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1"""Parse (absolute and relative) URLs.
2
3urlparse module is based upon the following RFC specifications.
4
5RFC 3986 (STD66): "Uniform Resource Identifiers" by T. Berners-Lee, R. Fielding
6and L.  Masinter, January 2005.
7
8RFC 2732 : "Format for Literal IPv6 Addresses in URL's by R.Hinden, B.Carpenter
9and L.Masinter, December 1999.
10
11RFC 2396:  "Uniform Resource Identifiers (URI)": Generic Syntax by T.
12Berners-Lee, R. Fielding, and L. Masinter, August 1998.
13
14RFC 2368: "The mailto URL scheme", by P.Hoffman , L Masinter, J. Zawinski, July 1998.
15
16RFC 1808: "Relative Uniform Resource Locators", by R. Fielding, UC Irvine, June
171995.
18
19RFC 1738: "Uniform Resource Locators (URL)" by T. Berners-Lee, L. Masinter, M.
20McCahill, December 1994
21
22RFC 3986 is considered the current standard and any future changes to
23urlparse module should conform with it.  The urlparse module is
24currently not entirely compliant with this RFC due to defacto
25scenarios for parsing, and for backward compatibility purposes, some
26parsing quirks from older RFCs are retained. The testcases in
27test_urlparse.py provides a good indicator of parsing behavior.
28"""
29
30import re
31import sys
32import types
33import collections
34import warnings
35
36__all__ = ["urlparse", "urlunparse", "urljoin", "urldefrag",
37           "urlsplit", "urlunsplit", "urlencode", "parse_qs",
38           "parse_qsl", "quote", "quote_plus", "quote_from_bytes",
39           "unquote", "unquote_plus", "unquote_to_bytes",
40           "DefragResult", "ParseResult", "SplitResult",
41           "DefragResultBytes", "ParseResultBytes", "SplitResultBytes"]
42
43# A classification of schemes.
44# The empty string classifies URLs with no scheme specified,
45# being the default value returned by “urlsplit” and “urlparse”.
46
47uses_relative = ['', 'ftp', 'http', 'gopher', 'nntp', 'imap',
48                 'wais', 'file', 'https', 'shttp', 'mms',
49                 'prospero', 'rtsp', 'rtspu', 'sftp',
50                 'svn', 'svn+ssh', 'ws', 'wss']
51
52uses_netloc = ['', 'ftp', 'http', 'gopher', 'nntp', 'telnet',
53               'imap', 'wais', 'file', 'mms', 'https', 'shttp',
54               'snews', 'prospero', 'rtsp', 'rtspu', 'rsync',
55               'svn', 'svn+ssh', 'sftp', 'nfs', 'git', 'git+ssh',
56               'ws', 'wss']
57
58uses_params = ['', 'ftp', 'hdl', 'prospero', 'http', 'imap',
59               'https', 'shttp', 'rtsp', 'rtspu', 'sip', 'sips',
60               'mms', 'sftp', 'tel']
61
62# These are not actually used anymore, but should stay for backwards
63# compatibility.  (They are undocumented, but have a public-looking name.)
64
65non_hierarchical = ['gopher', 'hdl', 'mailto', 'news',
66                    'telnet', 'wais', 'imap', 'snews', 'sip', 'sips']
67
68uses_query = ['', 'http', 'wais', 'imap', 'https', 'shttp', 'mms',
69              'gopher', 'rtsp', 'rtspu', 'sip', 'sips']
70
71uses_fragment = ['', 'ftp', 'hdl', 'http', 'gopher', 'news',
72                 'nntp', 'wais', 'https', 'shttp', 'snews',
73                 'file', 'prospero']
74
75# Characters valid in scheme names
76scheme_chars = ('abcdefghijklmnopqrstuvwxyz'
77                'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
78                '0123456789'
79                '+-.')
80
81# Unsafe bytes to be removed per WHATWG spec
82_UNSAFE_URL_BYTES_TO_REMOVE = ['\t', '\r', '\n']
83
84# XXX: Consider replacing with functools.lru_cache
85MAX_CACHE_SIZE = 20
86_parse_cache = {}
87
88def clear_cache():
89    """Clear the parse cache and the quoters cache."""
90    _parse_cache.clear()
91    _safe_quoters.clear()
92
93
94# Helpers for bytes handling
95# For 3.2, we deliberately require applications that
96# handle improperly quoted URLs to do their own
97# decoding and encoding. If valid use cases are
98# presented, we may relax this by using latin-1
99# decoding internally for 3.3
100_implicit_encoding = 'ascii'
101_implicit_errors = 'strict'
102
103def _noop(obj):
104    return obj
105
106def _encode_result(obj, encoding=_implicit_encoding,
107                        errors=_implicit_errors):
108    return obj.encode(encoding, errors)
109
110def _decode_args(args, encoding=_implicit_encoding,
111                       errors=_implicit_errors):
112    return tuple(x.decode(encoding, errors) if x else '' for x in args)
113
114def _coerce_args(*args):
115    # Invokes decode if necessary to create str args
116    # and returns the coerced inputs along with
117    # an appropriate result coercion function
118    #   - noop for str inputs
119    #   - encoding function otherwise
120    str_input = isinstance(args[0], str)
121    for arg in args[1:]:
122        # We special-case the empty string to support the
123        # "scheme=''" default argument to some functions
124        if arg and isinstance(arg, str) != str_input:
125            raise TypeError("Cannot mix str and non-str arguments")
126    if str_input:
127        return args + (_noop,)
128    return _decode_args(args) + (_encode_result,)
129
130# Result objects are more helpful than simple tuples
131class _ResultMixinStr(object):
132    """Standard approach to encoding parsed results from str to bytes"""
133    __slots__ = ()
134
135    def encode(self, encoding='ascii', errors='strict'):
136        return self._encoded_counterpart(*(x.encode(encoding, errors) for x in self))
137
138
139class _ResultMixinBytes(object):
140    """Standard approach to decoding parsed results from bytes to str"""
141    __slots__ = ()
142
143    def decode(self, encoding='ascii', errors='strict'):
144        return self._decoded_counterpart(*(x.decode(encoding, errors) for x in self))
145
146
147class _NetlocResultMixinBase(object):
148    """Shared methods for the parsed result objects containing a netloc element"""
149    __slots__ = ()
150
151    @property
152    def username(self):
153        return self._userinfo[0]
154
155    @property
156    def password(self):
157        return self._userinfo[1]
158
159    @property
160    def hostname(self):
161        hostname = self._hostinfo[0]
162        if not hostname:
163            return None
164        # Scoped IPv6 address may have zone info, which must not be lowercased
165        # like http://[fe80::822a:a8ff:fe49:470c%tESt]:1234/keys
166        separator = '%' if isinstance(hostname, str) else b'%'
167        hostname, percent, zone = hostname.partition(separator)
168        return hostname.lower() + percent + zone
169
170    @property
171    def port(self):
172        port = self._hostinfo[1]
173        if port is not None:
174            try:
175                port = int(port, 10)
176            except ValueError:
177                message = f'Port could not be cast to integer value as {port!r}'
178                raise ValueError(message) from None
179            if not ( 0 <= port <= 65535):
180                raise ValueError("Port out of range 0-65535")
181        return port
182
183    __class_getitem__ = classmethod(types.GenericAlias)
184
185
186class _NetlocResultMixinStr(_NetlocResultMixinBase, _ResultMixinStr):
187    __slots__ = ()
188
189    @property
190    def _userinfo(self):
191        netloc = self.netloc
192        userinfo, have_info, hostinfo = netloc.rpartition('@')
193        if have_info:
194            username, have_password, password = userinfo.partition(':')
195            if not have_password:
196                password = None
197        else:
198            username = password = None
199        return username, password
200
201    @property
202    def _hostinfo(self):
203        netloc = self.netloc
204        _, _, hostinfo = netloc.rpartition('@')
205        _, have_open_br, bracketed = hostinfo.partition('[')
206        if have_open_br:
207            hostname, _, port = bracketed.partition(']')
208            _, _, port = port.partition(':')
209        else:
210            hostname, _, port = hostinfo.partition(':')
211        if not port:
212            port = None
213        return hostname, port
214
215
216class _NetlocResultMixinBytes(_NetlocResultMixinBase, _ResultMixinBytes):
217    __slots__ = ()
218
219    @property
220    def _userinfo(self):
221        netloc = self.netloc
222        userinfo, have_info, hostinfo = netloc.rpartition(b'@')
223        if have_info:
224            username, have_password, password = userinfo.partition(b':')
225            if not have_password:
226                password = None
227        else:
228            username = password = None
229        return username, password
230
231    @property
232    def _hostinfo(self):
233        netloc = self.netloc
234        _, _, hostinfo = netloc.rpartition(b'@')
235        _, have_open_br, bracketed = hostinfo.partition(b'[')
236        if have_open_br:
237            hostname, _, port = bracketed.partition(b']')
238            _, _, port = port.partition(b':')
239        else:
240            hostname, _, port = hostinfo.partition(b':')
241        if not port:
242            port = None
243        return hostname, port
244
245
246from collections import namedtuple
247
248_DefragResultBase = namedtuple('DefragResult', 'url fragment')
249_SplitResultBase = namedtuple(
250    'SplitResult', 'scheme netloc path query fragment')
251_ParseResultBase = namedtuple(
252    'ParseResult', 'scheme netloc path params query fragment')
253
254_DefragResultBase.__doc__ = """
255DefragResult(url, fragment)
256
257A 2-tuple that contains the url without fragment identifier and the fragment
258identifier as a separate argument.
259"""
260
261_DefragResultBase.url.__doc__ = """The URL with no fragment identifier."""
262
263_DefragResultBase.fragment.__doc__ = """
264Fragment identifier separated from URL, that allows indirect identification of a
265secondary resource by reference to a primary resource and additional identifying
266information.
267"""
268
269_SplitResultBase.__doc__ = """
270SplitResult(scheme, netloc, path, query, fragment)
271
272A 5-tuple that contains the different components of a URL. Similar to
273ParseResult, but does not split params.
274"""
275
276_SplitResultBase.scheme.__doc__ = """Specifies URL scheme for the request."""
277
278_SplitResultBase.netloc.__doc__ = """
279Network location where the request is made to.
280"""
281
282_SplitResultBase.path.__doc__ = """
283The hierarchical path, such as the path to a file to download.
284"""
285
286_SplitResultBase.query.__doc__ = """
287The query component, that contains non-hierarchical data, that along with data
288in path component, identifies a resource in the scope of URI's scheme and
289network location.
290"""
291
292_SplitResultBase.fragment.__doc__ = """
293Fragment identifier, that allows indirect identification of a secondary resource
294by reference to a primary resource and additional identifying information.
295"""
296
297_ParseResultBase.__doc__ = """
298ParseResult(scheme, netloc, path, params, query, fragment)
299
300A 6-tuple that contains components of a parsed URL.
301"""
302
303_ParseResultBase.scheme.__doc__ = _SplitResultBase.scheme.__doc__
304_ParseResultBase.netloc.__doc__ = _SplitResultBase.netloc.__doc__
305_ParseResultBase.path.__doc__ = _SplitResultBase.path.__doc__
306_ParseResultBase.params.__doc__ = """
307Parameters for last path element used to dereference the URI in order to provide
308access to perform some operation on the resource.
309"""
310
311_ParseResultBase.query.__doc__ = _SplitResultBase.query.__doc__
312_ParseResultBase.fragment.__doc__ = _SplitResultBase.fragment.__doc__
313
314
315# For backwards compatibility, alias _NetlocResultMixinStr
316# ResultBase is no longer part of the documented API, but it is
317# retained since deprecating it isn't worth the hassle
318ResultBase = _NetlocResultMixinStr
319
320# Structured result objects for string data
321class DefragResult(_DefragResultBase, _ResultMixinStr):
322    __slots__ = ()
323    def geturl(self):
324        if self.fragment:
325            return self.url + '#' + self.fragment
326        else:
327            return self.url
328
329class SplitResult(_SplitResultBase, _NetlocResultMixinStr):
330    __slots__ = ()
331    def geturl(self):
332        return urlunsplit(self)
333
334class ParseResult(_ParseResultBase, _NetlocResultMixinStr):
335    __slots__ = ()
336    def geturl(self):
337        return urlunparse(self)
338
339# Structured result objects for bytes data
340class DefragResultBytes(_DefragResultBase, _ResultMixinBytes):
341    __slots__ = ()
342    def geturl(self):
343        if self.fragment:
344            return self.url + b'#' + self.fragment
345        else:
346            return self.url
347
348class SplitResultBytes(_SplitResultBase, _NetlocResultMixinBytes):
349    __slots__ = ()
350    def geturl(self):
351        return urlunsplit(self)
352
353class ParseResultBytes(_ParseResultBase, _NetlocResultMixinBytes):
354    __slots__ = ()
355    def geturl(self):
356        return urlunparse(self)
357
358# Set up the encode/decode result pairs
359def _fix_result_transcoding():
360    _result_pairs = (
361        (DefragResult, DefragResultBytes),
362        (SplitResult, SplitResultBytes),
363        (ParseResult, ParseResultBytes),
364    )
365    for _decoded, _encoded in _result_pairs:
366        _decoded._encoded_counterpart = _encoded
367        _encoded._decoded_counterpart = _decoded
368
369_fix_result_transcoding()
370del _fix_result_transcoding
371
372def urlparse(url, scheme='', allow_fragments=True):
373    """Parse a URL into 6 components:
374    <scheme>://<netloc>/<path>;<params>?<query>#<fragment>
375
376    The result is a named 6-tuple with fields corresponding to the
377    above. It is either a ParseResult or ParseResultBytes object,
378    depending on the type of the url parameter.
379
380    The username, password, hostname, and port sub-components of netloc
381    can also be accessed as attributes of the returned object.
382
383    The scheme argument provides the default value of the scheme
384    component when no scheme is found in url.
385
386    If allow_fragments is False, no attempt is made to separate the
387    fragment component from the previous component, which can be either
388    path or query.
389
390    Note that % escapes are not expanded.
391    """
392    url, scheme, _coerce_result = _coerce_args(url, scheme)
393    splitresult = urlsplit(url, scheme, allow_fragments)
394    scheme, netloc, url, query, fragment = splitresult
395    if scheme in uses_params and ';' in url:
396        url, params = _splitparams(url)
397    else:
398        params = ''
399    result = ParseResult(scheme, netloc, url, params, query, fragment)
400    return _coerce_result(result)
401
402def _splitparams(url):
403    if '/'  in url:
404        i = url.find(';', url.rfind('/'))
405        if i < 0:
406            return url, ''
407    else:
408        i = url.find(';')
409    return url[:i], url[i+1:]
410
411def _splitnetloc(url, start=0):
412    delim = len(url)   # position of end of domain part of url, default is end
413    for c in '/?#':    # look for delimiters; the order is NOT important
414        wdelim = url.find(c, start)        # find first of this delim
415        if wdelim >= 0:                    # if found
416            delim = min(delim, wdelim)     # use earliest delim position
417    return url[start:delim], url[delim:]   # return (domain, rest)
418
419def _checknetloc(netloc):
420    if not netloc or netloc.isascii():
421        return
422    # looking for characters like \u2100 that expand to 'a/c'
423    # IDNA uses NFKC equivalence, so normalize for this check
424    import unicodedata
425    n = netloc.replace('@', '')   # ignore characters already included
426    n = n.replace(':', '')        # but not the surrounding text
427    n = n.replace('#', '')
428    n = n.replace('?', '')
429    netloc2 = unicodedata.normalize('NFKC', n)
430    if n == netloc2:
431        return
432    for c in '/?#@:':
433        if c in netloc2:
434            raise ValueError("netloc '" + netloc + "' contains invalid " +
435                             "characters under NFKC normalization")
436
437def urlsplit(url, scheme='', allow_fragments=True):
438    """Parse a URL into 5 components:
439    <scheme>://<netloc>/<path>?<query>#<fragment>
440
441    The result is a named 5-tuple with fields corresponding to the
442    above. It is either a SplitResult or SplitResultBytes object,
443    depending on the type of the url parameter.
444
445    The username, password, hostname, and port sub-components of netloc
446    can also be accessed as attributes of the returned object.
447
448    The scheme argument provides the default value of the scheme
449    component when no scheme is found in url.
450
451    If allow_fragments is False, no attempt is made to separate the
452    fragment component from the previous component, which can be either
453    path or query.
454
455    Note that % escapes are not expanded.
456    """
457
458    url, scheme, _coerce_result = _coerce_args(url, scheme)
459
460    for b in _UNSAFE_URL_BYTES_TO_REMOVE:
461        url = url.replace(b, "")
462        scheme = scheme.replace(b, "")
463
464    allow_fragments = bool(allow_fragments)
465    key = url, scheme, allow_fragments, type(url), type(scheme)
466    cached = _parse_cache.get(key, None)
467    if cached:
468        return _coerce_result(cached)
469    if len(_parse_cache) >= MAX_CACHE_SIZE: # avoid runaway growth
470        clear_cache()
471    netloc = query = fragment = ''
472    i = url.find(':')
473    if i > 0:
474        for c in url[:i]:
475            if c not in scheme_chars:
476                break
477        else:
478            scheme, url = url[:i].lower(), url[i+1:]
479
480    if url[:2] == '//':
481        netloc, url = _splitnetloc(url, 2)
482        if (('[' in netloc and ']' not in netloc) or
483                (']' in netloc and '[' not in netloc)):
484            raise ValueError("Invalid IPv6 URL")
485    if allow_fragments and '#' in url:
486        url, fragment = url.split('#', 1)
487    if '?' in url:
488        url, query = url.split('?', 1)
489    _checknetloc(netloc)
490    v = SplitResult(scheme, netloc, url, query, fragment)
491    _parse_cache[key] = v
492    return _coerce_result(v)
493
494def urlunparse(components):
495    """Put a parsed URL back together again.  This may result in a
496    slightly different, but equivalent URL, if the URL that was parsed
497    originally had redundant delimiters, e.g. a ? with an empty query
498    (the draft states that these are equivalent)."""
499    scheme, netloc, url, params, query, fragment, _coerce_result = (
500                                                  _coerce_args(*components))
501    if params:
502        url = "%s;%s" % (url, params)
503    return _coerce_result(urlunsplit((scheme, netloc, url, query, fragment)))
504
505def urlunsplit(components):
506    """Combine the elements of a tuple as returned by urlsplit() into a
507    complete URL as a string. The data argument can be any five-item iterable.
508    This may result in a slightly different, but equivalent URL, if the URL that
509    was parsed originally had unnecessary delimiters (for example, a ? with an
510    empty query; the RFC states that these are equivalent)."""
511    scheme, netloc, url, query, fragment, _coerce_result = (
512                                          _coerce_args(*components))
513    if netloc or (scheme and scheme in uses_netloc and url[:2] != '//'):
514        if url and url[:1] != '/': url = '/' + url
515        url = '//' + (netloc or '') + url
516    if scheme:
517        url = scheme + ':' + url
518    if query:
519        url = url + '?' + query
520    if fragment:
521        url = url + '#' + fragment
522    return _coerce_result(url)
523
524def urljoin(base, url, allow_fragments=True):
525    """Join a base URL and a possibly relative URL to form an absolute
526    interpretation of the latter."""
527    if not base:
528        return url
529    if not url:
530        return base
531
532    base, url, _coerce_result = _coerce_args(base, url)
533    bscheme, bnetloc, bpath, bparams, bquery, bfragment = \
534            urlparse(base, '', allow_fragments)
535    scheme, netloc, path, params, query, fragment = \
536            urlparse(url, bscheme, allow_fragments)
537
538    if scheme != bscheme or scheme not in uses_relative:
539        return _coerce_result(url)
540    if scheme in uses_netloc:
541        if netloc:
542            return _coerce_result(urlunparse((scheme, netloc, path,
543                                              params, query, fragment)))
544        netloc = bnetloc
545
546    if not path and not params:
547        path = bpath
548        params = bparams
549        if not query:
550            query = bquery
551        return _coerce_result(urlunparse((scheme, netloc, path,
552                                          params, query, fragment)))
553
554    base_parts = bpath.split('/')
555    if base_parts[-1] != '':
556        # the last item is not a directory, so will not be taken into account
557        # in resolving the relative path
558        del base_parts[-1]
559
560    # for rfc3986, ignore all base path should the first character be root.
561    if path[:1] == '/':
562        segments = path.split('/')
563    else:
564        segments = base_parts + path.split('/')
565        # filter out elements that would cause redundant slashes on re-joining
566        # the resolved_path
567        segments[1:-1] = filter(None, segments[1:-1])
568
569    resolved_path = []
570
571    for seg in segments:
572        if seg == '..':
573            try:
574                resolved_path.pop()
575            except IndexError:
576                # ignore any .. segments that would otherwise cause an IndexError
577                # when popped from resolved_path if resolving for rfc3986
578                pass
579        elif seg == '.':
580            continue
581        else:
582            resolved_path.append(seg)
583
584    if segments[-1] in ('.', '..'):
585        # do some post-processing here. if the last segment was a relative dir,
586        # then we need to append the trailing '/'
587        resolved_path.append('')
588
589    return _coerce_result(urlunparse((scheme, netloc, '/'.join(
590        resolved_path) or '/', params, query, fragment)))
591
592
593def urldefrag(url):
594    """Removes any existing fragment from URL.
595
596    Returns a tuple of the defragmented URL and the fragment.  If
597    the URL contained no fragments, the second element is the
598    empty string.
599    """
600    url, _coerce_result = _coerce_args(url)
601    if '#' in url:
602        s, n, p, a, q, frag = urlparse(url)
603        defrag = urlunparse((s, n, p, a, q, ''))
604    else:
605        frag = ''
606        defrag = url
607    return _coerce_result(DefragResult(defrag, frag))
608
609_hexdig = '0123456789ABCDEFabcdef'
610_hextobyte = None
611
612def unquote_to_bytes(string):
613    """unquote_to_bytes('abc%20def') -> b'abc def'."""
614    # Note: strings are encoded as UTF-8. This is only an issue if it contains
615    # unescaped non-ASCII characters, which URIs should not.
616    if not string:
617        # Is it a string-like object?
618        string.split
619        return b''
620    if isinstance(string, str):
621        string = string.encode('utf-8')
622    bits = string.split(b'%')
623    if len(bits) == 1:
624        return string
625    res = [bits[0]]
626    append = res.append
627    # Delay the initialization of the table to not waste memory
628    # if the function is never called
629    global _hextobyte
630    if _hextobyte is None:
631        _hextobyte = {(a + b).encode(): bytes.fromhex(a + b)
632                      for a in _hexdig for b in _hexdig}
633    for item in bits[1:]:
634        try:
635            append(_hextobyte[item[:2]])
636            append(item[2:])
637        except KeyError:
638            append(b'%')
639            append(item)
640    return b''.join(res)
641
642_asciire = re.compile('([\x00-\x7f]+)')
643
644def unquote(string, encoding='utf-8', errors='replace'):
645    """Replace %xx escapes by their single-character equivalent. The optional
646    encoding and errors parameters specify how to decode percent-encoded
647    sequences into Unicode characters, as accepted by the bytes.decode()
648    method.
649    By default, percent-encoded sequences are decoded with UTF-8, and invalid
650    sequences are replaced by a placeholder character.
651
652    unquote('abc%20def') -> 'abc def'.
653    """
654    if isinstance(string, bytes):
655        return unquote_to_bytes(string).decode(encoding, errors)
656    if '%' not in string:
657        string.split
658        return string
659    if encoding is None:
660        encoding = 'utf-8'
661    if errors is None:
662        errors = 'replace'
663    bits = _asciire.split(string)
664    res = [bits[0]]
665    append = res.append
666    for i in range(1, len(bits), 2):
667        append(unquote_to_bytes(bits[i]).decode(encoding, errors))
668        append(bits[i + 1])
669    return ''.join(res)
670
671
672def parse_qs(qs, keep_blank_values=False, strict_parsing=False,
673             encoding='utf-8', errors='replace', max_num_fields=None, separator='&'):
674    """Parse a query given as a string argument.
675
676        Arguments:
677
678        qs: percent-encoded query string to be parsed
679
680        keep_blank_values: flag indicating whether blank values in
681            percent-encoded queries should be treated as blank strings.
682            A true value indicates that blanks should be retained as
683            blank strings.  The default false value indicates that
684            blank values are to be ignored and treated as if they were
685            not included.
686
687        strict_parsing: flag indicating what to do with parsing errors.
688            If false (the default), errors are silently ignored.
689            If true, errors raise a ValueError exception.
690
691        encoding and errors: specify how to decode percent-encoded sequences
692            into Unicode characters, as accepted by the bytes.decode() method.
693
694        max_num_fields: int. If set, then throws a ValueError if there
695            are more than n fields read by parse_qsl().
696
697        separator: str. The symbol to use for separating the query arguments.
698            Defaults to &.
699
700        Returns a dictionary.
701    """
702    parsed_result = {}
703    pairs = parse_qsl(qs, keep_blank_values, strict_parsing,
704                      encoding=encoding, errors=errors,
705                      max_num_fields=max_num_fields, separator=separator)
706    for name, value in pairs:
707        if name in parsed_result:
708            parsed_result[name].append(value)
709        else:
710            parsed_result[name] = [value]
711    return parsed_result
712
713
714def parse_qsl(qs, keep_blank_values=False, strict_parsing=False,
715              encoding='utf-8', errors='replace', max_num_fields=None, separator='&'):
716    """Parse a query given as a string argument.
717
718        Arguments:
719
720        qs: percent-encoded query string to be parsed
721
722        keep_blank_values: flag indicating whether blank values in
723            percent-encoded queries should be treated as blank strings.
724            A true value indicates that blanks should be retained as blank
725            strings.  The default false value indicates that blank values
726            are to be ignored and treated as if they were  not included.
727
728        strict_parsing: flag indicating what to do with parsing errors. If
729            false (the default), errors are silently ignored. If true,
730            errors raise a ValueError exception.
731
732        encoding and errors: specify how to decode percent-encoded sequences
733            into Unicode characters, as accepted by the bytes.decode() method.
734
735        max_num_fields: int. If set, then throws a ValueError
736            if there are more than n fields read by parse_qsl().
737
738        separator: str. The symbol to use for separating the query arguments.
739            Defaults to &.
740
741        Returns a list, as G-d intended.
742    """
743    qs, _coerce_result = _coerce_args(qs)
744    separator, _ = _coerce_args(separator)
745
746    if not separator or (not isinstance(separator, (str, bytes))):
747        raise ValueError("Separator must be of type string or bytes.")
748
749    # If max_num_fields is defined then check that the number of fields
750    # is less than max_num_fields. This prevents a memory exhaustion DOS
751    # attack via post bodies with many fields.
752    if max_num_fields is not None:
753        num_fields = 1 + qs.count(separator)
754        if max_num_fields < num_fields:
755            raise ValueError('Max number of fields exceeded')
756
757    r = []
758    for name_value in qs.split(separator):
759        if not name_value and not strict_parsing:
760            continue
761        nv = name_value.split('=', 1)
762        if len(nv) != 2:
763            if strict_parsing:
764                raise ValueError("bad query field: %r" % (name_value,))
765            # Handle case of a control-name with no equal sign
766            if keep_blank_values:
767                nv.append('')
768            else:
769                continue
770        if len(nv[1]) or keep_blank_values:
771            name = nv[0].replace('+', ' ')
772            name = unquote(name, encoding=encoding, errors=errors)
773            name = _coerce_result(name)
774            value = nv[1].replace('+', ' ')
775            value = unquote(value, encoding=encoding, errors=errors)
776            value = _coerce_result(value)
777            r.append((name, value))
778    return r
779
780def unquote_plus(string, encoding='utf-8', errors='replace'):
781    """Like unquote(), but also replace plus signs by spaces, as required for
782    unquoting HTML form values.
783
784    unquote_plus('%7e/abc+def') -> '~/abc def'
785    """
786    string = string.replace('+', ' ')
787    return unquote(string, encoding, errors)
788
789_ALWAYS_SAFE = frozenset(b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
790                         b'abcdefghijklmnopqrstuvwxyz'
791                         b'0123456789'
792                         b'_.-~')
793_ALWAYS_SAFE_BYTES = bytes(_ALWAYS_SAFE)
794_safe_quoters = {}
795
796class Quoter(collections.defaultdict):
797    """A mapping from bytes (in range(0,256)) to strings.
798
799    String values are percent-encoded byte values, unless the key < 128, and
800    in the "safe" set (either the specified safe set, or default set).
801    """
802    # Keeps a cache internally, using defaultdict, for efficiency (lookups
803    # of cached keys don't call Python code at all).
804    def __init__(self, safe):
805        """safe: bytes object."""
806        self.safe = _ALWAYS_SAFE.union(safe)
807
808    def __repr__(self):
809        # Without this, will just display as a defaultdict
810        return "<%s %r>" % (self.__class__.__name__, dict(self))
811
812    def __missing__(self, b):
813        # Handle a cache miss. Store quoted string in cache and return.
814        res = chr(b) if b in self.safe else '%{:02X}'.format(b)
815        self[b] = res
816        return res
817
818def quote(string, safe='/', encoding=None, errors=None):
819    """quote('abc def') -> 'abc%20def'
820
821    Each part of a URL, e.g. the path info, the query, etc., has a
822    different set of reserved characters that must be quoted. The
823    quote function offers a cautious (not minimal) way to quote a
824    string for most of these parts.
825
826    RFC 3986 Uniform Resource Identifier (URI): Generic Syntax lists
827    the following (un)reserved characters.
828
829    unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
830    reserved      = gen-delims / sub-delims
831    gen-delims    = ":" / "/" / "?" / "#" / "[" / "]" / "@"
832    sub-delims    = "!" / "$" / "&" / "'" / "(" / ")"
833                  / "*" / "+" / "," / ";" / "="
834
835    Each of the reserved characters is reserved in some component of a URL,
836    but not necessarily in all of them.
837
838    The quote function %-escapes all characters that are neither in the
839    unreserved chars ("always safe") nor the additional chars set via the
840    safe arg.
841
842    The default for the safe arg is '/'. The character is reserved, but in
843    typical usage the quote function is being called on a path where the
844    existing slash characters are to be preserved.
845
846    Python 3.7 updates from using RFC 2396 to RFC 3986 to quote URL strings.
847    Now, "~" is included in the set of unreserved characters.
848
849    string and safe may be either str or bytes objects. encoding and errors
850    must not be specified if string is a bytes object.
851
852    The optional encoding and errors parameters specify how to deal with
853    non-ASCII characters, as accepted by the str.encode method.
854    By default, encoding='utf-8' (characters are encoded with UTF-8), and
855    errors='strict' (unsupported characters raise a UnicodeEncodeError).
856    """
857    if isinstance(string, str):
858        if not string:
859            return string
860        if encoding is None:
861            encoding = 'utf-8'
862        if errors is None:
863            errors = 'strict'
864        string = string.encode(encoding, errors)
865    else:
866        if encoding is not None:
867            raise TypeError("quote() doesn't support 'encoding' for bytes")
868        if errors is not None:
869            raise TypeError("quote() doesn't support 'errors' for bytes")
870    return quote_from_bytes(string, safe)
871
872def quote_plus(string, safe='', encoding=None, errors=None):
873    """Like quote(), but also replace ' ' with '+', as required for quoting
874    HTML form values. Plus signs in the original string are escaped unless
875    they are included in safe. It also does not have safe default to '/'.
876    """
877    # Check if ' ' in string, where string may either be a str or bytes.  If
878    # there are no spaces, the regular quote will produce the right answer.
879    if ((isinstance(string, str) and ' ' not in string) or
880        (isinstance(string, bytes) and b' ' not in string)):
881        return quote(string, safe, encoding, errors)
882    if isinstance(safe, str):
883        space = ' '
884    else:
885        space = b' '
886    string = quote(string, safe + space, encoding, errors)
887    return string.replace(' ', '+')
888
889def quote_from_bytes(bs, safe='/'):
890    """Like quote(), but accepts a bytes object rather than a str, and does
891    not perform string-to-bytes encoding.  It always returns an ASCII string.
892    quote_from_bytes(b'abc def\x3f') -> 'abc%20def%3f'
893    """
894    if not isinstance(bs, (bytes, bytearray)):
895        raise TypeError("quote_from_bytes() expected bytes")
896    if not bs:
897        return ''
898    if isinstance(safe, str):
899        # Normalize 'safe' by converting to bytes and removing non-ASCII chars
900        safe = safe.encode('ascii', 'ignore')
901    else:
902        safe = bytes([c for c in safe if c < 128])
903    if not bs.rstrip(_ALWAYS_SAFE_BYTES + safe):
904        return bs.decode()
905    try:
906        quoter = _safe_quoters[safe]
907    except KeyError:
908        _safe_quoters[safe] = quoter = Quoter(safe).__getitem__
909    return ''.join([quoter(char) for char in bs])
910
911def urlencode(query, doseq=False, safe='', encoding=None, errors=None,
912              quote_via=quote_plus):
913    """Encode a dict or sequence of two-element tuples into a URL query string.
914
915    If any values in the query arg are sequences and doseq is true, each
916    sequence element is converted to a separate parameter.
917
918    If the query arg is a sequence of two-element tuples, the order of the
919    parameters in the output will match the order of parameters in the
920    input.
921
922    The components of a query arg may each be either a string or a bytes type.
923
924    The safe, encoding, and errors parameters are passed down to the function
925    specified by quote_via (encoding and errors only if a component is a str).
926    """
927
928    if hasattr(query, "items"):
929        query = query.items()
930    else:
931        # It's a bother at times that strings and string-like objects are
932        # sequences.
933        try:
934            # non-sequence items should not work with len()
935            # non-empty strings will fail this
936            if len(query) and not isinstance(query[0], tuple):
937                raise TypeError
938            # Zero-length sequences of all types will get here and succeed,
939            # but that's a minor nit.  Since the original implementation
940            # allowed empty dicts that type of behavior probably should be
941            # preserved for consistency
942        except TypeError:
943            ty, va, tb = sys.exc_info()
944            raise TypeError("not a valid non-string sequence "
945                            "or mapping object").with_traceback(tb)
946
947    l = []
948    if not doseq:
949        for k, v in query:
950            if isinstance(k, bytes):
951                k = quote_via(k, safe)
952            else:
953                k = quote_via(str(k), safe, encoding, errors)
954
955            if isinstance(v, bytes):
956                v = quote_via(v, safe)
957            else:
958                v = quote_via(str(v), safe, encoding, errors)
959            l.append(k + '=' + v)
960    else:
961        for k, v in query:
962            if isinstance(k, bytes):
963                k = quote_via(k, safe)
964            else:
965                k = quote_via(str(k), safe, encoding, errors)
966
967            if isinstance(v, bytes):
968                v = quote_via(v, safe)
969                l.append(k + '=' + v)
970            elif isinstance(v, str):
971                v = quote_via(v, safe, encoding, errors)
972                l.append(k + '=' + v)
973            else:
974                try:
975                    # Is this a sufficient test for sequence-ness?
976                    x = len(v)
977                except TypeError:
978                    # not a sequence
979                    v = quote_via(str(v), safe, encoding, errors)
980                    l.append(k + '=' + v)
981                else:
982                    # loop over the sequence
983                    for elt in v:
984                        if isinstance(elt, bytes):
985                            elt = quote_via(elt, safe)
986                        else:
987                            elt = quote_via(str(elt), safe, encoding, errors)
988                        l.append(k + '=' + elt)
989    return '&'.join(l)
990
991
992def to_bytes(url):
993    warnings.warn("urllib.parse.to_bytes() is deprecated as of 3.8",
994                  DeprecationWarning, stacklevel=2)
995    return _to_bytes(url)
996
997
998def _to_bytes(url):
999    """to_bytes(u"URL") --> 'URL'."""
1000    # Most URL schemes require ASCII. If that changes, the conversion
1001    # can be relaxed.
1002    # XXX get rid of to_bytes()
1003    if isinstance(url, str):
1004        try:
1005            url = url.encode("ASCII").decode()
1006        except UnicodeError:
1007            raise UnicodeError("URL " + repr(url) +
1008                               " contains non-ASCII characters")
1009    return url
1010
1011
1012def unwrap(url):
1013    """Transform a string like '<URL:scheme://host/path>' into 'scheme://host/path'.
1014
1015    The string is returned unchanged if it's not a wrapped URL.
1016    """
1017    url = str(url).strip()
1018    if url[:1] == '<' and url[-1:] == '>':
1019        url = url[1:-1].strip()
1020    if url[:4] == 'URL:':
1021        url = url[4:].strip()
1022    return url
1023
1024
1025def splittype(url):
1026    warnings.warn("urllib.parse.splittype() is deprecated as of 3.8, "
1027                  "use urllib.parse.urlparse() instead",
1028                  DeprecationWarning, stacklevel=2)
1029    return _splittype(url)
1030
1031
1032_typeprog = None
1033def _splittype(url):
1034    """splittype('type:opaquestring') --> 'type', 'opaquestring'."""
1035    global _typeprog
1036    if _typeprog is None:
1037        _typeprog = re.compile('([^/:]+):(.*)', re.DOTALL)
1038
1039    match = _typeprog.match(url)
1040    if match:
1041        scheme, data = match.groups()
1042        return scheme.lower(), data
1043    return None, url
1044
1045
1046def splithost(url):
1047    warnings.warn("urllib.parse.splithost() is deprecated as of 3.8, "
1048                  "use urllib.parse.urlparse() instead",
1049                  DeprecationWarning, stacklevel=2)
1050    return _splithost(url)
1051
1052
1053_hostprog = None
1054def _splithost(url):
1055    """splithost('//host[:port]/path') --> 'host[:port]', '/path'."""
1056    global _hostprog
1057    if _hostprog is None:
1058        _hostprog = re.compile('//([^/#?]*)(.*)', re.DOTALL)
1059
1060    match = _hostprog.match(url)
1061    if match:
1062        host_port, path = match.groups()
1063        if path and path[0] != '/':
1064            path = '/' + path
1065        return host_port, path
1066    return None, url
1067
1068
1069def splituser(host):
1070    warnings.warn("urllib.parse.splituser() is deprecated as of 3.8, "
1071                  "use urllib.parse.urlparse() instead",
1072                  DeprecationWarning, stacklevel=2)
1073    return _splituser(host)
1074
1075
1076def _splituser(host):
1077    """splituser('user[:passwd]@host[:port]') --> 'user[:passwd]', 'host[:port]'."""
1078    user, delim, host = host.rpartition('@')
1079    return (user if delim else None), host
1080
1081
1082def splitpasswd(user):
1083    warnings.warn("urllib.parse.splitpasswd() is deprecated as of 3.8, "
1084                  "use urllib.parse.urlparse() instead",
1085                  DeprecationWarning, stacklevel=2)
1086    return _splitpasswd(user)
1087
1088
1089def _splitpasswd(user):
1090    """splitpasswd('user:passwd') -> 'user', 'passwd'."""
1091    user, delim, passwd = user.partition(':')
1092    return user, (passwd if delim else None)
1093
1094
1095def splitport(host):
1096    warnings.warn("urllib.parse.splitport() is deprecated as of 3.8, "
1097                  "use urllib.parse.urlparse() instead",
1098                  DeprecationWarning, stacklevel=2)
1099    return _splitport(host)
1100
1101
1102# splittag('/path#tag') --> '/path', 'tag'
1103_portprog = None
1104def _splitport(host):
1105    """splitport('host:port') --> 'host', 'port'."""
1106    global _portprog
1107    if _portprog is None:
1108        _portprog = re.compile('(.*):([0-9]*)', re.DOTALL)
1109
1110    match = _portprog.fullmatch(host)
1111    if match:
1112        host, port = match.groups()
1113        if port:
1114            return host, port
1115    return host, None
1116
1117
1118def splitnport(host, defport=-1):
1119    warnings.warn("urllib.parse.splitnport() is deprecated as of 3.8, "
1120                  "use urllib.parse.urlparse() instead",
1121                  DeprecationWarning, stacklevel=2)
1122    return _splitnport(host, defport)
1123
1124
1125def _splitnport(host, defport=-1):
1126    """Split host and port, returning numeric port.
1127    Return given default port if no ':' found; defaults to -1.
1128    Return numerical port if a valid number are found after ':'.
1129    Return None if ':' but not a valid number."""
1130    host, delim, port = host.rpartition(':')
1131    if not delim:
1132        host = port
1133    elif port:
1134        try:
1135            nport = int(port)
1136        except ValueError:
1137            nport = None
1138        return host, nport
1139    return host, defport
1140
1141
1142def splitquery(url):
1143    warnings.warn("urllib.parse.splitquery() is deprecated as of 3.8, "
1144                  "use urllib.parse.urlparse() instead",
1145                  DeprecationWarning, stacklevel=2)
1146    return _splitquery(url)
1147
1148
1149def _splitquery(url):
1150    """splitquery('/path?query') --> '/path', 'query'."""
1151    path, delim, query = url.rpartition('?')
1152    if delim:
1153        return path, query
1154    return url, None
1155
1156
1157def splittag(url):
1158    warnings.warn("urllib.parse.splittag() is deprecated as of 3.8, "
1159                  "use urllib.parse.urlparse() instead",
1160                  DeprecationWarning, stacklevel=2)
1161    return _splittag(url)
1162
1163
1164def _splittag(url):
1165    """splittag('/path#tag') --> '/path', 'tag'."""
1166    path, delim, tag = url.rpartition('#')
1167    if delim:
1168        return path, tag
1169    return url, None
1170
1171
1172def splitattr(url):
1173    warnings.warn("urllib.parse.splitattr() is deprecated as of 3.8, "
1174                  "use urllib.parse.urlparse() instead",
1175                  DeprecationWarning, stacklevel=2)
1176    return _splitattr(url)
1177
1178
1179def _splitattr(url):
1180    """splitattr('/path;attr1=value1;attr2=value2;...') ->
1181        '/path', ['attr1=value1', 'attr2=value2', ...]."""
1182    words = url.split(';')
1183    return words[0], words[1:]
1184
1185
1186def splitvalue(attr):
1187    warnings.warn("urllib.parse.splitvalue() is deprecated as of 3.8, "
1188                  "use urllib.parse.parse_qsl() instead",
1189                  DeprecationWarning, stacklevel=2)
1190    return _splitvalue(attr)
1191
1192
1193def _splitvalue(attr):
1194    """splitvalue('attr=value') --> 'attr', 'value'."""
1195    attr, delim, value = attr.partition('=')
1196    return attr, (value if delim else None)
1197