source file: /System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/urllib2.py
file stats: 730 lines, 155 executed: 21.2% covered
   1. """An extensible library for opening URLs using a variety of protocols
   2. 
   3. The simplest way to use this module is to call the urlopen function,
   4. which accepts a string containing a URL or a Request object (described
   5. below).  It opens the URL and returns the results as file-like
   6. object; the returned object has some extra methods described below.
   7. 
   8. The OpenerDirector manages a collection of Handler objects that do
   9. all the actual work.  Each Handler implements a particular protocol or
  10. option.  The OpenerDirector is a composite object that invokes the
  11. Handlers needed to open the requested URL.  For example, the
  12. HTTPHandler performs HTTP GET and POST requests and deals with
  13. non-error returns.  The HTTPRedirectHandler automatically deals with
  14. HTTP 301, 302, 303 and 307 redirect errors, and the HTTPDigestAuthHandler
  15. deals with digest authentication.
  16. 
  17. urlopen(url, data=None) -- basic usage is that same as original
  18. urllib.  pass the url and optionally data to post to an HTTP URL, and
  19. get a file-like object back.  One difference is that you can also pass
  20. a Request instance instead of URL.  Raises a URLError (subclass of
  21. IOError); for HTTP errors, raises an HTTPError, which can also be
  22. treated as a valid response.
  23. 
  24. build_opener -- function that creates a new OpenerDirector instance.
  25. will install the default handlers.  accepts one or more Handlers as
  26. arguments, either instances or Handler classes that it will
  27. instantiate.  if one of the argument is a subclass of the default
  28. handler, the argument will be installed instead of the default.
  29. 
  30. install_opener -- installs a new opener as the default opener.
  31. 
  32. objects of interest:
  33. OpenerDirector --
  34. 
  35. Request -- an object that encapsulates the state of a request.  the
  36. state can be a simple as the URL.  it can also include extra HTTP
  37. headers, e.g. a User-Agent.
  38. 
  39. BaseHandler --
  40. 
  41. exceptions:
  42. URLError-- a subclass of IOError, individual protocols have their own
  43. specific subclass
  44. 
  45. HTTPError-- also a valid HTTP response, so you can treat an HTTP error
  46. as an exceptional event or valid response
  47. 
  48. internals:
  49. BaseHandler and parent
  50. _call_chain conventions
  51. 
  52. Example usage:
  53. 
  54. import urllib2
  55. 
  56. # set up authentication info
  57. authinfo = urllib2.HTTPBasicAuthHandler()
  58. authinfo.add_password('realm', 'host', 'username', 'password')
  59. 
  60. proxy_support = urllib2.ProxyHandler({"http" : "http://ahad-haam:3128"})
  61. 
  62. # build a new opener that adds authentication and caching FTP handlers
  63. opener = urllib2.build_opener(proxy_support, authinfo, urllib2.CacheFTPHandler)
  64. 
  65. # install it
  66. urllib2.install_opener(opener)
  67. 
  68. f = urllib2.urlopen('http://www.python.org/')
  69. 
  70. 
  71. """
  72. 
  73. # XXX issues:
  74. # If an authentication error handler that tries to perform
  75. # authentication for some reason but fails, how should the error be
  76. # signalled?  The client needs to know the HTTP error code.  But if
  77. # the handler knows that the problem was, e.g., that it didn't know
  78. # that hash algo that requested in the challenge, it would be good to
  79. # pass that information along to the client, too.
  80. 
  81. # XXX to do:
  82. # name!
  83. # documentation (getting there)
  84. # complex proxies
  85. # abstract factory for opener
  86. # ftp errors aren't handled cleanly
  87. # gopher can return a socket.error
  88. # check digest against correct (i.e. non-apache) implementation
  89. 
  90. import base64
  91. import ftplib
  92. import gopherlib
  93. import httplib
  94. import inspect
  95. import md5
  96. import mimetypes
  97. import mimetools
  98. import os
  99. import posixpath
 100. import random
 101. import re
 102. import rfc822
 103. import sha
 104. import socket
 105. import sys
 106. import time
 107. import urlparse
 108. 
 109. try:
 110.     from cStringIO import StringIO
 111. except ImportError:
 112.     from StringIO import StringIO
 113. 
 114. # not sure how many of these need to be gotten rid of
 115. from urllib import unwrap, unquote, splittype, splithost, \
 116.      addinfourl, splitport, splitgophertype, splitquery, \
 117.      splitattr, ftpwrapper, noheaders, splituser, splitpasswd
 118. 
 119. # support for FileHandler, proxies via environment variables
 120. from urllib import localhost, url2pathname, getproxies
 121. 
 122. __version__ = "2.1"
 123. 
 124. _opener = None
 125. def urlopen(url, data=None):
 126.     global _opener
 127.     if _opener is None:
 128.         _opener = build_opener()
 129.     return _opener.open(url, data)
 130. 
 131. def install_opener(opener):
 132.     global _opener
 133.     _opener = opener
 134. 
 135. # do these error classes make sense?
 136. # make sure all of the IOError stuff is overridden.  we just want to be
 137. # subtypes.
 138. 
 139. class URLError(IOError):
 140.     # URLError is a sub-type of IOError, but it doesn't share any of
 141.     # the implementation.  need to override __init__ and __str__
 142.     def __init__(self, reason):
 143.         self.reason = reason
 144. 
 145.     def __str__(self):
 146.         return '<urlopen error %s>' % self.reason
 147. 
 148. class HTTPError(URLError, addinfourl):
 149.     """Raised when HTTP error occurs, but also acts like non-error return"""
 150.     __super_init = addinfourl.__init__
 151. 
 152.     def __init__(self, url, code, msg, hdrs, fp):
 153.         self.code = code
 154.         self.msg = msg
 155.         self.hdrs = hdrs
 156.         self.fp = fp
 157.         self.filename = url
 158.         # The addinfourl classes depend on fp being a valid file
 159.         # object.  In some cases, the HTTPError may not have a valid
 160.         # file object.  If this happens, the simplest workaround is to
 161.         # not initialize the base classes.
 162.         if fp is not None:
 163.             self.__super_init(fp, hdrs, url)
 164. 
 165.     def __str__(self):
 166.         return 'HTTP Error %s: %s' % (self.code, self.msg)
 167. 
 168.     def __del__(self):
 169.         # XXX is this safe? what if user catches exception, then
 170.         # extracts fp and discards exception?
 171.         if self.fp:
 172.             self.fp.close()
 173. 
 174. class GopherError(URLError):
 175.     pass
 176. 
 177. 
 178. class Request:
 179. 
 180.     def __init__(self, url, data=None, headers={}):
 181.         # unwrap('<URL:type://host/path>') --> 'type://host/path'
 182.         self.__original = unwrap(url)
 183.         self.type = None
 184.         # self.__r_type is what's left after doing the splittype
 185.         self.host = None
 186.         self.port = None
 187.         self.data = data
 188.         self.headers = {}
 189.         for key, value in headers.items():
 190.             self.add_header(key, value)
 191. 
 192.     def __getattr__(self, attr):
 193.         # XXX this is a fallback mechanism to guard against these
 194.         # methods getting called in a non-standard order.  this may be
 195.         # too complicated and/or unnecessary.
 196.         # XXX should the __r_XXX attributes be public?
 197.         if attr[:12] == '_Request__r_':
 198.             name = attr[12:]
 199.             if hasattr(Request, 'get_' + name):
 200.                 getattr(self, 'get_' + name)()
 201.                 return getattr(self, attr)
 202.         raise AttributeError, attr
 203. 
 204.     def get_method(self):
 205.         if self.has_data():
 206.             return "POST"
 207.         else:
 208.             return "GET"
 209. 
 210.     def add_data(self, data):
 211.         self.data = data
 212. 
 213.     def has_data(self):
 214.         return self.data is not None
 215. 
 216.     def get_data(self):
 217.         return self.data
 218. 
 219.     def get_full_url(self):
 220.         return self.__original
 221. 
 222.     def get_type(self):
 223.         if self.type is None:
 224.             self.type, self.__r_type = splittype(self.__original)
 225.             if self.type is None:
 226.                 raise ValueError, "unknown url type: %s" % self.__original
 227.         return self.type
 228. 
 229.     def get_host(self):
 230.         if self.host is None:
 231.             self.host, self.__r_host = splithost(self.__r_type)
 232.             if self.host:
 233.                 self.host = unquote(self.host)
 234.         return self.host
 235. 
 236.     def get_selector(self):
 237.         return self.__r_host
 238. 
 239.     def set_proxy(self, host, type):
 240.         self.host, self.type = host, type
 241.         self.__r_host = self.__original
 242. 
 243.     def add_header(self, key, val):
 244.         # useful for something like authentication
 245.         self.headers[key.capitalize()] = val
 246. 
 247. class OpenerDirector:
 248.     def __init__(self):
 249.         server_version = "Python-urllib/%s" % __version__
 250.         self.addheaders = [('User-agent', server_version)]
 251.         # manage the individual handlers
 252.         self.handlers = []
 253.         self.handle_open = {}
 254.         self.handle_error = {}
 255. 
 256.     def add_handler(self, handler):
 257.         added = 0
 258.         for meth in dir(handler):
 259.             if meth[-5:] == '_open':
 260.                 protocol = meth[:-5]
 261.                 if protocol in self.handle_open:
 262.                     self.handle_open[protocol].append(handler)
 263.                     self.handle_open[protocol].sort()
 264.                 else:
 265.                     self.handle_open[protocol] = [handler]
 266.                 added = 1
 267.                 continue
 268.             i = meth.find('_')
 269.             j = meth[i+1:].find('_') + i + 1
 270.             if j != -1 and meth[i+1:j] == 'error':
 271.                 proto = meth[:i]
 272.                 kind = meth[j+1:]
 273.                 try:
 274.                     kind = int(kind)
 275.                 except ValueError:
 276.                     pass
 277.                 dict = self.handle_error.get(proto, {})
 278.                 if kind in dict:
 279.                     dict[kind].append(handler)
 280.                     dict[kind].sort()
 281.                 else:
 282.                     dict[kind] = [handler]
 283.                 self.handle_error[proto] = dict
 284.                 added = 1
 285.                 continue
 286.         if added:
 287.             self.handlers.append(handler)
 288.             self.handlers.sort()
 289.             handler.add_parent(self)
 290. 
 291.     def __del__(self):
 292.         self.close()
 293. 
 294.     def close(self):
 295.         for handler in self.handlers:
 296.             handler.close()
 297.         self.handlers = []
 298. 
 299.     def _call_chain(self, chain, kind, meth_name, *args):
 300.         # XXX raise an exception if no one else should try to handle
 301.         # this url.  return None if you can't but someone else could.
 302.         handlers = chain.get(kind, ())
 303.         for handler in handlers:
 304.             func = getattr(handler, meth_name)
 305. 
 306.             result = func(*args)
 307.             if result is not None:
 308.                 return result
 309. 
 310.     def open(self, fullurl, data=None):
 311.         # accept a URL or a Request object
 312.         if isinstance(fullurl, basestring):
 313.             req = Request(fullurl, data)
 314.         else:
 315.             req = fullurl
 316.             if data is not None:
 317.                 req.add_data(data)
 318. 
 319.         result = self._call_chain(self.handle_open, 'default',
 320.                                   'default_open', req)
 321.         if result:
 322.             return result
 323. 
 324.         type_ = req.get_type()
 325.         result = self._call_chain(self.handle_open, type_, type_ + \
 326.                                   '_open', req)
 327.         if result:
 328.             return result
 329. 
 330.         return self._call_chain(self.handle_open, 'unknown',
 331.                                 'unknown_open', req)
 332. 
 333.     def error(self, proto, *args):
 334.         if proto in ['http', 'https']:
 335.             # XXX http[s] protocols are special-cased
 336.             dict = self.handle_error['http'] # https is not different than http
 337.             proto = args[2]  # YUCK!
 338.             meth_name = 'http_error_%d' % proto
 339.             http_err = 1
 340.             orig_args = args
 341.         else:
 342.             dict = self.handle_error
 343.             meth_name = proto + '_error'
 344.             http_err = 0
 345.         args = (dict, proto, meth_name) + args
 346.         result = self._call_chain(*args)
 347.         if result:
 348.             return result
 349. 
 350.         if http_err:
 351.             args = (dict, 'default', 'http_error_default') + orig_args
 352.             return self._call_chain(*args)
 353. 
 354. # XXX probably also want an abstract factory that knows when it makes
 355. # sense to skip a superclass in favor of a subclass and when it might
 356. # make sense to include both
 357. 
 358. def build_opener(*handlers):
 359.     """Create an opener object from a list of handlers.
 360. 
 361.     The opener will use several default handlers, including support
 362.     for HTTP and FTP.
 363. 
 364.     If any of the handlers passed as arguments are subclasses of the
 365.     default handlers, the default handlers will not be used.
 366.     """
 367. 
 368.     opener = OpenerDirector()
 369.     default_classes = [ProxyHandler, UnknownHandler, HTTPHandler,
 370.                        HTTPDefaultErrorHandler, HTTPRedirectHandler,
 371.                        FTPHandler, FileHandler]
 372.     if hasattr(httplib, 'HTTPS'):
 373.         default_classes.append(HTTPSHandler)
 374.     skip = []
 375.     for klass in default_classes:
 376.         for check in handlers:
 377.             if inspect.isclass(check):
 378.                 if issubclass(check, klass):
 379.                     skip.append(klass)
 380.             elif isinstance(check, klass):
 381.                 skip.append(klass)
 382.     for klass in skip:
 383.         default_classes.remove(klass)
 384. 
 385.     for klass in default_classes:
 386.         opener.add_handler(klass())
 387. 
 388.     for h in handlers:
 389.         if inspect.isclass(h):
 390.             h = h()
 391.         opener.add_handler(h)
 392.     return opener
 393. 
 394. class BaseHandler:
 395.     handler_order = 500
 396. 
 397.     def add_parent(self, parent):
 398.         self.parent = parent
 399.     def close(self):
 400.         self.parent = None
 401.     def __lt__(self, other):
 402.         if not hasattr(other, "handler_order"):
 403.             # Try to preserve the old behavior of having custom classes
 404.             # inserted after default ones (works only for custom user
 405.             # classes which are not aware of handler_order).
 406.             return True
 407.         return self.handler_order < other.handler_order
 408. 
 409. 
 410. class HTTPDefaultErrorHandler(BaseHandler):
 411.     def http_error_default(self, req, fp, code, msg, hdrs):
 412.         raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
 413. 
 414. class HTTPRedirectHandler(BaseHandler):
 415.     def redirect_request(self, req, fp, code, msg, headers, newurl):
 416.         """Return a Request or None in response to a redirect.
 417. 
 418.         This is called by the http_error_30x methods when a
 419.         redirection response is received.  If a redirection should
 420.         take place, return a new Request to allow http_error_30x to
 421.         perform the redirect.  Otherwise, raise HTTPError if no-one
 422.         else should try to handle this url.  Return None if you can't
 423.         but another Handler might.
 424.         """
 425.         m = req.get_method()
 426.         if (code in (301, 302, 303, 307) and m in ("GET", "HEAD")
 427.             or code in (301, 302, 303) and m == "POST"):
 428.             # Strictly (according to RFC 2616), 301 or 302 in response
 429.             # to a POST MUST NOT cause a redirection without confirmation
 430.             # from the user (of urllib2, in this case).  In practice,
 431.             # essentially all clients do redirect in this case, so we
 432.             # do the same.
 433.             return Request(newurl, headers=req.headers)
 434.         else:
 435.             raise HTTPError(req.get_full_url(), code, msg, headers, fp)
 436. 
 437.     # Implementation note: To avoid the server sending us into an
 438.     # infinite loop, the request object needs to track what URLs we
 439.     # have already seen.  Do this by adding a handler-specific
 440.     # attribute to the Request object.
 441.     def http_error_302(self, req, fp, code, msg, headers):
 442.         if 'location' in headers:
 443.             newurl = headers['location']
 444.         elif 'uri' in headers:
 445.             newurl = headers['uri']
 446.         else:
 447.             return
 448.         newurl = urlparse.urljoin(req.get_full_url(), newurl)
 449. 
 450.         # XXX Probably want to forget about the state of the current
 451.         # request, although that might interact poorly with other
 452.         # handlers that also use handler-specific request attributes
 453.         new = self.redirect_request(req, fp, code, msg, headers, newurl)
 454.         if new is None:
 455.             return
 456. 
 457.         # loop detection
 458.         new.error_302_dict = {}
 459.         if hasattr(req, 'error_302_dict'):
 460.             if len(req.error_302_dict)>10 or \
 461.                newurl in req.error_302_dict:
 462.                 raise HTTPError(req.get_full_url(), code,
 463.                                 self.inf_msg + msg, headers, fp)
 464.             new.error_302_dict.update(req.error_302_dict)
 465.         new.error_302_dict[newurl] = newurl
 466. 
 467.         # Don't close the fp until we are sure that we won't use it
 468.         # with HTTPError.
 469.         fp.read()
 470.         fp.close()
 471. 
 472.         return self.parent.open(new)
 473. 
 474.     http_error_301 = http_error_303 = http_error_307 = http_error_302
 475. 
 476.     inf_msg = "The HTTP server returned a redirect error that would " \
 477.               "lead to an infinite loop.\n" \
 478.               "The last 30x error message was:\n"
 479. 
 480. class ProxyHandler(BaseHandler):
 481.     # Proxies must be in front
 482.     handler_order = 100
 483. 
 484.     def __init__(self, proxies=None):
 485.         if proxies is None:
 486.             proxies = getproxies()
 487.         assert hasattr(proxies, 'has_key'), "proxies must be a mapping"
 488.         self.proxies = proxies
 489.         for type, url in proxies.items():
 490.             setattr(self, '%s_open' % type,
 491.                     lambda r, proxy=url, type=type, meth=self.proxy_open: \
 492.                     meth(r, proxy, type))
 493. 
 494.     def proxy_open(self, req, proxy, type):
 495.         orig_type = req.get_type()
 496.         type, r_type = splittype(proxy)
 497.         host, XXX = splithost(r_type)
 498.         if '@' in host:
 499.             user_pass, host = host.split('@', 1)
 500.             if ':' in user_pass:
 501.                 user, password = user_pass.split(':', 1)
 502.                 user_pass = base64.encodestring('%s:%s' % (unquote(user),
 503.                                                            unquote(password)))
 504.                 req.add_header('Proxy-authorization', 'Basic ' + user_pass)
 505.         host = unquote(host)
 506.         req.set_proxy(host, type)
 507.         if orig_type == type:
 508.             # let other handlers take care of it
 509.             # XXX this only makes sense if the proxy is before the
 510.             # other handlers
 511.             return None
 512.         else:
 513.             # need to start over, because the other handlers don't
 514.             # grok the proxy's URL type
 515.             return self.parent.open(req)
 516. 
 517. # feature suggested by Duncan Booth
 518. # XXX custom is not a good name
 519. class CustomProxy:
 520.     # either pass a function to the constructor or override handle
 521.     def __init__(self, proto, func=None, proxy_addr=None):
 522.         self.proto = proto
 523.         self.func = func
 524.         self.addr = proxy_addr
 525. 
 526.     def handle(self, req):
 527.         if self.func and self.func(req):
 528.             return 1
 529. 
 530.     def get_proxy(self):
 531.         return self.addr
 532. 
 533. class CustomProxyHandler(BaseHandler):
 534.     # Proxies must be in front
 535.     handler_order = 100
 536. 
 537.     def __init__(self, *proxies):
 538.         self.proxies = {}
 539. 
 540.     def proxy_open(self, req):
 541.         proto = req.get_type()
 542.         try:
 543.             proxies = self.proxies[proto]
 544.         except KeyError:
 545.             return None
 546.         for p in proxies:
 547.             if p.handle(req):
 548.                 req.set_proxy(p.get_proxy())
 549.                 return self.parent.open(req)
 550.         return None
 551. 
 552.     def do_proxy(self, p, req):
 553.         return self.parent.open(req)
 554. 
 555.     def add_proxy(self, cpo):
 556.         if cpo.proto in self.proxies:
 557.             self.proxies[cpo.proto].append(cpo)
 558.         else:
 559.             self.proxies[cpo.proto] = [cpo]
 560. 
 561. class HTTPPasswordMgr:
 562.     def __init__(self):
 563.         self.passwd = {}
 564. 
 565.     def add_password(self, realm, uri, user, passwd):
 566.         # uri could be a single URI or a sequence
 567.         if isinstance(uri, basestring):
 568.             uri = [uri]
 569.         uri = tuple(map(self.reduce_uri, uri))
 570.         if not realm in self.passwd:
 571.             self.passwd[realm] = {}
 572.         self.passwd[realm][uri] = (user, passwd)
 573. 
 574.     def find_user_password(self, realm, authuri):
 575.         domains = self.passwd.get(realm, {})
 576.         authuri = self.reduce_uri(authuri)
 577.         for uris, authinfo in domains.iteritems():
 578.             for uri in uris:
 579.                 if self.is_suburi(uri, authuri):
 580.                     return authinfo
 581.         return None, None
 582. 
 583.     def reduce_uri(self, uri):
 584.         """Accept netloc or URI and extract only the netloc and path"""
 585.         parts = urlparse.urlparse(uri)
 586.         if parts[1]:
 587.             return parts[1], parts[2] or '/'
 588.         else:
 589.             return parts[2], '/'
 590. 
 591.     def is_suburi(self, base, test):
 592.         """Check if test is below base in a URI tree
 593. 
 594.         Both args must be URIs in reduced form.
 595.         """
 596.         if base == test:
 597.             return True
 598.         if base[0] != test[0]:
 599.             return False
 600.         common = posixpath.commonprefix((base[1], test[1]))
 601.         if len(common) == len(base[1]):
 602.             return True
 603.         return False
 604. 
 605. 
 606. class HTTPPasswordMgrWithDefaultRealm(HTTPPasswordMgr):
 607. 
 608.     def find_user_password(self, realm, authuri):
 609.         user, password = HTTPPasswordMgr.find_user_password(self, realm,
 610.                                                             authuri)
 611.         if user is not None:
 612.             return user, password
 613.         return HTTPPasswordMgr.find_user_password(self, None, authuri)
 614. 
 615. 
 616. class AbstractBasicAuthHandler:
 617. 
 618.     rx = re.compile('[ \t]*([^ \t]+)[ \t]+realm="([^"]*)"', re.I)
 619. 
 620.     # XXX there can actually be multiple auth-schemes in a
 621.     # www-authenticate header.  should probably be a lot more careful
 622.     # in parsing them to extract multiple alternatives
 623. 
 624.     def __init__(self, password_mgr=None):
 625.         if password_mgr is None:
 626.             password_mgr = HTTPPasswordMgr()
 627.         self.passwd = password_mgr
 628.         self.add_password = self.passwd.add_password
 629. 
 630.     def http_error_auth_reqed(self, authreq, host, req, headers):
 631.         # XXX could be multiple headers
 632.         authreq = headers.get(authreq, None)
 633.         if authreq:
 634.             mo = AbstractBasicAuthHandler.rx.search(authreq)
 635.             if mo:
 636.                 scheme, realm = mo.groups()
 637.                 if scheme.lower() == 'basic':
 638.                     return self.retry_http_basic_auth(host, req, realm)
 639. 
 640.     def retry_http_basic_auth(self, host, req, realm):
 641.         user,pw = self.passwd.find_user_password(realm, host)
 642.         if pw is not None:
 643.             raw = "%s:%s" % (user, pw)
 644.             auth = 'Basic %s' % base64.encodestring(raw).strip()
 645.             if req.headers.get(self.auth_header, None) == auth:
 646.                 return None
 647.             req.add_header(self.auth_header, auth)
 648.             return self.parent.open(req)
 649.         else:
 650.             return None
 651. 
 652. class HTTPBasicAuthHandler(AbstractBasicAuthHandler, BaseHandler):
 653. 
 654.     auth_header = 'Authorization'
 655. 
 656.     def http_error_401(self, req, fp, code, msg, headers):
 657.         host = urlparse.urlparse(req.get_full_url())[1]
 658.         return self.http_error_auth_reqed('www-authenticate',
 659.                                           host, req, headers)
 660. 
 661. 
 662. class ProxyBasicAuthHandler(AbstractBasicAuthHandler, BaseHandler):
 663. 
 664.     auth_header = 'Proxy-authorization'
 665. 
 666.     def http_error_407(self, req, fp, code, msg, headers):
 667.         host = req.get_host()
 668.         return self.http_error_auth_reqed('proxy-authenticate',
 669.                                           host, req, headers)
 670. 
 671. 
 672. def randombytes(n):
 673.     """Return n random bytes."""
 674.     # Use /dev/urandom if it is available.  Fall back to random module
 675.     # if not.  It might be worthwhile to extend this function to use
 676.     # other platform-specific mechanisms for getting random bytes.
 677.     if os.path.exists("/dev/urandom"):
 678.         f = open("/dev/urandom")
 679.         s = f.read(n)
 680.         f.close()
 681.         return s
 682.     else:
 683.         L = [chr(random.randrange(0, 256)) for i in range(n)]
 684.         return "".join(L)
 685. 
 686. class AbstractDigestAuthHandler:
 687.     # Digest authentication is specified in RFC 2617.
 688. 
 689.     # XXX The client does not inspect the Authentication-Info header
 690.     # in a successful response.
 691. 
 692.     # XXX It should be possible to test this implementation against
 693.     # a mock server that just generates a static set of challenges.
 694. 
 695.     # XXX qop="auth-int" supports is shaky
 696. 
 697.     def __init__(self, passwd=None):
 698.         if passwd is None:
 699.             passwd = HTTPPasswordMgr()
 700.         self.passwd = passwd
 701.         self.add_password = self.passwd.add_password
 702.         self.retried = 0
 703.         self.nonce_count = 0
 704. 
 705.     def reset_retry_count(self):
 706.         self.retried = 0
 707. 
 708.     def http_error_auth_reqed(self, auth_header, host, req, headers):
 709.         authreq = headers.get(auth_header, None)
 710.         if self.retried > 5:
 711.             # Don't fail endlessly - if we failed once, we'll probably
 712.             # fail a second time. Hm. Unless the Password Manager is
 713.             # prompting for the information. Crap. This isn't great
 714.             # but it's better than the current 'repeat until recursion
 715.             # depth exceeded' approach <wink>
 716.             raise HTTPError(req.get_full_url(), 401, "digest auth failed",
 717.                             headers, None)
 718.         else:
 719.             self.retried += 1
 720.         if authreq:
 721.             scheme = authreq.split()[0]
 722.             if scheme.lower() == 'digest':
 723.                 return self.retry_http_digest_auth(req, authreq)
 724.             else:
 725.                 raise ValueError("AbstractDigestAuthHandler doesn't know "
 726.                                  "about %s"%(scheme))
 727. 
 728.     def retry_http_digest_auth(self, req, auth):
 729.         token, challenge = auth.split(' ', 1)
 730.         chal = parse_keqv_list(parse_http_list(challenge))
 731.         auth = self.get_authorization(req, chal)
 732.         if auth:
 733.             auth_val = 'Digest %s' % auth
 734.             if req.headers.get(self.auth_header, None) == auth_val:
 735.                 return None
 736.             req.add_header(self.auth_header, auth_val)
 737.             resp = self.parent.open(req)
 738.             return resp
 739. 
 740.     def get_cnonce(self, nonce):
 741.         # The cnonce-value is an opaque
 742.         # quoted string value provided by the client and used by both client
 743.         # and server to avoid chosen plaintext attacks, to provide mutual
 744.         # authentication, and to provide some message integrity protection.
 745.         # This isn't a fabulous effort, but it's probably Good Enough.
 746.         dig = sha.new("%s:%s:%s:%s" % (self.nonce_count, nonce, time.ctime(),
 747.                                        randombytes(8))).hexdigest()
 748.         return dig[:16]
 749. 
 750.     def get_authorization(self, req, chal):
 751.         try:
 752.             realm = chal['realm']
 753.             nonce = chal['nonce']
 754.             qop = chal.get('qop')
 755.             algorithm = chal.get('algorithm', 'MD5')
 756.             # mod_digest doesn't send an opaque, even though it isn't
 757.             # supposed to be optional
 758.             opaque = chal.get('opaque', None)
 759.         except KeyError:
 760.             return None
 761. 
 762.         H, KD = self.get_algorithm_impls(algorithm)
 763.         if H is None:
 764.             return None
 765. 
 766.         user, pw = self.passwd.find_user_password(realm, req.get_full_url())
 767.         if user is None:
 768.             return None
 769. 
 770.         # XXX not implemented yet
 771.         if req.has_data():
 772.             entdig = self.get_entity_digest(req.get_data(), chal)
 773.         else:
 774.             entdig = None
 775. 
 776.         A1 = "%s:%s:%s" % (user, realm, pw)
 777.         A2 = "%s:%s" % (req.has_data() and 'POST' or 'GET',
 778.                         # XXX selector: what about proxies and full urls
 779.                         req.get_selector())
 780.         if qop == 'auth':
 781.             self.nonce_count += 1
 782.             ncvalue = '%08x' % self.nonce_count
 783.             cnonce = self.get_cnonce(nonce)
 784.             noncebit = "%s:%s:%s:%s:%s" % (nonce, ncvalue, cnonce, qop, H(A2))
 785.             respdig = KD(H(A1), noncebit)
 786.         elif qop is None:
 787.             respdig = KD(H(A1), "%s:%s" % (nonce, H(A2)))
 788.         else:
 789.             # XXX handle auth-int.
 790.             pass
 791. 
 792.         # XXX should the partial digests be encoded too?
 793. 
 794.         base = 'username="%s", realm="%s", nonce="%s", uri="%s", ' \
 795.                'response="%s"' % (user, realm, nonce, req.get_selector(),
 796.                                   respdig)
 797.         if opaque:
 798.             base = base + ', opaque="%s"' % opaque
 799.         if entdig:
 800.             base = base + ', digest="%s"' % entdig
 801.         if algorithm != 'MD5':
 802.             base = base + ', algorithm="%s"' % algorithm
 803.         if qop:
 804.             base = base + ', qop=auth, nc=%s, cnonce="%s"' % (ncvalue, cnonce)
 805.         return base
 806. 
 807.     def get_algorithm_impls(self, algorithm):
 808.         # lambdas assume digest modules are imported at the top level
 809.         if algorithm == 'MD5':
 810.             H = lambda x: md5.new(x).hexdigest()
 811.         elif algorithm == 'SHA':
 812.             H = lambda x: sha.new(x).hexdigest()
 813.         # XXX MD5-sess
 814.         KD = lambda s, d: H("%s:%s" % (s, d))
 815.         return H, KD
 816. 
 817.     def get_entity_digest(self, data, chal):
 818.         # XXX not implemented yet
 819.         return None
 820. 
 821. 
 822. class HTTPDigestAuthHandler(BaseHandler, AbstractDigestAuthHandler):
 823.     """An authentication protocol defined by RFC 2069
 824. 
 825.     Digest authentication improves on basic authentication because it
 826.     does not transmit passwords in the clear.
 827.     """
 828. 
 829.     auth_header = 'Authorization'
 830. 
 831.     def http_error_401(self, req, fp, code, msg, headers):
 832.         host = urlparse.urlparse(req.get_full_url())[1]
 833.         retry = self.http_error_auth_reqed('www-authenticate',
 834.                                            host, req, headers)
 835.         self.reset_retry_count()
 836.         return retry
 837. 
 838. 
 839. class ProxyDigestAuthHandler(BaseHandler, AbstractDigestAuthHandler):
 840. 
 841.     auth_header = 'Proxy-Authorization'
 842. 
 843.     def http_error_407(self, req, fp, code, msg, headers):
 844.         host = req.get_host()
 845.         retry = self.http_error_auth_reqed('proxy-authenticate',
 846.                                            host, req, headers)
 847.         self.reset_retry_count()
 848.         return retry
 849. 
 850. class AbstractHTTPHandler(BaseHandler):
 851. 
 852.     # XXX Should rewrite do_open() to use the new httplib interface,
 853.     # would be a little simpler.
 854. 
 855.     def do_open(self, http_class, req):
 856.         host = req.get_host()
 857.         if not host:
 858.             raise URLError('no host given')
 859. 
 860.         h = http_class(host) # will parse host:port
 861.         if req.has_data():
 862.             data = req.get_data()
 863.             h.putrequest('POST', req.get_selector())
 864.             if not 'Content-type' in req.headers:
 865.                 h.putheader('Content-type',
 866.                             'application/x-www-form-urlencoded')
 867.             if not 'Content-length' in req.headers:
 868.                 h.putheader('Content-length', '%d' % len(data))
 869.         else:
 870.             h.putrequest('GET', req.get_selector())
 871. 
 872.         scheme, sel = splittype(req.get_selector())
 873.         sel_host, sel_path = splithost(sel)
 874.         h.putheader('Host', sel_host or host)
 875.         for name, value in self.parent.addheaders:
 876.             name = name.capitalize()
 877.             if name not in req.headers:
 878.                 h.putheader(name, value)
 879.         for k, v in req.headers.items():
 880.             h.putheader(k, v)
 881.         # httplib will attempt to connect() here.  be prepared
 882.         # to convert a socket error to a URLError.
 883.         try:
 884.             h.endheaders()
 885.         except socket.error, err:
 886.             raise URLError(err)
 887.         if req.has_data():
 888.             h.send(data)
 889. 
 890.         code, msg, hdrs = h.getreply()
 891.         fp = h.getfile()
 892.         if code == 200:
 893.             return addinfourl(fp, hdrs, req.get_full_url())
 894.         else:
 895.             return self.parent.error('http', req, fp, code, msg, hdrs)
 896. 
 897. 
 898. class HTTPHandler(AbstractHTTPHandler):
 899. 
 900.     def http_open(self, req):
 901.         return self.do_open(httplib.HTTP, req)
 902. 
 903. 
 904. if hasattr(httplib, 'HTTPS'):
 905.     class HTTPSHandler(AbstractHTTPHandler):
 906. 
 907.         def https_open(self, req):
 908.             return self.do_open(httplib.HTTPS, req)
 909. 
 910. 
 911. class UnknownHandler(BaseHandler):
 912.     def unknown_open(self, req):
 913.         type = req.get_type()
 914.         raise URLError('unknown url type: %s' % type)
 915. 
 916. def parse_keqv_list(l):
 917.     """Parse list of key=value strings where keys are not duplicated."""
 918.     parsed = {}
 919.     for elt in l:
 920.         k, v = elt.split('=', 1)
 921.         if v[0] == '"' and v[-1] == '"':
 922.             v = v[1:-1]
 923.         parsed[k] = v
 924.     return parsed
 925. 
 926. def parse_http_list(s):
 927.     """Parse lists as described by RFC 2068 Section 2.
 928. 
 929.     In particular, parse comman-separated lists where the elements of
 930.     the list may include quoted-strings.  A quoted-string could
 931.     contain a comma.
 932.     """
 933.     # XXX this function could probably use more testing
 934. 
 935.     list = []
 936.     end = len(s)
 937.     i = 0
 938.     inquote = 0
 939.     start = 0
 940.     while i < end:
 941.         cur = s[i:]
 942.         c = cur.find(',')
 943.         q = cur.find('"')
 944.         if c == -1:
 945.             list.append(s[start:])
 946.             break
 947.         if q == -1:
 948.             if inquote:
 949.                 raise ValueError, "unbalanced quotes"
 950.             else:
 951.                 list.append(s[start:i+c])
 952.                 i = i + c + 1
 953.                 continue
 954.         if inquote:
 955.             if q < c:
 956.                 list.append(s[start:i+c])
 957.                 i = i + c + 1
 958.                 start = i
 959.                 inquote = 0
 960.             else:
 961.                 i = i + q
 962.         else:
 963.             if c < q:
 964.                 list.append(s[start:i+c])
 965.                 i = i + c + 1
 966.                 start = i
 967.             else:
 968.                 inquote = 1
 969.                 i = i + q + 1
 970.     return map(lambda x: x.strip(), list)
 971. 
 972. class FileHandler(BaseHandler):
 973.     # Use local file or FTP depending on form of URL
 974.     def file_open(self, req):
 975.         url = req.get_selector()
 976.         if url[:2] == '//' and url[2:3] != '/':
 977.             req.type = 'ftp'
 978.             return self.parent.open(req)
 979.         else:
 980.             return self.open_local_file(req)
 981. 
 982.     # names for the localhost
 983.     names = None
 984.     def get_names(self):
 985.         if FileHandler.names is None:
 986.             FileHandler.names = (socket.gethostbyname('localhost'),
 987.                                  socket.gethostbyname(socket.gethostname()))
 988.         return FileHandler.names
 989. 
 990.     # not entirely sure what the rules are here
 991.     def open_local_file(self, req):
 992.         host = req.get_host()
 993.         file = req.get_selector()
 994.         localfile = url2pathname(file)
 995.         stats = os.stat(localfile)
 996.         size = stats.st_size
 997.         modified = rfc822.formatdate(stats.st_mtime)
 998.         mtype = mimetypes.guess_type(file)[0]
 999.         headers = mimetools.Message(StringIO(
1000.             'Content-type: %s\nContent-length: %d\nLast-modified: %s\n' %
1001.             (mtype or 'text/plain', size, modified)))
1002.         if host:
1003.             host, port = splitport(host)
1004.         if not host or \
1005.            (not port and socket.gethostbyname(host) in self.get_names()):
1006.             return addinfourl(open(localfile, 'rb'),
1007.                               headers, 'file:'+file)
1008.         raise URLError('file not on local host')
1009. 
1010. class FTPHandler(BaseHandler):
1011.     def ftp_open(self, req):
1012.         host = req.get_host()
1013.         if not host:
1014.             raise IOError, ('ftp error', 'no host given')
1015.         host, port = splitport(host)
1016.         if port is None:
1017.             port = ftplib.FTP_PORT
1018. 
1019.         # username/password handling
1020.         user, host = splituser(host)
1021.         if user:
1022.             user, passwd = splitpasswd(user)
1023.         else:
1024.             passwd = None
1025.         host = unquote(host)
1026.         user = unquote(user or '')
1027.         passwd = unquote(passwd or '')
1028. 
1029.         try:
1030.             host = socket.gethostbyname(host)
1031.         except socket.error, msg:
1032.             raise URLError(msg)
1033.         path, attrs = splitattr(req.get_selector())
1034.         dirs = path.split('/')
1035.         dirs = map(unquote, dirs)
1036.         dirs, file = dirs[:-1], dirs[-1]
1037.         if dirs and not dirs[0]:
1038.             dirs = dirs[1:]
1039.         try:
1040.             fw = self.connect_ftp(user, passwd, host, port, dirs)
1041.             type = file and 'I' or 'D'
1042.             for attr in attrs:
1043.                 attr, value = splitattr(attr)
1044.                 if attr.lower() == 'type' and \
1045.                    value in ('a', 'A', 'i', 'I', 'd', 'D'):
1046.                     type = value.upper()
1047.             fp, retrlen = fw.retrfile(file, type)
1048.             headers = ""
1049.             mtype = mimetypes.guess_type(req.get_full_url())[0]
1050.             if mtype:
1051.                 headers += "Content-type: %s\n" % mtype
1052.             if retrlen is not None and retrlen >= 0:
1053.                 headers += "Content-length: %d\n" % retrlen
1054.             sf = StringIO(headers)
1055.             headers = mimetools.Message(sf)
1056.             return addinfourl(fp, headers, req.get_full_url())
1057.         except ftplib.all_errors, msg:
1058.             raise IOError, ('ftp error', msg), sys.exc_info()[2]
1059. 
1060.     def connect_ftp(self, user, passwd, host, port, dirs):
1061.         fw = ftpwrapper(user, passwd, host, port, dirs)
1062. ##        fw.ftp.set_debuglevel(1)
1063.         return fw
1064. 
1065. class CacheFTPHandler(FTPHandler):
1066.     # XXX would be nice to have pluggable cache strategies
1067.     # XXX this stuff is definitely not thread safe
1068.     def __init__(self):
1069.         self.cache = {}
1070.         self.timeout = {}
1071.         self.soonest = 0
1072.         self.delay = 60
1073.         self.max_conns = 16
1074. 
1075.     def setTimeout(self, t):
1076.         self.delay = t
1077. 
1078.     def setMaxConns(self, m):
1079.         self.max_conns = m
1080. 
1081.     def connect_ftp(self, user, passwd, host, port, dirs):
1082.         key = user, host, port, '/'.join(dirs)
1083.         if key in self.cache:
1084.             self.timeout[key] = time.time() + self.delay
1085.         else:
1086.             self.cache[key] = ftpwrapper(user, passwd, host, port, dirs)
1087.             self.timeout[key] = time.time() + self.delay
1088.         self.check_cache()
1089.         return self.cache[key]
1090. 
1091.     def check_cache(self):
1092.         # first check for old ones
1093.         t = time.time()
1094.         if self.soonest <= t:
1095.             for k, v in self.timeout.items():
1096.                 if v < t:
1097.                     self.cache[k].close()
1098.                     del self.cache[k]
1099.                     del self.timeout[k]
1100.         self.soonest = min(self.timeout.values())
1101. 
1102.         # then check the size
1103.         if len(self.cache) == self.max_conns:
1104.             for k, v in self.timeout.items():
1105.                 if v == self.soonest:
1106.                     del self.cache[k]
1107.                     del self.timeout[k]
1108.                     break
1109.             self.soonest = min(self.timeout.values())
1110. 
1111. class GopherHandler(BaseHandler):
1112.     def gopher_open(self, req):
1113.         host = req.get_host()
1114.         if not host:
1115.             raise GopherError('no host given')
1116.         host = unquote(host)
1117.         selector = req.get_selector()
1118.         type, selector = splitgophertype(selector)
1119.         selector, query = splitquery(selector)
1120.         selector = unquote(selector)
1121.         if query:
1122.             query = unquote(query)
1123.             fp = gopherlib.send_query(selector, query, host)
1124.         else:
1125.             fp = gopherlib.send_selector(selector, host)
1126.         return addinfourl(fp, noheaders(), req.get_full_url())
1127. 
1128. #bleck! don't use this yet
1129. class OpenerFactory:
1130. 
1131.     default_handlers = [UnknownHandler, HTTPHandler,
1132.                         HTTPDefaultErrorHandler, HTTPRedirectHandler,
1133.                         FTPHandler, FileHandler]
1134.     handlers = []
1135.     replacement_handlers = []
1136. 
1137.     def add_handler(self, h):
1138.         self.handlers = self.handlers + [h]
1139. 
1140.     def replace_handler(self, h):
1141.         pass
1142. 
1143.     def build_opener(self):
1144.         opener = OpenerDirector()
1145.         for ph in self.default_handlers:
1146.             if inspect.isclass(ph):
1147.                 ph = ph()
1148.             opener.add_handler(ph)
1149. 
1150. if __name__ == "__main__":
1151.     # XXX some of the test code depends on machine configurations that
1152.     # are internal to CNRI.   Need to set up a public server with the
1153.     # right authentication configuration for test purposes.
1154.     if socket.gethostname() == 'bitdiddle':
1155.         localhost = 'bitdiddle.cnri.reston.va.us'
1156.     elif socket.gethostname() == 'bitdiddle.concentric.net':
1157.         localhost = 'localhost'
1158.     else:
1159.         localhost = None
1160.     urls = [
1161.         # Thanks to Fred for finding these!
1162.         'gopher://gopher.lib.ncsu.edu/11/library/stacks/Alex',
1163.         'gopher://gopher.vt.edu:10010/10/33',
1164. 
1165.         'file:/etc/passwd',
1166.         'file://nonsensename/etc/passwd',
1167.         'ftp://www.python.org/pub/python/misc/sousa.au',
1168.         'ftp://www.python.org/pub/tmp/blat',
1169.         'http://www.espn.com/', # redirect
1170.         'http://www.python.org/Spanish/Inquistion/',
1171.         ('http://www.python.org/cgi-bin/faqw.py',
1172.          'query=pythonistas&querytype=simple&casefold=yes&req=search'),
1173.         'http://www.python.org/',
1174.         'ftp://gatekeeper.research.compaq.com/pub/DEC/SRC/research-reports/00README-Legal-Rules-Regs',
1175.             ]
1176. 
1177. ##    if localhost is not None:
1178. ##        urls = urls + [
1179. ##            'file://%s/etc/passwd' % localhost,
1180. ##            'http://%s/simple/' % localhost,
1181. ##            'http://%s/digest/' % localhost,
1182. ##            'http://%s/not/found.h' % localhost,
1183. ##            ]
1184. 
1185. ##        bauth = HTTPBasicAuthHandler()
1186. ##        bauth.add_password('basic_test_realm', localhost, 'jhylton',
1187. ##                           'password')
1188. ##        dauth = HTTPDigestAuthHandler()
1189. ##        dauth.add_password('digest_test_realm', localhost, 'jhylton',
1190. ##                           'password')
1191. 
1192. 
1193.     cfh = CacheFTPHandler()
1194.     cfh.setTimeout(1)
1195. 
1196. ##    # XXX try out some custom proxy objects too!
1197. ##    def at_cnri(req):
1198. ##        host = req.get_host()
1199. ##        print host
1200. ##        if host[-18:] == '.cnri.reston.va.us':
1201. ##            return 1
1202. ##    p = CustomProxy('http', at_cnri, 'proxy.cnri.reston.va.us')
1203. ##    ph = CustomProxyHandler(p)
1204. 
1205. ##    install_opener(build_opener(dauth, bauth, cfh, GopherHandler, ph))
1206.     install_opener(build_opener(cfh, GopherHandler))
1207. 
1208.     for url in urls:
1209.         if isinstance(url, tuple):
1210.             url, req = url
1211.         else:
1212.             req = None
1213.         print url
1214.         try:
1215.             f = urlopen(url, req)
1216.         except IOError, err:
1217.             print "IOError:", err
1218.         except socket.error, err:
1219.             print "socket.error:", err
1220.         else:
1221.             buf = f.read()
1222.             f.close()
1223.             print "read %d bytes" % len(buf)
1224.         print
1225.         time.sleep(0.1)