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', '_current_confirm']
  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                 self._current_confirm = None
  46
  47         def monitor_download(self, dl):
  48                 """Called when a new L{download} is started.
  49                 This is mainly used by the GUI to display the progress bar."""
  50                 dl.start()
  51                 self.monitored_downloads[dl.url] = dl
  52                 self.downloads_changed()
  53
  54                 @tasks.async
  55                 def download_done_stats():
  56                         yield dl.downloaded
  57                         # NB: we don't check for exceptions here; someone else should be doing that
  58                         try:
  59                                 self.n_completed_downloads += 1
  60                                 self.total_bytes_downloaded += dl.get_bytes_downloaded_so_far()
  61                                 del self.monitored_downloads[dl.url]
  62                                 self.downloads_changed()
  63                         except Exception, ex:
  64                                 self.report_error(ex)
  65                 download_done_stats()
  66
  67         def impl_added_to_store(self, impl):
  68                 """Called by the L{fetch.Fetcher} when adding an implementation.
  69                 The GUI uses this to update its display.
  70                 @param impl: the implementation which has been added
  71                 @type impl: L{model.Implementation}
  72                 """
  73                 pass
  74
  75         def downloads_changed(self):
  76                 """This is just for the GUI to override to update its display."""
  77                 pass
  78
  79         def wait_for_blocker(self, blocker):
  80                 """Run a recursive mainloop until blocker is triggered.
  81                 @param blocker: event to wait on
  82                 @type blocker: L{tasks.Blocker}"""
  83                 if not blocker.happened:
  84                         import gobject
  85
  86                         def quitter():
  87                                 yield blocker
  88                                 self._loop.quit()
  89                         quit = tasks.Task(quitter(), "quitter")
  90
  91                         assert self._loop is None       # Avoid recursion
  92                         self._loop = gobject.MainLoop(gobject.main_context_default())
  93                         try:
  94                                 debug(_("Entering mainloop, waiting for %s"), blocker)
  95                                 self._loop.run()
  96                         finally:
  97                                 self._loop = None
  98
  99                         assert blocker.happened, "Someone quit the main loop!"
 100
 101                 tasks.check(blocker)
 102
 103         def get_download(self, url, force = False, hint = None):
 104                 """Return the Download object currently downloading 'url'.
 105                 If no download for this URL has been started, start one now (and
 106                 start monitoring it).
 107                 If the download failed and force is False, return it anyway.
 108                 If force is True, abort any current or failed download and start
 109                 a new one.
 110                 @rtype: L{download.Download}
 111                 """
 112                 if self.dry_run:
 113                         raise NeedDownload(url)
 114
 115                 try:
 116                         dl = self.monitored_downloads[url]
 117                         if dl and force:
 118                                 dl.abort()
 119                                 raise KeyError
 120                 except KeyError:
 121                         dl = download.Download(url, hint)
 122                         self.monitor_download(dl)
 123                 return dl
 124
 125         def confirm_keys(self, pending, fetch_key_info):
 126                 """We don't trust any of the signatures yet. Ask the user.
 127                 When done update the L{trust} database, and then call L{trust.TrustDB.notify}.
 128                 This method just calls L{confirm_import_feed} if the handler (self) is
 129                 new-style, or L{confirm_trust_keys} for older classes. A class
 130                 is considered old-style if it overrides confirm_trust_keys and
 131                 not confirm_import_feed.
 132                 @since: 0.42
 133                 @arg pending: an object holding details of the updated feed
 134                 @type pending: L{PendingFeed}
 135                 @arg fetch_key_info: a function which can be used to fetch information about a key fingerprint
 136                 @type fetch_key_info: str -> L{Blocker}
 137                 @return: A blocker that triggers when the user has chosen, or None if already done.
 138                 @rtype: None | L{Blocker}"""
 139
 140                 assert pending.sigs
 141
 142                 if hasattr(self.confirm_trust_keys, 'original') or not hasattr(self.confirm_import_feed, 'original'):
 143                         # new-style class
 144                         from zeroinstall.injector import gpg
 145                         valid_sigs = [s for s in pending.sigs if isinstance(s, gpg.ValidSig)]
 146                         if not valid_sigs:
 147                                 raise SafeException(_('No valid signatures found on "%s". Signatures:%s') %
 148                                                 (pending.url, ''.join(['\n- ' + str(s) for s in pending.sigs])))
 149
 150                         # Start downloading information about the keys...
 151                         kfs = {}
 152                         for sig in valid_sigs:
 153                                 kfs[sig] = fetch_key_info(sig.fingerprint)
 154
 155                         return self._queue_confirm_import_feed(pending, kfs)
 156                 else:
 157                         # old-style class
 158                         from zeroinstall.injector import iface_cache
 159                         import warnings
 160                         warnings.warn(_("Should override confirm_import_feed(); using old confirm_trust_keys() for now"), DeprecationWarning, stacklevel = 2)
 161
 162                         iface = iface_cache.iface_cache.get_interface(pending.url)
 163                         return self.confirm_trust_keys(iface, pending.sigs, pending.new_xml)
 164
 165         @tasks.async
 166         def _queue_confirm_import_feed(self, pending, valid_sigs):
 167                 # If we're already confirming something else, wait for that to finish...
 168                 while self._current_confirm is not None:
 169                         yield self._current_confirm
 170
 171                 self._current_confirm = lock = tasks.Blocker('confirm key lock')
 172                 try:
 173                         done = self.confirm_import_feed(pending, valid_sigs)
 174                         yield done
 175                         tasks.check(done)
 176                 finally:
 177                         self._current_confirm = None
 178                         lock.trigger()
 179
 180         @tasks.async
 181         def confirm_import_feed(self, pending, valid_sigs):
 182                 """Sub-classes should override this method to interact with the user about new feeds.
 183                 If multiple feeds need confirmation, L{confirm_keys} will only invoke one instance of this
 184                 method at a time.
 185                 @param pending: the new feed to be imported
 186                 @type pending: L{PendingFeed}
 187                 @param valid_sigs: maps signatures to a list of fetchers collecting information about the key
 188                 @type valid_sigs: {L{gpg.ValidSig} : L{fetch.KeyInfoFetcher}}
 189                 @since: 0.42
 190                 @see: L{confirm_keys}"""
 191                 from zeroinstall.injector import trust
 192
 193                 assert valid_sigs
 194
 195                 domain = trust.domain_from_url(pending.url)
 196
 197                 # Ask on stderr, because we may be writing XML to stdout
 198                 print >>sys.stderr, _("Feed: %s"), pending.url
 199                 print >>sys.stderr, _("The feed is correctly signed with the following keys:")
 200                 for x in valid_sigs:
 201                         print >>sys.stderr, "-", x
 202
 203                 def text(parent):
 204                         text = ""
 205                         for node in parent.childNodes:
 206                                 if node.nodeType == node.TEXT_NODE:
 207                                         text = text + node.data
 208                         return text
 209
 210                 shown = set()
 211                 key_info_fetchers = valid_sigs.values()
 212                 while key_info_fetchers:
 213                         old_kfs = key_info_fetchers
 214                         key_info_fetchers = []
 215                         for kf in old_kfs:
 216                                 infos = set(kf.info) - shown
 217                                 if infos:
 218                                         if len(valid_sigs) > 1:
 219                                                 print "%s: " % kf.fingerprint
 220                                         for info in infos:
 221                                                 print >>sys.stderr, "-", text(info)
 222                                                 shown.add(info)
 223                                 if kf.blocker:
 224                                         key_info_fetchers.append(kf)
 225                         if key_info_fetchers:
 226                                 for kf in key_info_fetchers: print >>sys.stderr, kf.status
 227                                 stdin = tasks.InputBlocker(0, 'console')
 228                                 blockers = [kf.blocker for kf in key_info_fetchers] + [stdin]
 229                                 yield blockers
 230                                 for b in blockers:
 231                                         try:
 232                                                 tasks.check(b)
 233                                         except Exception, ex:
 234                                                 warn(_("Failed to get key info: %s"), ex)
 235                                 if stdin.happened:
 236                                         print >>sys.stderr, _("Skipping remaining key lookups due to input from user")
 237                                         break
 238
 239                 if len(valid_sigs) == 1:
 240                         print >>sys.stderr, _("Do you want to trust this key to sign feeds from '%s'?") % domain
 241                 else:
 242                         print >>sys.stderr, _("Do you want to trust all of these keys to sign feeds from '%s'?") % domain
 243                 while True:
 244                         print >>sys.stderr, _("Trust [Y/N] "),
 245                         i = raw_input()
 246                         if not i: continue
 247                         if i in 'Nn':
 248                                 raise NoTrustedKeys(_('Not signed with a trusted key'))
 249                         if i in 'Yy':
 250                                 break
 251                 for key in valid_sigs:
 252                         print >>sys.stderr, _("Trusting %s for %s") % (key.fingerprint, domain)
 253                         trust.trust_db.trust_key(key.fingerprint, domain)
 254
 255         confirm_import_feed.original = True
 256
 257         def confirm_trust_keys(self, interface, sigs, iface_xml):
 258                 """We don't trust any of the signatures yet. Ask the user.
 259                 When done update the L{trust} database, and then call L{trust.TrustDB.notify}.
 260                 @deprecated: see L{confirm_keys}
 261                 @arg interface: the interface being updated
 262                 @arg sigs: a list of signatures (from L{gpg.check_stream})
 263                 @arg iface_xml: the downloaded data (not yet trusted)
 264                 @return: a blocker, if confirmation will happen asynchronously, or None
 265                 @rtype: L{tasks.Blocker}"""
 266                 import warnings
 267                 warnings.warn(_("Use confirm_keys, not confirm_trust_keys"), DeprecationWarning, stacklevel = 2)
 268                 from zeroinstall.injector import trust, gpg
 269                 assert sigs
 270                 valid_sigs = [s for s in sigs if isinstance(s, gpg.ValidSig)]
 271                 if not valid_sigs:
 272                         raise SafeException('No valid signatures found on "%s". Signatures:%s' %
 273                                         (interface.uri, ''.join(['\n- ' + str(s) for s in sigs])))
 274
 275                 domain = trust.domain_from_url(interface.uri)
 276
 277                 # Ask on stderr, because we may be writing XML to stdout
 278                 print >>sys.stderr, "\nInterface:", interface.uri
 279                 print >>sys.stderr, "The interface is correctly signed with the following keys:"
 280                 for x in valid_sigs:
 281                         print >>sys.stderr, "-", x
 282
 283                 if len(valid_sigs) == 1:
 284                         print >>sys.stderr, "Do you want to trust this key to sign feeds from '%s'?" % domain
 285                 else:
 286                         print >>sys.stderr, "Do you want to trust all of these keys to sign feeds from '%s'?" % domain
 287                 while True:
 288                         print >>sys.stderr, "Trust [Y/N] ",
 289                         i = raw_input()
 290                         if not i: continue
 291                         if i in 'Nn':
 292                                 raise NoTrustedKeys(_('Not signed with a trusted key'))
 293                         if i in 'Yy':
 294                                 break
 295                 for key in valid_sigs:
 296                         print >>sys.stderr, "Trusting", key.fingerprint, "for", domain
 297                         trust.trust_db.trust_key(key.fingerprint, domain)
 298
 299                 trust.trust_db.notify()
 300
 301         confirm_trust_keys.original = True              # Detect if someone overrides it
 302
 303         def report_error(self, exception, tb = None):
 304                 """Report an exception to the user.
 305                 @param exception: the exception to report
 306                 @type exception: L{SafeException}
 307                 @param tb: optional traceback
 308                 @since: 0.25"""
 309                 warn("%s", str(exception) or type(exception))
 310                 #import traceback
 311                 #traceback.print_exception(exception, None, tb)