zeroinstall/injector/handler.py

   1 """
   2 Integrates download callbacks with an external mainloop.
   3 While things are being downloaded, Zero Install returns control to your program.
   4 Your mainloop is responsible for monitoring the state of the downloads and notifying
   5 Zero Install when they are complete.
   6
   7 To do this, you supply a L{Handler} to the L{policy}.
   8 """
   9
  10 # Copyright (C) 2009, Thomas Leonard
  11 # See the README file for details, or visit http://0install.net.
  12
  13 from zeroinstall import _
  14 import sys
  15 from logging import debug, warn
  16
  17 from zeroinstall import NeedDownload, SafeException
  18 from zeroinstall.support import tasks
  19 from zeroinstall.injector import download
  20
  21 class NoTrustedKeys(SafeException):
  22         """Thrown by L{Handler.confirm_trust_keys} on failure."""
  23         pass
  24
  25 class Handler(object):
  26         """
  27         This implementation uses the GLib mainloop. Note that QT4 can use the GLib mainloop too.
  28
  29         @ivar monitored_downloads: dict of downloads in progress
  30         @type monitored_downloads: {URL: L{download.Download}}
  31         @ivar n_completed_downloads: number of downloads which have finished for GUIs, etc (can be reset as desired).
  32         @type n_completed_downloads: int
  33         @ivar total_bytes_downloaded: informational counter for GUIs, etc (can be reset as desired). Updated when download finishes.
  34         @type total_bytes_downloaded: int
  35         """
  36
  37         __slots__ = ['monitored_downloads', '_loop', 'dry_run', 'total_bytes_downloaded', 'n_completed_downloads']
  38
  39         def __init__(self, mainloop = None, dry_run = False):
  40                 self.monitored_downloads = {}
  41                 self._loop = None
  42                 self.dry_run = dry_run
  43                 self.n_completed_downloads = 0
  44                 self.total_bytes_downloaded = 0
  45
  46         def monitor_download(self, dl):
  47                 """Called when a new L{download} is started.
  48                 This is mainly used by the GUI to display the progress bar."""
  49                 dl.start()
  50                 self.monitored_downloads[dl.url] = dl
  51                 self.downloads_changed()
  52
  53                 @tasks.async
  54                 def download_done_stats():
  55                         yield dl.downloaded
  56                         # NB: we don't check for exceptions here; someone else should be doing that
  57                         try:
  58                                 self.n_completed_downloads += 1
  59                                 self.total_bytes_downloaded += dl.get_bytes_downloaded_so_far()
  60                                 del self.monitored_downloads[dl.url]
  61                                 self.downloads_changed()
  62                         except Exception, ex:
  63                                 self.report_error(ex)
  64                 download_done_stats()
  65
  66         def impl_added_to_store(self, impl):
  67                 """Called by the L{fetch.Fetcher} when adding an implementation.
  68                 The GUI uses this to update its display.
  69                 @param impl: the implementation which has been added
  70                 @type impl: L{model.Implementation}
  71                 """
  72                 pass
  73
  74         def downloads_changed(self):
  75                 """This is just for the GUI to override to update its display."""
  76                 pass
  77
  78         def wait_for_blocker(self, blocker):
  79                 """Run a recursive mainloop until blocker is triggered.
  80                 @param blocker: event to wait on
  81                 @type blocker: L{tasks.Blocker}"""
  82                 if not blocker.happened:
  83                         import gobject
  84
  85                         def quitter():
  86                                 yield blocker
  87                                 self._loop.quit()
  88                         quit = tasks.Task(quitter(), "quitter")
  89
  90                         assert self._loop is None       # Avoid recursion
  91                         self._loop = gobject.MainLoop(gobject.main_context_default())
  92                         try:
  93                                 debug(_("Entering mainloop, waiting for %s"), blocker)
  94                                 self._loop.run()
  95                         finally:
  96                                 self._loop = None
  97
  98                         assert blocker.happened, "Someone quit the main loop!"
  99
 100                 tasks.check(blocker)
 101
 102         def get_download(self, url, force = False, hint = None):
 103                 """Return the Download object currently downloading 'url'.
 104                 If no download for this URL has been started, start one now (and
 105                 start monitoring it).
 106                 If the download failed and force is False, return it anyway.
 107                 If force is True, abort any current or failed download and start
 108                 a new one.
 109                 @rtype: L{download.Download}
 110                 """
 111                 if self.dry_run:
 112                         raise NeedDownload(url)
 113
 114                 try:
 115                         dl = self.monitored_downloads[url]
 116                         if dl and force:
 117                                 dl.abort()
 118                                 raise KeyError
 119                 except KeyError:
 120                         dl = download.Download(url, hint)
 121                         self.monitor_download(dl)
 122                 return dl
 123
 124         def confirm_trust_keys(self, interface, sigs, iface_xml):
 125                 """We don't trust any of the signatures yet. Ask the user.
 126                 When done update the L{trust} database, and then call L{trust.TrustDB.notify}.
 127                 @arg interface: the interface being updated
 128                 @arg sigs: a list of signatures (from L{gpg.check_stream})
 129                 @arg iface_xml: the downloaded data (not yet trusted)
 130                 @return: a blocker, if confirmation will happen asynchronously, or None
 131                 @rtype: L{tasks.Blocker}"""
 132                 from zeroinstall.injector import trust, gpg
 133                 assert sigs
 134                 valid_sigs = [s for s in sigs if isinstance(s, gpg.ValidSig)]
 135                 if not valid_sigs:
 136                         raise SafeException('No valid signatures found on "%s". Signatures:%s' %
 137                                         (interface.uri, ''.join(['\n- ' + str(s) for s in sigs])))
 138
 139                 domain = trust.domain_from_url(interface.uri)
 140
 141                 # Ask on stderr, because we may be writing XML to stdout
 142                 print >>sys.stderr, "\nInterface:", interface.uri
 143                 print >>sys.stderr, "The interface is correctly signed with the following keys:"
 144                 for x in valid_sigs:
 145                         print >>sys.stderr, "-", x
 146
 147                 if len(valid_sigs) == 1:
 148                         print >>sys.stderr, "Do you want to trust this key to sign feeds from '%s'?" % domain
 149                 else:
 150                         print >>sys.stderr, "Do you want to trust all of these keys to sign feeds from '%s'?" % domain
 151                 while True:
 152                         print >>sys.stderr, "Trust [Y/N] ",
 153                         i = raw_input()
 154                         if not i: continue
 155                         if i in 'Nn':
 156                                 raise NoTrustedKeys(_('Not signed with a trusted key'))
 157                         if i in 'Yy':
 158                                 break
 159                 for key in valid_sigs:
 160                         print >>sys.stderr, "Trusting", key.fingerprint, "for", domain
 161                         trust.trust_db.trust_key(key.fingerprint, domain)
 162
 163                 trust.trust_db.notify()
 164
 165         def report_error(self, exception, tb = None):
 166                 """Report an exception to the user.
 167                 @param exception: the exception to report
 168                 @type exception: L{SafeException}
 169                 @param tb: optional traceback
 170                 @since: 0.25"""
 171                 warn("%s", str(exception) or type(exception))
 172                 #import traceback
 173                 #traceback.print_exception(exception, None, tb)