zeroinstall/injector/fetch.py

   1 """
   2 Downloads feeds, keys, packages and icons.
   3 """
   4
   5 # Copyright (C) 2009, Thomas Leonard
   6 # See the README file for details, or visit http://0install.net.
   7
   8 from zeroinstall import _
   9 import os
  10 from logging import info, debug, warn
  11
  12 from zeroinstall.support import tasks, basedir
  13 from zeroinstall.injector.namespaces import XMLNS_IFACE, config_site
  14 from zeroinstall.injector.model import DownloadSource, Recipe, SafeException, escape
  15 from zeroinstall.injector.iface_cache import PendingFeed, ReplayAttack
  16 from zeroinstall.injector.handler import NoTrustedKeys
  17 from zeroinstall.injector import download
  18
  19 def _escape_slashes(path):
  20         return path.replace('/', '%23')
  21
  22 def _get_feed_dir(feed):
  23         """The algorithm from 0mirror."""
  24         if '#' in feed:
  25                 raise SafeException(_("Invalid URL '%s'") % feed)
  26         scheme, rest = feed.split('://', 1)
  27         domain, rest = rest.split('/', 1)
  28         for x in [scheme, domain, rest]:
  29                 if not x or x.startswith(','):
  30                         raise SafeException(_("Invalid URL '%s'") % feed)
  31         return os.path.join('feeds', scheme, domain, _escape_slashes(rest))
  32
  33 class Fetcher(object):
  34         """Downloads and stores various things.
  35         @ivar handler: handler to use for user-interaction
  36         @type handler: L{handler.Handler}
  37         @ivar feed_mirror: the base URL of a mirror site for keys and feeds
  38         @type feed_mirror: str
  39         """
  40         __slots__ = ['handler', 'feed_mirror']
  41
  42         def __init__(self, handler):
  43                 self.handler = handler
  44                 self.feed_mirror = "http://roscidus.com/0mirror"
  45
  46         @tasks.async
  47         def cook(self, required_digest, recipe, stores, force = False, impl_hint = None):
  48                 """Follow a Recipe.
  49                 @param impl_hint: the Implementation this is for (if any) as a hint for the GUI
  50                 @see: L{download_impl} uses this method when appropriate"""
  51                 # Maybe we're taking this metaphor too far?
  52
  53                 # Start downloading all the ingredients.
  54                 downloads = {}  # Downloads that are not yet successful
  55                 streams = {}    # Streams collected from successful downloads
  56
  57                 # Start a download for each ingredient
  58                 blockers = []
  59                 for step in recipe.steps:
  60                         blocker, stream = self.download_archive(step, force = force, impl_hint = impl_hint)
  61                         assert stream
  62                         blockers.append(blocker)
  63                         streams[step] = stream
  64
  65                 while blockers:
  66                         yield blockers
  67                         tasks.check(blockers)
  68                         blockers = [b for b in blockers if not b.happened]
  69
  70                 from zeroinstall.zerostore import unpack
  71
  72                 # Create an empty directory for the new implementation
  73                 store = stores.stores[0]
  74                 tmpdir = store.get_tmp_dir_for(required_digest)
  75                 try:
  76                         # Unpack each of the downloaded archives into it in turn
  77                         for step in recipe.steps:
  78                                 stream = streams[step]
  79                                 stream.seek(0)
  80                                 unpack.unpack_archive_over(step.url, stream, tmpdir, step.extract)
  81                         # Check that the result is correct and store it in the cache
  82                         store.check_manifest_and_rename(required_digest, tmpdir)
  83                         tmpdir = None
  84                 finally:
  85                         # If unpacking fails, remove the temporary directory
  86                         if tmpdir is not None:
  87                                 from zeroinstall import support
  88                                 support.ro_rmtree(tmpdir)
  89
  90         def get_feed_mirror(self, url):
  91                 """Return the URL of a mirror for this feed."""
  92                 import urlparse
  93                 if urlparse.urlparse(url).hostname == 'localhost':
  94                         return None
  95                 return '%s/%s/latest.xml' % (self.feed_mirror, _get_feed_dir(url))
  96
  97         def download_and_import_feed(self, feed_url, iface_cache, force = False):
  98                 """Download the feed, download any required keys, confirm trust if needed and import.
  99                 @param feed_url: the feed to be downloaded
 100                 @type feed_url: str
 101                 @param iface_cache: cache in which to store the feed
 102                 @type iface_cache: L{iface_cache.IfaceCache}
 103                 @param force: whether to abort and restart an existing download"""
 104                 from download import DownloadAborted
 105
 106                 debug(_("download_and_import_feed %(url)s (force = %(force)d)"), {'url': feed_url, 'force': force})
 107                 assert not feed_url.startswith('/')
 108
 109                 primary = self._download_and_import_feed(feed_url, iface_cache, force, use_mirror = False)
 110
 111                 @tasks.named_async("monitor feed downloads for " + feed_url)
 112                 def wait_for_downloads(primary):
 113                         # Download just the upstream feed, unless it takes too long...
 114                         timeout = tasks.TimeoutBlocker(5, 'Mirror timeout')             # 5 seconds
 115
 116                         yield primary, timeout
 117                         tasks.check(timeout)
 118
 119                         try:
 120                                 tasks.check(primary)
 121                                 if primary.happened:
 122                                         return          # OK, primary succeeded!
 123                                 # OK, maybe it's just being slow...
 124                                 info("Feed download from %s is taking a long time. Trying mirror too...", feed_url)
 125                                 primary_ex = None
 126                         except NoTrustedKeys, ex:
 127                                 raise                   # Don't bother trying the mirror if we have a trust problem
 128                         except ReplayAttack, ex:
 129                                 raise                   # Don't bother trying the mirror if we have a replay attack
 130                         except DownloadAborted, ex:
 131                                 raise                   # Don't bother trying the mirror if the user cancelled
 132                         except SafeException, ex:
 133                                 # Primary failed
 134                                 primary = None
 135                                 primary_ex = ex
 136                                 warn(_("Trying mirror, as feed download from %(url)s failed: %(exception)s"), {'url': feed_url, 'exception': ex})
 137
 138                         # Start downloading from mirror...
 139                         mirror = self._download_and_import_feed(feed_url, iface_cache, force, use_mirror = True)
 140
 141                         # Wait until both mirror and primary tasks are complete...
 142                         while True:
 143                                 blockers = filter(None, [primary, mirror])
 144                                 if not blockers:
 145                                         break
 146                                 yield blockers
 147
 148                                 if primary:
 149                                         try:
 150                                                 tasks.check(primary)
 151                                                 if primary.happened:
 152                                                         primary = None
 153                                                         # No point carrying on with the mirror once the primary has succeeded
 154                                                         if mirror:
 155                                                                 info(_("Primary feed download succeeded; aborting mirror download for %s") % feed_url)
 156                                                                 mirror.dl.abort()
 157                                         except SafeException, ex:
 158                                                 primary = None
 159                                                 primary_ex = ex
 160                                                 info(_("Feed download from %(url)s failed; still trying mirror: %(exception)s"), {'url': feed_url, 'exception': ex})
 161
 162                                 if mirror:
 163                                         try:
 164                                                 tasks.check(mirror)
 165                                                 if mirror.happened:
 166                                                         mirror = None
 167                                                         if primary_ex:
 168                                                                 # We already warned; no need to raise an exception too,
 169                                                                 # as the mirror download succeeded.
 170                                                                 primary_ex = None
 171                                         except ReplayAttack, ex:
 172                                                 info(_("Version from mirror is older than cached version; ignoring it: %s"), ex)
 173                                                 mirror = None
 174                                                 primary_ex = None
 175                                         except SafeException, ex:
 176                                                 info(_("Mirror download failed: %s"), ex)
 177                                                 mirror = None
 178
 179                         if primary_ex:
 180                                 raise primary_ex
 181
 182                 return wait_for_downloads(primary)
 183
 184         def _download_and_import_feed(self, feed_url, iface_cache, force, use_mirror):
 185                 """Download and import a feed.
 186                 @param use_mirror: False to use primary location; True to use mirror."""
 187                 if use_mirror:
 188                         url = self.get_feed_mirror(feed_url)
 189                         if url is None: return None
 190                 else:
 191                         url = feed_url
 192
 193                 dl = self.handler.get_download(url, force = force, hint = feed_url)
 194                 stream = dl.tempfile
 195
 196                 @tasks.named_async("fetch_feed " + url)
 197                 def fetch_feed():
 198                         yield dl.downloaded
 199                         tasks.check(dl.downloaded)
 200
 201                         pending = PendingFeed(feed_url, stream)
 202
 203                         if use_mirror:
 204                                 # If we got the feed from a mirror, get the key from there too
 205                                 key_mirror = self.feed_mirror + '/keys/'
 206                         else:
 207                                 key_mirror = None
 208
 209                         keys_downloaded = tasks.Task(pending.download_keys(self.handler, feed_hint = feed_url, key_mirror = key_mirror), _("download keys for %s") % feed_url)
 210                         yield keys_downloaded.finished
 211                         tasks.check(keys_downloaded.finished)
 212
 213                         iface = iface_cache.get_interface(pending.url)
 214                         if not iface_cache.update_interface_if_trusted(iface, pending.sigs, pending.new_xml):
 215                                 blocker = self.handler.confirm_trust_keys(iface, pending.sigs, pending.new_xml)
 216                                 if blocker:
 217                                         yield blocker
 218                                         tasks.check(blocker)
 219                                 if not iface_cache.update_interface_if_trusted(iface, pending.sigs, pending.new_xml):
 220                                         raise NoTrustedKeys(_("No signing keys trusted; not importing"))
 221
 222                 task = fetch_feed()
 223                 task.dl = dl
 224                 return task
 225
 226         def download_impl(self, impl, retrieval_method, stores, force = False):
 227                 """Download an implementation.
 228                 @param impl: the selected implementation
 229                 @type impl: L{model.ZeroInstallImplementation}
 230                 @param retrieval_method: a way of getting the implementation (e.g. an Archive or a Recipe)
 231                 @type retrieval_method: L{model.RetrievalMethod}
 232                 @param stores: where to store the downloaded implementation
 233                 @type stores: L{zerostore.Stores}
 234                 @param force: whether to abort and restart an existing download
 235                 @rtype: L{tasks.Blocker}"""
 236                 assert impl
 237                 assert retrieval_method
 238
 239                 from zeroinstall.zerostore import manifest
 240                 alg = impl.id.split('=', 1)[0]
 241                 if alg not in manifest.algorithms:
 242                         raise SafeException(_("Unknown digest algorithm '%(algorithm)s' for '%(implementation)s' version %(version)s") %
 243                                         {'algorithm': alg, 'implementation': impl.feed.get_name(), 'version': impl.get_version()})
 244
 245                 @tasks.async
 246                 def download_impl():
 247                         if isinstance(retrieval_method, DownloadSource):
 248                                 blocker, stream = self.download_archive(retrieval_method, force = force, impl_hint = impl)
 249                                 yield blocker
 250                                 tasks.check(blocker)
 251
 252                                 stream.seek(0)
 253                                 self._add_to_cache(stores, retrieval_method, stream)
 254                         elif isinstance(retrieval_method, Recipe):
 255                                 blocker = self.cook(impl.id, retrieval_method, stores, force, impl_hint = impl)
 256                                 yield blocker
 257                                 tasks.check(blocker)
 258                         else:
 259                                 raise Exception(_("Unknown download type for '%s'") % retrieval_method)
 260
 261                         self.handler.impl_added_to_store(impl)
 262                 return download_impl()
 263
 264         def _add_to_cache(self, stores, retrieval_method, stream):
 265                 assert isinstance(retrieval_method, DownloadSource)
 266                 required_digest = retrieval_method.implementation.id
 267                 url = retrieval_method.url
 268                 stores.add_archive_to_cache(required_digest, stream, retrieval_method.url, retrieval_method.extract,
 269                                                  type = retrieval_method.type, start_offset = retrieval_method.start_offset or 0)
 270
 271         def download_archive(self, download_source, force = False, impl_hint = None):
 272                 """Fetch an archive. You should normally call L{download_impl}
 273                 instead, since it handles other kinds of retrieval method too."""
 274                 from zeroinstall.zerostore import unpack
 275
 276                 url = download_source.url
 277                 if not (url.startswith('http:') or url.startswith('https:') or url.startswith('ftp:')):
 278                         raise SafeException(_("Unknown scheme in download URL '%s'") % url)
 279
 280                 mime_type = download_source.type
 281                 if not mime_type:
 282                         mime_type = unpack.type_from_url(download_source.url)
 283                 if not mime_type:
 284                         raise SafeException(_("No 'type' attribute on archive, and I can't guess from the name (%s)") % download_source.url)
 285                 unpack.check_type_ok(mime_type)
 286                 dl = self.handler.get_download(download_source.url, force = force, hint = impl_hint)
 287                 dl.expected_size = download_source.size + (download_source.start_offset or 0)
 288                 return (dl.downloaded, dl.tempfile)
 289
 290         def download_icon(self, interface, force = False, modification_time = None):
 291                 """Download an icon for this interface and add it to the
 292                 icon cache. If the interface has no icon or we are offline, do nothing.
 293                 @return: the task doing the import, or None
 294                 @rtype: L{tasks.Task}"""
 295                 debug(_("download_icon %(interface)s (force = %(force)d)"), {'interface': interface, 'force': force})
 296
 297                 # Find a suitable icon to download
 298                 for icon in interface.get_metadata(XMLNS_IFACE, 'icon'):
 299                         type = icon.getAttribute('type')
 300                         if type != 'image/png':
 301                                 debug(_('Skipping non-PNG icon'))
 302                                 continue
 303                         source = icon.getAttribute('href')
 304                         if source:
 305                                 break
 306                         warn(_('Missing "href" attribute on <icon> in %s'), interface)
 307                 else:
 308                         info(_('No PNG icons found in %s'), interface)
 309                         return
 310
 311                 try:
 312                         dl = self.handler.monitored_downloads[source]
 313                         if dl and force:
 314                                 dl.abort()
 315                                 raise KeyError
 316                 except KeyError:
 317                         dl = download.Download(source, hint = interface, modification_time = modification_time)
 318                         self.handler.monitor_download(dl)
 319
 320                 @tasks.async
 321                 def download_and_add_icon():
 322                         stream = dl.tempfile
 323                         yield dl.downloaded
 324                         try:
 325                                 tasks.check(dl.downloaded)
 326                                 if dl.unmodified: return
 327                                 stream.seek(0)
 328
 329                                 import shutil
 330                                 icons_cache = basedir.save_cache_path(config_site, 'interface_icons')
 331                                 icon_file = file(os.path.join(icons_cache, escape(interface.uri)), 'w')
 332                                 shutil.copyfileobj(stream, icon_file)
 333                         except Exception, ex:
 334                                 self.handler.report_error(ex)
 335
 336                 return download_and_add_icon()
 337
 338         def download_impls(self, implementations, stores):
 339                 """Download the given implementations, choosing a suitable retrieval method for each."""
 340                 blockers = []
 341
 342                 to_download = []
 343                 for impl in implementations:
 344                         debug(_("start_downloading_impls: for %(feed)s get %(implementation)s"), {'feed': impl.feed, 'implementation': impl})
 345                         source = self.get_best_source(impl)
 346                         if not source:
 347                                 raise SafeException(_("Implementation %(implementation_id)s of interface %(interface)s"
 348                                         " cannot be downloaded (no download locations given in "
 349                                         "interface!)") % {'implementation_id': impl.id, 'interface': impl.feed.get_name()})
 350                         to_download.append((impl, source))
 351
 352                 for impl, source in to_download:
 353                         blockers.append(self.download_impl(impl, source, stores))
 354
 355                 if not blockers:
 356                         return None
 357
 358                 @tasks.async
 359                 def download_impls(blockers):
 360                         # Record the first error log the rest
 361                         error = []
 362                         def dl_error(ex, tb = None):
 363                                 if error:
 364                                         self.handler.report_error(ex)
 365                                 else:
 366                                         error.append(ex)
 367                         while blockers:
 368                                 yield blockers
 369                                 tasks.check(blockers, dl_error)
 370
 371                                 blockers = [b for b in blockers if not b.happened]
 372                         if error:
 373                                 raise error[0]
 374
 375                 return download_impls(blockers)
 376
 377         def get_best_source(self, impl):
 378                 """Return the best download source for this implementation.
 379                 @rtype: L{model.RetrievalMethod}"""
 380                 if impl.download_sources:
 381                         return impl.download_sources[0]
 382                 return None
 383