git.maemo.org Git - theonering/blob - src/gvoice/browser_emu.py

   1 """
   2 @author:          Laszlo Nagy
   3 @copyright:   (c) 2005 by Szoftver Messias Bt.
   4 @licence:        BSD style
   5
   6 Objects of the MozillaEmulator class can emulate a browser that is capable of:
   7
   8         - cookie management
   9         - configurable user agent string
  10         - GET and POST
  11         - multipart POST (send files)
  12         - receive content into file
  13
  14 I have seen many requests on the python mailing list about how to emulate a browser. I'm using this class for years now, without any problems. This is how you can use it:
  15
  16         1. Use firefox
  17         2. Install and open the livehttpheaders plugin
  18         3. Use the website manually with firefox
  19         4. Check the GET and POST requests in the livehttpheaders capture window
  20         5. Create an instance of the above class and send the same GET and POST requests to the server.
  21
  22 Optional steps:
  23
  24         - You can change user agent string in the build_opened method
  25         - The "encode_multipart_formdata" function can be used alone to create POST data from a list of field values and files
  26 """
  27
  28 import urllib2
  29 import cookielib
  30 import logging
  31
  32 import socket
  33
  34
  35 _moduleLogger = logging.getLogger("gvoice.browser_emu")
  36 socket.setdefaulttimeout(10)
  37
  38
  39 class MozillaEmulator(object):
  40
  41         def __init__(self, trycount = 1):
  42                 """Create a new MozillaEmulator object.
  43
  44                 @param trycount: The download() method will retry the operation if it fails. You can specify -1 for infinite retrying.
  45                          A value of 0 means no retrying. A value of 1 means one retry. etc."""
  46                 self.debug = False
  47                 self.trycount = trycount
  48                 self._cookies = cookielib.LWPCookieJar()
  49                 self._loadedFromCookies = False
  50
  51         def load_cookies(self, path):
  52                 assert not self._loadedFromCookies, "Load cookies only once"
  53                 if path is None:
  54                         return
  55
  56                 self._cookies.filename = path
  57                 try:
  58                         self._cookies.load()
  59                 except cookielib.LoadError:
  60                         _moduleLogger.exception("Bad cookie file")
  61                 except IOError:
  62                         _moduleLogger.exception("No cookie file")
  63                 except Exception, e:
  64                         _moduleLogger.exception("Unknown error with cookies")
  65                 else:
  66                         self._loadedFromCookies = True
  67
  68                 return self._loadedFromCookies
  69
  70         def save_cookies(self):
  71                 if self._loadedFromCookies:
  72                         self._cookies.save()
  73
  74         def clear_cookies(self):
  75                 if self._loadedFromCookies:
  76                         self._cookies.clear()
  77
  78         def download(self, url,
  79                         postdata = None, extraheaders = None, forbidRedirect = False,
  80                         trycount = None, only_head = False,
  81                 ):
  82                 """Download an URL with GET or POST methods.
  83
  84                 @param postdata: It can be a string that will be POST-ed to the URL.
  85                         When None is given, the method will be GET instead.
  86                 @param extraheaders: You can add/modify HTTP headers with a dict here.
  87                 @param forbidRedirect: Set this flag if you do not want to handle
  88                         HTTP 301 and 302 redirects.
  89                 @param trycount: Specify the maximum number of retries here.
  90                         0 means no retry on error. Using -1 means infinite retring.
  91                         None means the default value (that is self.trycount).
  92                 @param only_head: Create the openerdirector and return it. In other
  93                         words, this will not retrieve any content except HTTP headers.
  94
  95                 @return: The raw HTML page data
  96                 """
  97                 _moduleLogger.info("Performing download of %s" % url)
  98
  99                 if extraheaders is None:
 100                         extraheaders = {}
 101                 if trycount is None:
 102                         trycount = self.trycount
 103                 cnt = 0
 104
 105                 while True:
 106                         try:
 107                                 req, u = self._build_opener(url, postdata, extraheaders, forbidRedirect)
 108                                 openerdirector = u.open(req)
 109                                 if self.debug:
 110                                         _moduleLogger.info("%r - %r" % (req.get_method(), url))
 111                                         _moduleLogger.info("%r - %r" % (openerdirector.code, openerdirector.msg))
 112                                         _moduleLogger.info("%r" % (openerdirector.headers))
 113                                 self._cookies.extract_cookies(openerdirector, req)
 114                                 if only_head:
 115                                         return openerdirector
 116
 117                                 return self._read(openerdirector, trycount)
 118                         except urllib2.URLError:
 119                                 cnt += 1
 120                                 if (-1 < trycount) and (trycount < cnt):
 121                                         raise
 122
 123                         # Retry :-)
 124                         _moduleLogger.info("MozillaEmulator: urllib2.URLError, retryting %d" % cnt)
 125
 126         def _build_opener(self, url, postdata = None, extraheaders = None, forbidRedirect = False):
 127                 if extraheaders is None:
 128                         extraheaders = {}
 129
 130                 txheaders = {
 131                         'Accept': 'text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png',
 132                         'Accept-Language': 'en,en-us;q=0.5',
 133                         'Accept-Charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
 134                 }
 135                 for key, value in extraheaders.iteritems():
 136                         txheaders[key] = value
 137                 req = urllib2.Request(url, postdata, txheaders)
 138                 self._cookies.add_cookie_header(req)
 139                 if forbidRedirect:
 140                         redirector = HTTPNoRedirector()
 141                         #_moduleLogger.info("Redirection disabled")
 142                 else:
 143                         redirector = urllib2.HTTPRedirectHandler()
 144                         #_moduleLogger.info("Redirection enabled")
 145
 146                 http_handler = urllib2.HTTPHandler(debuglevel=self.debug)
 147                 https_handler = urllib2.HTTPSHandler(debuglevel=self.debug)
 148
 149                 u = urllib2.build_opener(
 150                         http_handler,
 151                         https_handler,
 152                         urllib2.HTTPCookieProcessor(self._cookies),
 153                         redirector
 154                 )
 155                 u.addheaders = [(
 156                         'User-Agent',
 157                         'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511 Firefox/1.0.4'
 158                 )]
 159                 if not postdata is None:
 160                         req.add_data(postdata)
 161                 return (req, u)
 162
 163         def _read(self, openerdirector, trycount):
 164                 chunks = []
 165
 166                 chunk = openerdirector.read()
 167                 chunks.append(chunk)
 168                 #while chunk and cnt < trycount:
 169                 #       time.sleep(1)
 170                 #       cnt += 1
 171                 #       chunk = openerdirector.read()
 172                 #       chunks.append(chunk)
 173
 174                 data = "".join(chunks)
 175
 176                 if "Content-Length" in openerdirector.info():
 177                         assert len(data) == int(openerdirector.info()["Content-Length"]), "The packet header promised %s of data but only was able to read %s of data" % (
 178                                 openerdirector.info()["Content-Length"],
 179                                 len(data),
 180                         )
 181
 182                 return data
 183
 184
 185 class HTTPNoRedirector(urllib2.HTTPRedirectHandler):
 186         """This is a custom http redirect handler that FORBIDS redirection."""
 187
 188         def http_error_302(self, req, fp, code, msg, headers):
 189                 e = urllib2.HTTPError(req.get_full_url(), code, msg, headers, fp)
 190                 if e.code in (301, 302):
 191                         if 'location' in headers:
 192                                 newurl = headers.getheaders('location')[0]
 193                         elif 'uri' in headers:
 194                                 newurl = headers.getheaders('uri')[0]
 195                         e.newurl = newurl
 196                 _moduleLogger.info("New url: %s" % e.newurl)
 197                 raise e