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 self.stats:
 163                 self.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 self.stats:
 171                 self.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             if self.manager:
 224                 self.factory.protocol.stats = self.manager.stats
 225         return self.factory
 226
 227     def render(self, ctx):
 228         """Render a web page with descriptive statistics."""
 229         if self.manager:
 230             return http.Response(
 231                 200,
 232                 {'content-type': http_headers.MimeType('text', 'html')},
 233                 self.manager.getStats())
 234         else:
 235             return http.Response(
 236                 200,
 237                 {'content-type': http_headers.MimeType('text', 'html')},
 238                 '<html><body><p>Some Statistics</body></html>')
 239
 240     def locateChild(self, request, segments):
 241         """Process the incoming request."""
 242         log.msg('Got HTTP request for %s from %s' % (request.uri, request.remoteAddr))
 243         name = segments[0]
 244
 245         # If the request is for a shared file (from a peer)
 246         if name == '~':
 247             if len(segments) != 2:
 248                 log.msg('Got a malformed request from %s' % request.remoteAddr)
 249                 return None, ()
 250
 251             # Find the file in the database
 252             # Have to unquote_plus the uri, because the segments are unquoted by twisted
 253             hash = unquote_plus(request.uri[3:])
 254             files = self.db.lookupHash(hash)
 255             if files:
 256                 # If it is a file, return it
 257                 if 'path' in files[0]:
 258                     log.msg('Sharing %s with %s' % (files[0]['path'].path, request.remoteAddr))
 259                     return FileUploader(files[0]['path'].path), ()
 260                 else:
 261                     # It's not for a file, but for a piece string, so return that
 262                     log.msg('Sending torrent string %s to %s' % (b2a_hex(hash), request.remoteAddr))
 263                     return static.Data(bencode({'t': files[0]['pieces']}), 'application/x-bencoded'), ()
 264             else:
 265                 log.msg('Hash could not be found in database: %r' % hash)
 266
 267         # Only local requests (apt) get past this point
 268         if request.remoteAddr.host != "127.0.0.1":
 269             log.msg('Blocked illegal access to %s from %s' % (request.uri, request.remoteAddr))
 270             return None, ()
 271
 272         # Block access to index .diff files (for now)
 273         if 'Packages.diff' in segments or 'Sources.diff' in segments:
 274             return None, ()
 275
 276         if len(name) > 1:
 277             # It's a request from apt
 278             return FileDownloader(self.directory.path, self.manager), segments[0:]
 279         else:
 280             # Will render the statistics page
 281             return self, ()
 282
 283         log.msg('Got a malformed request for "%s" from %s' % (request.uri, request.remoteAddr))
 284         return None, ()
 285
 286 class TestTopLevel(unittest.TestCase):
 287     """Unit tests for the HTTP Server."""
 288
 289     client = None
 290     pending_calls = []
 291     torrent_hash = '\xca \xb8\x0c\x00\xe7\x07\xf8~])+\x9d\xe5_B\xff\x1a\xc4!'
 292     torrent = 'abcdefghij0123456789\xca\xec\xb8\x0c\x00\xe7\x07\xf8~])\x8f\x9d\xe5_B\xff\x1a\xc4!'
 293     file_hash = '\xf8~])+\x9d\xe5_B\xff\x1a\xc4!\xca \xb8\x0c\x00\xe7\x07'
 294
 295     def setUp(self):
 296         self.client = TopLevel(FilePath('/boot'), self, None)
 297
 298     def lookupHash(self, hash):
 299         if hash == self.torrent_hash:
 300             return [{'pieces': self.torrent}]
 301         elif hash == self.file_hash:
 302             return [{'path': FilePath('/boot/grub/stage2')}]
 303         else:
 304             return []
 305
 306     def create_request(self, host, path):
 307         req = server.Request(None, 'GET', path, (1,1), 0, http_headers.Headers())
 308         class addr:
 309             host = ''
 310             port = 0
 311         req.remoteAddr = addr()
 312         req.remoteAddr.host = host
 313         req.remoteAddr.port = 23456
 314         server.Request._parseURL(req)
 315         return req
 316
 317     def test_unauthorized(self):
 318         req = self.create_request('128.0.0.1', '/foo/bar')
 319         self.failUnlessRaises(http.HTTPError, req._getChild, None, self.client, req.postpath)
 320
 321     def test_Packages_diff(self):
 322         req = self.create_request('127.0.0.1',
 323                 '/ftp.us.debian.org/debian/dists/unstable/main/binary-i386/Packages.diff/Index')
 324         self.failUnlessRaises(http.HTTPError, req._getChild, None, self.client, req.postpath)
 325
 326     def test_Statistics(self):
 327         req = self.create_request('127.0.0.1', '/')
 328         res = req._getChild(None, self.client, req.postpath)
 329         self.failIfEqual(res, None)
 330         df = defer.maybeDeferred(res.renderHTTP, req)
 331         df.addCallback(self.check_resp, 200)
 332         return df
 333
 334     def test_apt_download(self):
 335         req = self.create_request('127.0.0.1',
 336                 '/ftp.us.debian.org/debian/dists/stable/Release')
 337         res = req._getChild(None, self.client, req.postpath)
 338         self.failIfEqual(res, None)
 339         self.failUnless(isinstance(res, FileDownloader))
 340         df = defer.maybeDeferred(res.renderHTTP, req)
 341         df.addCallback(self.check_resp, 404)
 342         return df
 343
 344     def test_torrent_upload(self):
 345         req = self.create_request('123.45.67.89',
 346                                   '/~/' + quote_plus(self.torrent_hash))
 347         res = req._getChild(None, self.client, req.postpath)
 348         self.failIfEqual(res, None)
 349         self.failUnless(isinstance(res, static.Data))
 350         df = defer.maybeDeferred(res.renderHTTP, req)
 351         df.addCallback(self.check_resp, 200)
 352         return df
 353
 354     def test_file_upload(self):
 355         req = self.create_request('123.45.67.89',
 356                                   '/~/' + quote_plus(self.file_hash))
 357         res = req._getChild(None, self.client, req.postpath)
 358         self.failIfEqual(res, None)
 359         self.failUnless(isinstance(res, FileUploader))
 360         df = defer.maybeDeferred(res.renderHTTP, req)
 361         df.addCallback(self.check_resp, 200)
 362         return df
 363
 364     def test_missing_hash(self):
 365         req = self.create_request('123.45.67.89',
 366                                   '/~/' + quote_plus('foobar'))
 367         self.failUnlessRaises(http.HTTPError, req._getChild, None, self.client, req.postpath)
 368
 369     def check_resp(self, resp, code):
 370         self.failUnlessEqual(resp.code, code)
 371         return resp
 372
 373     def tearDown(self):
 374         for p in self.pending_calls:
 375             if p.active():
 376                 p.cancel()
 377         self.pending_calls = []
 378         if self.client:
 379             self.client = None
 380
 381 if __name__ == '__builtin__':
 382     # Running from twistd -ny HTTPServer.py
 383     # Then test with:
 384     #   wget -S 'http://localhost:18080/~/whatever'
 385     #   wget -S 'http://localhost:18080/~/pieces'
 386
 387     import os.path
 388     from twisted.python.filepath import FilePath
 389
 390     class DB:
 391         def lookupHash(self, hash):
 392             if hash == 'pieces':
 393                 return [{'pieces': 'abcdefghij0123456789\xca\xec\xb8\x0c\x00\xe7\x07\xf8~])\x8f\x9d\xe5_B\xff\x1a\xc4!'}]
 394             return [{'path': FilePath(os.path.expanduser('~/school/optout'))}]
 395
 396     t = TopLevel(FilePath(os.path.expanduser('~')), DB(), None, 0)
 397     factory = t.getHTTPFactory()
 398
 399     # Standard twisted application Boilerplate
 400     from twisted.application import service, strports
 401     application = service.Application("demoserver")
 402     s = strports.service('tcp:18080', factory)
 403     s.setServiceParent(application)