관리-도구
편집 파일: request.py
"""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, 307, and 308 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 OSError); 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 -- internals: BaseHandler and parent _call_chain conventions Example usage: import urllib.request # set up authentication info authinfo = urllib.request.HTTPBasicAuthHandler() authinfo.add_password(realm='PDQ Application', uri='https://mahler:8092/site-updates.py', user='klem', passwd='geheim$parole') proxy_support = urllib.request.ProxyHandler({"http" : "http://ahad-haam:3128"}) # build a new opener that adds authentication and caching FTP handlers opener = urllib.request.build_opener(proxy_support, authinfo, urllib.request.CacheFTPHandler) # install it urllib.request.install_opener(opener) f = urllib.request.urlopen('https://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 bisect import email import hashlib import http.client import io import os import posixpath import re import socket import string import sys import time import tempfile import contextlib import warnings from urllib.error import URLError, HTTPError, ContentTooShortError from urllib.parse import ( urlparse, urlsplit, urljoin, unwrap, quote, unquote, _splittype, _splithost, _splitport, _splituser, _splitpasswd, _splitattr, _splitquery, _splitvalue, _splittag, _to_bytes, unquote_to_bytes, urlunparse) from urllib.response import addinfourl, addclosehook # check for SSL try: import ssl except ImportError: _have_ssl = False else: _have_ssl = True __all__ = [ # Classes 'Request', 'OpenerDirector', 'BaseHandler', 'HTTPDefaultErrorHandler', 'HTTPRedirectHandler', 'HTTPCookieProcessor', 'ProxyHandler', 'HTTPPasswordMgr', 'HTTPPasswordMgrWithDefaultRealm', 'HTTPPasswordMgrWithPriorAuth', 'AbstractBasicAuthHandler', 'HTTPBasicAuthHandler', 'ProxyBasicAuthHandler', 'AbstractDigestAuthHandler', 'HTTPDigestAuthHandler', 'ProxyDigestAuthHandler', 'HTTPHandler', 'FileHandler', 'FTPHandler', 'CacheFTPHandler', 'DataHandler', 'UnknownHandler', 'HTTPErrorProcessor', # Functions 'urlopen', 'install_opener', 'build_opener', 'pathname2url', 'url2pathname', 'getproxies', # Legacy interface 'urlretrieve', 'urlcleanup', 'URLopener', 'FancyURLopener', ] # used in User-Agent header sent __version__ = '%d.%d' % sys.version_info[:2] _opener = None def urlopen(url, data=None, timeout=socket._GLOBAL_DEFAULT_TIMEOUT, *, cafile=None, capath=None, cadefault=False, context=None): '''Open the URL url, which can be either a string or a Request object. *data* must be an object specifying additional data to be sent to the server, or None if no such data is needed. See Request for details. urllib.request module uses HTTP/1.1 and includes a "Connection:close" header in its HTTP requests. The optional *timeout* parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). This only works for HTTP, HTTPS and FTP connections. If *context* is specified, it must be a ssl.SSLContext instance describing the various SSL options. See HTTPSConnection for more details. The optional *cafile* and *capath* parameters specify a set of trusted CA certificates for HTTPS requests. cafile should point to a single file containing a bundle of CA certificates, whereas capath should point to a directory of hashed certificate files. More information can be found in ssl.SSLContext.load_verify_locations(). The *cadefault* parameter is ignored. This function always returns an object which can work as a context manager and has the properties url, headers, and status. See urllib.response.addinfourl for more detail on these properties. For HTTP and HTTPS URLs, this function returns a http.client.HTTPResponse object slightly modified. In addition to the three new methods above, the msg attribute contains the same information as the reason attribute --- the reason phrase returned by the server --- instead of the response headers as it is specified in the documentation for HTTPResponse. For FTP, file, and data URLs and requests explicitly handled by legacy URLopener and FancyURLopener classes, this function returns a urllib.response.addinfourl object. Note that None may be returned if no handler handles the request (though the default installed global OpenerDirector uses UnknownHandler to ensure this never happens). In addition, if proxy settings are detected (for example, when a *_proxy environment variable like http_proxy is set), ProxyHandler is default installed and makes sure the requests are handled through the proxy. ''' global _opener if cafile or capath or cadefault: import warnings warnings.warn("cafile, capath and cadefault are deprecated, use a " "custom context instead.", DeprecationWarning, 2) 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(ssl.Purpose.SERVER_AUTH, cafile=cafile, capath=capath) # send ALPN extension to indicate HTTP/1.1 protocol context.set_alpn_protocols(['http/1.1']) 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) def install_opener(opener): global _opener _opener = opener _url_tempfiles = [] def urlretrieve(url, filename=None, reporthook=None, data=None): """ Retrieve a URL into a temporary location on disk. Requires a URL argument. If a filename is passed, it is used as the temporary file location. The reporthook argument should be a callable that accepts a block number, a read size, and the total file size of the URL target. The data argument should be valid URL encoded data. If a filename is passed and the URL points to a local resource, the result is a copy from local file to new file. Returns a tuple containing the path to the newly created data file as well as the resulting HTTPMessage object. """ url_type, path = _splittype(url) with contextlib.closing(urlopen(url, data)) as fp: headers = fp.info() # Just return the local path and the "headers" for file:// # URLs. No sense in performing a copy unless requested. if url_type == "file" and not filename: return os.path.normpath(path), headers # Handle temporary file setup. if filename: tfp = open(filename, 'wb') else: tfp = tempfile.NamedTemporaryFile(delete=False) filename = tfp.name _url_tempfiles.append(filename) with tfp: result = filename, headers bs = 1024*8 size = -1 read = 0 blocknum = 0 if "content-length" in headers: size = int(headers["Content-Length"]) if reporthook: reporthook(blocknum, bs, size) while True: block = fp.read(bs) if not block: break read += len(block) tfp.write(block) blocknum += 1 if reporthook: reporthook(blocknum, bs, size) if size >= 0 and read < size: raise ContentTooShortError( "retrieval incomplete: got only %i out of %i bytes" % (read, size), result) return result def urlcleanup(): """Clean up temporary files from urlretrieve calls.""" for temp_file in _url_tempfiles: try: os.unlink(temp_file) except OSError: pass del _url_tempfiles[:] global _opener if _opener: _opener = None # copied from cookielib.py _cut_port_re = re.compile(r":\d+$", re.ASCII) def request_host(request): """Return request-host, as defined by RFC 2965. Variation from RFC: returned value is lowercased, for convenient comparison. """ url = request.full_url host = 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, method=None): self.full_url = url self.headers = {} self.unredirected_hdrs = {} self._data = None self.data = data self._tunnel_host = None for key, value in headers.items(): self.add_header(key, value) if origin_req_host is None: origin_req_host = request_host(self) self.origin_req_host = origin_req_host self.unverifiable = unverifiable if method: self.method = method @property def full_url(self): if self.fragment: return '{}#{}'.format(self._full_url, self.fragment) return self._full_url @full_url.setter def full_url(self, url): # unwrap('<URL:type://host/path>') --> 'type://host/path' self._full_url = unwrap(url) self._full_url, self.fragment = _splittag(self._full_url) self._parse() @full_url.deleter def full_url(self): self._full_url = None self.fragment = None self.selector = '' @property def data(self): return self._data @data.setter def data(self, data): if data != self._data: self._data = data # issue 16464 # if we change data we need to remove content-length header # (cause it's most probably calculated for previous value) if self.has_header("Content-length"): self.remove_header("Content-length") @data.deleter def data(self): self.data = None def _parse(self): self.type, rest = _splittype(self._full_url) if self.type is None: raise ValueError("unknown url type: %r" % self.full_url) self.host, self.selector = _splithost(rest) if self.host: self.host = unquote(self.host) def get_method(self): """Return a string indicating the HTTP request method.""" default_method = "POST" if self.data is not None else "GET" return getattr(self, 'method', default_method) def get_full_url(self): return self.full_url 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.selector = self.full_url self.host = host def has_proxy(self): return self.selector == self.full_url 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 remove_header(self, header_name): self.headers.pop(header_name, None) self.unredirected_hdrs.pop(header_name, None) def header_items(self): hdrs = {**self.unredirected_hdrs, **self.headers} return list(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, str): req = Request(fullurl, data) else: req = fullurl if data is not None: req.data = data req.timeout = timeout protocol = req.type # pre-process request meth_name = protocol+"_request" for processor in self.process_request.get(protocol, []): meth = getattr(processor, meth_name) req = meth(req) sys.audit('urllib.Request', req.full_url, req.data, req.headers, req.get_method()) 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.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 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. """ opener = OpenerDirector() default_classes = [ProxyHandler, UnknownHandler, HTTPHandler, HTTPDefaultErrorHandler, HTTPRedirectHandler, FTPHandler, FileHandler, HTTPErrorProcessor, DataHandler] if hasattr(http.client, "HTTPSConnection"): default_classes.append(HTTPSHandler) skip = set() for klass in default_classes: for check in handlers: if isinstance(check, type): 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 isinstance(h, type): 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.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 (not (code in (301, 302, 303, 307, 308) and m in ("GET", "HEAD") or code in (301, 302, 303) and m == "POST")): raise HTTPError(req.full_url, code, msg, headers, fp) # Strictly (according to RFC 2616), 301 or 302 in response to # a POST MUST NOT cause a redirection without confirmation # from the user (of urllib.request, 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. This is mainly # redundant with the more complete encoding done in http_error_302(), # but it is kept for compatibility with other callers. newurl = newurl.replace(' ', '%20') CONTENT_HEADERS = ("content-length", "content-type") newheaders = {k: v for k, v in req.headers.items() if k.lower() not in CONTENT_HEADERS} return Request(newurl, headers=newheaders, origin_req_host=req.origin_req_host, unverifiable=True) # 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["location"] elif "uri" in headers: newurl = headers["uri"] else: return # fix a possible malformed URL urlparts = urlparse(newurl) # For security reasons we don't allow redirection to anything other # than http, https or ftp. if urlparts.scheme not in ('http', 'https', 'ftp', ''): raise HTTPError( newurl, code, "%s - Redirection to url '%s' is not allowed" % (msg, newurl), headers, fp) if not urlparts.path and urlparts.netloc: urlparts = list(urlparts) urlparts[2] = "/" newurl = urlunparse(urlparts) # http.client.parse_headers() decodes as ISO-8859-1. Recover the # original bytes and percent-encode non-ASCII bytes, and any special # characters such as the space. newurl = quote( newurl, encoding="iso-8859-1", safe=string.punctuation) newurl = urljoin(req.full_url, newurl) # 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.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_308 = 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. """ 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 '/' if '@' in r_scheme: host_separator = r_scheme.find('@') end = r_scheme.find("/", host_separator) else: 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 class ProxyHandler(BaseHandler): # Proxies must be in front handler_order = 100 def __init__(self, proxies=None): if proxies is None: proxies = getproxies() assert hasattr(proxies, 'keys'), "proxies must be a mapping" self.proxies = proxies for type, url in proxies.items(): type = type.lower() 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.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.encode()).decode("ascii") 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, str): uri = [uri] if realm not 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.items(): 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 = 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 prefix = base[1] if prefix[-1:] != '/': prefix += '/' return test[1].startswith(prefix) 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 HTTPPasswordMgrWithPriorAuth(HTTPPasswordMgrWithDefaultRealm): def __init__(self, *args, **kwargs): self.authenticated = {} super().__init__(*args, **kwargs) def add_password(self, realm, uri, user, passwd, is_authenticated=False): self.update_authenticated(uri, is_authenticated) # Add a default for prior auth requests if realm is not None: super().add_password(None, uri, user, passwd) super().add_password(realm, uri, user, passwd) def update_authenticated(self, uri, is_authenticated=False): # uri could be a single URI or a sequence if isinstance(uri, str): uri = [uri] for default_port in True, False: for u in uri: reduced_uri = self.reduce_uri(u, default_port) self.authenticated[reduced_uri] = is_authenticated def is_authenticated(self, authuri): for default_port in True, False: reduced_authuri = self.reduce_uri(authuri, default_port) for uri in self.authenticated: if self.is_suburi(uri, reduced_authuri): return self.authenticated[uri] 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('(?:^|,)' # start of the string or ',' '[ \t]*' # optional whitespaces '([^ \t,]+)' # scheme like "Basic" '[ \t]+' # mandatory whitespaces # realm=xxx # realm='xxx' # realm="xxx" '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 _parse_realm(self, header): # parse WWW-Authenticate header: accept multiple challenges per header found_challenge = False for mo in AbstractBasicAuthHandler.rx.finditer(header): scheme, quote, realm = mo.groups() if quote not in ['"', "'"]: warnings.warn("Basic Auth Realm was unquoted", UserWarning, 3) yield (scheme, realm) found_challenge = True if not found_challenge: if header: scheme = header.split()[0] else: scheme = '' yield (scheme, None) def http_error_auth_reqed(self, authreq, host, req, headers): # host may be an authority (without userinfo) or a URL with an # authority headers = headers.get_all(authreq) if not headers: # no header found return unsupported = None for header in headers: for scheme, realm in self._parse_realm(header): if scheme.lower() != 'basic': unsupported = scheme continue if realm is not None: # Use the first matching Basic challenge. # Ignore following challenges even if they use the Basic # scheme. return self.retry_http_basic_auth(host, req, realm) if unsupported is not None: raise ValueError("AbstractBasicAuthHandler does not " "support the following scheme: %r" % (scheme,)) 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 " + base64.b64encode(raw.encode()).decode("ascii") 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 def http_request(self, req): if (not hasattr(self.passwd, 'is_authenticated') or not self.passwd.is_authenticated(req.full_url)): return req if not req.has_header('Authorization'): user, passwd = self.passwd.find_user_password(None, req.full_url) credentials = '{0}:{1}'.format(user, passwd).encode() auth_str = base64.standard_b64encode(credentials).decode() req.add_unredirected_header('Authorization', 'Basic {}'.format(auth_str.strip())) return req def http_response(self, req, response): if hasattr(self.passwd, 'is_authenticated'): if 200 <= response.code < 300: self.passwd.update_authenticated(req.full_url, True) else: self.passwd.update_authenticated(req.full_url, False) return response https_request = http_request https_response = http_response class HTTPBasicAuthHandler(AbstractBasicAuthHandler, BaseHandler): auth_header = 'Authorization' def http_error_401(self, req, fp, code, msg, headers): url = req.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 urllib.request does not (and # should not, RFC 3986 s. 3.2.1) support requests for URLs containing # userinfo. authority = req.host response = self.http_error_auth_reqed('proxy-authenticate', authority, req, headers) return response # Return n random bytes. _randombytes = os.urandom 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.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) elif scheme.lower() != 'basic': raise ValueError("AbstractDigestAuthHandler does not support" " the following scheme: '%s'" % scheme) def retry_http_digest_auth(self, req, auth): token, challenge = auth.split(' ', 1) chal = parse_keqv_list(filter(None, 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. s = "%s:%s:%s:" % (self.nonce_count, nonce, time.ctime()) b = s.encode("ascii") + _randombytes(8) dig = hashlib.sha1(b).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.full_url) if user is None: return None # XXX not implemented yet if req.data is not None: entdig = self.get_entity_digest(req.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.selector) # NOTE: As per RFC 2617, when server sends "auth,auth-int", the client could use either `auth` # or `auth-int` to the response back. we use `auth` to send the response back. if qop is None: respdig = KD(H(A1), "%s:%s" % (nonce, H(A2))) elif 'auth' in qop.split(','): 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, 'auth', H(A2)) respdig = KD(H(A1), noncebit) 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.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): # lambdas assume digest modules are imported at the top level if algorithm == 'MD5': H = lambda x: hashlib.md5(x.encode("ascii")).hexdigest() elif algorithm == 'SHA': H = lambda x: hashlib.sha1(x.encode("ascii")).hexdigest() # XXX MD5-sess else: raise ValueError("Unsupported digest authentication " "algorithm %r" % algorithm) 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(req.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.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 _get_content_length(self, request): return http.client.HTTPConnection._get_content_length( request.data, request.get_method()) def do_request_(self, request): host = request.host if not host: raise URLError('no host given') if request.data is not None: # POST data = request.data if isinstance(data, str): msg = "POST data should be bytes, an iterable of bytes, " \ "or a file object. It cannot be of type str." raise TypeError(msg) 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') and not request.has_header('Transfer-encoding')): content_length = self._get_content_length(request) if content_length is not None: request.add_unredirected_header( 'Content-length', str(content_length)) else: request.add_unredirected_header( 'Transfer-encoding', 'chunked') sel_host = host if request.has_proxy(): scheme, sel = _splittype(request.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 HTTPResponse object for the request, using http_class. http_class must implement the HTTPConnection API from http.client. """ host = req.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({k: v for k, v in req.headers.items() if k not in headers}) # TODO(jhylton): Should this be redesigned to handle # persistent connections? # 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 = {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: try: h.request(req.get_method(), req.selector, req.data, headers, encode_chunked=req.has_header('Transfer-encoding')) except OSError as err: # timeout error raise URLError(err) r = h.getresponse() except: h.close() raise # If the server does not send us a 'Connection: close' header, # HTTPConnection assumes the socket should be left open. Manually # mark the socket to be closed when this response object goes away. if h.sock: h.sock.close() h.sock = None r.url = req.get_full_url() # This line replaces the .msg attribute of the HTTPResponse # with .headers, because urllib clients expect the response to # have the reason in .msg. It would be good to mark this # attribute is deprecated and get then to use info() or # .headers. r.msg = r.reason return r class HTTPHandler(AbstractHTTPHandler): def http_open(self, req): return self.do_open(http.client.HTTPConnection, req) http_request = AbstractHTTPHandler.do_request_ if hasattr(http.client, 'HTTPSConnection'): class HTTPSHandler(AbstractHTTPHandler): def __init__(self, debuglevel=0, context=None, check_hostname=None): AbstractHTTPHandler.__init__(self, debuglevel) self._context = context self._check_hostname = check_hostname def https_open(self, req): return self.do_open(http.client.HTTPSConnection, req, context=self._context, check_hostname=self._check_hostname) https_request = AbstractHTTPHandler.do_request_ __all__.append('HTTPSHandler') class HTTPCookieProcessor(BaseHandler): def __init__(self, cookiejar=None): import http.cookiejar if cookiejar is None: cookiejar = http.cookiejar.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.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] class FileHandler(BaseHandler): # Use local file or FTP depending on form of URL def file_open(self, req): url = req.selector if url[:2] == '//' and url[2:3] != '/' and (req.host and req.host != 'localhost'): if not req.host in self.get_names(): raise URLError("file:// scheme is supported only on localhost") 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.host filename = req.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 = email.message_from_string( '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 as exp: raise URLError(exp) raise URLError('file not on local host') def _safe_gethostbyname(host): try: return socket.gethostbyname(host) except socket.gaierror: return None class FTPHandler(BaseHandler): def ftp_open(self, req): import ftplib import mimetypes host = req.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 OSError as msg: raise URLError(msg) path, attrs = _splitattr(req.selector) dirs = path.split('/') dirs = list(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.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 headers = email.message_from_string(headers) return addinfourl(fp, headers, req.full_url) except ftplib.all_errors as exp: raise URLError(exp) from exp def connect_ftp(self, user, passwd, host, port, dirs, timeout): return ftpwrapper(user, passwd, host, port, dirs, timeout, persistent=False) 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 list(self.timeout.items()): if v < t: self.cache[k].close() del self.cache[k] del self.timeout[k] self.soonest = min(list(self.timeout.values())) # then check the size if len(self.cache) == self.max_conns: for k, v in list(self.timeout.items()): if v == self.soonest: del self.cache[k] del self.timeout[k] break self.soonest = min(list(self.timeout.values())) def clear_cache(self): for conn in self.cache.values(): conn.close() self.cache.clear() self.timeout.clear() class DataHandler(BaseHandler): def data_open(self, req): # data URLs as specified in RFC 2397. # # ignores POSTed data # # syntax: # dataurl := "data:" [ mediatype ] [ ";base64" ] "," data # mediatype := [ type "/" subtype ] *( ";" parameter ) # data := *urlchar # parameter := attribute "=" value url = req.full_url scheme, data = url.split(":",1) mediatype, data = data.split(",",1) # even base64 encoded data URLs might be quoted so unquote in any case: data = unquote_to_bytes(data) if mediatype.endswith(";base64"): data = base64.decodebytes(data) mediatype = mediatype[:-7] if not mediatype: mediatype = "text/plain;charset=US-ASCII" headers = email.message_from_string("Content-type: %s\nContent-length: %d\n" % (mediatype, len(data))) return addinfourl(io.BytesIO(data), headers, url) # Code move from the old urllib module MAXFTPCACHE = 10 # Trim the ftp cache beyond this size # Helper for non-unix systems if os.name == 'nt': from nturl2path import url2pathname, pathname2url else: def url2pathname(pathname): """OS-specific conversion from a relative URL of the 'file' scheme to a file system path; not recommended for general use.""" return unquote(pathname) def pathname2url(pathname): """OS-specific conversion from a file system path to a relative URL of the 'file' scheme; not recommended for general use.""" return quote(pathname) ftpcache = {} class URLopener: """Class to open URLs. This is a class rather than just a subroutine because we may need more than one set of global protocol-specific options. Note -- this is a base class for those who don't want the automatic handling of errors type 302 (relocated) and 401 (authorization needed).""" __tempfiles = None version = "Python-urllib/%s" % __version__ # Constructor def __init__(self, proxies=None, **x509): msg = "%(class)s style of invoking requests is deprecated. " \ "Use newer urlopen functions/methods" % {'class': self.__class__.__name__} warnings.warn(msg, DeprecationWarning, stacklevel=3) if proxies is None: proxies = getproxies() assert hasattr(proxies, 'keys'), "proxies must be a mapping" self.proxies = proxies self.key_file = x509.get('key_file') self.cert_file = x509.get('cert_file') self.addheaders = [('User-Agent', self.version), ('Accept', '*/*')] self.__tempfiles = [] self.__unlink = os.unlink # See cleanup() self.tempcache = None # Undocumented feature: if you assign {} to tempcache, # it is used to cache files retrieved with # self.retrieve(). This is not enabled by default # since it does not work for changing documents (and I # haven't got the logic to check expiration headers # yet). self.ftpcache = ftpcache # Undocumented feature: you can use a different # ftp cache by assigning to the .ftpcache member; # in case you want logically independent URL openers # XXX This is not threadsafe. Bah. def __del__(self): self.close() def close(self): self.cleanup() def cleanup(self): # This code sometimes runs when the rest of this module # has already been deleted, so it can't use any globals # or import anything. if self.__tempfiles: for file in self.__tempfiles: try: self.__unlink(file) except OSError: pass del self.__tempfiles[:] if self.tempcache: self.tempcache.clear() def addheader(self, *args): """Add a header to be used by the HTTP interface only e.g. u.addheader('Accept', 'sound/basic')""" self.addheaders.append(args) # External interface def open(self, fullurl, data=None): """Use URLopener().open(file) instead of open(file, 'r').""" fullurl = unwrap(_to_bytes(fullurl)) fullurl = quote(fullurl, safe="%/:=&?~#+!$,;'@()*[]|") if self.tempcache and fullurl in self.tempcache: filename, headers = self.tempcache[fullurl] fp = open(filename, 'rb') return addinfourl(fp, headers, fullurl) urltype, url = _splittype(fullurl) if not urltype: urltype = 'file' if urltype in self.proxies: proxy = self.proxies[urltype] urltype, proxyhost = _splittype(proxy) host, selector = _splithost(proxyhost) url = (host, fullurl) # Signal special case to open_*() else: proxy = None name = 'open_' + urltype self.type = urltype name = name.replace('-', '_') if not hasattr(self, name) or name == 'open_local_file': if proxy: return self.open_unknown_proxy(proxy, fullurl, data) else: return self.open_unknown(fullurl, data) try: if data is None: return getattr(self, name)(url) else: return getattr(self, name)(url, data) except (HTTPError, URLError): raise except OSError as msg: raise OSError('socket error', msg) from msg def open_unknown(self, fullurl, data=None): """Overridable interface to open unknown URL type.""" type, url = _splittype(fullurl) raise OSError('url error', 'unknown url type', type) def open_unknown_proxy(self, proxy, fullurl, data=None): """Overridable interface to open unknown URL type.""" type, url = _splittype(fullurl) raise OSError('url error', 'invalid proxy for %s' % type, proxy) # External interface def retrieve(self, url, filename=None, reporthook=None, data=None): """retrieve(url) returns (filename, headers) for a local object or (tempfilename, headers) for a remote object.""" url = unwrap(_to_bytes(url)) if self.tempcache and url in self.tempcache: return self.tempcache[url] type, url1 = _splittype(url) if filename is None and (not type or type == 'file'): try: fp = self.open_local_file(url1) hdrs = fp.info() fp.close() return url2pathname(_splithost(url1)[1]), hdrs except OSError: pass fp = self.open(url, data) try: headers = fp.info() if filename: tfp = open(filename, 'wb') else: garbage, path = _splittype(url) garbage, path = _splithost(path or "") path, garbage = _splitquery(path or "") path, garbage = _splitattr(path or "") suffix = os.path.splitext(path)[1] (fd, filename) = tempfile.mkstemp(suffix) self.__tempfiles.append(filename) tfp = os.fdopen(fd, 'wb') try: result = filename, headers if self.tempcache is not None: self.tempcache[url] = result bs = 1024*8 size = -1 read = 0 blocknum = 0 if "content-length" in headers: size = int(headers["Content-Length"]) if reporthook: reporthook(blocknum, bs, size) while 1: block = fp.read(bs) if not block: break read += len(block) tfp.write(block) blocknum += 1 if reporthook: reporthook(blocknum, bs, size) finally: tfp.close() finally: fp.close() # raise exception if actual size does not match content-length header if size >= 0 and read < size: raise ContentTooShortError( "retrieval incomplete: got only %i out of %i bytes" % (read, size), result) return result # Each method named open_<type> knows how to open that type of URL def _open_generic_http(self, connection_factory, url, data): """Make an HTTP connection using connection_class. This is an internal method that should be called from open_http() or open_https(). Arguments: - connection_factory should take a host name and return an HTTPConnection instance. - url is the url to retrieval or a host, relative-path pair. - data is payload for a POST request or None. """ user_passwd = None proxy_passwd= None if isinstance(url, str): host, selector = _splithost(url) if host: user_passwd, host = _splituser(host) host = unquote(host) realhost = host else: host, selector = url # check whether the proxy contains authorization information proxy_passwd, host = _splituser(host) # now we proceed with the url we want to obtain urltype, rest = _splittype(selector) url = rest user_passwd = None if urltype.lower() != 'http': realhost = None else: realhost, rest = _splithost(rest) if realhost: user_passwd, realhost = _splituser(realhost) if user_passwd: selector = "%s://%s%s" % (urltype, realhost, rest) if proxy_bypass(realhost): host = realhost if not host: raise OSError('http error', 'no host given') if proxy_passwd: proxy_passwd = unquote(proxy_passwd) proxy_auth = base64.b64encode(proxy_passwd.encode()).decode('ascii') else: proxy_auth = None if user_passwd: user_passwd = unquote(user_passwd) auth = base64.b64encode(user_passwd.encode()).decode('ascii') else: auth = None http_conn = connection_factory(host) headers = {} if proxy_auth: headers["Proxy-Authorization"] = "Basic %s" % proxy_auth if auth: headers["Authorization"] = "Basic %s" % auth if realhost: headers["Host"] = realhost # Add Connection:close as we don't support persistent connections yet. # This helps in closing the socket and avoiding ResourceWarning headers["Connection"] = "close" for header, value in self.addheaders: headers[header] = value if data is not None: headers["Content-Type"] = "application/x-www-form-urlencoded" http_conn.request("POST", selector, data, headers) else: http_conn.request("GET", selector, headers=headers) try: response = http_conn.getresponse() except http.client.BadStatusLine: # something went wrong with the HTTP status line raise URLError("http protocol error: bad status line") # According to RFC 2616, "2xx" code indicates that the client's # request was successfully received, understood, and accepted. if 200 <= response.status < 300: return addinfourl(response, response.msg, "http:" + url, response.status) else: return self.http_error( url, response.fp, response.status, response.reason, response.msg, data) def open_http(self, url, data=None): """Use HTTP protocol.""" return self._open_generic_http(http.client.HTTPConnection, url, data) def http_error(self, url, fp, errcode, errmsg, headers, data=None): """Handle http errors. Derived class can override this, or provide specific handlers named http_error_DDD where DDD is the 3-digit error code.""" # First check if there's a specific handler for this error name = 'http_error_%d' % errcode if hasattr(self, name): method = getattr(self, name) if data is None: result = method(url, fp, errcode, errmsg, headers) else: result = method(url, fp, errcode, errmsg, headers, data) if result: return result return self.http_error_default(url, fp, errcode, errmsg, headers) def http_error_default(self, url, fp, errcode, errmsg, headers): """Default error handler: close the connection and raise OSError.""" fp.close() raise HTTPError(url, errcode, errmsg, headers, None) if _have_ssl: def _https_connection(self, host): return http.client.HTTPSConnection(host, key_file=self.key_file, cert_file=self.cert_file) def open_https(self, url, data=None): """Use HTTPS protocol.""" return self._open_generic_http(self._https_connection, url, data) def open_file(self, url): """Use local file or FTP depending on form of URL.""" if not isinstance(url, str): raise URLError('file error: proxy support for file protocol currently not implemented') if url[:2] == '//' and url[2:3] != '/' and url[2:12].lower() != 'localhost/': raise ValueError("file:// scheme is supported only on localhost") else: return self.open_local_file(url) def open_local_file(self, url): """Use local file.""" import email.utils import mimetypes host, file = _splithost(url) localname = url2pathname(file) try: stats = os.stat(localname) except OSError as e: raise URLError(e.strerror, e.filename) size = stats.st_size modified = email.utils.formatdate(stats.st_mtime, usegmt=True) mtype = mimetypes.guess_type(url)[0] headers = email.message_from_string( 'Content-Type: %s\nContent-Length: %d\nLast-modified: %s\n' % (mtype or 'text/plain', size, modified)) if not host: urlfile = file if file[:1] == '/': urlfile = 'file://' + file return addinfourl(open(localname, 'rb'), headers, urlfile) host, port = _splitport(host) if (not port and socket.gethostbyname(host) in ((localhost(),) + thishost())): urlfile = file if file[:1] == '/': urlfile = 'file://' + file elif file[:2] == './': raise ValueError("local file url may start with / or file:. Unknown url of type: %s" % url) return addinfourl(open(localname, 'rb'), headers, urlfile) raise URLError('local file error: not on local host') def open_ftp(self, url): """Use FTP protocol.""" if not isinstance(url, str): raise URLError('ftp error: proxy support for ftp protocol currently not implemented') import mimetypes host, path = _splithost(url) if not host: raise URLError('ftp error: no host given') host, port = _splitport(host) user, host = _splituser(host) if user: user, passwd = _splitpasswd(user) else: passwd = None host = unquote(host) user = unquote(user or '') passwd = unquote(passwd or '') host = socket.gethostbyname(host) if not port: import ftplib port = ftplib.FTP_PORT else: port = int(port) path, attrs = _splitattr(path) path = unquote(path) dirs = path.split('/') dirs, file = dirs[:-1], dirs[-1] if dirs and not dirs[0]: dirs = dirs[1:] if dirs and not dirs[0]: dirs[0] = '/' key = user, host, port, '/'.join(dirs) # XXX thread unsafe! if len(self.ftpcache) > MAXFTPCACHE: # Prune the cache, rather arbitrarily for k in list(self.ftpcache): if k != key: v = self.ftpcache[k] del self.ftpcache[k] v.close() try: if key not in self.ftpcache: self.ftpcache[key] = \ ftpwrapper(user, passwd, host, port, dirs) if not file: type = 'D' else: type = 'I' 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) = self.ftpcache[key].retrfile(file, type) mtype = mimetypes.guess_type("ftp:" + url)[0] headers = "" if mtype: headers += "Content-Type: %s\n" % mtype if retrlen is not None and retrlen >= 0: headers += "Content-Length: %d\n" % retrlen headers = email.message_from_string(headers) return addinfourl(fp, headers, "ftp:" + url) except ftperrors() as exp: raise URLError(f'ftp error: {exp}') from exp def open_data(self, url, data=None): """Use "data" URL.""" if not isinstance(url, str): raise URLError('data error: proxy support for data protocol currently not implemented') # ignore POSTed data # # syntax of data URLs: # dataurl := "data:" [ mediatype ] [ ";base64" ] "," data # mediatype := [ type "/" subtype ] *( ";" parameter ) # data := *urlchar # parameter := attribute "=" value try: [type, data] = url.split(',', 1) except ValueError: raise OSError('data error', 'bad data URL') if not type: type = 'text/plain;charset=US-ASCII' semi = type.rfind(';') if semi >= 0 and '=' not in type[semi:]: encoding = type[semi+1:] type = type[:semi] else: encoding = '' msg = [] msg.append('Date: %s'%time.strftime('%a, %d %b %Y %H:%M:%S GMT', time.gmtime(time.time()))) msg.append('Content-type: %s' % type) if encoding == 'base64': # XXX is this encoding/decoding ok? data = base64.decodebytes(data.encode('ascii')).decode('latin-1') else: data = unquote(data) msg.append('Content-Length: %d' % len(data)) msg.append('') msg.append(data) msg = '\n'.join(msg) headers = email.message_from_string(msg) f = io.StringIO(msg) #f.fileno = None # needed for addinfourl return addinfourl(f, headers, url) class FancyURLopener(URLopener): """Derived class with handlers for errors we can handle (perhaps).""" def __init__(self, *args, **kwargs): URLopener.__init__(self, *args, **kwargs) self.auth_cache = {} self.tries = 0 self.maxtries = 10 def http_error_default(self, url, fp, errcode, errmsg, headers): """Default error handling -- don't raise an exception.""" return addinfourl(fp, headers, "http:" + url, errcode) def http_error_302(self, url, fp, errcode, errmsg, headers, data=None): """Error 302 -- relocated (temporarily).""" self.tries += 1 try: if self.maxtries and self.tries >= self.maxtries: if hasattr(self, "http_error_500"): meth = self.http_error_500 else: meth = self.http_error_default return meth(url, fp, 500, "Internal Server Error: Redirect Recursion", headers) result = self.redirect_internal(url, fp, errcode, errmsg, headers, data) return result finally: self.tries = 0 def redirect_internal(self, url, fp, errcode, errmsg, headers, data): if 'location' in headers: newurl = headers['location'] elif 'uri' in headers: newurl = headers['uri'] else: return fp.close() # In case the server sent a relative URL, join with original: newurl = urljoin(self.type + ":" + url, newurl) urlparts = urlparse(newurl) # For security reasons, we don't allow redirection to anything other # than http, https and ftp. # We are using newer HTTPError with older redirect_internal method # This older method will get deprecated in 3.3 if urlparts.scheme not in ('http', 'https', 'ftp', ''): raise HTTPError(newurl, errcode, errmsg + " Redirection to url '%s' is not allowed." % newurl, headers, fp) return self.open(newurl) def http_error_301(self, url, fp, errcode, errmsg, headers, data=None): """Error 301 -- also relocated (permanently).""" return self.http_error_302(url, fp, errcode, errmsg, headers, data) def http_error_303(self, url, fp, errcode, errmsg, headers, data=None): """Error 303 -- also relocated (essentially identical to 302).""" return self.http_error_302(url, fp, errcode, errmsg, headers, data) def http_error_307(self, url, fp, errcode, errmsg, headers, data=None): """Error 307 -- relocated, but turn POST into error.""" if data is None: return self.http_error_302(url, fp, errcode, errmsg, headers, data) else: return self.http_error_default(url, fp, errcode, errmsg, headers) def http_error_308(self, url, fp, errcode, errmsg, headers, data=None): """Error 308 -- relocated, but turn POST into error.""" if data is None: return self.http_error_301(url, fp, errcode, errmsg, headers, data) else: return self.http_error_default(url, fp, errcode, errmsg, headers) def http_error_401(self, url, fp, errcode, errmsg, headers, data=None, retry=False): """Error 401 -- authentication required. This function supports Basic authentication only.""" if 'www-authenticate' not in headers: URLopener.http_error_default(self, url, fp, errcode, errmsg, headers) stuff = headers['www-authenticate'] match = re.match('[ \t]*([^ \t]+)[ \t]+realm="([^"]*)"', stuff) if not match: URLopener.http_error_default(self, url, fp, errcode, errmsg, headers) scheme, realm = match.groups() if scheme.lower() != 'basic': URLopener.http_error_default(self, url, fp, errcode, errmsg, headers) if not retry: URLopener.http_error_default(self, url, fp, errcode, errmsg, headers) name = 'retry_' + self.type + '_basic_auth' if data is None: return getattr(self,name)(url, realm) else: return getattr(self,name)(url, realm, data) def http_error_407(self, url, fp, errcode, errmsg, headers, data=None, retry=False): """Error 407 -- proxy authentication required. This function supports Basic authentication only.""" if 'proxy-authenticate' not in headers: URLopener.http_error_default(self, url, fp, errcode, errmsg, headers) stuff = headers['proxy-authenticate'] match = re.match('[ \t]*([^ \t]+)[ \t]+realm="([^"]*)"', stuff) if not match: URLopener.http_error_default(self, url, fp, errcode, errmsg, headers) scheme, realm = match.groups() if scheme.lower() != 'basic': URLopener.http_error_default(self, url, fp, errcode, errmsg, headers) if not retry: URLopener.http_error_default(self, url, fp, errcode, errmsg, headers) name = 'retry_proxy_' + self.type + '_basic_auth' if data is None: return getattr(self,name)(url, realm) else: return getattr(self,name)(url, realm, data) def retry_proxy_http_basic_auth(self, url, realm, data=None): host, selector = _splithost(url) newurl = 'http://' + host + selector proxy = self.proxies['http'] urltype, proxyhost = _splittype(proxy) proxyhost, proxyselector = _splithost(proxyhost) i = proxyhost.find('@') + 1 proxyhost = proxyhost[i:] user, passwd = self.get_user_passwd(proxyhost, realm, i) if not (user or passwd): return None proxyhost = "%s:%s@%s" % (quote(user, safe=''), quote(passwd, safe=''), proxyhost) self.proxies['http'] = 'http://' + proxyhost + proxyselector if data is None: return self.open(newurl) else: return self.open(newurl, data) def retry_proxy_https_basic_auth(self, url, realm, data=None): host, selector = _splithost(url) newurl = 'https://' + host + selector proxy = self.proxies['https'] urltype, proxyhost = _splittype(proxy) proxyhost, proxyselector = _splithost(proxyhost) i = proxyhost.find('@') + 1 proxyhost = proxyhost[i:] user, passwd = self.get_user_passwd(proxyhost, realm, i) if not (user or passwd): return None proxyhost = "%s:%s@%s" % (quote(user, safe=''), quote(passwd, safe=''), proxyhost) self.proxies['https'] = 'https://' + proxyhost + proxyselector if data is None: return self.open(newurl) else: return self.open(newurl, data) def retry_http_basic_auth(self, url, realm, data=None): host, selector = _splithost(url) i = host.find('@') + 1 host = host[i:] user, passwd = self.get_user_passwd(host, realm, i) if not (user or passwd): return None host = "%s:%s@%s" % (quote(user, safe=''), quote(passwd, safe=''), host) newurl = 'http://' + host + selector if data is None: return self.open(newurl) else: return self.open(newurl, data) def retry_https_basic_auth(self, url, realm, data=None): host, selector = _splithost(url) i = host.find('@') + 1 host = host[i:] user, passwd = self.get_user_passwd(host, realm, i) if not (user or passwd): return None host = "%s:%s@%s" % (quote(user, safe=''), quote(passwd, safe=''), host) newurl = 'https://' + host + selector if data is None: return self.open(newurl) else: return self.open(newurl, data) def get_user_passwd(self, host, realm, clear_cache=0): key = realm + '@' + host.lower() if key in self.auth_cache: if clear_cache: del self.auth_cache[key] else: return self.auth_cache[key] user, passwd = self.prompt_user_passwd(host, realm) if user or passwd: self.auth_cache[key] = (user, passwd) return user, passwd def prompt_user_passwd(self, host, realm): """Override this in a GUI environment!""" import getpass try: user = input("Enter username for %s at %s: " % (realm, host)) passwd = getpass.getpass("Enter password for %s in %s at %s: " % (user, realm, host)) return user, passwd except KeyboardInterrupt: print() return None, None # Utility functions _localhost = None def localhost(): """Return the IP address of the magic hostname 'localhost'.""" global _localhost if _localhost is None: _localhost = socket.gethostbyname('localhost') return _localhost _thishost = None def thishost(): """Return the IP addresses of the current host.""" global _thishost if _thishost is None: try: _thishost = tuple(socket.gethostbyname_ex(socket.gethostname())[2]) except socket.gaierror: _thishost = tuple(socket.gethostbyname_ex('localhost')[2]) return _thishost _ftperrors = None def ftperrors(): """Return the set of errors raised by the FTP class.""" global _ftperrors if _ftperrors is None: import ftplib _ftperrors = ftplib.all_errors return _ftperrors _noheaders = None def noheaders(): """Return an empty email Message object.""" global _noheaders if _noheaders is None: _noheaders = email.message_from_string("") return _noheaders # Utility classes class ftpwrapper: """Class used by open_ftp() for cache of open FTP connections.""" def __init__(self, user, passwd, host, port, dirs, timeout=None, persistent=True): self.user = user self.passwd = passwd self.host = host self.port = port self.dirs = dirs self.timeout = timeout self.refcount = 0 self.keepalive = persistent try: self.init() except: self.close() raise def init(self): import ftplib self.busy = 0 self.ftp = ftplib.FTP() self.ftp.connect(self.host, self.port, self.timeout) self.ftp.login(self.user, self.passwd) _target = '/'.join(self.dirs) self.ftp.cwd(_target) def retrfile(self, file, type): import ftplib self.endtransfer() if type in ('d', 'D'): cmd = 'TYPE A'; isdir = 1 else: cmd = 'TYPE ' + type; isdir = 0 try: self.ftp.voidcmd(cmd) except ftplib.all_errors: self.init() self.ftp.voidcmd(cmd) conn = None if file and not isdir: # Try to retrieve as a file try: cmd = 'RETR ' + file conn, retrlen = self.ftp.ntransfercmd(cmd) except ftplib.error_perm as reason: if str(reason)[:3] != '550': raise URLError(f'ftp error: {reason}') from reason if not conn: # Set transfer mode to ASCII! self.ftp.voidcmd('TYPE A') # Try a directory listing. Verify that directory exists. if file: pwd = self.ftp.pwd() try: try: self.ftp.cwd(file) except ftplib.error_perm as reason: raise URLError('ftp error: %r' % reason) from reason finally: self.ftp.cwd(pwd) cmd = 'LIST ' + file else: cmd = 'LIST' conn, retrlen = self.ftp.ntransfercmd(cmd) self.busy = 1 ftpobj = addclosehook(conn.makefile('rb'), self.file_close) self.refcount += 1 conn.close() # Pass back both a suitably decorated object and a retrieval length return (ftpobj, retrlen) def endtransfer(self): if not self.busy: return self.busy = 0 try: self.ftp.voidresp() except ftperrors(): pass def close(self): self.keepalive = False if self.refcount <= 0: self.real_close() def file_close(self): self.endtransfer() self.refcount -= 1 if self.refcount <= 0 and not self.keepalive: self.real_close() def real_close(self): self.endtransfer() try: self.ftp.close() except ftperrors(): pass # Proxy handling def getproxies_environment(): """Return a dictionary of scheme -> proxy server URL mappings. Scan the environment for variables named <scheme>_proxy; this seems to be the standard convention. If you need a different way, you can pass a proxies dictionary to the [Fancy]URLopener constructor. """ proxies = {} # in order to prefer lowercase variables, process environment in # two passes: first matches any, second pass matches lowercase only for name, value in os.environ.items(): name = name.lower() if value and name[-6:] == '_proxy': proxies[name[:-6]] = value # CVE-2016-1000110 - If we are running as CGI script, forget HTTP_PROXY # (non-all-lowercase) as it may be set from the web server by a "Proxy:" # header from the client # If "proxy" is lowercase, it will still be used thanks to the next block if 'REQUEST_METHOD' in os.environ: proxies.pop('http', None) for name, value in os.environ.items(): if name[-6:] == '_proxy': name = name.lower() if value: proxies[name[:-6]] = value else: proxies.pop(name[:-6], None) return proxies def proxy_bypass_environment(host, proxies=None): """Test if proxies should not be used for a particular host. Checks the proxy dict for the value of no_proxy, which should be a list of comma separated DNS suffixes, or '*' for all hosts. """ if proxies is None: proxies = getproxies_environment() # don't bypass, if no_proxy isn't specified try: no_proxy = proxies['no'] except KeyError: return False # '*' is special case for always bypass if no_proxy == '*': return True host = host.lower() # strip port off host hostonly, port = _splitport(host) # check if the host ends with any of the DNS suffixes for name in no_proxy.split(','): name = name.strip() if name: name = name.lstrip('.') # ignore leading dots name = name.lower() if hostonly == name or host == name: return True name = '.' + name if hostonly.endswith(name) or host.endswith(name): return True # otherwise, don't bypass return False # This code tests an OSX specific data structure but is testable on all # platforms def _proxy_bypass_macosx_sysconf(host, proxy_settings): """ Return True iff this host shouldn't be accessed using a proxy This function uses the MacOSX framework SystemConfiguration to fetch the proxy information. proxy_settings come from _scproxy._get_proxy_settings or get mocked ie: { 'exclude_simple': bool, 'exceptions': ['foo.bar', '*.bar.com', '127.0.0.1', '10.1', '10.0/16'] } """ from fnmatch import fnmatch from ipaddress import AddressValueError, IPv4Address hostonly, port = _splitport(host) def ip2num(ipAddr): parts = ipAddr.split('.') parts = list(map(int, parts)) if len(parts) != 4: parts = (parts + [0, 0, 0, 0])[:4] return (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8) | parts[3] # Check for simple host names: if '.' not in host: if proxy_settings['exclude_simple']: return True hostIP = None try: hostIP = int(IPv4Address(hostonly)) except AddressValueError: pass for value in proxy_settings.get('exceptions', ()): # Items in the list are strings like these: *.local, 169.254/16 if not value: continue m = re.match(r"(\d+(?:\.\d+)*)(/\d+)?", value) if m is not None and hostIP is not None: base = ip2num(m.group(1)) mask = m.group(2) if mask is None: mask = 8 * (m.group(1).count('.') + 1) else: mask = int(mask[1:]) if mask < 0 or mask > 32: # System libraries ignore invalid prefix lengths continue mask = 32 - mask if (hostIP >> mask) == (base >> mask): return True elif fnmatch(host, value): return True return False # Same as _proxy_bypass_macosx_sysconf, testable on all platforms def _proxy_bypass_winreg_override(host, override): """Return True if the host should bypass the proxy server. The proxy override list is obtained from the Windows Internet settings proxy override registry value. An example of a proxy override value is: "www.example.com;*.example.net; 192.168.0.1" """ from fnmatch import fnmatch host, _ = _splitport(host) proxy_override = override.split(';') for test in proxy_override: test = test.strip() # "<local>" should bypass the proxy server for all intranet addresses if test == '<local>': if '.' not in host: return True elif fnmatch(host, test): return True return False if sys.platform == 'darwin': from _scproxy import _get_proxy_settings, _get_proxies def proxy_bypass_macosx_sysconf(host): proxy_settings = _get_proxy_settings() return _proxy_bypass_macosx_sysconf(host, proxy_settings) def getproxies_macosx_sysconf(): """Return a dictionary of scheme -> proxy server URL mappings. This function uses the MacOSX framework SystemConfiguration to fetch the proxy information. """ return _get_proxies() def proxy_bypass(host): """Return True, if host should be bypassed. Checks proxy settings gathered from the environment, if specified, or from the MacOSX framework SystemConfiguration. """ proxies = getproxies_environment() if proxies: return proxy_bypass_environment(host, proxies) else: return proxy_bypass_macosx_sysconf(host) def getproxies(): return getproxies_environment() or getproxies_macosx_sysconf() elif os.name == 'nt': def getproxies_registry(): """Return a dictionary of scheme -> proxy server URL mappings. Win32 uses the registry to store proxies. """ proxies = {} try: import winreg except ImportError: # Std module, so should be around - but you never know! return proxies try: internetSettings = winreg.OpenKey(winreg.HKEY_CURRENT_USER, r'Software\Microsoft\Windows\CurrentVersion\Internet Settings') proxyEnable = winreg.QueryValueEx(internetSettings, 'ProxyEnable')[0] if proxyEnable: # Returned as Unicode but problems if not converted to ASCII proxyServer = str(winreg.QueryValueEx(internetSettings, 'ProxyServer')[0]) if '=' not in proxyServer and ';' not in proxyServer: # Use one setting for all protocols. proxyServer = 'http={0};https={0};ftp={0}'.format(proxyServer) for p in proxyServer.split(';'): protocol, address = p.split('=', 1) # See if address has a type:// prefix if not re.match('(?:[^/:]+)://', address): # Add type:// prefix to address without specifying type if protocol in ('http', 'https', 'ftp'): # The default proxy type of Windows is HTTP address = 'http://' + address elif protocol == 'socks': address = 'socks://' + address proxies[protocol] = address # Use SOCKS proxy for HTTP(S) protocols if proxies.get('socks'): # The default SOCKS proxy type of Windows is SOCKS4 address = re.sub(r'^socks://', 'socks4://', proxies['socks']) proxies['http'] = proxies.get('http') or address proxies['https'] = proxies.get('https') or address internetSettings.Close() except (OSError, ValueError, TypeError): # Either registry key not found etc, or the value in an # unexpected format. # proxies already set up to be empty so nothing to do pass return proxies def getproxies(): """Return a dictionary of scheme -> proxy server URL mappings. Returns settings gathered from the environment, if specified, or the registry. """ return getproxies_environment() or getproxies_registry() def proxy_bypass_registry(host): try: import winreg except ImportError: # Std modules, so should be around - but you never know! return False try: internetSettings = winreg.OpenKey(winreg.HKEY_CURRENT_USER, r'Software\Microsoft\Windows\CurrentVersion\Internet Settings') proxyEnable = winreg.QueryValueEx(internetSettings, 'ProxyEnable')[0] proxyOverride = str(winreg.QueryValueEx(internetSettings, 'ProxyOverride')[0]) # ^^^^ Returned as Unicode but problems if not converted to ASCII except OSError: return False if not proxyEnable or not proxyOverride: return False return _proxy_bypass_winreg_override(host, proxyOverride) def proxy_bypass(host): """Return True, if host should be bypassed. Checks proxy settings gathered from the environment, if specified, or the registry. """ proxies = getproxies_environment() if proxies: return proxy_bypass_environment(host, proxies) else: return proxy_bypass_registry(host) else: # By default use environment variables getproxies = getproxies_environment proxy_bypass = proxy_bypass_environment