| """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', ''] |
| uses_netloc = ['ftp', 'http', 'gopher', 'nntp', 'telnet', |
| 'imap', 'wais', 'file', 'mms', 'https', 'shttp', |
| 'snews', 'prospero', 'rtsp', 'rtspu', 'rsync', ''] |
| non_hierarchical = ['gopher', 'hdl', 'mailto', 'news', |
| 'telnet', 'wais', 'imap', 'snews', 'sip'] |
| uses_params = ['ftp', 'hdl', 'prospero', 'http', 'imap', |
| 'https', 'shttp', 'rtsp', 'rtspu', 'sip', |
| 'mms', ''] |
| uses_query = ['http', 'wais', 'imap', 'https', 'shttp', 'mms', |
| 'gopher', 'rtsp', 'rtspu', 'sip', ''] |
| uses_fragment = ['ftp', 'hdl', 'http', 'gopher', 'news', |
| 'nntp', 'wais', 'https', 'shttp', 'snews', |
| 'file', 'prospero', ''] |
| |
| # Characters valid in scheme names |
| scheme_chars = ('abcdefghijklmnopqrstuvwxyz' |
| 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' |
| '0123456789' |
| '+-.') |
| |
| MAX_CACHE_SIZE = 20 |
| _parse_cache = {} |
| |
| def clear_cache(): |
| """Clear the parse cache.""" |
| global _parse_cache |
| _parse_cache = {} |
| |
| |
| def urlparse(url, scheme='', allow_fragments=1): |
| """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 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 urlsplit(url, scheme='', allow_fragments=1): |
| """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.""" |
| 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] == '//': |
| i = url.find('/', 2) |
| if i < 0: |
| i = url.find('#') |
| if i < 0: |
| i = len(url) |
| netloc = url[2:i] |
| url = url[i:] |
| if allow_fragments and '#' in url: |
| url, fragment = url.split('#', 1) |
| if '?' in url: |
| url, query = url.split('?', 1) |
| tuple = scheme, netloc, url, query, fragment |
| _parse_cache[key] = tuple |
| return tuple |
| 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: |
| if url[:2] == '//': |
| i = url.find('/', 2) |
| if i < 0: |
| i = len(url) |
| netloc, url = url[2:i], url[i:] |
| 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) |
| tuple = scheme, netloc, url, query, fragment |
| _parse_cache[key] = tuple |
| return tuple |
| |
| 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 = 1): |
| """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: |
| import StringIO |
| fp = StringIO.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() |