Guido van Rossum | ededb58 | 1996-03-29 21:23:25 +0000 | [diff] [blame] | 1 | # Parse (absolute and relative) URLs. See RFC 1808: "Relative Uniform |
| 2 | # Resource Locators", by R. Fielding, UC Irvine, June 1995. |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 3 | |
| 4 | # Standard/builtin Python modules |
| 5 | import string |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 6 | from string import joinfields, splitfields, find, rfind |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 7 | |
| 8 | # A classification of schemes ('' means apply by default) |
| 9 | uses_relative = ['ftp', 'http', 'gopher', 'nntp', 'wais', 'file', |
| 10 | 'prospero', ''] |
| 11 | uses_netloc = ['ftp', 'http', 'gopher', 'nntp', 'telnet', 'wais', |
Guido van Rossum | 1a16c86 | 1995-08-10 19:45:41 +0000 | [diff] [blame] | 12 | 'prospero', ''] |
Guido van Rossum | 5feb54c | 1996-05-28 23:10:02 +0000 | [diff] [blame] | 13 | non_hierarchical = ['gopher', 'hdl', 'mailto', 'news', 'telnet', 'wais'] |
| 14 | uses_params = ['ftp', 'hdl', 'prospero', 'http', ''] |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 15 | uses_query = ['http', 'wais', ''] |
Guido van Rossum | 5feb54c | 1996-05-28 23:10:02 +0000 | [diff] [blame] | 16 | uses_fragment = ['ftp', 'hdl', 'http', 'gopher', 'news', 'nntp', 'wais', |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 17 | 'file', 'prospero', ''] |
| 18 | |
| 19 | # Characters valid in scheme names |
| 20 | scheme_chars = string.letters + string.digits + '+-.' |
| 21 | |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 22 | _parse_cache = {} |
| 23 | |
| 24 | def clear_cache(): |
| 25 | global _parse_cache |
| 26 | _parse_cache = {} |
| 27 | |
| 28 | |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 29 | # Parse a URL into 6 components: |
| 30 | # <scheme>://<netloc>/<path>;<params>?<query>#<fragment> |
| 31 | # Return a 6-tuple: (scheme, netloc, path, params, query, fragment). |
| 32 | # Note that we don't break the components up in smaller bits |
| 33 | # (e.g. netloc is a single string) and we don't expand % escapes. |
| 34 | def urlparse(url, scheme = '', allow_framents = 1): |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 35 | key = url, scheme, allow_framents |
| 36 | if _parse_cache.has_key(key): |
| 37 | return _parse_cache[key] |
| 38 | netloc = path = params = query = fragment = '' |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 39 | i = string.find(url, ':') |
| 40 | if i > 0: |
| 41 | for c in url[:i]: |
| 42 | if c not in scheme_chars: |
| 43 | break |
| 44 | else: |
| 45 | scheme, url = string.lower(url[:i]), url[i+1:] |
| 46 | if scheme in uses_netloc: |
| 47 | if url[:2] == '//': |
| 48 | i = string.find(url, '/', 2) |
| 49 | if i < 0: |
| 50 | i = len(url) |
| 51 | netloc, url = url[2:i], url[i:] |
| 52 | if allow_framents and scheme in uses_fragment: |
| 53 | i = string.rfind(url, '#') |
| 54 | if i >= 0: |
| 55 | url, fragment = url[:i], url[i+1:] |
| 56 | if scheme in uses_query: |
| 57 | i = string.find(url, '?') |
| 58 | if i >= 0: |
| 59 | url, query = url[:i], url[i+1:] |
| 60 | if scheme in uses_params: |
| 61 | i = string.find(url, ';') |
| 62 | if i >= 0: |
| 63 | url, params = url[:i], url[i+1:] |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 64 | tuple = scheme, netloc, url, params, query, fragment |
| 65 | _parse_cache[key] = tuple |
| 66 | return tuple |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 67 | |
| 68 | # Put a parsed URL back together again. This may result in a slightly |
| 69 | # different, but equivalent URL, if the URL that was parsed originally |
| 70 | # had redundant delimiters, e.g. a ? with an empty query (the draft |
| 71 | # states that these are equivalent). |
| 72 | def urlunparse((scheme, netloc, url, params, query, fragment)): |
| 73 | if netloc: |
Guido van Rossum | fb1a0cd | 1995-08-04 04:29:32 +0000 | [diff] [blame] | 74 | if url[:1] != '/': url = '/' + url |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 75 | url = '//' + netloc + url |
| 76 | if scheme: |
| 77 | url = scheme + ':' + url |
| 78 | if params: |
| 79 | url = url + ';' + params |
| 80 | if query: |
| 81 | url = url + '?' + query |
| 82 | if fragment: |
| 83 | url = url + '#' + fragment |
| 84 | return url |
| 85 | |
| 86 | # Join a base URL and a possibly relative URL to form an absolute |
| 87 | # interpretation of the latter. |
| 88 | def urljoin(base, url, allow_framents = 1): |
| 89 | if not base: |
| 90 | return url |
| 91 | bscheme, bnetloc, bpath, bparams, bquery, bfragment = \ |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 92 | urlparse(base, '', allow_framents) |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 93 | scheme, netloc, path, params, query, fragment = \ |
| 94 | urlparse(url, bscheme, allow_framents) |
Guido van Rossum | a112470 | 1994-12-30 17:18:59 +0000 | [diff] [blame] | 95 | # XXX Unofficial hack: default netloc to bnetloc even if |
| 96 | # schemes differ |
| 97 | if scheme != bscheme and not netloc and \ |
| 98 | scheme in uses_relative and bscheme in uses_relative and \ |
| 99 | scheme in uses_netloc and bscheme in uses_netloc: |
| 100 | netloc = bnetloc |
| 101 | # Strip the port number |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 102 | i = find(netloc, '@') |
Guido van Rossum | a112470 | 1994-12-30 17:18:59 +0000 | [diff] [blame] | 103 | if i < 0: i = 0 |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 104 | i = find(netloc, ':', i) |
Guido van Rossum | a112470 | 1994-12-30 17:18:59 +0000 | [diff] [blame] | 105 | if i >= 0: |
| 106 | netloc = netloc[:i] |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 107 | if scheme != bscheme or scheme not in uses_relative: |
| 108 | return urlunparse((scheme, netloc, path, |
| 109 | params, query, fragment)) |
| 110 | if scheme in uses_netloc: |
| 111 | if netloc: |
| 112 | return urlunparse((scheme, netloc, path, |
| 113 | params, query, fragment)) |
| 114 | netloc = bnetloc |
| 115 | if path[:1] == '/': |
| 116 | return urlunparse((scheme, netloc, path, |
| 117 | params, query, fragment)) |
| 118 | if not path: |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 119 | return urlunparse((scheme, netloc, bpath, |
| 120 | params, query or bquery, fragment)) |
| 121 | i = rfind(bpath, '/') |
Guido van Rossum | fb1a0cd | 1995-08-04 04:29:32 +0000 | [diff] [blame] | 122 | if i >= 0: |
| 123 | path = bpath[:i] + '/' + path |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 124 | segments = splitfields(path, '/') |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 125 | if segments[-1] == '.': |
| 126 | segments[-1] = '' |
| 127 | while '.' in segments: |
| 128 | segments.remove('.') |
| 129 | while 1: |
| 130 | i = 1 |
| 131 | n = len(segments) - 1 |
| 132 | while i < n: |
| 133 | if segments[i] == '..' and segments[i-1]: |
| 134 | del segments[i-1:i+1] |
| 135 | break |
| 136 | i = i+1 |
| 137 | else: |
| 138 | break |
| 139 | if len(segments) >= 2 and segments[-1] == '..': |
| 140 | segments[-2:] = [''] |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 141 | return urlunparse((scheme, netloc, joinfields(segments, '/'), |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 142 | params, query, fragment)) |
| 143 | |
Guido van Rossum | 3fd32ec | 1996-05-28 23:54:24 +0000 | [diff] [blame] | 144 | def urldefrag(url): |
| 145 | """Removes any existing fragment from URL. |
| 146 | |
| 147 | Returns a tuple of the defragmented URL and the fragment. If |
| 148 | the URL contained no fragments, the second element is the |
| 149 | empty string. |
| 150 | """ |
| 151 | s, n, p, a, q, frag = urlparse(url) |
| 152 | defrag = urlunparse((s, n, p, a, q, '')) |
| 153 | return defrag, frag |
| 154 | |
| 155 | |
Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 156 | test_input = """ |
| 157 | http://a/b/c/d |
| 158 | |
| 159 | g:h = <URL:g:h> |
| 160 | http:g = <URL:http://a/b/c/g> |
| 161 | http: = <URL:http://a/b/c/d> |
| 162 | g = <URL:http://a/b/c/g> |
| 163 | ./g = <URL:http://a/b/c/g> |
| 164 | g/ = <URL:http://a/b/c/g/> |
| 165 | /g = <URL:http://a/g> |
| 166 | //g = <URL:http://g> |
| 167 | ?y = <URL:http://a/b/c/d?y> |
| 168 | g?y = <URL:http://a/b/c/g?y> |
| 169 | g?y/./x = <URL:http://a/b/c/g?y/./x> |
| 170 | . = <URL:http://a/b/c/> |
| 171 | ./ = <URL:http://a/b/c/> |
| 172 | .. = <URL:http://a/b/> |
| 173 | ../ = <URL:http://a/b/> |
| 174 | ../g = <URL:http://a/b/g> |
| 175 | ../.. = <URL:http://a/> |
| 176 | ../../g = <URL:http://a/g> |
| 177 | ../../../g = <URL:http://a/../g> |
| 178 | ./../g = <URL:http://a/b/g> |
| 179 | ./g/. = <URL:http://a/b/c/g/> |
| 180 | /./g = <URL:http://a/./g> |
| 181 | g/./h = <URL:http://a/b/c/g/h> |
| 182 | g/../h = <URL:http://a/b/c/h> |
| 183 | http:g = <URL:http://a/b/c/g> |
| 184 | http: = <URL:http://a/b/c/d> |
| 185 | """ |
| 186 | |
| 187 | def test(): |
| 188 | import sys |
| 189 | base = '' |
| 190 | if sys.argv[1:]: |
| 191 | fn = sys.argv[1] |
| 192 | if fn == '-': |
| 193 | fp = sys.stdin |
| 194 | else: |
| 195 | fp = open(fn) |
| 196 | else: |
| 197 | import StringIO |
| 198 | fp = StringIO.StringIO(test_input) |
| 199 | while 1: |
| 200 | line = fp.readline() |
| 201 | if not line: break |
| 202 | words = string.split(line) |
| 203 | if not words: |
| 204 | continue |
| 205 | url = words[0] |
| 206 | parts = urlparse(url) |
| 207 | print '%-10s : %s' % (url, parts) |
| 208 | abs = urljoin(base, url) |
| 209 | if not base: |
| 210 | base = abs |
| 211 | wrapped = '<URL:%s>' % abs |
| 212 | print '%-10s = %s' % (url, wrapped) |
| 213 | if len(words) == 3 and words[1] == '=': |
| 214 | if wrapped != words[2]: |
| 215 | print 'EXPECTED', words[2], '!!!!!!!!!!' |
| 216 | |
| 217 | if __name__ == '__main__': |
| 218 | test() |