Source code for urllib2

"""An extensible library for opening URLs using a variety of protocols

The simplest way to use this module is to call the urlopen function,
which accepts a string containing a URL or a Request object (described
below).  It opens the URL and returns the results as file-like
object; the returned object has some extra methods described below.

The OpenerDirector manages a collection of Handler objects that do
all the actual work.  Each Handler implements a particular protocol or
option.  The OpenerDirector is a composite object that invokes the
Handlers needed to open the requested URL.  For example, the
HTTPHandler performs HTTP GET and POST requests and deals with
non-error returns.  The HTTPRedirectHandler automatically deals with
HTTP 301, 302, 303 and 307 redirect errors, and the HTTPDigestAuthHandler
deals with digest authentication.

urlopen(url, data=None) -- Basic usage is the same as original
urllib.  pass the url and optionally data to post to an HTTP URL, and
get a file-like object back.  One difference is that you can also pass
a Request instance instead of URL.  Raises a URLError (subclass of
IOError); for HTTP errors, raises an HTTPError, which can also be
treated as a valid response.

build_opener -- Function that creates a new OpenerDirector instance.
Will install the default handlers.  Accepts one or more Handlers as
arguments, either instances or Handler classes that it will
instantiate.  If one of the argument is a subclass of the default
handler, the argument will be installed instead of the default.

install_opener -- Installs a new opener as the default opener.

objects of interest:

OpenerDirector -- Sets up the User Agent as the Python-urllib client and manages
the Handler classes, while dealing with requests and responses.

Request -- An object that encapsulates the state of a request.  The
state can be as simple as the URL.  It can also include extra HTTP
headers, e.g. a User-Agent.

BaseHandler --

exceptions:
URLError -- A subclass of IOError, individual protocols have their own
specific subclass.

HTTPError -- Also a valid HTTP response, so you can treat an HTTP error
as an exceptional event or valid response.

internals:
BaseHandler and parent
_call_chain conventions

Example usage:

import urllib2

# set up authentication info
authinfo = urllib2.HTTPBasicAuthHandler()
authinfo.add_password(realm='PDQ Application',
                      uri='https://mahler:8092/site-updates.py',
                      user='klem',
                      passwd='geheim$parole')

proxy_support = urllib2.ProxyHandler({"http" : "http://ahad-haam:3128"})

# build a new opener that adds authentication and caching FTP handlers
opener = urllib2.build_opener(proxy_support, authinfo, urllib2.CacheFTPHandler)

# install it
urllib2.install_opener(opener)

f = urllib2.urlopen('http://www.python.org/')


"""

# XXX issues:
# If an authentication error handler that tries to perform
# authentication for some reason but fails, how should the error be
# signalled?  The client needs to know the HTTP error code.  But if
# the handler knows that the problem was, e.g., that it didn't know
# that hash algo that requested in the challenge, it would be good to
# pass that information along to the client, too.
# ftp errors aren't handled cleanly
# check digest against correct (i.e. non-apache) implementation

# Possible extensions:
# complex proxies  XXX not sure what exactly was meant by this
# abstract factory for opener

import base64
import hashlib
import httplib
import mimetools
import os
import posixpath
import random
import re
import socket
import sys
import time
import urlparse
import bisect
import warnings

try:
    from cStringIO import StringIO
except ImportError:
    from StringIO import StringIO

# check for SSL
try:
    import ssl
except ImportError:
    _have_ssl = False
else:
    _have_ssl = True

from urllib import (unwrap, unquote, splittype, splithost, quote,
     addinfourl, splitport, splittag, toBytes,
     splitattr, ftpwrapper, splituser, splitpasswd, splitvalue)

# support for FileHandler, proxies via environment variables
from urllib import localhost, url2pathname, getproxies, proxy_bypass

# used in User-Agent header sent
__version__ = sys.version[:3]

_opener = None
[docs]def urlopen(url, data=None, timeout=socket._GLOBAL_DEFAULT_TIMEOUT, cafile=None, capath=None, cadefault=False, context=None): global _opener if cafile or capath or cadefault: if context is not None: raise ValueError( "You can't pass both context and any of cafile, capath, and " "cadefault" ) if not _have_ssl: raise ValueError('SSL support not available') context = ssl.create_default_context(purpose=ssl.Purpose.SERVER_AUTH, cafile=cafile, capath=capath) https_handler = HTTPSHandler(context=context) opener = build_opener(https_handler) elif context: https_handler = HTTPSHandler(context=context) opener = build_opener(https_handler) elif _opener is None: _opener = opener = build_opener() else: opener = _opener return opener.open(url, data, timeout)
[docs]def install_opener(opener): global _opener _opener = opener
# do these error classes make sense? # make sure all of the IOError stuff is overridden. we just want to be # subtypes.
[docs]class URLError(IOError): # URLError is a sub-type of IOError, but it doesn't share any of # the implementation. need to override __init__ and __str__. # It sets self.args for compatibility with other EnvironmentError # subclasses, but args doesn't have the typical format with errno in # slot 0 and strerror in slot 1. This may be better than nothing. def __init__(self, reason): self.args = reason, self.reason = reason def __str__(self): return '<urlopen error %s>' % self.reason
class HTTPError(URLError, addinfourl): """Raised when HTTP error occurs, but also acts like non-error return""" __super_init = addinfourl.__init__ def __init__(self, url, code, msg, hdrs, fp): self.code = code self.msg = msg self.hdrs = hdrs self.fp = fp self.filename = url # The addinfourl classes depend on fp being a valid file # object. In some cases, the HTTPError may not have a valid # file object. If this happens, the simplest workaround is to # not initialize the base classes. if fp is not None: self.__super_init(fp, hdrs, url, code) def __str__(self): return 'HTTP Error %s: %s' % (self.code, self.msg) # since URLError specifies a .reason attribute, HTTPError should also # provide this attribute. See issue13211 fo discussion. @property def reason(self): return self.msg def info(self): return self.hdrs # copied from cookielib.py _cut_port_re = re.compile(r":\d+$") def request_host(request): """Return request-host, as defined by RFC 2965. Variation from RFC: returned value is lowercased, for convenient comparison. """ url = request.get_full_url() host = urlparse.urlparse(url)[1] if host == "": host = request.get_header("Host", "") # remove port, if present host = _cut_port_re.sub("", host, 1) return host.lower() class Request: def __init__(self, url, data=None, headers={}, origin_req_host=None, unverifiable=False): # unwrap('<URL:type://host/path>') --> 'type://host/path' self.__original = unwrap(url) self.__original, self.__fragment = splittag(self.__original) self.type = None # self.__r_type is what's left after doing the splittype self.host = None self.port = None self._tunnel_host = None self.data = data self.headers = {} for key, value in headers.items(): self.add_header(key, value) self.unredirected_hdrs = {} if origin_req_host is None: origin_req_host = request_host(self) self.origin_req_host = origin_req_host self.unverifiable = unverifiable def __getattr__(self, attr): # XXX this is a fallback mechanism to guard against these # methods getting called in a non-standard order. this may be # too complicated and/or unnecessary. # XXX should the __r_XXX attributes be public? if attr[:12] == '_Request__r_': name = attr[12:] if hasattr(Request, 'get_' + name): getattr(self, 'get_' + name)() return getattr(self, attr) raise AttributeError, attr def get_method(self): if self.has_data(): return "POST" else: return "GET" # XXX these helper methods are lame def add_data(self, data): self.data = data def has_data(self): return self.data is not None def get_data(self): return self.data def get_full_url(self): if self.__fragment: return '%s#%s' % (self.__original, self.__fragment) else: return self.__original def get_type(self): if self.type is None: self.type, self.__r_type = splittype(self.__original) if self.type is None: raise ValueError, "unknown url type: %s" % self.__original return self.type def get_host(self): if self.host is None: self.host, self.__r_host = splithost(self.__r_type) if self.host: self.host = unquote(self.host) return self.host def get_selector(self): return self.__r_host def set_proxy(self, host, type): if self.type == 'https' and not self._tunnel_host: self._tunnel_host = self.host else: self.type = type self.__r_host = self.__original self.host = host def has_proxy(self): return self.__r_host == self.__original def get_origin_req_host(self): return self.origin_req_host def is_unverifiable(self): return self.unverifiable def add_header(self, key, val): # useful for something like authentication self.headers[key.capitalize()] = val def add_unredirected_header(self, key, val): # will not be added to a redirected request self.unredirected_hdrs[key.capitalize()] = val def has_header(self, header_name): return (header_name in self.headers or header_name in self.unredirected_hdrs) def get_header(self, header_name, default=None): return self.headers.get( header_name, self.unredirected_hdrs.get(header_name, default)) def header_items(self): hdrs = self.unredirected_hdrs.copy() hdrs.update(self.headers) return hdrs.items() class OpenerDirector: def __init__(self): client_version = "Python-urllib/%s" % __version__ self.addheaders = [('User-agent', client_version)] # self.handlers is retained only for backward compatibility self.handlers = [] # manage the individual handlers self.handle_open = {} self.handle_error = {} self.process_response = {} self.process_request = {} def add_handler(self, handler): if not hasattr(handler, "add_parent"): raise TypeError("expected BaseHandler instance, got %r" % type(handler)) added = False for meth in dir(handler): if meth in ["redirect_request", "do_open", "proxy_open"]: # oops, coincidental match continue i = meth.find("_") protocol = meth[:i] condition = meth[i+1:] if condition.startswith("error"): j = condition.find("_") + i + 1 kind = meth[j+1:] try: kind = int(kind) except ValueError: pass lookup = self.handle_error.get(protocol, {}) self.handle_error[protocol] = lookup elif condition == "open": kind = protocol lookup = self.handle_open elif condition == "response": kind = protocol lookup = self.process_response elif condition == "request": kind = protocol lookup = self.process_request else: continue handlers = lookup.setdefault(kind, []) if handlers: bisect.insort(handlers, handler) else: handlers.append(handler) added = True if added: bisect.insort(self.handlers, handler) handler.add_parent(self) def close(self): # Only exists for backwards compatibility. pass def _call_chain(self, chain, kind, meth_name, *args): # Handlers raise an exception if no one else should try to handle # the request, or return None if they can't but another handler # could. Otherwise, they return the response. handlers = chain.get(kind, ()) for handler in handlers: func = getattr(handler, meth_name) result = func(*args) if result is not None: return result def open(self, fullurl, data=None, timeout=socket._GLOBAL_DEFAULT_TIMEOUT): # accept a URL or a Request object if isinstance(fullurl, basestring): req = Request(fullurl, data) else: req = fullurl if data is not None: req.add_data(data) req.timeout = timeout protocol = req.get_type() # pre-process request meth_name = protocol+"_request" for processor in self.process_request.get(protocol, []): meth = getattr(processor, meth_name) req = meth(req) response = self._open(req, data) # post-process response meth_name = protocol+"_response" for processor in self.process_response.get(protocol, []): meth = getattr(processor, meth_name) response = meth(req, response) return response def _open(self, req, data=None): result = self._call_chain(self.handle_open, 'default', 'default_open', req) if result: return result protocol = req.get_type() result = self._call_chain(self.handle_open, protocol, protocol + '_open', req) if result: return result return self._call_chain(self.handle_open, 'unknown', 'unknown_open', req) def error(self, proto, *args): if proto in ('http', 'https'): # XXX http[s] protocols are special-cased dict = self.handle_error['http'] # https is not different than http proto = args[2] # YUCK! meth_name = 'http_error_%s' % proto http_err = 1 orig_args = args else: dict = self.handle_error meth_name = proto + '_error' http_err = 0 args = (dict, proto, meth_name) + args result = self._call_chain(*args) if result: return result if http_err: args = (dict, 'default', 'http_error_default') + orig_args return self._call_chain(*args) # XXX probably also want an abstract factory that knows when it makes # sense to skip a superclass in favor of a subclass and when it might # make sense to include both
[docs]def build_opener(*handlers): """Create an opener object from a list of handlers. The opener will use several default handlers, including support for HTTP, FTP and when applicable, HTTPS. If any of the handlers passed as arguments are subclasses of the default handlers, the default handlers will not be used. """ import types def isclass(obj): return isinstance(obj, (types.ClassType, type)) opener = OpenerDirector() default_classes = [ProxyHandler, UnknownHandler, HTTPHandler, HTTPDefaultErrorHandler, HTTPRedirectHandler, FTPHandler, FileHandler, HTTPErrorProcessor] if hasattr(httplib, 'HTTPS'): default_classes.append(HTTPSHandler) skip = set() for klass in default_classes: for check in handlers: if isclass(check): if issubclass(check, klass): skip.add(klass) elif isinstance(check, klass): skip.add(klass) for klass in skip: default_classes.remove(klass) for klass in default_classes: opener.add_handler(klass()) for h in handlers: if isclass(h): h = h() opener.add_handler(h) return opener
class BaseHandler: handler_order = 500 def add_parent(self, parent): self.parent = parent def close(self): # Only exists for backwards compatibility pass def __lt__(self, other): if not hasattr(other, "handler_order"): # Try to preserve the old behavior of having custom classes # inserted after default ones (works only for custom user # classes which are not aware of handler_order). return True return self.handler_order < other.handler_order class HTTPErrorProcessor(BaseHandler): """Process HTTP error responses.""" handler_order = 1000 # after all other processing def http_response(self, request, response): code, msg, hdrs = response.code, response.msg, response.info() # According to RFC 2616, "2xx" code indicates that the client's # request was successfully received, understood, and accepted. if not (200 <= code < 300): response = self.parent.error( 'http', request, response, code, msg, hdrs) return response https_response = http_response class HTTPDefaultErrorHandler(BaseHandler): def http_error_default(self, req, fp, code, msg, hdrs): raise HTTPError(req.get_full_url(), code, msg, hdrs, fp) class HTTPRedirectHandler(BaseHandler): # maximum number of redirections to any single URL # this is needed because of the state that cookies introduce max_repeats = 4 # maximum total number of redirections (regardless of URL) before # assuming we're in a loop max_redirections = 10 def redirect_request(self, req, fp, code, msg, headers, newurl): """Return a Request or None in response to a redirect. This is called by the http_error_30x methods when a redirection response is received. If a redirection should take place, return a new Request to allow http_error_30x to perform the redirect. Otherwise, raise HTTPError if no-one else should try to handle this url. Return None if you can't but another Handler might. """ m = req.get_method() if (code in (301, 302, 303, 307) and m in ("GET", "HEAD") or code in (301, 302, 303) and m == "POST"): # Strictly (according to RFC 2616), 301 or 302 in response # to a POST MUST NOT cause a redirection without confirmation # from the user (of urllib2, in this case). In practice, # essentially all clients do redirect in this case, so we # do the same. # be conciliant with URIs containing a space newurl = newurl.replace(' ', '%20') newheaders = dict((k,v) for k,v in req.headers.items() if k.lower() not in ("content-length", "content-type") ) return Request(newurl, headers=newheaders, origin_req_host=req.get_origin_req_host(), unverifiable=True) else: raise HTTPError(req.get_full_url(), code, msg, headers, fp) # Implementation note: To avoid the server sending us into an # infinite loop, the request object needs to track what URLs we # have already seen. Do this by adding a handler-specific # attribute to the Request object. def http_error_302(self, req, fp, code, msg, headers): # Some servers (incorrectly) return multiple Location headers # (so probably same goes for URI). Use first header. if 'location' in headers: newurl = headers.getheaders('location')[0] elif 'uri' in headers: newurl = headers.getheaders('uri')[0] else: return # fix a possible malformed URL urlparts = urlparse.urlparse(newurl) if not urlparts.path: urlparts = list(urlparts) urlparts[2] = "/" newurl = urlparse.urlunparse(urlparts) newurl = urlparse.urljoin(req.get_full_url(), newurl) # For security reasons we do not allow redirects to protocols # other than HTTP, HTTPS or FTP. newurl_lower = newurl.lower() if not (newurl_lower.startswith('http://') or newurl_lower.startswith('https://') or newurl_lower.startswith('ftp://')): raise HTTPError(newurl, code, msg + " - Redirection to url '%s' is not allowed" % newurl, headers, fp) # XXX Probably want to forget about the state of the current # request, although that might interact poorly with other # handlers that also use handler-specific request attributes new = self.redirect_request(req, fp, code, msg, headers, newurl) if new is None: return # loop detection # .redirect_dict has a key url if url was previously visited. if hasattr(req, 'redirect_dict'): visited = new.redirect_dict = req.redirect_dict if (visited.get(newurl, 0) >= self.max_repeats or len(visited) >= self.max_redirections): raise HTTPError(req.get_full_url(), code, self.inf_msg + msg, headers, fp) else: visited = new.redirect_dict = req.redirect_dict = {} visited[newurl] = visited.get(newurl, 0) + 1 # Don't close the fp until we are sure that we won't use it # with HTTPError. fp.read() fp.close() return self.parent.open(new, timeout=req.timeout) http_error_301 = http_error_303 = http_error_307 = http_error_302 inf_msg = "The HTTP server returned a redirect error that would " \ "lead to an infinite loop.\n" \ "The last 30x error message was:\n" def _parse_proxy(proxy): """Return (scheme, user, password, host/port) given a URL or an authority. If a URL is supplied, it must have an authority (host:port) component. According to RFC 3986, having an authority component means the URL must have two slashes after the scheme: >>> _parse_proxy('file:/ftp.example.com/') Traceback (most recent call last): ValueError: proxy URL with no authority: 'file:/ftp.example.com/' The first three items of the returned tuple may be None. Examples of authority parsing: >>> _parse_proxy('proxy.example.com') (None, None, None, 'proxy.example.com') >>> _parse_proxy('proxy.example.com:3128') (None, None, None, 'proxy.example.com:3128') The authority component may optionally include userinfo (assumed to be username:password): >>> _parse_proxy('joe:[email protected]') (None, 'joe', 'password', 'proxy.example.com') >>> _parse_proxy('joe:[email protected]:3128') (None, 'joe', 'password', 'proxy.example.com:3128') Same examples, but with URLs instead: >>> _parse_proxy('http://proxy.example.com/') ('http', None, None, 'proxy.example.com') >>> _parse_proxy('http://proxy.example.com:3128/') ('http', None, None, 'proxy.example.com:3128') >>> _parse_proxy('http://joe:[email protected]/') ('http', 'joe', 'password', 'proxy.example.com') >>> _parse_proxy('http://joe:[email protected]:3128') ('http', 'joe', 'password', 'proxy.example.com:3128') Everything after the authority is ignored: >>> _parse_proxy('ftp://joe:[email protected]/rubbish:3128') ('ftp', 'joe', 'password', 'proxy.example.com') Test for no trailing '/' case: >>> _parse_proxy('http://joe:[email protected]') ('http', 'joe', 'password', 'proxy.example.com') """ scheme, r_scheme = splittype(proxy) if not r_scheme.startswith("/"): # authority scheme = None authority = proxy else: # URL if not r_scheme.startswith("//"): raise ValueError("proxy URL with no authority: %r" % proxy) # We have an authority, so for RFC 3986-compliant URLs (by ss 3. # and 3.3.), path is empty or starts with '/' end = r_scheme.find("/", 2) if end == -1: end = None authority = r_scheme[2:end] userinfo, hostport = splituser(authority) if userinfo is not None: user, password = splitpasswd(userinfo) else: user = password = None return scheme, user, password, hostport
[docs]class ProxyHandler(BaseHandler): # Proxies must be in front handler_order = 100
[docs] def __init__(self, proxies=None): if proxies is None: proxies = getproxies() assert hasattr(proxies, 'has_key'), "proxies must be a mapping" self.proxies = proxies for type, url in proxies.items(): setattr(self, '%s_open' % type, lambda r, proxy=url, type=type, meth=self.proxy_open: \ meth(r, proxy, type))
def proxy_open(self, req, proxy, type): orig_type = req.get_type() proxy_type, user, password, hostport = _parse_proxy(proxy) if proxy_type is None: proxy_type = orig_type if req.host and proxy_bypass(req.host): return None if user and password: user_pass = '%s:%s' % (unquote(user), unquote(password)) creds = base64.b64encode(user_pass).strip() req.add_header('Proxy-authorization', 'Basic ' + creds) hostport = unquote(hostport) req.set_proxy(hostport, proxy_type) if orig_type == proxy_type or orig_type == 'https': # let other handlers take care of it return None else: # need to start over, because the other handlers don't # grok the proxy's URL type # e.g. if we have a constructor arg proxies like so: # {'http': 'ftp://proxy.example.com'}, we may end up turning # a request for http://acme.example.com/a into one for # ftp://proxy.example.com/a return self.parent.open(req, timeout=req.timeout)
class HTTPPasswordMgr: def __init__(self): self.passwd = {} def add_password(self, realm, uri, user, passwd): # uri could be a single URI or a sequence if isinstance(uri, basestring): uri = [uri] if not realm in self.passwd: self.passwd[realm] = {} for default_port in True, False: reduced_uri = tuple( [self.reduce_uri(u, default_port) for u in uri]) self.passwd[realm][reduced_uri] = (user, passwd) def find_user_password(self, realm, authuri): domains = self.passwd.get(realm, {}) for default_port in True, False: reduced_authuri = self.reduce_uri(authuri, default_port) for uris, authinfo in domains.iteritems(): for uri in uris: if self.is_suburi(uri, reduced_authuri): return authinfo return None, None def reduce_uri(self, uri, default_port=True): """Accept authority or URI and extract only the authority and path.""" # note HTTP URLs do not have a userinfo component parts = urlparse.urlsplit(uri) if parts[1]: # URI scheme = parts[0] authority = parts[1] path = parts[2] or '/' else: # host or host:port scheme = None authority = uri path = '/' host, port = splitport(authority) if default_port and port is None and scheme is not None: dport = {"http": 80, "https": 443, }.get(scheme) if dport is not None: authority = "%s:%d" % (host, dport) return authority, path def is_suburi(self, base, test): """Check if test is below base in a URI tree Both args must be URIs in reduced form. """ if base == test: return True if base[0] != test[0]: return False common = posixpath.commonprefix((base[1], test[1])) if len(common) == len(base[1]): return True return False class HTTPPasswordMgrWithDefaultRealm(HTTPPasswordMgr): def find_user_password(self, realm, authuri): user, password = HTTPPasswordMgr.find_user_password(self, realm, authuri) if user is not None: return user, password return HTTPPasswordMgr.find_user_password(self, None, authuri) class AbstractBasicAuthHandler: # XXX this allows for multiple auth-schemes, but will stupidly pick # the last one with a realm specified. # allow for double- and single-quoted realm values # (single quotes are a violation of the RFC, but appear in the wild) rx = re.compile('(?:.*,)*[ \t]*([^ \t]+)[ \t]+' 'realm=(["\']?)([^"\']*)\\2', re.I) # XXX could pre-emptively send auth info already accepted (RFC 2617, # end of section 2, and section 1.2 immediately after "credentials" # production). def __init__(self, password_mgr=None): if password_mgr is None: password_mgr = HTTPPasswordMgr() self.passwd = password_mgr self.add_password = self.passwd.add_password def http_error_auth_reqed(self, authreq, host, req, headers): # host may be an authority (without userinfo) or a URL with an # authority # XXX could be multiple headers authreq = headers.get(authreq, None) if authreq: mo = AbstractBasicAuthHandler.rx.search(authreq) if mo: scheme, quote, realm = mo.groups() if quote not in ['"', "'"]: warnings.warn("Basic Auth Realm was unquoted", UserWarning, 2) if scheme.lower() == 'basic': return self.retry_http_basic_auth(host, req, realm) def retry_http_basic_auth(self, host, req, realm): user, pw = self.passwd.find_user_password(realm, host) if pw is not None: raw = "%s:%s" % (user, pw) auth = 'Basic %s' % base64.b64encode(raw).strip() if req.get_header(self.auth_header, None) == auth: return None req.add_unredirected_header(self.auth_header, auth) return self.parent.open(req, timeout=req.timeout) else: return None class HTTPBasicAuthHandler(AbstractBasicAuthHandler, BaseHandler): auth_header = 'Authorization' def http_error_401(self, req, fp, code, msg, headers): url = req.get_full_url() response = self.http_error_auth_reqed('www-authenticate', url, req, headers) return response class ProxyBasicAuthHandler(AbstractBasicAuthHandler, BaseHandler): auth_header = 'Proxy-authorization' def http_error_407(self, req, fp, code, msg, headers): # http_error_auth_reqed requires that there is no userinfo component in # authority. Assume there isn't one, since urllib2 does not (and # should not, RFC 3986 s. 3.2.1) support requests for URLs containing # userinfo. authority = req.get_host() response = self.http_error_auth_reqed('proxy-authenticate', authority, req, headers) return response def randombytes(n): """Return n random bytes.""" # Use /dev/urandom if it is available. Fall back to random module # if not. It might be worthwhile to extend this function to use # other platform-specific mechanisms for getting random bytes. if os.path.exists("/dev/urandom"): f = open("/dev/urandom") s = f.read(n) f.close() return s else: L = [chr(random.randrange(0, 256)) for i in range(n)] return "".join(L) class AbstractDigestAuthHandler: # Digest authentication is specified in RFC 2617. # XXX The client does not inspect the Authentication-Info header # in a successful response. # XXX It should be possible to test this implementation against # a mock server that just generates a static set of challenges. # XXX qop="auth-int" supports is shaky def __init__(self, passwd=None): if passwd is None: passwd = HTTPPasswordMgr() self.passwd = passwd self.add_password = self.passwd.add_password self.retried = 0 self.nonce_count = 0 self.last_nonce = None def reset_retry_count(self): self.retried = 0 def http_error_auth_reqed(self, auth_header, host, req, headers): authreq = headers.get(auth_header, None) if self.retried > 5: # Don't fail endlessly - if we failed once, we'll probably # fail a second time. Hm. Unless the Password Manager is # prompting for the information. Crap. This isn't great # but it's better than the current 'repeat until recursion # depth exceeded' approach <wink> raise HTTPError(req.get_full_url(), 401, "digest auth failed", headers, None) else: self.retried += 1 if authreq: scheme = authreq.split()[0] if scheme.lower() == 'digest': return self.retry_http_digest_auth(req, authreq) def retry_http_digest_auth(self, req, auth): token, challenge = auth.split(' ', 1) chal = parse_keqv_list(parse_http_list(challenge)) auth = self.get_authorization(req, chal) if auth: auth_val = 'Digest %s' % auth if req.headers.get(self.auth_header, None) == auth_val: return None req.add_unredirected_header(self.auth_header, auth_val) resp = self.parent.open(req, timeout=req.timeout) return resp def get_cnonce(self, nonce): # The cnonce-value is an opaque # quoted string value provided by the client and used by both client # and server to avoid chosen plaintext attacks, to provide mutual # authentication, and to provide some message integrity protection. # This isn't a fabulous effort, but it's probably Good Enough. dig = hashlib.sha1("%s:%s:%s:%s" % (self.nonce_count, nonce, time.ctime(), randombytes(8))).hexdigest() return dig[:16] def get_authorization(self, req, chal): try: realm = chal['realm'] nonce = chal['nonce'] qop = chal.get('qop') algorithm = chal.get('algorithm', 'MD5') # mod_digest doesn't send an opaque, even though it isn't # supposed to be optional opaque = chal.get('opaque', None) except KeyError: return None H, KD = self.get_algorithm_impls(algorithm) if H is None: return None user, pw = self.passwd.find_user_password(realm, req.get_full_url()) if user is None: return None # XXX not implemented yet if req.has_data(): entdig = self.get_entity_digest(req.get_data(), chal) else: entdig = None A1 = "%s:%s:%s" % (user, realm, pw) A2 = "%s:%s" % (req.get_method(), # XXX selector: what about proxies and full urls req.get_selector()) if qop == 'auth': if nonce == self.last_nonce: self.nonce_count += 1 else: self.nonce_count = 1 self.last_nonce = nonce ncvalue = '%08x' % self.nonce_count cnonce = self.get_cnonce(nonce) noncebit = "%s:%s:%s:%s:%s" % (nonce, ncvalue, cnonce, qop, H(A2)) respdig = KD(H(A1), noncebit) elif qop is None: respdig = KD(H(A1), "%s:%s" % (nonce, H(A2))) else: # XXX handle auth-int. raise URLError("qop '%s' is not supported." % qop) # XXX should the partial digests be encoded too? base = 'username="%s", realm="%s", nonce="%s", uri="%s", ' \ 'response="%s"' % (user, realm, nonce, req.get_selector(), respdig) if opaque: base += ', opaque="%s"' % opaque if entdig: base += ', digest="%s"' % entdig base += ', algorithm="%s"' % algorithm if qop: base += ', qop=auth, nc=%s, cnonce="%s"' % (ncvalue, cnonce) return base def get_algorithm_impls(self, algorithm): # algorithm should be case-insensitive according to RFC2617 algorithm = algorithm.upper() # lambdas assume digest modules are imported at the top level if algorithm == 'MD5': H = lambda x: hashlib.md5(x).hexdigest() elif algorithm == 'SHA': H = lambda x: hashlib.sha1(x).hexdigest() # XXX MD5-sess KD = lambda s, d: H("%s:%s" % (s, d)) return H, KD def get_entity_digest(self, data, chal): # XXX not implemented yet return None class HTTPDigestAuthHandler(BaseHandler, AbstractDigestAuthHandler): """An authentication protocol defined by RFC 2069 Digest authentication improves on basic authentication because it does not transmit passwords in the clear. """ auth_header = 'Authorization' handler_order = 490 # before Basic auth def http_error_401(self, req, fp, code, msg, headers): host = urlparse.urlparse(req.get_full_url())[1] retry = self.http_error_auth_reqed('www-authenticate', host, req, headers) self.reset_retry_count() return retry class ProxyDigestAuthHandler(BaseHandler, AbstractDigestAuthHandler): auth_header = 'Proxy-Authorization' handler_order = 490 # before Basic auth def http_error_407(self, req, fp, code, msg, headers): host = req.get_host() retry = self.http_error_auth_reqed('proxy-authenticate', host, req, headers) self.reset_retry_count() return retry class AbstractHTTPHandler(BaseHandler): def __init__(self, debuglevel=0): self._debuglevel = debuglevel def set_http_debuglevel(self, level): self._debuglevel = level def do_request_(self, request): host = request.get_host() if not host: raise URLError('no host given') if request.has_data(): # POST data = request.get_data() if not request.has_header('Content-type'): request.add_unredirected_header( 'Content-type', 'application/x-www-form-urlencoded') if not request.has_header('Content-length'): request.add_unredirected_header( 'Content-length', '%d' % len(data)) sel_host = host if request.has_proxy(): scheme, sel = splittype(request.get_selector()) sel_host, sel_path = splithost(sel) if not request.has_header('Host'): request.add_unredirected_header('Host', sel_host) for name, value in self.parent.addheaders: name = name.capitalize() if not request.has_header(name): request.add_unredirected_header(name, value) return request def do_open(self, http_class, req, **http_conn_args): """Return an addinfourl object for the request, using http_class. http_class must implement the HTTPConnection API from httplib. The addinfourl return value is a file-like object. It also has methods and attributes including: - info(): return a mimetools.Message object for the headers - geturl(): return the original request URL - code: HTTP status code """ host = req.get_host() if not host: raise URLError('no host given') # will parse host:port h = http_class(host, timeout=req.timeout, **http_conn_args) h.set_debuglevel(self._debuglevel) headers = dict(req.unredirected_hdrs) headers.update(dict((k, v) for k, v in req.headers.items() if k not in headers)) # We want to make an HTTP/1.1 request, but the addinfourl # class isn't prepared to deal with a persistent connection. # It will try to read all remaining data from the socket, # which will block while the server waits for the next request. # So make sure the connection gets closed after the (only) # request. headers["Connection"] = "close" headers = dict( (name.title(), val) for name, val in headers.items()) if req._tunnel_host: tunnel_headers = {} proxy_auth_hdr = "Proxy-Authorization" if proxy_auth_hdr in headers: tunnel_headers[proxy_auth_hdr] = headers[proxy_auth_hdr] # Proxy-Authorization should not be sent to origin # server. del headers[proxy_auth_hdr] h.set_tunnel(req._tunnel_host, headers=tunnel_headers) try: h.request(req.get_method(), req.get_selector(), req.data, headers) except socket.error, err: # XXX what error? h.close() raise URLError(err) else: try: r = h.getresponse(buffering=True) except TypeError: # buffering kw not supported r = h.getresponse() # Pick apart the HTTPResponse object to get the addinfourl # object initialized properly. # Wrap the HTTPResponse object in socket's file object adapter # for Windows. That adapter calls recv(), so delegate recv() # to read(). This weird wrapping allows the returned object to # have readline() and readlines() methods. # XXX It might be better to extract the read buffering code # out of socket._fileobject() and into a base class. r.recv = r.read fp = socket._fileobject(r, close=True) resp = addinfourl(fp, r.msg, req.get_full_url()) resp.code = r.status resp.msg = r.reason return resp class HTTPHandler(AbstractHTTPHandler): def http_open(self, req): return self.do_open(httplib.HTTPConnection, req) http_request = AbstractHTTPHandler.do_request_ if hasattr(httplib, 'HTTPS'): class HTTPSHandler(AbstractHTTPHandler): def __init__(self, debuglevel=0, context=None): AbstractHTTPHandler.__init__(self, debuglevel) self._context = context def https_open(self, req): return self.do_open(httplib.HTTPSConnection, req, context=self._context) https_request = AbstractHTTPHandler.do_request_ class HTTPCookieProcessor(BaseHandler): def __init__(self, cookiejar=None): import cookielib if cookiejar is None: cookiejar = cookielib.CookieJar() self.cookiejar = cookiejar def http_request(self, request): self.cookiejar.add_cookie_header(request) return request def http_response(self, request, response): self.cookiejar.extract_cookies(response, request) return response https_request = http_request https_response = http_response class UnknownHandler(BaseHandler): def unknown_open(self, req): type = req.get_type() raise URLError('unknown url type: %s' % type) def parse_keqv_list(l): """Parse list of key=value strings where keys are not duplicated.""" parsed = {} for elt in l: k, v = elt.split('=', 1) if v[0] == '"' and v[-1] == '"': v = v[1:-1] parsed[k] = v return parsed def parse_http_list(s): """Parse lists as described by RFC 2068 Section 2. In particular, parse comma-separated lists where the elements of the list may include quoted-strings. A quoted-string could contain a comma. A non-quoted string could have quotes in the middle. Neither commas nor quotes count if they are escaped. Only double-quotes count, not single-quotes. """ res = [] part = '' escape = quote = False for cur in s: if escape: part += cur escape = False continue if quote: if cur == '\\': escape = True continue elif cur == '"': quote = False part += cur continue if cur == ',': res.append(part) part = '' continue if cur == '"': quote = True part += cur # append last part if part: res.append(part) return [part.strip() for part in res] def _safe_gethostbyname(host): try: return socket.gethostbyname(host) except socket.gaierror: return None class FileHandler(BaseHandler): # Use local file or FTP depending on form of URL def file_open(self, req): url = req.get_selector() if url[:2] == '//' and url[2:3] != '/' and (req.host and req.host != 'localhost'): req.type = 'ftp' return self.parent.open(req) else: return self.open_local_file(req) # names for the localhost names = None def get_names(self): if FileHandler.names is None: try: FileHandler.names = tuple( socket.gethostbyname_ex('localhost')[2] + socket.gethostbyname_ex(socket.gethostname())[2]) except socket.gaierror: FileHandler.names = (socket.gethostbyname('localhost'),) return FileHandler.names # not entirely sure what the rules are here def open_local_file(self, req): import email.utils import mimetypes host = req.get_host() filename = req.get_selector() localfile = url2pathname(filename) try: stats = os.stat(localfile) size = stats.st_size modified = email.utils.formatdate(stats.st_mtime, usegmt=True) mtype = mimetypes.guess_type(filename)[0] headers = mimetools.Message(StringIO( 'Content-type: %s\nContent-length: %d\nLast-modified: %s\n' % (mtype or 'text/plain', size, modified))) if host: host, port = splitport(host) if not host or \ (not port and _safe_gethostbyname(host) in self.get_names()): if host: origurl = 'file://' + host + filename else: origurl = 'file://' + filename return addinfourl(open(localfile, 'rb'), headers, origurl) except OSError, msg: # urllib2 users shouldn't expect OSErrors coming from urlopen() raise URLError(msg) raise URLError('file not on local host') class FTPHandler(BaseHandler): def ftp_open(self, req): import ftplib import mimetypes host = req.get_host() if not host: raise URLError('ftp error: no host given') host, port = splitport(host) if port is None: port = ftplib.FTP_PORT else: port = int(port) # username/password handling user, host = splituser(host) if user: user, passwd = splitpasswd(user) else: passwd = None host = unquote(host) user = user or '' passwd = passwd or '' try: host = socket.gethostbyname(host) except socket.error, msg: raise URLError(msg) path, attrs = splitattr(req.get_selector()) dirs = path.split('/') dirs = map(unquote, dirs) dirs, file = dirs[:-1], dirs[-1] if dirs and not dirs[0]: dirs = dirs[1:] try: fw = self.connect_ftp(user, passwd, host, port, dirs, req.timeout) type = file and 'I' or 'D' for attr in attrs: attr, value = splitvalue(attr) if attr.lower() == 'type' and \ value in ('a', 'A', 'i', 'I', 'd', 'D'): type = value.upper() fp, retrlen = fw.retrfile(file, type) headers = "" mtype = mimetypes.guess_type(req.get_full_url())[0] if mtype: headers += "Content-type: %s\n" % mtype if retrlen is not None and retrlen >= 0: headers += "Content-length: %d\n" % retrlen sf = StringIO(headers) headers = mimetools.Message(sf) return addinfourl(fp, headers, req.get_full_url()) except ftplib.all_errors, msg: raise URLError, ('ftp error: %s' % msg), sys.exc_info()[2] def connect_ftp(self, user, passwd, host, port, dirs, timeout): fw = ftpwrapper(user, passwd, host, port, dirs, timeout, persistent=False) ## fw.ftp.set_debuglevel(1) return fw class CacheFTPHandler(FTPHandler): # XXX would be nice to have pluggable cache strategies # XXX this stuff is definitely not thread safe def __init__(self): self.cache = {} self.timeout = {} self.soonest = 0 self.delay = 60 self.max_conns = 16 def setTimeout(self, t): self.delay = t def setMaxConns(self, m): self.max_conns = m def connect_ftp(self, user, passwd, host, port, dirs, timeout): key = user, host, port, '/'.join(dirs), timeout if key in self.cache: self.timeout[key] = time.time() + self.delay else: self.cache[key] = ftpwrapper(user, passwd, host, port, dirs, timeout) self.timeout[key] = time.time() + self.delay self.check_cache() return self.cache[key] def check_cache(self): # first check for old ones t = time.time() if self.soonest <= t: for k, v in self.timeout.items(): if v < t: self.cache[k].close() del self.cache[k] del self.timeout[k] self.soonest = min(self.timeout.values()) # then check the size if len(self.cache) == self.max_conns: for k, v in self.timeout.items(): if v == self.soonest: del self.cache[k] del self.timeout[k] break self.soonest = min(self.timeout.values()) def clear_cache(self): for conn in self.cache.values(): conn.close() self.cache.clear() self.timeout.clear()