Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 1 | # Open an arbitrary URL |
| 2 | # |
| 3 | # See the following document for a tentative description of URLs: |
| 4 | # Uniform Resource Locators Tim Berners-Lee |
| 5 | # INTERNET DRAFT CERN |
| 6 | # IETF URL Working Group 14 July 1993 |
| 7 | # draft-ietf-uri-url-01.txt |
| 8 | # |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 9 | # The object returned by URLopener().open(file) will differ per |
| 10 | # protocol. All you know is that is has methods read(), readline(), |
| 11 | # readlines(), fileno(), close() and info(). The read*(), fileno() |
| 12 | # and close() methods work like those of open files. |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 13 | # The info() method returns an rfc822.Message object which can be |
| 14 | # used to query various info about the object, if available. |
| 15 | # (rfc822.Message objects are queried with the getheader() method.) |
| 16 | |
| 17 | import socket |
| 18 | import regex |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 19 | |
| 20 | |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 21 | # This really consists of two pieces: |
| 22 | # (1) a class which handles opening of all sorts of URLs |
| 23 | # (plus assorted utilities etc.) |
| 24 | # (2) a set of functions for parsing URLs |
| 25 | # XXX Should these be separated out into different modules? |
| 26 | |
| 27 | |
| 28 | # Shortcut for basic usage |
| 29 | _urlopener = None |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 30 | def urlopen(url): |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 31 | global _urlopener |
| 32 | if not _urlopener: |
| 33 | _urlopener = URLopener() |
| 34 | return _urlopener.open(url) |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 35 | |
| 36 | |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 37 | # Class to open URLs. |
| 38 | # This is a class rather than just a subroutine because we may need |
| 39 | # more than one set of global protocol-specific options. |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 40 | ftpcache = {} |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 41 | class URLopener: |
| 42 | |
| 43 | # Constructor |
| 44 | def __init__(self): |
| 45 | self.addheaders = [] |
| 46 | self.ftpcache = ftpcache |
| 47 | # Undocumented feature: you can use a different |
| 48 | # ftp cache by assigning to the .ftpcache member; |
| 49 | # in case you want logically independent URL openers |
| 50 | |
| 51 | # Add a header to be used by the HTTP interface only |
| 52 | # e.g. u.addheader('Accept', 'sound/basic') |
| 53 | def addheader(self, *args): |
| 54 | self.addheaders.append(args) |
| 55 | |
| 56 | # External interface |
| 57 | # Use URLopener().open(file) instead of open(file, 'r') |
| 58 | def open(self, url): |
| 59 | import string |
| 60 | url = string.strip(url) |
| 61 | if url[:1] == '<' and url[-1:] == '>': |
| 62 | url = string.strip(url[1:-1]) |
| 63 | if url[:4] == 'URL:': url = string.strip(url[4:]) |
| 64 | type, url = splittype(url) |
| 65 | if not type: type = 'file' |
| 66 | name = 'open_' + type |
| 67 | if '-' in name: |
| 68 | import regsub |
| 69 | name = regsub.gsub('-', '_', name) |
| 70 | if not hasattr(self, name): |
| 71 | raise IOError, ('url error', 'unknown url type', type) |
| 72 | meth = getattr(self, name) |
| 73 | try: |
| 74 | return meth(url) |
| 75 | except socket.error, msg: |
| 76 | raise IOError, ('socket error', msg) |
| 77 | |
| 78 | # Each method named open_<type> knows how to open that type of URL |
| 79 | |
| 80 | # Use HTTP protocol |
| 81 | def open_http(self, url): |
| 82 | import httplib |
| 83 | host, selector = splithost(url) |
| 84 | h = httplib.HTTP(host) |
| 85 | h.putrequest('GET', selector) |
| 86 | for args in self.addheaders: apply(h.putheader, args) |
| 87 | errcode, errmsg, headers = h.getreply() |
| 88 | if errcode == 200: return addinfo(h.getfile(), headers) |
| 89 | else: raise IOError, ('http error', errcode, errmsg, headers) |
| 90 | |
| 91 | # Use Gopher protocol |
| 92 | def open_gopher(self, url): |
| 93 | import gopherlib |
| 94 | host, selector = splithost(url) |
| 95 | type, selector = splitgophertype(selector) |
| 96 | selector, query = splitquery(selector) |
| 97 | if query: fp = gopherlib.send_query(selector, query, host) |
| 98 | else: fp = gopherlib.send_selector(selector, host) |
| 99 | return addinfo(fp, noheaders()) |
| 100 | |
| 101 | # Use local file or FTP depending on form of URL |
| 102 | def open_file(self, url): |
| 103 | host, file = splithost(url) |
| 104 | if not host: return addinfo(open(file, 'r'), noheaders()) |
| 105 | host, port = splitport(host) |
| 106 | if not port and socket.gethostbyname(host) in ( |
| 107 | localhost(), thishost()): |
| 108 | try: fp = open(file, 'r') |
| 109 | except IOError: fp = None |
| 110 | if fp: return addinfo(fp, noheaders()) |
| 111 | return self.open_ftp(url) |
| 112 | |
| 113 | # Use FTP protocol |
| 114 | def open_ftp(self, url): |
| 115 | host, file = splithost(url) |
| 116 | host, port = splitport(host) |
| 117 | host = socket.gethostbyname(host) |
| 118 | if not port: |
| 119 | import ftplib |
| 120 | port = ftplib.FTP_PORT |
| 121 | key = (host, port) |
| 122 | try: |
| 123 | if not self.ftpcache.has_key(key): |
| 124 | self.ftpcache[key] = ftpwrapper(host, port) |
| 125 | return addinfo(self.ftpcache[key].retrfile(file), |
| 126 | noheaders()) |
| 127 | except ftperrors(), msg: |
| 128 | raise IOError, ('ftp error', msg) |
| 129 | |
| 130 | |
| 131 | # Utility functions |
| 132 | |
| 133 | # Return the IP address of the magic hostname 'localhost' |
| 134 | _localhost = None |
| 135 | def localhost(): |
| 136 | global _localhost |
| 137 | if not _localhost: |
| 138 | _localhost = socket.gethostbyname('localhost') |
| 139 | return _localhost |
| 140 | |
| 141 | # Return the IP address of the current host |
| 142 | _thishost = None |
| 143 | def thishost(): |
| 144 | global _thishost |
| 145 | if not _thishost: |
| 146 | _thishost = socket.gethostbyname(socket.gethostname()) |
| 147 | return _thishost |
| 148 | |
| 149 | # Return the set of errors raised by the FTP class |
| 150 | _ftperrors = None |
| 151 | def ftperrors(): |
| 152 | global _ftperrors |
| 153 | if not _ftperrors: |
| 154 | import ftplib |
| 155 | _ftperrors = (ftplib.error_reply, |
| 156 | ftplib.error_temp, |
| 157 | ftplib.error_perm, |
| 158 | ftplib.error_proto) |
| 159 | return _ftperrors |
| 160 | |
| 161 | # Return an empty rfc822.Message object |
| 162 | _noheaders = None |
| 163 | def noheaders(): |
| 164 | global _noheaders |
| 165 | if not _noheaders: |
| 166 | import rfc822 |
| 167 | _noheaders = rfc822.Message(open('/dev/null', 'r')) |
| 168 | _noheaders.fp.close() # Recycle file descriptor |
| 169 | return _noheaders |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 170 | |
| 171 | |
| 172 | # Utility classes |
| 173 | |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 174 | # Class used by open_ftp() for cache of open FTP connections |
| 175 | class ftpwrapper: |
| 176 | def __init__(self, host, port): |
| 177 | self.host = host |
| 178 | self.port = port |
| 179 | self.init() |
| 180 | def init(self): |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 181 | import ftplib |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 182 | self.ftp = ftplib.FTP() |
| 183 | self.ftp.connect(self.host, self.port) |
| 184 | self.ftp.login() |
| 185 | def retrfile(self, file): |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 186 | import ftplib |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 187 | try: |
| 188 | self.ftp.voidcmd('TYPE I') |
| 189 | except ftplib.all_errors: |
| 190 | self.init() |
| 191 | self.ftp.voidcmd('TYPE I') |
| 192 | conn = None |
| 193 | if file: |
| 194 | try: |
| 195 | cmd = 'RETR ' + file |
| 196 | conn = self.ftp.transfercmd(cmd) |
| 197 | except ftplib.error_perm, reason: |
| 198 | if reason[:3] != '550': |
| 199 | raise IOError, ('ftp error', reason) |
| 200 | if not conn: |
| 201 | # Try a directory listing |
| 202 | if file: cmd = 'NLST ' + file |
| 203 | else: cmd = 'NLST' |
| 204 | conn = self.ftp.transfercmd(cmd) |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 205 | return addclosehook(conn.makefile('r'), self.ftp.voidresp) |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 206 | |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 207 | # Base class for addinfo and addclosehook |
| 208 | class addbase: |
| 209 | def __init__(self, fp): |
| 210 | self.fp = fp |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 211 | self.read = self.fp.read |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 212 | self.readline = self.fp.readline |
| 213 | self.readlines = self.fp.readlines |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 214 | self.fileno = self.fp.fileno |
| 215 | def __del__(self): |
| 216 | self.close() |
| 217 | def close(self): |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 218 | self.fp = None |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 219 | |
| 220 | # Class to add a close hook to an open file |
| 221 | class addclosehook(addbase): |
| 222 | def __init__(self, fp, closehook, *hookargs): |
| 223 | addbase.__init__(self, fp) |
| 224 | self.closehook = closehook |
| 225 | self.hookargs = hookargs |
| 226 | def close(self): |
| 227 | if self.closehook: |
| 228 | apply(self.closehook, self.hookargs) |
| 229 | self.closehook = None |
| 230 | self.fp = None |
| 231 | |
| 232 | # class to add an info() method to an open file |
| 233 | class addinfo(addbase): |
| 234 | def __init__(self, fp, headers): |
| 235 | addbase.__init__(self, fp) |
| 236 | self.headers = headers |
| 237 | def info(self): |
| 238 | return self.headers |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 239 | |
| 240 | |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 241 | # Utilities to parse URLs: |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 242 | # splittype('type:opaquestring') --> 'type', 'opaquestring' |
| 243 | # splithost('//host[:port]/path') --> 'host[:port]', '/path' |
| 244 | # splitport('host:port') --> 'host', 'port' |
| 245 | # splitquery('/path?query') --> '/path', 'query' |
| 246 | # splittag('/path#tag') --> '/path', 'tag' |
| 247 | # splitgophertype('/Xselector') --> 'X', 'selector' |
| 248 | |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 249 | _typeprog = regex.compile('^\([^/:]+\):\(.*\)$') |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 250 | def splittype(url): |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 251 | if _typeprog.match(url) >= 0: return _typeprog.group(1, 2) |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 252 | return None, url |
| 253 | |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 254 | _hostprog = regex.compile('^//\([^/]+\)\(.*\)$') |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 255 | def splithost(url): |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 256 | if _hostprog.match(url) >= 0: return _hostprog.group(1, 2) |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 257 | return None, url |
| 258 | |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 259 | _portprog = regex.compile('^\(.*\):\([0-9]+\)$') |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 260 | def splitport(host): |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 261 | if _portprog.match(host) >= 0: return _portprog.group(1, 2) |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 262 | return host, None |
| 263 | |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 264 | _queryprog = regex.compile('^\(.*\)\?\([^?]*\)$') |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 265 | def splitquery(url): |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 266 | if _queryprog.match(url) >= 0: return _queryprog.group(1, 2) |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 267 | return url, None |
| 268 | |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 269 | _tagprog = regex.compile('^\(.*\)#\([^#]*\)$') |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 270 | def splittag(url): |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 271 | if _tagprog.match(url) >= 0: return _tagprog.group(1, 2) |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 272 | return url, None |
| 273 | |
| 274 | def splitgophertype(selector): |
| 275 | if selector[:1] == '/' and selector[1:2]: |
| 276 | return selector[1], selector[2:] |
| 277 | return None, selector |
| 278 | |
| 279 | |
| 280 | # Test program |
| 281 | def test(): |
| 282 | import sys |
Guido van Rossum | 749057b | 1994-02-22 19:03:38 +0000 | [diff] [blame^] | 283 | import regsub |
Guido van Rossum | 23acc95 | 1994-02-21 16:36:04 +0000 | [diff] [blame] | 284 | args = sys.argv[1:] |
| 285 | if not args: |
| 286 | args = [ |
| 287 | '/etc/passwd', |
| 288 | 'file:/etc/passwd', |
| 289 | 'file://localhost/etc/passwd', |
| 290 | 'ftp://ftp.cwi.nl/etc/passwd', |
| 291 | 'gopher://gopher.cwi.nl/11/', |
| 292 | 'http://www.cwi.nl/index.html', |
| 293 | ] |
| 294 | for arg in args: |
| 295 | print '-'*10, arg, '-'*10 |
| 296 | print regsub.gsub('\r', '', urlopen(arg).read()) |
| 297 | print '-'*40 |
| 298 | |
| 299 | # Run test program when run as a script |
| 300 | if __name__ == '__main__': |
| 301 | test() |