apt_p2p/HTTPServer.py

   1
   2 """Serve local requests from apt and remote requests from peers."""
   3
   4 from urllib import quote_plus, unquote_plus
   5 from binascii import b2a_hex
   6 import operator
   7
   8 from twisted.python import log
   9 from twisted.internet import defer
  10 from twisted.web2 import server, http, resource, channel, stream
  11 from twisted.web2 import static, http_headers, responsecode
  12 from twisted.trial import unittest
  13 from twisted.python.filepath import FilePath
  14
  15 from policies import ThrottlingFactory, ThrottlingProtocol, ProtocolWrapper
  16 from apt_p2p_conf import config
  17 from apt_p2p_Khashmir.bencode import bencode
  18
  19 class FileDownloader(static.File):
  20     """Modified to make it suitable for apt requests.
  21
  22     Tries to find requests in the cache. Found files are first checked for
  23     freshness before being sent. Requests for unfound and stale files are
  24     forwarded to the main program for downloading.
  25
  26     @type manager: L{apt_p2p.AptP2P}
  27     @ivar manager: the main program to query
  28     """
  29
  30     def __init__(self, path, manager, defaultType="text/plain", ignoredExts=(), processors=None, indexNames=None):
  31         self.manager = manager
  32         super(FileDownloader, self).__init__(path, defaultType, ignoredExts, processors, indexNames)
  33
  34     def renderHTTP(self, req):
  35         log.msg('Got request for %s from %s' % (req.uri, req.remoteAddr))
  36         resp = super(FileDownloader, self).renderHTTP(req)
  37         if isinstance(resp, defer.Deferred):
  38             resp.addCallbacks(self._renderHTTP_done, self._renderHTTP_error,
  39                               callbackArgs = (req, ), errbackArgs = (req, ))
  40         else:
  41             resp = self._renderHTTP_done(resp, req)
  42         return resp
  43
  44     def _renderHTTP_done(self, resp, req):
  45         log.msg('Initial response to %s: %r' % (req.uri, resp))
  46
  47         if self.manager:
  48             path = 'http:/' + req.uri
  49             if resp.code >= 200 and resp.code < 400:
  50                 return self.manager.check_freshness(req, path, resp.headers.getHeader('Last-Modified'), resp)
  51
  52             log.msg('Not found, trying other methods for %s' % req.uri)
  53             return self.manager.get_resp(req, path)
  54
  55         return resp
  56
  57     def _renderHTTP_error(self, err, req):
  58         log.msg('Failed to render %s: %r' % (req.uri, err))
  59         log.err(err)
  60
  61         if self.manager:
  62             path = 'http:/' + req.uri
  63             return self.manager.get_resp(req, path)
  64
  65         return err
  66
  67     def createSimilarFile(self, path):
  68         return self.__class__(path, self.manager, self.defaultType, self.ignoredExts,
  69                               self.processors, self.indexNames[:])
  70
  71 class FileUploaderStream(stream.FileStream):
  72     """Modified to make it suitable for streaming to peers.
  73
  74     Streams the file in small chunks to make it easier to throttle the
  75     streaming to peers.
  76
  77     @ivar CHUNK_SIZE: the size of chunks of data to send at a time
  78     """
  79
  80     CHUNK_SIZE = 4*1024
  81
  82     def read(self, sendfile=False):
  83         if self.f is None:
  84             return None
  85
  86         length = self.length
  87         if length == 0:
  88             self.f = None
  89             return None
  90
  91         # Remove the SendFileBuffer and mmap use, just use string reads and writes
  92
  93         readSize = min(length, self.CHUNK_SIZE)
  94
  95         self.f.seek(self.start)
  96         b = self.f.read(readSize)
  97         bytesRead = len(b)
  98         if not bytesRead:
  99             raise RuntimeError("Ran out of data reading file %r, expected %d more bytes" % (self.f, length))
 100         else:
 101             self.length -= bytesRead
 102             self.start += bytesRead
 103             return b
 104
 105
 106 class FileUploader(static.File):
 107     """Modified to make it suitable for peer requests.
 108
 109     Uses the modified L{FileUploaderStream} to stream the file for throttling,
 110     and doesn't do any listing of directory contents.
 111     """
 112
 113     def render(self, req):
 114         if not self.fp.exists():
 115             return responsecode.NOT_FOUND
 116
 117         if self.fp.isdir():
 118             # Don't try to render a directory listing
 119             return responsecode.NOT_FOUND
 120
 121         try:
 122             f = self.fp.open()
 123         except IOError, e:
 124             import errno
 125             if e[0] == errno.EACCES:
 126                 return responsecode.FORBIDDEN
 127             elif e[0] == errno.ENOENT:
 128                 return responsecode.NOT_FOUND
 129             else:
 130                 raise
 131
 132         response = http.Response()
 133         # Use the modified FileStream
 134         response.stream = FileUploaderStream(f, 0, self.fp.getsize())
 135
 136         for (header, value) in (
 137             ("content-type", self.contentType()),
 138             ("content-encoding", self.contentEncoding()),
 139         ):
 140             if value is not None:
 141                 response.headers.setHeader(header, value)
 142
 143         return response
 144
 145 class UploadThrottlingProtocol(ThrottlingProtocol):
 146     """Protocol for throttling uploads.
 147
 148     Determines whether or not to throttle the upload based on the type of stream.
 149     Uploads use L{FileUploaderStream} or L{twisted.web2.stream.MemorySTream},
 150     apt uses L{CacheManager.ProxyFileStream} or L{twisted.web.stream.FileStream}.
 151     """
 152
 153     stats = None
 154
 155     def __init__(self, factory, wrappedProtocol):
 156         ThrottlingProtocol.__init__(self, factory, wrappedProtocol)
 157         self.throttle = False
 158
 159     def write(self, data):
 160         if self.throttle:
 161             ThrottlingProtocol.write(self, data)
 162             if stats:
 163                 stats.sentBytes(len(data))
 164         else:
 165             ProtocolWrapper.write(self, data)
 166
 167     def writeSequence(self, seq):
 168         if self.throttle:
 169             ThrottlingProtocol.writeSequence(self, seq)
 170             if stats:
 171                 stats.sentBytes(reduce(operator.add, map(len, seq)))
 172         else:
 173             ProtocolWrapper.writeSequence(self, seq)
 174
 175     def registerProducer(self, producer, streaming):
 176         ThrottlingProtocol.registerProducer(self, producer, streaming)
 177         streamType = getattr(producer, 'stream', None)
 178         if isinstance(streamType, FileUploaderStream) or isinstance(streamType, stream.MemoryStream):
 179             self.throttle = True
 180
 181
 182 class TopLevel(resource.Resource):
 183     """The HTTP server for all requests, both from peers and apt.
 184
 185     @type directory: L{twisted.python.filepath.FilePath}
 186     @ivar directory: the directory to check for cached files
 187     @type db: L{db.DB}
 188     @ivar db: the database to use for looking up files and hashes
 189     @type manager: L{apt_p2p.AptP2P}
 190     @ivar manager: the main program object to send requests to
 191     @type factory: L{twisted.web2.channel.HTTPFactory} or L{policies.ThrottlingFactory}
 192     @ivar factory: the factory to use to serve HTTP requests
 193     """
 194
 195     addSlash = True
 196
 197     def __init__(self, directory, db, manager):
 198         """Initialize the instance.
 199
 200         @type directory: L{twisted.python.filepath.FilePath}
 201         @param directory: the directory to check for cached files
 202         @type db: L{db.DB}
 203         @param db: the database to use for looking up files and hashes
 204         @type manager: L{apt_p2p.AptP2P}
 205         @param manager: the main program object to send requests to
 206         """
 207         self.directory = directory
 208         self.db = db
 209         self.manager = manager
 210         self.uploadLimit = None
 211         if config.getint('DEFAULT', 'UPLOAD_LIMIT') > 0:
 212             self.uploadLimit = int(config.getint('DEFAULT', 'UPLOAD_LIMIT')*1024)
 213         self.factory = None
 214
 215     def getHTTPFactory(self):
 216         """Initialize and get the factory for this HTTP server."""
 217         if self.factory is None:
 218             self.factory = channel.HTTPFactory(server.Site(self),
 219                                                **{'maxPipeline': 10,
 220                                                   'betweenRequestsTimeOut': 60})
 221             self.factory = ThrottlingFactory(self.factory, writeLimit = self.uploadLimit)
 222             self.factory.protocol = UploadThrottlingProtocol
 223             self.factory.protocol.stats = self.manager.stats
 224         return self.factory
 225
 226     def render(self, ctx):
 227         """Render a web page with descriptive statistics."""
 228         if self.manager:
 229             return http.Response(
 230                 200,
 231                 {'content-type': http_headers.MimeType('text', 'html')},
 232                 self.manager.getStats())
 233         else:
 234             return http.Response(
 235                 200,
 236                 {'content-type': http_headers.MimeType('text', 'html')},
 237                 '<html><body><p>Some Statistics</body></html>')
 238
 239     def locateChild(self, request, segments):
 240         """Process the incoming request."""
 241         log.msg('Got HTTP request for %s from %s' % (request.uri, request.remoteAddr))
 242         name = segments[0]
 243
 244         # If the request is for a shared file (from a peer)
 245         if name == '~':
 246             if len(segments) != 2:
 247                 log.msg('Got a malformed request from %s' % request.remoteAddr)
 248                 return None, ()
 249
 250             # Find the file in the database
 251             # Have to unquote_plus the uri, because the segments are unquoted by twisted
 252             hash = unquote_plus(request.uri[3:])
 253             files = self.db.lookupHash(hash)
 254             if files:
 255                 # If it is a file, return it
 256                 if 'path' in files[0]:
 257                     log.msg('Sharing %s with %s' % (files[0]['path'].path, request.remoteAddr))
 258                     return FileUploader(files[0]['path'].path), ()
 259                 else:
 260                     # It's not for a file, but for a piece string, so return that
 261                     log.msg('Sending torrent string %s to %s' % (b2a_hex(hash), request.remoteAddr))
 262                     return static.Data(bencode({'t': files[0]['pieces']}), 'application/x-bencoded'), ()
 263             else:
 264                 log.msg('Hash could not be found in database: %r' % hash)
 265
 266         # Only local requests (apt) get past this point
 267         if request.remoteAddr.host != "127.0.0.1":
 268             log.msg('Blocked illegal access to %s from %s' % (request.uri, request.remoteAddr))
 269             return None, ()
 270
 271         # Block access to index .diff files (for now)
 272         if 'Packages.diff' in segments or 'Sources.diff' in segments:
 273             return None, ()
 274
 275         if len(name) > 1:
 276             # It's a request from apt
 277             return FileDownloader(self.directory.path, self.manager), segments[0:]
 278         else:
 279             # Will render the statistics page
 280             return self, ()
 281
 282         log.msg('Got a malformed request for "%s" from %s' % (request.uri, request.remoteAddr))
 283         return None, ()
 284
 285 class TestTopLevel(unittest.TestCase):
 286     """Unit tests for the HTTP Server."""
 287
 288     client = None
 289     pending_calls = []
 290     torrent_hash = '\xca \xb8\x0c\x00\xe7\x07\xf8~])+\x9d\xe5_B\xff\x1a\xc4!'
 291     torrent = 'abcdefghij0123456789\xca\xec\xb8\x0c\x00\xe7\x07\xf8~])\x8f\x9d\xe5_B\xff\x1a\xc4!'
 292     file_hash = '\xf8~])+\x9d\xe5_B\xff\x1a\xc4!\xca \xb8\x0c\x00\xe7\x07'
 293
 294     def setUp(self):
 295         self.client = TopLevel(FilePath('/boot'), self, None)
 296
 297     def lookupHash(self, hash):
 298         if hash == self.torrent_hash:
 299             return [{'pieces': self.torrent}]
 300         elif hash == self.file_hash:
 301             return [{'path': FilePath('/boot/grub/stage2')}]
 302         else:
 303             return []
 304
 305     def create_request(self, host, path):
 306         req = server.Request(None, 'GET', path, (1,1), 0, http_headers.Headers())
 307         class addr:
 308             host = ''
 309             port = 0
 310         req.remoteAddr = addr()
 311         req.remoteAddr.host = host
 312         req.remoteAddr.port = 23456
 313         server.Request._parseURL(req)
 314         return req
 315
 316     def test_unauthorized(self):
 317         req = self.create_request('128.0.0.1', '/foo/bar')
 318         self.failUnlessRaises(http.HTTPError, req._getChild, None, self.client, req.postpath)
 319
 320     def test_Packages_diff(self):
 321         req = self.create_request('127.0.0.1',
 322                 '/ftp.us.debian.org/debian/dists/unstable/main/binary-i386/Packages.diff/Index')
 323         self.failUnlessRaises(http.HTTPError, req._getChild, None, self.client, req.postpath)
 324
 325     def test_Statistics(self):
 326         req = self.create_request('127.0.0.1', '/')
 327         res = req._getChild(None, self.client, req.postpath)
 328         self.failIfEqual(res, None)
 329         df = defer.maybeDeferred(res.renderHTTP, req)
 330         df.addCallback(self.check_resp, 200)
 331         return df
 332
 333     def test_apt_download(self):
 334         req = self.create_request('127.0.0.1',
 335                 '/ftp.us.debian.org/debian/dists/stable/Release')
 336         res = req._getChild(None, self.client, req.postpath)
 337         self.failIfEqual(res, None)
 338         self.failUnless(isinstance(res, FileDownloader))
 339         df = defer.maybeDeferred(res.renderHTTP, req)
 340         df.addCallback(self.check_resp, 404)
 341         return df
 342
 343     def test_torrent_upload(self):
 344         req = self.create_request('123.45.67.89',
 345                                   '/~/' + quote_plus(self.torrent_hash))
 346         res = req._getChild(None, self.client, req.postpath)
 347         self.failIfEqual(res, None)
 348         self.failUnless(isinstance(res, static.Data))
 349         df = defer.maybeDeferred(res.renderHTTP, req)
 350         df.addCallback(self.check_resp, 200)
 351         return df
 352
 353     def test_file_upload(self):
 354         req = self.create_request('123.45.67.89',
 355                                   '/~/' + quote_plus(self.file_hash))
 356         res = req._getChild(None, self.client, req.postpath)
 357         self.failIfEqual(res, None)
 358         self.failUnless(isinstance(res, FileUploader))
 359         df = defer.maybeDeferred(res.renderHTTP, req)
 360         df.addCallback(self.check_resp, 200)
 361         return df
 362
 363     def test_missing_hash(self):
 364         req = self.create_request('123.45.67.89',
 365                                   '/~/' + quote_plus('foobar'))
 366         self.failUnlessRaises(http.HTTPError, req._getChild, None, self.client, req.postpath)
 367
 368     def check_resp(self, resp, code):
 369         self.failUnlessEqual(resp.code, code)
 370         return resp
 371
 372     def tearDown(self):
 373         for p in self.pending_calls:
 374             if p.active():
 375                 p.cancel()
 376         self.pending_calls = []
 377         if self.client:
 378             self.client = None
 379
 380 if __name__ == '__builtin__':
 381     # Running from twistd -ny HTTPServer.py
 382     # Then test with:
 383     #   wget -S 'http://localhost:18080/~/whatever'
 384     #   wget -S 'http://localhost:18080/~/pieces'
 385
 386     import os.path
 387     from twisted.python.filepath import FilePath
 388
 389     class DB:
 390         def lookupHash(self, hash):
 391             if hash == 'pieces':
 392                 return [{'pieces': 'abcdefghij0123456789\xca\xec\xb8\x0c\x00\xe7\x07\xf8~])\x8f\x9d\xe5_B\xff\x1a\xc4!'}]
 393             return [{'path': FilePath(os.path.expanduser('~/school/optout'))}]
 394
 395     t = TopLevel(FilePath(os.path.expanduser('~')), DB(), None, 0)
 396     factory = t.getHTTPFactory()
 397
 398     # Standard twisted application Boilerplate
 399     from twisted.application import service, strports
 400     application = service.Application("demoserver")
 401     s = strports.service('tcp:18080', factory)
 402     s.setServiceParent(application)