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 util import findMyIPAddr, compact
35 download_dir = 'cache'
38 """The main code object that does all of the work.
40 Contains all of the sub-components that do all the low-level work, and
41 coordinates communication between them.
43 @type dhtClass: L{interfaces.IDHT}
44 @ivar dhtClass: the DHT class to use
45 @type cache_dir: L{twisted.python.filepath.FilePath}
46 @ivar cache_dir: the directory to use for storing all files
48 @ivar db: the database to use for tracking files and hashes
49 @type dht: L{interfaces.IDHT}
50 @ivar dht: the DHT instance
51 @type http_server: L{HTTPServer.TopLevel}
52 @ivar http_server: the web server that will handle all requests from apt
54 @type peers: L{PeerManager.PeerManager}
55 @ivar peers: the manager of all downloads from mirrors and other peers
56 @type mirrors: L{MirrorManager.MirrorManager}
57 @ivar mirrors: the manager of downloaded information about mirrors which
58 can be queried to get hashes from file names
59 @type cache: L{CacheManager.CacheManager}
60 @ivar cache: the manager of all downloaded files
61 @type my_contact: C{string}
62 @ivar my_contact: the 6-byte compact peer representation of this peer's
63 download information (IP address and port)
66 def __init__(self, dhtClass):
67 """Initialize all the sub-components.
69 @type dhtClass: L{interfaces.IDHT}
70 @param dhtClass: the DHT class to use
72 log.msg('Initializing the main apt_p2p application')
73 self.dhtClass = dhtClass
74 self.cache_dir = FilePath(config.get('DEFAULT', 'CACHE_DIR'))
75 if not self.cache_dir.child(download_dir).exists():
76 self.cache_dir.child(download_dir).makedirs()
77 self.db = DB(self.cache_dir.child('apt-p2p.db'))
79 self.dht.loadConfig(config, config.get('DEFAULT', 'DHT'))
80 self.dht.join().addCallbacks(self.joinComplete, self.joinError)
81 self.http_server = TopLevel(self.cache_dir.child(download_dir), self.db, self)
82 self.getHTTPFactory = self.http_server.getHTTPFactory
83 self.peers = PeerManager(self.cache_dir, self.dht)
84 self.mirrors = MirrorManager(self.cache_dir)
85 self.cache = CacheManager(self.cache_dir.child(download_dir), self.db, self)
86 self.my_contact = None
89 def joinComplete(self, result):
90 """Complete the DHT join process and determine our download information.
92 Called by the DHT when the join has been completed with information
93 on the external IP address and port of this peer.
95 my_addr = findMyIPAddr(result,
96 config.getint(config.get('DEFAULT', 'DHT'), 'PORT'),
97 config.getboolean('DEFAULT', 'LOCAL_OK'))
99 raise RuntimeError, "IP address for this machine could not be found"
100 self.my_contact = compact(my_addr, config.getint('DEFAULT', 'PORT'))
101 self.cache.scanDirectories()
102 reactor.callLater(60, self.refreshFiles)
104 def joinError(self, failure):
105 """Joining the DHT has failed."""
106 log.msg("joining DHT failed miserably")
108 raise RuntimeError, "IP address for this machine could not be found"
110 def refreshFiles(self):
111 """Refresh any files in the DHT that are about to expire."""
112 expireAfter = config.gettime('DEFAULT', 'KEY_REFRESH')
113 hashes = self.db.expiredHashes(expireAfter)
114 if len(hashes.keys()) > 0:
115 log.msg('Refreshing the keys of %d DHT values' % len(hashes.keys()))
116 self._refreshFiles(None, hashes)
118 def _refreshFiles(self, result, hashes):
119 if result is not None:
120 log.msg('Storage resulted in: %r' % result)
123 raw_hash = hashes.keys()[0]
124 self.db.refreshHash(raw_hash)
125 hash = HashObject(raw_hash, pieces = hashes[raw_hash]['pieces'])
127 storeDefer = self.store(hash)
128 storeDefer.addBoth(self._refreshFiles, hashes)
130 reactor.callLater(60, self.refreshFiles)
133 """Retrieve and format the statistics for the program.
136 @return: the formatted HTML page containing the statistics
138 out = '<html><body>\n\n'
139 if IDHTStats.implementedBy(self.dhtClass):
140 out += self.dht.getStats()
141 out += '\n</body></html>\n'
145 def check_freshness(self, req, url, modtime, resp):
146 """Send a HEAD to the mirror to check if the response from the cache is still valid.
148 @type req: L{twisted.web2.http.Request}
149 @param req: the initial request sent to the HTTP server by apt
150 @param url: the URI of the actual mirror request
151 @type modtime: C{int}
152 @param modtime: the modified time of the cached file (seconds since epoch)
153 @type resp: L{twisted.web2.http.Response}
154 @param resp: the response from the cache to be sent to apt
155 @rtype: L{twisted.internet.defer.Deferred}
156 @return: a deferred that will be called back with the correct response
158 log.msg('Checking if %s is still fresh' % url)
159 d = self.peers.get('', url, method = "HEAD", modtime = modtime)
160 d.addCallbacks(self.check_freshness_done, self.check_freshness_error,
161 callbackArgs = (req, url, resp), errbackArgs = (req, url))
164 def check_freshness_done(self, resp, req, url, orig_resp):
165 """Process the returned response from the mirror.
167 @type resp: L{twisted.web2.http.Response}
168 @param resp: the response from the mirror to the HEAD request
169 @type req: L{twisted.web2.http.Request}
170 @param req: the initial request sent to the HTTP server by apt
171 @param url: the URI of the actual mirror request
172 @type orig_resp: L{twisted.web2.http.Response}
173 @param orig_resp: the response from the cache to be sent to apt
176 log.msg('Still fresh, returning: %s' % url)
179 log.msg('Stale, need to redownload: %s' % url)
180 return self.get_resp(req, url)
182 def check_freshness_error(self, err, req, url):
183 """Mirror request failed, continue with download.
185 @param err: the response from the mirror to the HEAD request
186 @type req: L{twisted.web2.http.Request}
187 @param req: the initial request sent to the HTTP server by apt
188 @param url: the URI of the actual mirror request
191 return self.get_resp(req, url)
193 def get_resp(self, req, url):
194 """Lookup a hash for the file in the local mirror info.
196 Starts the process of getting a response to an uncached apt request.
198 @type req: L{twisted.web2.http.Request}
199 @param req: the initial request sent to the HTTP server by apt
200 @param url: the URI of the actual mirror request
201 @rtype: L{twisted.internet.defer.Deferred}
202 @return: a deferred that will be called back with the response
206 log.msg('Trying to find hash for %s' % url)
207 findDefer = self.mirrors.findHash(unquote(url))
209 findDefer.addCallbacks(self.findHash_done, self.findHash_error,
210 callbackArgs=(req, url, d), errbackArgs=(req, url, d))
211 findDefer.addErrback(log.err)
214 def findHash_error(self, failure, req, url, d):
215 """Process the error in hash lookup by returning an empty L{HashObject}."""
217 self.findHash_done(HashObject(), req, url, d)
219 def findHash_done(self, hash, req, url, d):
220 """Use the returned hash to lookup the file in the cache.
222 If the hash was not found, the workflow skips down to download from
223 the mirror (L{lookupHash_done}).
225 @type hash: L{Hash.HashObject}
226 @param hash: the hash object containing the expected hash for the file
228 if hash.expected() is None:
229 log.msg('Hash for %s was not found' % url)
230 self.lookupHash_done([], hash, url, d)
232 log.msg('Found hash %s for %s' % (hash.hexexpected(), url))
234 # Lookup hash in cache
235 locations = self.db.lookupHash(hash.expected(), filesOnly = True)
236 self.getCachedFile(hash, req, url, d, locations)
238 def getCachedFile(self, hash, req, url, d, locations):
239 """Try to return the file from the cache, otherwise move on to a DHT lookup.
241 @type locations: C{list} of C{dictionary}
242 @param locations: the files in the cache that match the hash,
243 the dictionary contains a key 'path' whose value is a
244 L{twisted.python.filepath.FilePath} object for the file.
247 log.msg('Failed to return file from cache: %s' % url)
248 self.lookupHash(hash, url, d)
251 # Get the first possible location from the list
252 file = locations.pop(0)['path']
253 log.msg('Returning cached file: %s' % file.path)
256 resp = static.File(file.path).renderHTTP(req)
257 if isinstance(resp, defer.Deferred):
258 resp.addBoth(self._getCachedFile, hash, req, url, d, locations)
260 self._getCachedFile(resp, hash, req, url, d, locations)
262 def _getCachedFile(self, resp, hash, req, url, d, locations):
263 """Check the returned response to be sure it is valid."""
264 if isinstance(resp, failure.Failure):
265 log.msg('Got error trying to get cached file')
267 # Try the next possible location
268 self.getCachedFile(hash, req, url, d, locations)
271 log.msg('Cached response: %r' % resp)
273 if resp.code >= 200 and resp.code < 400:
276 # Try the next possible location
277 self.getCachedFile(hash, req, url, d, locations)
279 def lookupHash(self, hash, url, d):
280 """Lookup the hash in the DHT."""
281 log.msg('Looking up hash in DHT for file: %s' % url)
282 key = hash.expected()
283 lookupDefer = self.dht.getValue(key)
284 lookupDefer.addBoth(self.lookupHash_done, hash, url, d)
286 def lookupHash_done(self, values, hash, url, d):
287 """Start the download of the file.
289 The download will be from peers if the DHT lookup succeeded, or
290 from the mirror otherwise.
292 @type values: C{list} of C{dictionary}
293 @param values: the returned values from the DHT containing peer
296 if not isinstance(values, list) or not values:
297 if not isinstance(values, list):
298 log.msg('DHT lookup for %s failed with error %r' % (url, values))
300 log.msg('Peers for %s were not found' % url)
301 getDefer = self.peers.get(hash, url)
302 getDefer.addCallback(self.cache.save_file, hash, url)
303 getDefer.addErrback(self.cache.save_error, url)
304 getDefer.addCallbacks(d.callback, d.errback)
306 log.msg('Found peers for %s: %r' % (url, values))
307 # Download from the found peers
308 getDefer = self.peers.get(hash, url, values)
309 getDefer.addCallback(self.check_response, hash, url)
310 getDefer.addCallback(self.cache.save_file, hash, url)
311 getDefer.addErrback(self.cache.save_error, url)
312 getDefer.addCallbacks(d.callback, d.errback)
314 def check_response(self, response, hash, url):
315 """Check the response from peers, and download from the mirror if it is not."""
316 if response.code < 200 or response.code >= 300:
317 log.msg('Download from peers failed, going to direct download: %s' % url)
318 getDefer = self.peers.get(hash, url)
322 def new_cached_file(self, file_path, hash, new_hash, url = None, forceDHT = False):
323 """Add a newly cached file to the mirror info and/or the DHT.
325 If the file was downloaded, set url to the path it was downloaded for.
326 Doesn't add a file to the DHT unless a hash was found for it
327 (but does add it anyway if forceDHT is True).
329 @type file_path: L{twisted.python.filepath.FilePath}
330 @param file_path: the location of the file in the local cache
331 @type hash: L{Hash.HashObject}
332 @param hash: the original (expected) hash object containing also the
333 hash of the downloaded file
334 @type new_hash: C{boolean}
335 @param new_hash: whether the has was new to this peer, and so should
338 @param url: the URI of the location of the file in the mirror
339 (optional, defaults to not adding the file to the mirror info)
340 @type forceDHT: C{boolean}
341 @param forceDHT: whether to force addition of the file to the DHT
342 even if the hash was not found in a mirror
343 (optional, defaults to False)
346 self.mirrors.updatedFile(url, file_path)
348 if self.my_contact and hash and new_hash and (hash.expected() is not None or forceDHT):
349 return self.store(hash)
352 def store(self, hash):
353 """Add a key/value pair for the file to the DHT.
355 Sets the key and value from the hash information, and tries to add
359 value = {'c': self.my_contact}
360 pieces = hash.pieceDigests()
362 # Determine how to store any piece data
365 elif len(pieces) <= DHT_PIECES:
366 # Short enough to be stored with our peer contact info
367 value['t'] = {'t': ''.join(pieces)}
368 elif len(pieces) <= TORRENT_PIECES:
369 # Short enough to be stored in a separate key in the DHT
370 value['h'] = sha.new(''.join(pieces)).digest()
372 # Too long, must be served up by our peer HTTP server
373 value['l'] = sha.new(''.join(pieces)).digest()
375 storeDefer = self.dht.storeValue(key, value)
376 storeDefer.addCallbacks(self.store_done, self.store_error,
377 callbackArgs = (hash, ), errbackArgs = (hash.digest(), ))
380 def store_done(self, result, hash):
381 """Add a key/value pair for the pieces of the file to the DHT (if necessary)."""
382 log.msg('Added %s to the DHT: %r' % (hash.hexdigest(), result))
383 pieces = hash.pieceDigests()
384 if len(pieces) > DHT_PIECES and len(pieces) <= TORRENT_PIECES:
385 # Add the piece data key and value to the DHT
386 key = sha.new(''.join(pieces)).digest()
387 value = {'t': ''.join(pieces)}
389 storeDefer = self.dht.storeValue(key, value)
390 storeDefer.addCallbacks(self.store_torrent_done, self.store_error,
391 callbackArgs = (key, ), errbackArgs = (key, ))
395 def store_torrent_done(self, result, key):
396 """Adding the file to the DHT is complete, and so is the workflow."""
397 log.msg('Added torrent string %s to the DHT: %r' % (b2a_hex(key), result))
400 def store_error(self, err, key):
401 """Adding to the DHT failed."""
402 log.msg('An error occurred adding %s to the DHT: %r' % (b2a_hex(key), err))