"""Parse (absolute and relative) URLs. See RFC 1808: "Relative Uniform Resource Locators", by R. Fielding,UC Irvine, June 1995.""" __all__ = ["urlparse", "urlunparse", "urljoin", "urldefrag",           "urlsplit", "urlunsplit"] # A classification of schemes ('' means apply by default)uses_relative = ['ftp', 'http', 'gopher', 'nntp', 'imap',                 'wais', 'file', 'https', 'shttp', 'mms',                 'prospero', 'rtsp', 'rtspu', '', 'sftp']uses_netloc = ['ftp', 'http', 'gopher', 'nntp', 'telnet',               'imap', 'wais', 'file', 'mms', 'https', 'shttp',               'snews', 'prospero', 'rtsp', 'rtspu', 'rsync', '',               'svn', 'svn+ssh', 'sftp']non_hierarchical = ['gopher', 'hdl', 'mailto', 'news',                    'telnet', 'wais', 'imap', 'snews', 'sip', 'sips']uses_params = ['ftp', 'hdl', 'prospero', 'http', 'imap',               'https', 'shttp', 'rtsp', 'rtspu', 'sip', 'sips',               'mms', '', 'sftp']uses_query = ['http', 'wais', 'imap', 'https', 'shttp', 'mms',              'gopher', 'rtsp', 'rtspu', 'sip', 'sips', '']uses_fragment = ['ftp', 'hdl', 'http', 'gopher', 'news',                 'nntp', 'wais', 'https', 'shttp', 'snews',                 'file', 'prospero', ''] # Characters valid in scheme namesscheme_chars = ('abcdefghijklmnopqrstuvwxyz'                'ABCDEFGHIJKLMNOPQRSTUVWXYZ'                '0123456789'                '+-.') MAX_CACHE_SIZE = 20_parse_cache = {} def clear_cache():    """Clear the parse cache."""    global _parse_cache    _parse_cache = {}  class BaseResult(tuple):    """Base class for the parsed result objects.     This provides the attributes shared by the two derived result    objects as read-only properties.  The derived classes are    responsible for checking the right number of arguments were    supplied to the constructor.     """     __slots__ = ()     # Attributes that access the basic components of the URL:     @property    def scheme(self):        return self[0]     @property    def netloc(self):        return self[1]     @property    def path(self):        return self[2]     @property    def query(self):        return self[-2]     @property    def fragment(self):        return self[-1]     # Additional attributes that provide access to parsed-out portions    # of the netloc:     @property    def username(self):        netloc = self.netloc        if "@" in netloc:            userinfo = netloc.split("@", 1)[0]            if ":" in userinfo:                userinfo = userinfo.split(":", 1)[0]            return userinfo        return None     @property    def password(self):        netloc = self.netloc        if "@" in netloc:            userinfo = netloc.split("@", 1)[0]            if ":" in userinfo:                return userinfo.split(":", 1)[1]        return None     @property    def hostname(self):        netloc = self.netloc        if "@" in netloc:            netloc = netloc.split("@", 1)[1]        if ":" in netloc:            netloc = netloc.split(":", 1)[0]        return netloc.lower() or None     @property    def port(self):        netloc = self.netloc        if "@" in netloc:            netloc = netloc.split("@", 1)[1]        if ":" in netloc:            port = netloc.split(":", 1)[1]            return int(port, 10)        return None  class SplitResult(BaseResult):     __slots__ = ()     def __new__(cls, scheme, netloc, path, query, fragment):        return BaseResult.__new__(            cls, (scheme, netloc, path, query, fragment))     def geturl(self):        return urlunsplit(self)  class ParseResult(BaseResult):     __slots__ = ()     def __new__(cls, scheme, netloc, path, params, query, fragment):        return BaseResult.__new__(            cls, (scheme, netloc, path, params, query, fragment))     @property    def params(self):        return self[3]     def geturl(self):        return urlunparse(self)  def urlparse(url, scheme='', allow_fragments=True):    """Parse a URL into 6 components:    <scheme>://<netloc>/<path>;<params>?<query>#<fragment>    Return a 6-tuple: (scheme, netloc, path, params, query, fragment).    Note that we don't break the components up in smaller bits    (e.g. netloc is a single string) and we don't expand % escapes."""    tuple = urlsplit(url, scheme, allow_fragments)    scheme, netloc, url, query, fragment = tuple    if scheme in uses_params and ';' in url:        url, params = _splitparams(url)    else:        params = ''    return ParseResult(scheme, netloc, url, params, query, fragment) def _splitparams(url):    if '/'  in url:        i = url.find(';', url.rfind('/'))        if i < 0:            return url, ''    else:        i = url.find(';')    return url[:i], url[i+1:] def _splitnetloc(url, start=0):    for c in '/?#': # the order is important!        delim = url.find(c, start)        if delim >= 0:            break    else:        delim = len(url)    return url[start:delim], url[delim:] def urlsplit(url, scheme='', allow_fragments=True):    """Parse a URL into 5 components:    <scheme>://<netloc>/<path>?<query>#<fragment>    Return a 5-tuple: (scheme, netloc, path, query, fragment).    Note that we don't break the components up in smaller bits    (e.g. netloc is a single string) and we don't expand % escapes."""    allow_fragments = bool(allow_fragments)    key = url, scheme, allow_fragments    cached = _parse_cache.get(key, None)    if cached:        return cached    if len(_parse_cache) >= MAX_CACHE_SIZE: # avoid runaway growth        clear_cache()    netloc = query = fragment = ''    i = url.find(':')    if i > 0:        if url[:i] == 'http': # optimize the common case            scheme = url[:i].lower()            url = url[i+1:]            if url[:2] == '//':                netloc, url = _splitnetloc(url, 2)            if allow_fragments and '#' in url:                url, fragment = url.split('#', 1)            if '?' in url:                url, query = url.split('?', 1)            v = SplitResult(scheme, netloc, url, query, fragment)            _parse_cache[key] = v            return v        for c in url[:i]:            if c not in scheme_chars:                break        else:            scheme, url = url[:i].lower(), url[i+1:]    if scheme in uses_netloc and url[:2] == '//':        netloc, url = _splitnetloc(url, 2)    if allow_fragments and scheme in uses_fragment and '#' in url:        url, fragment = url.split('#', 1)    if scheme in uses_query and '?' in url:        url, query = url.split('?', 1)    v = SplitResult(scheme, netloc, url, query, fragment)    _parse_cache[key] = v    return v def urlunparse((scheme, netloc, url, params, query, fragment)):    """Put a parsed URL back together again.  This may result in a    slightly different, but equivalent URL, if the URL that was parsed    originally had redundant delimiters, e.g. a ? with an empty query    (the draft states that these are equivalent)."""    if params:        url = "%s;%s" % (url, params)    return urlunsplit((scheme, netloc, url, query, fragment)) def urlunsplit((scheme, netloc, url, query, fragment)):    if netloc or (scheme and scheme in uses_netloc and url[:2] != '//'):        if url and url[:1] != '/': url = '/' + url        url = '//' + (netloc or '') + url    if scheme:        url = scheme + ':' + url    if query:        url = url + '?' + query    if fragment:        url = url + '#' + fragment    return url def urljoin(base, url, allow_fragments=True):    """Join a base URL and a possibly relative URL to form an absolute    interpretation of the latter."""    if not base:        return url    if not url:        return base    bscheme, bnetloc, bpath, bparams, bquery, bfragment = \            urlparse(base, '', allow_fragments)    scheme, netloc, path, params, query, fragment = \            urlparse(url, bscheme, allow_fragments)    if scheme != bscheme or scheme not in uses_relative:        return url    if scheme in uses_netloc:        if netloc:            return urlunparse((scheme, netloc, path,                               params, query, fragment))        netloc = bnetloc    if path[:1] == '/':        return urlunparse((scheme, netloc, path,                           params, query, fragment))    if not (path or params or query):        return urlunparse((scheme, netloc, bpath,                           bparams, bquery, fragment))    segments = bpath.split('/')[:-1] + path.split('/')    # XXX The stuff below is bogus in various ways...    if segments[-1] == '.':        segments[-1] = ''    while '.' in segments:        segments.remove('.')    while 1:        i = 1        n = len(segments) - 1        while i < n:            if (segments[i] == '..'                and segments[i-1] not in ('', '..')):                del segments[i-1:i+1]                break            i = i+1        else:            break    if segments == ['', '..']:        segments[-1] = ''    elif len(segments) >= 2 and segments[-1] == '..':        segments[-2:] = ['']    return urlunparse((scheme, netloc, '/'.join(segments),                       params, query, fragment)) def urldefrag(url):    """Removes any existing fragment from URL.     Returns a tuple of the defragmented URL and the fragment.  If    the URL contained no fragments, the second element is the    empty string.    """    if '#' in url:        s, n, p, a, q, frag = urlparse(url)        defrag = urlunparse((s, n, p, a, q, ''))        return defrag, frag    else:        return url, ''  test_input = """      http://a/b/c/d       g:h        = <URL:g:h>      http:g     = <URL:http://a/b/c/g>      http:      = <URL:http://a/b/c/d>      g          = <URL:http://a/b/c/g>      ./g        = <URL:http://a/b/c/g>      g/         = <URL:http://a/b/c/g/>      /g         = <URL:http://a/g>      //g        = <URL:http://g>      ?y         = <URL:http://a/b/c/d?y>      g?y        = <URL:http://a/b/c/g?y>      g?y/./x    = <URL:http://a/b/c/g?y/./x>      .          = <URL:http://a/b/c/>      ./         = <URL:http://a/b/c/>      ..         = <URL:http://a/b/>      ../        = <URL:http://a/b/>      ../g       = <URL:http://a/b/g>      ../..      = <URL:http://a/>      ../../g    = <URL:http://a/g>      ../../../g = <URL:http://a/../g>      ./../g     = <URL:http://a/b/g>      ./g/.      = <URL:http://a/b/c/g/>      /./g       = <URL:http://a/./g>      g/./h      = <URL:http://a/b/c/g/h>      g/../h     = <URL:http://a/b/c/h>      http:g     = <URL:http://a/b/c/g>      http:      = <URL:http://a/b/c/d>      http:?y         = <URL:http://a/b/c/d?y>      http:g?y        = <URL:http://a/b/c/g?y>      http:g?y/./x    = <URL:http://a/b/c/g?y/./x>""" def test():    import sys    base = ''    if sys.argv[1:]:        fn = sys.argv[1]        if fn == '-':            fp = sys.stdin        else:            fp = open(fn)    else:        try:            from cStringIO import StringIO        except ImportError:            from StringIO import StringIO        fp = StringIO(test_input)    while 1:        line = fp.readline()        if not line: break        words = line.split()        if not words:            continue        url = words[0]        parts = urlparse(url)        print '%-10s : %s' % (url, parts)        abs = urljoin(base, url)        if not base:            base = abs        wrapped = '<URL:%s>' % abs        print '%-10s = %s' % (url, wrapped)        if len(words) == 3 and words[1] == '=':            if wrapped != words[2]:                print 'EXPECTED', words[2], '!!!!!!!!!!' if __name__ == '__main__':    test()