zeroinstall/injector/_download_child.py

   1 # Copyright (C) 2011, Thomas Leonard
   2 # See the README file for details, or visit http://0install.net.
   3
   4 import sys, os, socket, ssl
   5
   6 from zeroinstall import _
   7 from zeroinstall.injector import download
   8 from zeroinstall.support import ssl_match_hostname
   9
  10 if sys.version_info[0] > 2:
  11         from urllib import request as urllib2
  12         from http.client import HTTPSConnection, HTTPException
  13 else:
  14         import urllib2
  15         from httplib import HTTPSConnection, HTTPException
  16
  17 _fallback_ca_bundle = [
  18         os.path.join(os.path.dirname(__file__), "cacert.pem"),
  19         os.path.join(os.path.dirname(sys.executable), "cacert.pem"),
  20 ]
  21
  22 # Note: on MacOS X at least, it will also look in the system keychain provided that you supply *some* CAs.
  23 # (if you don't specify any trusted CAs, Python trusts everything!)
  24 # So, the "fallback" option doesn't necessarily mean that other sites won't work.
  25 for ca_bundle in [
  26                 "/etc/ssl/certs/ca-certificates.crt",   # Debian/Ubuntu/Arch Linux
  27                 "/etc/pki/tls/certs/ca-bundle.crt",     # Fedora/RHEL
  28                 "/etc/ssl/ca-bundle.pem",               # openSUSE/SLE (claimed)
  29                 "/var/lib/ca-certificates/ca-bundle.pem.new", # openSUSE (actual)
  30                 ] + _fallback_ca_bundle:
  31         if os.path.exists(ca_bundle):
  32                 class ValidatingHTTPSConnection(HTTPSConnection):
  33                         def connect(self):
  34                                 sock = socket.create_connection((self.host, self.port), self.timeout)
  35                                 if hasattr(self, '_tunnel_host') and self._tunnel_host:
  36                                         self.sock = sock
  37                                         self._tunnel()
  38                                 sock = ssl.wrap_socket(sock, cert_reqs = ssl.CERT_REQUIRED, ca_certs = ca_bundle)
  39                                 ssl_match_hostname.match_hostname(sock.getpeercert(), self.host)
  40                                 self.sock = sock
  41
  42                 class ValidatingHTTPSHandler(urllib2.HTTPSHandler):
  43                         def https_open(self, req):
  44                                 return self.do_open(self.getConnection, req)
  45
  46                         def getConnection(self, host, timeout=300):
  47                                 return ValidatingHTTPSConnection(host)
  48                 MyHTTPSHandler = ValidatingHTTPSHandler
  49                 break
  50 else:
  51         raise Exception("No root CA's found (not even the built-in one!); security of HTTPS connections cannot be verified")
  52
  53 class Redirect(Exception):
  54         def __init__(self, req):
  55                 Exception.__init__(self, "Redirect")
  56                 self.req = req
  57
  58 class MyRedirectHandler(urllib2.HTTPRedirectHandler):
  59         """Throw an exception on redirects instead of continuing. The redirect will be handled in the main thread
  60         so it can work with connection pooling."""
  61         def redirect_request(self, req, fp, code, msg, headers, newurl):
  62                 new_req = urllib2.HTTPRedirectHandler.redirect_request(self, req, fp, code, msg, headers, newurl)
  63                 if new_req:
  64                         raise Redirect(new_req)
  65
  66 # Our handler differs from the Python default in that:
  67 # - we don't support file:// URLs
  68 # - we don't follow HTTP redirects
  69 _my_urlopen = urllib2.OpenerDirector()
  70 for klass in [urllib2.ProxyHandler, urllib2.UnknownHandler, urllib2.HTTPHandler,
  71                        urllib2.HTTPDefaultErrorHandler, MyRedirectHandler,
  72                        urllib2.FTPHandler, urllib2.HTTPErrorProcessor, MyHTTPSHandler]:
  73         _my_urlopen.add_handler(klass())
  74
  75 def download_in_thread(url, target_file, if_modified_since, notify_done):
  76         try:
  77                 #print "Child downloading", url
  78                 if url.startswith('http:') or url.startswith('https:') or url.startswith('ftp:'):
  79                         req = urllib2.Request(url)
  80                         if url.startswith('http:') and if_modified_since:
  81                                 req.add_header('If-Modified-Since', if_modified_since)
  82                         src = _my_urlopen.open(req)
  83                 else:
  84                         raise Exception(_('Unsupported URL protocol in: %s') % url)
  85
  86                 if sys.version_info[0] > 2:
  87                         sock_recv = src.fp.read1                # Python 3
  88                 else:
  89                         try:
  90                                 sock_recv = src.fp._sock.recv   # Python 2
  91                         except AttributeError:
  92                                 sock_recv = src.fp.fp._sock.recv        # Python 2.5 on FreeBSD
  93                 while True:
  94                         data = sock_recv(256)
  95                         if not data: break
  96                         target_file.write(data)
  97                         target_file.flush()
  98
  99                 notify_done(download.RESULT_OK)
 100         except (urllib2.HTTPError, urllib2.URLError, HTTPException, socket.error) as ex:
 101                 if isinstance(ex, urllib2.HTTPError) and ex.code == 304: # Not modified
 102                         notify_done(download.RESULT_NOT_MODIFIED)
 103                 else:
 104                         #print >>sys.stderr, "Error downloading '" + url + "': " + (str(ex) or str(ex.__class__.__name__))
 105                         __, ex, tb = sys.exc_info()
 106                         notify_done(download.RESULT_FAILED, (download.DownloadError(_('Error downloading {url}: {ex}').format(url = url, ex = ex)), tb))
 107         except Redirect as ex:
 108                 notify_done(download.RESULT_REDIRECT, redirect = ex.req.get_full_url())
 109         except Exception as ex:
 110                 __, ex, tb = sys.exc_info()
 111                 notify_done(download.RESULT_FAILED, (ex, tb))