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, info
  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         @ivar dry_run: instead of starting a download, just report what we would have downloaded
  36         @type dry_run: bool
  37         """
  38
  39         __slots__ = ['monitored_downloads', '_loop', 'dry_run', 'total_bytes_downloaded', 'n_completed_downloads', '_current_confirm']
  40
  41         def __init__(self, mainloop = None, dry_run = False):
  42                 self.monitored_downloads = {}
  43                 self._loop = None
  44                 self.dry_run = dry_run
  45                 self.n_completed_downloads = 0
  46                 self.total_bytes_downloaded = 0
  47                 self._current_confirm = None
  48
  49         def monitor_download(self, dl):
  50                 """Called when a new L{download} is started.
  51                 This is mainly used by the GUI to display the progress bar."""
  52                 dl.start()
  53                 self.monitored_downloads[dl.url] = dl
  54                 self.downloads_changed()
  55
  56                 @tasks.async
  57                 def download_done_stats():
  58                         yield dl.downloaded
  59                         # NB: we don't check for exceptions here; someone else should be doing that
  60                         try:
  61                                 self.n_completed_downloads += 1
  62                                 self.total_bytes_downloaded += dl.get_bytes_downloaded_so_far()
  63                                 del self.monitored_downloads[dl.url]
  64                                 self.downloads_changed()
  65                         except Exception, ex:
  66                                 self.report_error(ex)
  67                 download_done_stats()
  68
  69         def impl_added_to_store(self, impl):
  70                 """Called by the L{fetch.Fetcher} when adding an implementation.
  71                 The GUI uses this to update its display.
  72                 @param impl: the implementation which has been added
  73                 @type impl: L{model.Implementation}
  74                 """
  75                 pass
  76
  77         def downloads_changed(self):
  78                 """This is just for the GUI to override to update its display."""
  79                 pass
  80
  81         def wait_for_blocker(self, blocker):
  82                 """Run a recursive mainloop until blocker is triggered.
  83                 @param blocker: event to wait on
  84                 @type blocker: L{tasks.Blocker}"""
  85                 if not blocker.happened:
  86                         import gobject
  87
  88                         def quitter():
  89                                 yield blocker
  90                                 self._loop.quit()
  91                         tasks.Task(quitter(), "quitter")
  92
  93                         assert self._loop is None       # Avoid recursion
  94                         self._loop = gobject.MainLoop(gobject.main_context_default())
  95                         try:
  96                                 debug(_("Entering mainloop, waiting for %s"), blocker)
  97                                 self._loop.run()
  98                         finally:
  99                                 self._loop = None
 100
 101                         assert blocker.happened, "Someone quit the main loop!"
 102
 103                 tasks.check(blocker)
 104
 105         def get_download(self, url, force = False, hint = None, factory = None):
 106                 """Return the Download object currently downloading 'url'.
 107                 If no download for this URL has been started, start one now (and
 108                 start monitoring it).
 109                 If the download failed and force is False, return it anyway.
 110                 If force is True, abort any current or failed download and start
 111                 a new one.
 112                 @rtype: L{download.Download}
 113                 """
 114                 if self.dry_run:
 115                         raise NeedDownload(url)
 116
 117                 try:
 118                         dl = self.monitored_downloads[url]
 119                         if dl and force:
 120                                 dl.abort()
 121                                 raise KeyError
 122                 except KeyError:
 123                         if factory is None:
 124                                 dl = download.Download(url, hint)
 125                         else:
 126                                 dl = factory(url, hint)
 127                         self.monitor_download(dl)
 128                 return dl
 129
 130         def confirm_keys(self, pending, fetch_key_info):
 131                 """We don't trust any of the signatures yet. Ask the user.
 132                 When done update the L{trust} database, and then call L{trust.TrustDB.notify}.
 133                 This method just calls L{confirm_import_feed} if the handler (self) is
 134                 new-style, or L{confirm_trust_keys} for older classes. A class
 135                 is considered old-style if it overrides confirm_trust_keys and
 136                 not confirm_import_feed.
 137                 @since: 0.42
 138                 @arg pending: an object holding details of the updated feed
 139                 @type pending: L{PendingFeed}
 140                 @arg fetch_key_info: a function which can be used to fetch information about a key fingerprint
 141                 @type fetch_key_info: str -> L{Blocker}
 142                 @return: A blocker that triggers when the user has chosen, or None if already done.
 143                 @rtype: None | L{Blocker}"""
 144
 145                 assert pending.sigs
 146
 147                 if hasattr(self.confirm_trust_keys, 'original') or not hasattr(self.confirm_import_feed, 'original'):
 148                         # new-style class
 149                         from zeroinstall.injector import gpg
 150                         valid_sigs = [s for s in pending.sigs if isinstance(s, gpg.ValidSig)]
 151                         if not valid_sigs:
 152                                 def format_sig(sig):
 153                                         msg = str(sig)
 154                                         if sig.messages:
 155                                                 msg += "\nMessages from GPG:\n" + sig.messages
 156                                         return msg
 157                                 raise SafeException(_('No valid signatures found on "%(url)s". Signatures:%(signatures)s') %
 158                                                 {'url': pending.url, 'signatures': ''.join(['\n- ' + format_sig(s) for s in pending.sigs])})
 159
 160                         # Start downloading information about the keys...
 161                         kfs = {}
 162                         for sig in valid_sigs:
 163                                 kfs[sig] = fetch_key_info(sig.fingerprint)
 164
 165                         return self._queue_confirm_import_feed(pending, kfs)
 166                 else:
 167                         # old-style class
 168                         from zeroinstall.injector import iface_cache
 169                         import warnings
 170                         warnings.warn("Should override confirm_import_feed(); using old confirm_trust_keys() for now", DeprecationWarning, stacklevel = 2)
 171
 172                         iface = iface_cache.iface_cache.get_interface(pending.url)
 173                         return self.confirm_trust_keys(iface, pending.sigs, pending.new_xml)
 174
 175         @tasks.async
 176         def _queue_confirm_import_feed(self, pending, valid_sigs):
 177                 # If we're already confirming something else, wait for that to finish...
 178                 while self._current_confirm is not None:
 179                         yield self._current_confirm
 180
 181                 # Check whether we still need to confirm. The user may have
 182                 # already approved one of the keys while dealing with another
 183                 # feed.
 184                 from zeroinstall.injector import trust
 185                 domain = trust.domain_from_url(pending.url)
 186                 for sig in valid_sigs:
 187                         is_trusted = trust.trust_db.is_trusted(sig.fingerprint, domain)
 188                         if is_trusted:
 189                                 return
 190
 191                 # Take the lock and confirm this feed
 192                 self._current_confirm = lock = tasks.Blocker('confirm key lock')
 193                 try:
 194                         done = self.confirm_import_feed(pending, valid_sigs)
 195                         if done is not None:
 196                                 yield done
 197                                 tasks.check(done)
 198                 finally:
 199                         self._current_confirm = None
 200                         lock.trigger()
 201
 202         @tasks.async
 203         def confirm_import_feed(self, pending, valid_sigs):
 204                 """Sub-classes should override this method to interact with the user about new feeds.
 205                 If multiple feeds need confirmation, L{confirm_keys} will only invoke one instance of this
 206                 method at a time.
 207                 @param pending: the new feed to be imported
 208                 @type pending: L{PendingFeed}
 209                 @param valid_sigs: maps signatures to a list of fetchers collecting information about the key
 210                 @type valid_sigs: {L{gpg.ValidSig} : L{fetch.KeyInfoFetcher}}
 211                 @since: 0.42
 212                 @see: L{confirm_keys}"""
 213                 from zeroinstall.injector import trust
 214
 215                 assert valid_sigs
 216
 217                 domain = trust.domain_from_url(pending.url)
 218
 219                 # Ask on stderr, because we may be writing XML to stdout
 220                 print >>sys.stderr, _("Feed: %s") % pending.url
 221                 print >>sys.stderr, _("The feed is correctly signed with the following keys:")
 222                 for x in valid_sigs:
 223                         print >>sys.stderr, "-", x
 224
 225                 def text(parent):
 226                         text = ""
 227                         for node in parent.childNodes:
 228                                 if node.nodeType == node.TEXT_NODE:
 229                                         text = text + node.data
 230                         return text
 231
 232                 shown = set()
 233                 key_info_fetchers = valid_sigs.values()
 234                 while key_info_fetchers:
 235                         old_kfs = key_info_fetchers
 236                         key_info_fetchers = []
 237                         for kf in old_kfs:
 238                                 infos = set(kf.info) - shown
 239                                 if infos:
 240                                         if len(valid_sigs) > 1:
 241                                                 print "%s: " % kf.fingerprint
 242                                         for key_info in infos:
 243                                                 print >>sys.stderr, "-", text(key_info)
 244                                                 shown.add(key_info)
 245                                 if kf.blocker:
 246                                         key_info_fetchers.append(kf)
 247                         if key_info_fetchers:
 248                                 for kf in key_info_fetchers: print >>sys.stderr, kf.status
 249                                 stdin = tasks.InputBlocker(0, 'console')
 250                                 blockers = [kf.blocker for kf in key_info_fetchers] + [stdin]
 251                                 yield blockers
 252                                 for b in blockers:
 253                                         try:
 254                                                 tasks.check(b)
 255                                         except Exception, ex:
 256                                                 warn(_("Failed to get key info: %s"), ex)
 257                                 if stdin.happened:
 258                                         print >>sys.stderr, _("Skipping remaining key lookups due to input from user")
 259                                         break
 260
 261                 if len(valid_sigs) == 1:
 262                         print >>sys.stderr, _("Do you want to trust this key to sign feeds from '%s'?") % domain
 263                 else:
 264                         print >>sys.stderr, _("Do you want to trust all of these keys to sign feeds from '%s'?") % domain
 265                 while True:
 266                         print >>sys.stderr, _("Trust [Y/N] "),
 267                         i = raw_input()
 268                         if not i: continue
 269                         if i in 'Nn':
 270                                 raise NoTrustedKeys(_('Not signed with a trusted key'))
 271                         if i in 'Yy':
 272                                 break
 273                 for key in valid_sigs:
 274                         print >>sys.stderr, _("Trusting %(key_fingerprint)s for %(domain)s") % {'key_fingerprint': key.fingerprint, 'domain': domain}
 275                         trust.trust_db.trust_key(key.fingerprint, domain)
 276
 277         confirm_import_feed.original = True
 278
 279         def confirm_trust_keys(self, interface, sigs, iface_xml):
 280                 """We don't trust any of the signatures yet. Ask the user.
 281                 When done update the L{trust} database, and then call L{trust.TrustDB.notify}.
 282                 @deprecated: see L{confirm_keys}
 283                 @arg interface: the interface being updated
 284                 @arg sigs: a list of signatures (from L{gpg.check_stream})
 285                 @arg iface_xml: the downloaded data (not yet trusted)
 286                 @return: a blocker, if confirmation will happen asynchronously, or None
 287                 @rtype: L{tasks.Blocker}"""
 288                 import warnings
 289                 warnings.warn("Use confirm_keys, not confirm_trust_keys", DeprecationWarning, stacklevel = 2)
 290                 from zeroinstall.injector import trust, gpg
 291                 assert sigs
 292                 valid_sigs = [s for s in sigs if isinstance(s, gpg.ValidSig)]
 293                 if not valid_sigs:
 294                         raise SafeException('No valid signatures found on "%s". Signatures:%s' %
 295                                         (interface.uri, ''.join(['\n- ' + str(s) for s in sigs])))
 296
 297                 domain = trust.domain_from_url(interface.uri)
 298
 299                 # Ask on stderr, because we may be writing XML to stdout
 300                 print >>sys.stderr, "\nInterface:", interface.uri
 301                 print >>sys.stderr, _("The feed is correctly signed with the following keys:")
 302                 for x in valid_sigs:
 303                         print >>sys.stderr, "-", x
 304
 305                 if len(valid_sigs) == 1:
 306                         print >>sys.stderr, _("Do you want to trust this key to sign feeds from '%s'?") % domain
 307                 else:
 308                         print >>sys.stderr, _("Do you want to trust all of these keys to sign feeds from '%s'?") % domain
 309                 while True:
 310                         print >>sys.stderr, _("Trust [Y/N] "),
 311                         i = raw_input()
 312                         if not i: continue
 313                         if i in 'Nn':
 314                                 raise NoTrustedKeys(_('Not signed with a trusted key'))
 315                         if i in 'Yy':
 316                                 break
 317                 for key in valid_sigs:
 318                         print >>sys.stderr, _("Trusting %s for %s") % (key.fingerprint, domain)
 319                         trust.trust_db.trust_key(key.fingerprint, domain)
 320
 321                 trust.trust_db.notify()
 322
 323         confirm_trust_keys.original = True              # Detect if someone overrides it
 324
 325         @tasks.async
 326         def confirm_install(self, msg):
 327                 """We need to check something with the user before continuing with the install.
 328                 @raise download.DownloadAborted: if the user cancels"""
 329                 yield
 330                 print >>sys.stderr, msg
 331                 while True:
 332                         sys.stderr.write(_("Install [Y/N] "))
 333                         i = raw_input()
 334                         if not i: continue
 335                         if i in 'Nn':
 336                                 raise download.DownloadAborted()
 337                         if i in 'Yy':
 338                                 break
 339
 340         def report_error(self, exception, tb = None):
 341                 """Report an exception to the user.
 342                 @param exception: the exception to report
 343                 @type exception: L{SafeException}
 344                 @param tb: optional traceback
 345                 @since: 0.25"""
 346                 warn("%s", str(exception) or type(exception))
 347                 #import traceback
 348                 #traceback.print_exception(exception, None, tb)
 349
 350 class ConsoleHandler(Handler):
 351         """A Handler that displays progress on stdout (a tty).
 352         @since: 0.44"""
 353         last_msg_len = None
 354         update = None
 355         disable_progress = 0
 356         screen_width = None
 357
 358         def downloads_changed(self):
 359                 import gobject
 360                 if self.monitored_downloads and self.update is None:
 361                         if self.screen_width is None:
 362                                 try:
 363                                         import curses
 364                                         curses.setupterm()
 365                                         self.screen_width = curses.tigetnum('cols') or 80
 366                                 except Exception, ex:
 367                                         info("Failed to initialise curses library: %s", ex)
 368                                         self.screen_width = 80
 369                         self.show_progress()
 370                         self.update = gobject.timeout_add(200, self.show_progress)
 371                 elif len(self.monitored_downloads) == 0:
 372                         if self.update:
 373                                 gobject.source_remove(self.update)
 374                                 self.update = None
 375                                 print
 376                                 self.last_msg_len = None
 377
 378         def show_progress(self):
 379                 urls = self.monitored_downloads.keys()
 380                 if not urls: return True
 381
 382                 if self.disable_progress: return True
 383
 384                 screen_width = self.screen_width - 2
 385                 item_width = max(16, screen_width / len(self.monitored_downloads))
 386                 url_width = item_width - 7
 387
 388                 msg = ""
 389                 for url in sorted(urls):
 390                         dl = self.monitored_downloads[url]
 391                         so_far = dl.get_bytes_downloaded_so_far()
 392                         leaf = url.rsplit('/', 1)[-1]
 393                         if len(leaf) >= url_width:
 394                                 display = leaf[:url_width]
 395                         else:
 396                                 display = url[-url_width:]
 397                         if dl.expected_size:
 398                                 msg += "[%s %d%%] " % (display, int(so_far * 100 / dl.expected_size))
 399                         else:
 400                                 msg += "[%s] " % (display)
 401                 msg = msg[:screen_width]
 402
 403                 if self.last_msg_len is None:
 404                         sys.stdout.write(msg)
 405                 else:
 406                         sys.stdout.write(chr(13) + msg)
 407                         if len(msg) < self.last_msg_len:
 408                                 sys.stdout.write(" " * (self.last_msg_len - len(msg)))
 409
 410                 self.last_msg_len = len(msg)
 411                 sys.stdout.flush()
 412
 413                 return True
 414
 415         def clear_display(self):
 416                 if self.last_msg_len != None:
 417                         sys.stdout.write(chr(13) + " " * self.last_msg_len + chr(13))
 418                         sys.stdout.flush()
 419                         self.last_msg_len = None
 420
 421         def report_error(self, exception, tb = None):
 422                 self.clear_display()
 423                 Handler.report_error(self, exception, tb)
 424
 425         def confirm_import_feed(self, pending, valid_sigs):
 426                 self.clear_display()
 427                 self.disable_progress += 1
 428                 blocker = Handler.confirm_import_feed(self, pending, valid_sigs)
 429                 @tasks.async
 430                 def enable():
 431                         yield blocker
 432                         self.disable_progress -= 1
 433                         self.show_progress()
 434                 enable()
 435                 return blocker