"""Integration with Python standard library module urllib2. Also includes a redirection bugfix, support for parsing HTML HEAD blocks for the META HTTP-EQUIV tag contents, and following Refresh header redirects. Copyright 2002-2006 John J Lee This code is free software; you can redistribute it and/or modify it under the terms of the BSD or ZPL 2.1 licenses (see the file COPYING.txt included with the distribution). """ import copy, time, tempfile, htmlentitydefs, re, logging, types, \ string, socket, urlparse, urllib2, urllib, httplib, sgmllib from urllib2 import URLError, HTTPError, BaseHandler from cStringIO import StringIO try: import threading as _threading except ImportError: import dummy_threading as _threading import _opener from _request import Request from _util import isstringlike, startswith, \ getheaders, closeable_response, response_seek_wrapper from _html import unescape, unescape_charref from _headersutil import is_html from _clientcookie import CookieJar, request_host debug = logging.getLogger("mechanize.cookies").debug CHUNK = 1024 # size of chunks fed to HTML HEAD parser, in bytes DEFAULT_ENCODING = 'latin-1' # This fixes a bug in urllib2 as of Python 2.1.3 and 2.2.2 # (http://www.python.org/sf/549151) # 2.2.3 is broken here (my fault!), 2.3 is fixed. 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 # Implementation notes: # 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. The value # of the dict is used to count the number of times the same URL has # been visited. This is needed because visiting the same URL twice # does not necessarily imply a loop, thanks to state introduced by # cookies. # Always unhandled redirection codes: # 300 Multiple Choices: should not handle this here. # 304 Not Modified: no need to handle here: only of interest to caches # that do conditional GETs # 305 Use Proxy: probably not worth dealing with here # 306 Unused: what was this for in the previous versions of protocol?? def redirect_request(self, newurl, req, fp, code, msg, headers): """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, return None to indicate that an HTTPError should be raised. """ if code in (301, 302, 303, "refresh") or \ (code == 307 and not req.has_data()): # 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. return Request(newurl, headers=req.headers, origin_req_host=req.get_origin_req_host(), unverifiable=True) else: raise HTTPError(req.get_full_url(), code, msg, headers, fp) 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 headers.has_key('location'): newurl = getheaders(headers, 'location')[0] elif headers.has_key('uri'): newurl = getheaders(headers, 'uri')[0] else: return newurl = urlparse.urljoin(req.get_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(newurl, req, fp, code, msg, headers) 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) http_error_301 = http_error_303 = http_error_307 = http_error_302 http_error_refresh = 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" class HTTPRequestUpgradeProcessor(BaseHandler): # upgrade urllib2.Request to this module's Request # yuck! handler_order = 0 # before anything else def http_request(self, request): if not hasattr(request, "add_unredirected_header"): newrequest = Request(request._Request__original, request.data, request.headers) try: newrequest.origin_req_host = request.origin_req_host except AttributeError: pass try: newrequest.unverifiable = request.unverifiable except AttributeError: pass request = newrequest return request https_request = http_request # XXX would self.reset() work, instead of raising this exception? class EndOfHeadError(Exception): pass class AbstractHeadParser: # only these elements are allowed in or before HEAD of document head_elems = ("html", "head", "title", "base", "script", "style", "meta", "link", "object") _entitydefs = htmlentitydefs.name2codepoint _encoding = DEFAULT_ENCODING def __init__(self): self.http_equiv = [] def start_meta(self, attrs): http_equiv = content = None for key, value in attrs: if key == "http-equiv": http_equiv = self.unescape_attr_if_required(value) elif key == "content": content = self.unescape_attr_if_required(value) if http_equiv is not None: self.http_equiv.append((http_equiv, content)) def end_head(self): raise EndOfHeadError() def handle_entityref(self, name): #debug("%s", name) self.handle_data(unescape( '&%s;' % name, self._entitydefs, self._encoding)) def handle_charref(self, name): #debug("%s", name) self.handle_data(unescape_charref(name, self._encoding)) def unescape_attr(self, name): #debug("%s", name) return unescape(name, self._entitydefs, self._encoding) def unescape_attrs(self, attrs): #debug("%s", attrs) escaped_attrs = {} for key, val in attrs.items(): escaped_attrs[key] = self.unescape_attr(val) return escaped_attrs def unknown_entityref(self, ref): self.handle_data("&%s;" % ref) def unknown_charref(self, ref): self.handle_data("&#%s;" % ref) try: import HTMLParser except ImportError: pass else: class XHTMLCompatibleHeadParser(AbstractHeadParser, HTMLParser.HTMLParser): def __init__(self): HTMLParser.HTMLParser.__init__(self) AbstractHeadParser.__init__(self) def handle_starttag(self, tag, attrs): if tag not in self.head_elems: raise EndOfHeadError() try: method = getattr(self, 'start_' + tag) except AttributeError: try: method = getattr(self, 'do_' + tag) except AttributeError: pass # unknown tag else: method(attrs) else: method(attrs) def handle_endtag(self, tag): if tag not in self.head_elems: raise EndOfHeadError() try: method = getattr(self, 'end_' + tag) except AttributeError: pass # unknown tag else: method() def unescape(self, name): # Use the entitydefs passed into constructor, not # HTMLParser.HTMLParser's entitydefs. return self.unescape_attr(name) def unescape_attr_if_required(self, name): return name # HTMLParser.HTMLParser already did it class HeadParser(AbstractHeadParser, sgmllib.SGMLParser): def _not_called(self): assert False def __init__(self): sgmllib.SGMLParser.__init__(self) AbstractHeadParser.__init__(self) def handle_starttag(self, tag, method, attrs): if tag not in self.head_elems: raise EndOfHeadError() if tag == "meta": method(attrs) def unknown_starttag(self, tag, attrs): self.handle_starttag(tag, self._not_called, attrs) def handle_endtag(self, tag, method): if tag in self.head_elems: method() else: raise EndOfHeadError() def unescape_attr_if_required(self, name): return self.unescape_attr(name) def parse_head(fileobj, parser): """Return a list of key, value pairs.""" while 1: data = fileobj.read(CHUNK) try: parser.feed(data) except EndOfHeadError: break if len(data) != CHUNK: # this should only happen if there is no HTML body, or if # CHUNK is big break return parser.http_equiv class HTTPEquivProcessor(BaseHandler): """Append META HTTP-EQUIV headers to regular HTTP headers.""" handler_order = 300 # before handlers that look at HTTP headers def __init__(self, head_parser_class=HeadParser, i_want_broken_xhtml_support=False, ): self.head_parser_class = head_parser_class self._allow_xhtml = i_want_broken_xhtml_support def http_response(self, request, response): if not hasattr(response, "seek"): response = response_seek_wrapper(response) headers = response.info() url = response.geturl() ct_hdrs = getheaders(response.info(), "content-type") if is_html(ct_hdrs, url, self._allow_xhtml): try: try: html_headers = parse_head(response, self.head_parser_class()) finally: response.seek(0) except (HTMLParser.HTMLParseError, sgmllib.SGMLParseError): pass else: for hdr, val in html_headers: # rfc822.Message interprets this as appending, not clobbering headers[hdr] = val return response https_response = http_response class SeekableProcessor(BaseHandler): """Make responses seekable.""" def any_response(self, request, response): if not hasattr(response, "seek"): return response_seek_wrapper(response) return response class HTTPCookieProcessor(BaseHandler): """Handle HTTP cookies. Public attributes: cookiejar: CookieJar instance """ def __init__(self, cookiejar=None): if cookiejar is None: 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 try: import robotparser except ImportError: pass else: class RobotExclusionError(urllib2.HTTPError): def __init__(self, request, *args): apply(urllib2.HTTPError.__init__, (self,)+args) self.request = request class HTTPRobotRulesProcessor(BaseHandler): # before redirections, after everything else handler_order = 800 try: from httplib import HTTPMessage except: from mimetools import Message http_response_class = Message else: http_response_class = HTTPMessage def __init__(self, rfp_class=robotparser.RobotFileParser): self.rfp_class = rfp_class self.rfp = None self._host = None def http_request(self, request): host = request.get_host() scheme = request.get_type() if host != self._host: self.rfp = self.rfp_class() self.rfp.set_url(scheme+"://"+host+"/robots.txt") self.rfp.read() self._host = host ua = request.get_header("User-agent", "") if self.rfp.can_fetch(ua, request.get_full_url()): return request else: msg = "request disallowed by robots.txt" raise RobotExclusionError( request, request.get_full_url(), 403, msg, self.http_response_class(StringIO()), StringIO(msg)) https_request = http_request class HTTPRefererProcessor(BaseHandler): """Add Referer header to requests. This only makes sense if you use each RefererProcessor for a single chain of requests only (so, for example, if you use a single HTTPRefererProcessor to fetch a series of URLs extracted from a single page, this will break). There's a proper implementation of this in module mechanize. """ def __init__(self): self.referer = None def http_request(self, request): if ((self.referer is not None) and not request.has_header("Referer")): request.add_unredirected_header("Referer", self.referer) return request def http_response(self, request, response): self.referer = response.geturl() return response https_request = http_request https_response = http_response class HTTPResponseDebugProcessor(BaseHandler): handler_order = 900 # before redirections, after everything else def http_response(self, request, response): if not hasattr(response, "seek"): response = response_seek_wrapper(response) info = getLogger("mechanize.http_responses").info try: info(response.read()) finally: response.seek(0) info("*****************************************************") return response https_response = http_response class HTTPRedirectDebugProcessor(BaseHandler): def http_request(self, request): if hasattr(request, "redirect_dict"): info = getLogger("mechanize.http_redirects").info info("redirecting to %s", request.get_full_url()) return request class HTTPRefreshProcessor(BaseHandler): """Perform HTTP Refresh redirections. Note that if a non-200 HTTP code has occurred (for example, a 30x redirect), this processor will do nothing. By default, only zero-time Refresh headers are redirected. Use the max_time attribute / constructor argument to allow Refresh with longer pauses. Use the honor_time attribute / constructor argument to control whether the requested pause is honoured (with a time.sleep()) or skipped in favour of immediate redirection. Public attributes: max_time: see above honor_time: see above """ handler_order = 1000 def __init__(self, max_time=0, honor_time=True): self.max_time = max_time self.honor_time = honor_time def http_response(self, request, response): code, msg, hdrs = response.code, response.msg, response.info() if code == 200 and hdrs.has_key("refresh"): refresh = getheaders(hdrs, "refresh")[0] ii = string.find(refresh, ";") if ii != -1: pause, newurl_spec = float(refresh[:ii]), refresh[ii+1:] jj = string.find(newurl_spec, "=") if jj != -1: key, newurl = newurl_spec[:jj], newurl_spec[jj+1:] if key.strip().lower() != "url": debug("bad Refresh header: %r" % refresh) return response else: pause, newurl = float(refresh), response.geturl() if (self.max_time is None) or (pause <= self.max_time): if pause > 1E-3 and self.honor_time: time.sleep(pause) hdrs["location"] = newurl # hardcoded http is NOT a bug response = self.parent.error( "http", request, response, "refresh", msg, hdrs) return response https_response = http_response class HTTPErrorProcessor(BaseHandler): """Process HTTP error responses. The purpose of this handler is to to allow other response processors a look-in by removing the call to parent.error() from AbstractHTTPHandler. For non-200 error codes, this just passes the job on to the Handler._error_ methods, via the OpenerDirector.error method. Eventually, urllib2.HTTPDefaultErrorHandler will raise an HTTPError if no other handler handles the error. """ handler_order = 1000 # after all other processors def http_response(self, request, response): code, msg, hdrs = response.code, response.msg, response.info() if code != 200: # hardcoded http is NOT a bug response = self.parent.error( "http", request, response, code, msg, hdrs) return response https_response = http_response 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') scheme, sel = urllib.splittype(request.get_selector()) sel_host, sel_path = urllib.splithost(sel) if not request.has_header('Host'): request.add_unredirected_header('Host', sel_host or host) for name, value in self.parent.addheaders: name = string.capitalize(name) if not request.has_header(name): request.add_unredirected_header(name, value) return request def do_open(self, http_class, req): """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') h = http_class(host) # will parse host:port h.set_debuglevel(self._debuglevel) headers = req.headers.copy() headers.update(req.unredirected_hdrs) # 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" try: h.request(req.get_method(), req.get_selector(), req.data, headers) r = h.getresponse() except socket.error, err: # XXX what error? raise URLError(err) # 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, 'rb', -1) resp = closeable_response(fp, r.msg, req.get_full_url(), r.status, 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 https_open(self, req): return self.do_open(httplib.HTTPSConnection, req) https_request = AbstractHTTPHandler.do_request_ class OpenerFactory: """This class's interface is quite likely to change.""" default_classes = [ # handlers urllib2.ProxyHandler, urllib2.UnknownHandler, HTTPHandler, # from this module (derived from new AbstractHTTPHandler) urllib2.HTTPDefaultErrorHandler, HTTPRedirectHandler, # from this module (bugfixed) urllib2.FTPHandler, urllib2.FileHandler, # processors HTTPRequestUpgradeProcessor, HTTPCookieProcessor, HTTPErrorProcessor ] handlers = [] replacement_handlers = [] def __init__(self, klass=_opener.OpenerDirector): self.klass = klass def build_opener(self, *handlers): """Create an opener object from a list of handlers and processors. The opener will use several default handlers and processors, including support for HTTP and FTP. If any of the handlers passed as arguments are subclasses of the default handlers, the default handlers will not be used. """ opener = self.klass() default_classes = list(self.default_classes) if hasattr(httplib, 'HTTPS'): default_classes.append(HTTPSHandler) skip = [] for klass in default_classes: for check in handlers: if type(check) == types.ClassType: if issubclass(check, klass): skip.append(klass) elif type(check) == types.InstanceType: if isinstance(check, klass): skip.append(klass) for klass in skip: default_classes.remove(klass) for klass in default_classes: opener.add_handler(klass()) for h in handlers: if type(h) == types.ClassType: h = h() opener.add_handler(h) return opener build_opener = OpenerFactory().build_opener _opener = None urlopen_lock = _threading.Lock() def urlopen(url, data=None): global _opener if _opener is None: urlopen_lock.acquire() try: if _opener is None: _opener = build_opener() finally: urlopen_lock.release() return _opener.open(url, data) def urlretrieve(url, filename=None, reporthook=None, data=None): global _opener if _opener is None: urlopen_lock.acquire() try: if _opener is None: _opener = build_opener() finally: urlopen_lock.release() return _opener.retrieve(url, filename, reporthook, data) def install_opener(opener): global _opener _opener = opener