
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bscheme, bnetloc, bpath, bparams, bquery, bfragment = \
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urlparse(base, '', allow_fragments)
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scheme, netloc, path, params, query, fragment = \
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urlparse(url, bscheme, allow_fragments)
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if scheme != bscheme or scheme not in uses_relative:
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return url
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if scheme in uses_netloc:
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if netloc:
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return urlunparse((scheme, netloc, path,
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params, query, fragment))
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netloc = bnetloc
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if path[:1] == '/':
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return urlunparse((scheme, netloc, path,
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params, query, fragment))
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if not path:
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path = bpath
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if not params:
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params = bparams
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else:
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path = path[:-1]
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return urlunparse((scheme, netloc, path,
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params, query, fragment))
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if not query:
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query = bquery
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return urlunparse((scheme, netloc, path,
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params, query, fragment))
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segments = bpath.split('/')[:-1] + path.split('/')
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# XXX The stuff below is bogus in various ways...
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if segments[-1] == '.':
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segments[-1] = ''
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while '.' in segments:
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segments.remove('.')
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while 1:
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i = 1
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n = len(segments) - 1
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while i < n:
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if (segments[i] == '..'
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and segments[i-1] not in ('', '..')):
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del segments[i-1:i+1]
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break
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i = i+1
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else:
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break
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if segments == ['', '..']:
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segments[-1] = ''
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elif len(segments) >= 2 and segments[-1] == '..':
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segments[-2:] = ['']
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return urlunparse((scheme, netloc, '/'.join(segments),
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params, query, fragment))
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def urldefrag(url):
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"""Removes any existing fragment from URL.
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Returns a tuple of the defragmented URL and the fragment. If
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the URL contained no fragments, the second element is the
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empty string.
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"""
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if '#' in url:
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s, n, p, a, q, frag = urlparse(url)
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defrag = urlunparse((s, n, p, a, q, ''))
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return defrag, frag
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else:
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return url, ''
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# unquote method for parse_qs and parse_qsl
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# Cannot use directly from urllib as it would create circular reference.
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# urllib uses urlparse methods ( urljoin)
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_hextochr = dict(('%02x' % i, chr(i)) for i in range(256))
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_hextochr.update(('%02X' % i, chr(i)) for i in range(256))
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def unquote(s):
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"""unquote('abc%20def') -> 'abc def'."""
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res = s.split('%')
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for i in xrange(1, len(res)):
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item = res[i]
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try:
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res[i] = _hextochr[item[:2]] + item[2:]
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except KeyError:
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res[i] = '%' + item
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except UnicodeDecodeError:
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res[i] = unichr(int(item[:2], 16)) + item[2:]
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return "".join(res)
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def parse_qs(qs, keep_blank_values=0, strict_parsing=0):
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"""Parse a query given as a string argument.
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Arguments:
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qs: URL-encoded query string to be parsed
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keep_blank_values: flag indicating whether blank values in
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URL encoded queries should be treated as blank strings.
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A true value indicates that blanks should be retained as
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blank strings. The default false value indicates that
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blank values are to be ignored and treated as if they were
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not included.
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strict_parsing: flag indicating what to do with parsing errors.
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If false (the default), errors are silently ignored.
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If true, errors raise a ValueError exception.
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"""
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dict = {}
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for name, value in parse_qsl(qs, keep_blank_values, strict_parsing):
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if name in dict:
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dict[name].append(value)
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else:
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dict[name] = [value]
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return dict
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def parse_qsl(qs, keep_blank_values=0, strict_parsing=0):
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"""Parse a query given as a string argument.
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Arguments:
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qs: URL-encoded query string to be parsed
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keep_blank_values: flag indicating whether blank values in
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URL encoded queries should be treated as blank strings. A
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true value indicates that blanks should be retained as blank
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strings. The default false value indicates that blank values
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are to be ignored and treated as if they were not included.
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strict_parsing: flag indicating what to do with parsing errors. If
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false (the default), errors are silently ignored. If true,
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errors raise a ValueError exception.
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Returns a list, as G-d intended.
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"""
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pairs = [s2 for s1 in qs.split('&') for s2 in s1.split(';')]
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r = []
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for name_value in pairs:
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if not name_value and not strict_parsing:
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continue
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nv = name_value.split('=', 1)
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if len(nv) != 2:
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if strict_parsing:
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raise ValueError, "bad query field: %r" % (name_value,)
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# Handle case of a control-name with no equal sign
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if keep_blank_values:
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nv.append('')
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else:
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continue
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if len(nv[1]) or keep_blank_values:
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name = unquote(nv[0].replace('+', ' '))
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value = unquote(nv[1].replace('+', ' '))
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r.append((name, value))
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return r
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test_input = """
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http://a/b/c/d
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g:h = <URL:g:h>
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http:g = <URL:http://a/b/c/g>
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http: = <URL:http://a/b/c/d>
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g = <URL:http://a/b/c/g>
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./g = <URL:http://a/b/c/g>
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g/ = <URL:http://a/b/c/g/>
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/g = <URL:http://a/g>
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//g = <URL:http://g>
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?y = <URL:http://a/b/c/d?y>
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g?y = <URL:http://a/b/c/g?y>
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g?y/./x = <URL:http://a/b/c/g?y/./x>
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. = <URL:http://a/b/c/>
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./ = <URL:http://a/b/c/>
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.. = <URL:http://a/b/>
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../ = <URL:http://a/b/>
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../g = <URL:http://a/b/g>
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../.. = <URL:http://a/>
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../../g = <URL:http://a/g>
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../../../g = <URL:http://a/../g>
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./../g = <URL:http://a/b/g>
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./g/. = <URL:http://a/b/c/g/>
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/./g = <URL:http://a/./g>
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g/./h = <URL:http://a/b/c/g/h>
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g/../h = <URL:http://a/b/c/h>
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http:g = <URL:http://a/b/c/g>
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http: = <URL:http://a/b/c/d>
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http:?y = <URL:http://a/b/c/d?y>
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http:g?y = <URL:http://a/b/c/g?y>
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http:g?y/./x = <URL:http://a/b/c/g?y/./x>
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"""
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def test():
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import sys
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base = ''
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if sys.argv[1:]:
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fn = sys.argv[1]
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if fn == '-':
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fp = sys.stdin
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else:
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fp = open(fn)
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else:
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try:
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from cStringIO import StringIO
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except ImportError:
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from StringIO import StringIO
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fp = StringIO(test_input)
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for line in fp:
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words = line.split()
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if not words:
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continue
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url = words[0]
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parts = urlparse(url)
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print '%-10s : %s' % (url, parts)
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abs = urljoin(base, url)
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if not base:
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base = abs
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wrapped = '<URL:%s>' % abs
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print '%-10s = %s' % (url, wrapped)
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if len(words) == 3 and words[1] == '=':
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if wrapped != words[2]:
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print 'EXPECTED', words[2], '!!!!!!!!!!'
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if __name__ == '__main__':
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test()
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