2 """The main program code.
4 @var DHT_PIECES: the maximum number of pieces to store with our contact info
6 @var TORRENT_PIECES: the maximum number of pieces to store as a separate entry
8 @var download_dir: the name of the directory to use for downloaded files
12 from binascii import b2a_hex
13 from urlparse import urlunparse
14 from urllib import unquote
17 from twisted.internet import defer, reactor
18 from twisted.web2 import server, http, http_headers, static
19 from twisted.python import log, failure
20 from twisted.python.filepath import FilePath
22 from interfaces import IDHT, IDHTStats
23 from apt_p2p_conf import config
24 from PeerManager import PeerManager
25 from HTTPServer import TopLevel
26 from MirrorManager import MirrorManager
27 from CacheManager import CacheManager
28 from Hash import HashObject
30 from stats import StatsLogger
31 from util import findMyIPAddr, compact
36 download_dir = 'cache'
39 """The main code object that does all of the work.
41 Contains all of the sub-components that do all the low-level work, and
42 coordinates communication between them.
44 @type dhtClass: L{interfaces.IDHT}
45 @ivar dhtClass: the DHT class to use
46 @type cache_dir: L{twisted.python.filepath.FilePath}
47 @ivar cache_dir: the directory to use for storing all files
49 @ivar db: the database to use for tracking files and hashes
50 @type dht: L{interfaces.IDHT}
51 @ivar dht: the DHT instance
52 @type stats: L{stats.StatsLogger}
53 @ivar stats: the statistics logger to record sent data to
54 @type http_server: L{HTTPServer.TopLevel}
55 @ivar http_server: the web server that will handle all requests from apt
57 @type peers: L{PeerManager.PeerManager}
58 @ivar peers: the manager of all downloads from mirrors and other peers
59 @type mirrors: L{MirrorManager.MirrorManager}
60 @ivar mirrors: the manager of downloaded information about mirrors which
61 can be queried to get hashes from file names
62 @type cache: L{CacheManager.CacheManager}
63 @ivar cache: the manager of all downloaded files
64 @type my_contact: C{string}
65 @ivar my_contact: the 6-byte compact peer representation of this peer's
66 download information (IP address and port)
69 def __init__(self, dhtClass):
70 """Initialize all the sub-components.
72 @type dhtClass: L{interfaces.IDHT}
73 @param dhtClass: the DHT class to use
75 log.msg('Initializing the main apt_p2p application')
76 self.dhtClass = dhtClass
77 self.cache_dir = FilePath(config.get('DEFAULT', 'CACHE_DIR'))
78 if not self.cache_dir.child(download_dir).exists():
79 self.cache_dir.child(download_dir).makedirs()
80 self.db = DB(self.cache_dir.child('apt-p2p.db'))
82 self.dht.loadConfig(config, config.get('DEFAULT', 'DHT'))
83 self.dht.join().addCallbacks(self.joinComplete, self.joinError)
84 self.stats = StatsLogger(self.db)
85 self.http_server = TopLevel(self.cache_dir.child(download_dir), self.db, self)
86 self.getHTTPFactory = self.http_server.getHTTPFactory
87 self.peers = PeerManager(self.cache_dir, self.dht, self.stats)
88 self.mirrors = MirrorManager(self.cache_dir)
89 self.cache = CacheManager(self.cache_dir.child(download_dir), self.db, self)
90 self.my_contact = None
93 def joinComplete(self, result):
94 """Complete the DHT join process and determine our download information.
96 Called by the DHT when the join has been completed with information
97 on the external IP address and port of this peer.
99 my_addr = findMyIPAddr(result,
100 config.getint(config.get('DEFAULT', 'DHT'), 'PORT'),
101 config.getboolean('DEFAULT', 'LOCAL_OK'))
103 raise RuntimeError, "IP address for this machine could not be found"
104 self.my_contact = compact(my_addr, config.getint('DEFAULT', 'PORT'))
105 self.cache.scanDirectories()
106 reactor.callLater(60, self.refreshFiles)
108 def joinError(self, failure):
109 """Joining the DHT has failed."""
110 log.msg("joining DHT failed miserably")
112 raise RuntimeError, "IP address for this machine could not be found"
114 def refreshFiles(self):
115 """Refresh any files in the DHT that are about to expire."""
116 expireAfter = config.gettime('DEFAULT', 'KEY_REFRESH')
117 hashes = self.db.expiredHashes(expireAfter)
118 if len(hashes.keys()) > 0:
119 log.msg('Refreshing the keys of %d DHT values' % len(hashes.keys()))
120 self._refreshFiles(None, hashes)
122 def _refreshFiles(self, result, hashes):
123 if result is not None:
124 log.msg('Storage resulted in: %r' % result)
127 raw_hash = hashes.keys()[0]
128 self.db.refreshHash(raw_hash)
129 hash = HashObject(raw_hash, pieces = hashes[raw_hash]['pieces'])
131 storeDefer = self.store(hash)
132 storeDefer.addBoth(self._refreshFiles, hashes)
134 reactor.callLater(60, self.refreshFiles)
137 """Retrieve and format the statistics for the program.
140 @return: the formatted HTML page containing the statistics
142 out = '<html><body>\n\n'
143 out += self.stats.formatHTML(self.my_contact)
145 if IDHTStats.implementedBy(self.dhtClass):
146 out += self.dht.getStats()
147 out += '\n</body></html>\n'
151 def check_freshness(self, req, url, modtime, resp):
152 """Send a HEAD to the mirror to check if the response from the cache is still valid.
154 @type req: L{twisted.web2.http.Request}
155 @param req: the initial request sent to the HTTP server by apt
156 @param url: the URI of the actual mirror request
157 @type modtime: C{int}
158 @param modtime: the modified time of the cached file (seconds since epoch)
159 @type resp: L{twisted.web2.http.Response}
160 @param resp: the response from the cache to be sent to apt
161 @rtype: L{twisted.internet.defer.Deferred}
162 @return: a deferred that will be called back with the correct response
164 log.msg('Checking if %s is still fresh' % url)
165 d = self.peers.get('', url, method = "HEAD", modtime = modtime)
166 d.addCallbacks(self.check_freshness_done, self.check_freshness_error,
167 callbackArgs = (req, url, resp), errbackArgs = (req, url))
170 def check_freshness_done(self, resp, req, url, orig_resp):
171 """Process the returned response from the mirror.
173 @type resp: L{twisted.web2.http.Response}
174 @param resp: the response from the mirror to the HEAD request
175 @type req: L{twisted.web2.http.Request}
176 @param req: the initial request sent to the HTTP server by apt
177 @param url: the URI of the actual mirror request
178 @type orig_resp: L{twisted.web2.http.Response}
179 @param orig_resp: the response from the cache to be sent to apt
182 log.msg('Still fresh, returning: %s' % url)
185 log.msg('Stale, need to redownload: %s' % url)
186 return self.get_resp(req, url)
188 def check_freshness_error(self, err, req, url):
189 """Mirror request failed, continue with download.
191 @param err: the response from the mirror to the HEAD request
192 @type req: L{twisted.web2.http.Request}
193 @param req: the initial request sent to the HTTP server by apt
194 @param url: the URI of the actual mirror request
197 return self.get_resp(req, url)
199 def get_resp(self, req, url):
200 """Lookup a hash for the file in the local mirror info.
202 Starts the process of getting a response to an uncached apt request.
204 @type req: L{twisted.web2.http.Request}
205 @param req: the initial request sent to the HTTP server by apt
206 @param url: the URI of the actual mirror request
207 @rtype: L{twisted.internet.defer.Deferred}
208 @return: a deferred that will be called back with the response
212 log.msg('Trying to find hash for %s' % url)
213 findDefer = self.mirrors.findHash(unquote(url))
215 findDefer.addCallbacks(self.findHash_done, self.findHash_error,
216 callbackArgs=(req, url, d), errbackArgs=(req, url, d))
217 findDefer.addErrback(log.err)
220 def findHash_error(self, failure, req, url, d):
221 """Process the error in hash lookup by returning an empty L{HashObject}."""
223 self.findHash_done(HashObject(), req, url, d)
225 def findHash_done(self, hash, req, url, d):
226 """Use the returned hash to lookup the file in the cache.
228 If the hash was not found, the workflow skips down to download from
229 the mirror (L{lookupHash_done}).
231 @type hash: L{Hash.HashObject}
232 @param hash: the hash object containing the expected hash for the file
234 if hash.expected() is None:
235 log.msg('Hash for %s was not found' % url)
236 self.lookupHash_done([], hash, url, d)
238 log.msg('Found hash %s for %s' % (hash.hexexpected(), url))
240 # Lookup hash in cache
241 locations = self.db.lookupHash(hash.expected(), filesOnly = True)
242 self.getCachedFile(hash, req, url, d, locations)
244 def getCachedFile(self, hash, req, url, d, locations):
245 """Try to return the file from the cache, otherwise move on to a DHT lookup.
247 @type locations: C{list} of C{dictionary}
248 @param locations: the files in the cache that match the hash,
249 the dictionary contains a key 'path' whose value is a
250 L{twisted.python.filepath.FilePath} object for the file.
253 log.msg('Failed to return file from cache: %s' % url)
254 self.lookupHash(hash, url, d)
257 # Get the first possible location from the list
258 file = locations.pop(0)['path']
259 log.msg('Returning cached file: %s' % file.path)
262 resp = static.File(file.path).renderHTTP(req)
263 if isinstance(resp, defer.Deferred):
264 resp.addBoth(self._getCachedFile, hash, req, url, d, locations)
266 self._getCachedFile(resp, hash, req, url, d, locations)
268 def _getCachedFile(self, resp, hash, req, url, d, locations):
269 """Check the returned response to be sure it is valid."""
270 if isinstance(resp, failure.Failure):
271 log.msg('Got error trying to get cached file')
273 # Try the next possible location
274 self.getCachedFile(hash, req, url, d, locations)
277 log.msg('Cached response: %r' % resp)
279 if resp.code >= 200 and resp.code < 400:
282 # Try the next possible location
283 self.getCachedFile(hash, req, url, d, locations)
285 def lookupHash(self, hash, url, d):
286 """Lookup the hash in the DHT."""
287 log.msg('Looking up hash in DHT for file: %s' % url)
288 key = hash.expected()
289 lookupDefer = self.dht.getValue(key)
290 lookupDefer.addBoth(self.lookupHash_done, hash, url, d)
292 def lookupHash_done(self, values, hash, url, d):
293 """Start the download of the file.
295 The download will be from peers if the DHT lookup succeeded, or
296 from the mirror otherwise.
298 @type values: C{list} of C{dictionary}
299 @param values: the returned values from the DHT containing peer
302 if not isinstance(values, list) or not values:
303 if not isinstance(values, list):
304 log.msg('DHT lookup for %s failed with error %r' % (url, values))
306 log.msg('Peers for %s were not found' % url)
307 getDefer = self.peers.get(hash, url)
308 getDefer.addCallback(self.cache.save_file, hash, url)
309 getDefer.addErrback(self.cache.save_error, url)
310 getDefer.addCallbacks(d.callback, d.errback)
312 log.msg('Found peers for %s: %r' % (url, values))
313 # Download from the found peers
314 getDefer = self.peers.get(hash, url, values)
315 getDefer.addCallback(self.check_response, hash, url)
316 getDefer.addCallback(self.cache.save_file, hash, url)
317 getDefer.addErrback(self.cache.save_error, url)
318 getDefer.addCallbacks(d.callback, d.errback)
320 def check_response(self, response, hash, url):
321 """Check the response from peers, and download from the mirror if it is not."""
322 if response.code < 200 or response.code >= 300:
323 log.msg('Download from peers failed, going to direct download: %s' % url)
324 getDefer = self.peers.get(hash, url)
328 def new_cached_file(self, file_path, hash, new_hash, url = None, forceDHT = False):
329 """Add a newly cached file to the mirror info and/or the DHT.
331 If the file was downloaded, set url to the path it was downloaded for.
332 Doesn't add a file to the DHT unless a hash was found for it
333 (but does add it anyway if forceDHT is True).
335 @type file_path: L{twisted.python.filepath.FilePath}
336 @param file_path: the location of the file in the local cache
337 @type hash: L{Hash.HashObject}
338 @param hash: the original (expected) hash object containing also the
339 hash of the downloaded file
340 @type new_hash: C{boolean}
341 @param new_hash: whether the has was new to this peer, and so should
344 @param url: the URI of the location of the file in the mirror
345 (optional, defaults to not adding the file to the mirror info)
346 @type forceDHT: C{boolean}
347 @param forceDHT: whether to force addition of the file to the DHT
348 even if the hash was not found in a mirror
349 (optional, defaults to False)
352 self.mirrors.updatedFile(url, file_path)
354 if self.my_contact and hash and new_hash and (hash.expected() is not None or forceDHT):
355 return self.store(hash)
358 def store(self, hash):
359 """Add a key/value pair for the file to the DHT.
361 Sets the key and value from the hash information, and tries to add
365 value = {'c': self.my_contact}
366 pieces = hash.pieceDigests()
368 # Determine how to store any piece data
371 elif len(pieces) <= DHT_PIECES:
372 # Short enough to be stored with our peer contact info
373 value['t'] = {'t': ''.join(pieces)}
374 elif len(pieces) <= TORRENT_PIECES:
375 # Short enough to be stored in a separate key in the DHT
376 value['h'] = sha.new(''.join(pieces)).digest()
378 # Too long, must be served up by our peer HTTP server
379 value['l'] = sha.new(''.join(pieces)).digest()
381 storeDefer = self.dht.storeValue(key, value)
382 storeDefer.addCallbacks(self.store_done, self.store_error,
383 callbackArgs = (hash, ), errbackArgs = (hash.digest(), ))
386 def store_done(self, result, hash):
387 """Add a key/value pair for the pieces of the file to the DHT (if necessary)."""
388 log.msg('Added %s to the DHT: %r' % (hash.hexdigest(), result))
389 pieces = hash.pieceDigests()
390 if len(pieces) > DHT_PIECES and len(pieces) <= TORRENT_PIECES:
391 # Add the piece data key and value to the DHT
392 key = sha.new(''.join(pieces)).digest()
393 value = {'t': ''.join(pieces)}
395 storeDefer = self.dht.storeValue(key, value)
396 storeDefer.addCallbacks(self.store_torrent_done, self.store_error,
397 callbackArgs = (key, ), errbackArgs = (key, ))
401 def store_torrent_done(self, result, key):
402 """Adding the file to the DHT is complete, and so is the workflow."""
403 log.msg('Added torrent string %s to the DHT: %r' % (b2a_hex(key), result))
406 def store_error(self, err, key):
407 """Adding to the DHT failed."""
408 log.msg('An error occurred adding %s to the DHT: %r' % (b2a_hex(key), err))