apt_dht/apt_dht.py

   1
   2 from binascii import b2a_hex
   3 import os.path
   4
   5 from twisted.internet import defer
   6 from twisted.web2 import server, http, http_headers
   7 from twisted.python import log
   8
   9 from apt_dht_conf import config
  10 from PeerManager import PeerManager
  11 from HTTPServer import TopLevel
  12 from MirrorManager import MirrorManager
  13 from Hash import HashObject
  14
  15 class AptDHT:
  16     def __init__(self, dht):
  17         log.msg('Initializing the main apt_dht application')
  18         self.dht = dht
  19         self.http_server = TopLevel(config.get('DEFAULT', 'cache_dir'), self)
  20         self.http_site = server.Site(self.http_server)
  21         self.peers = PeerManager()
  22         self.mirrors = MirrorManager(self, config.get('DEFAULT', 'cache_dir'))
  23
  24     def getSite(self):
  25         return self.http_site
  26
  27     def check_freshness(self, path, modtime, resp):
  28         log.msg('Checking if %s is still fresh' % path)
  29         d = self.peers.get([path], "HEAD", modtime)
  30         d.addCallback(self.check_freshness_done, path, resp)
  31         return d
  32
  33     def check_freshness_done(self, resp, path, orig_resp):
  34         if resp.code == 304:
  35             log.msg('Still fresh, returning: %s' % path)
  36             return orig_resp
  37         else:
  38             log.msg('Stale, need to redownload: %s' % path)
  39             return self.get_resp(path)
  40
  41     def get_resp(self, path):
  42         d = defer.Deferred()
  43
  44         log.msg('Trying to find hash for %s' % path)
  45         findDefer = self.mirrors.findHash(path)
  46
  47         findDefer.addCallbacks(self.findHash_done, self.findHash_error,
  48                                callbackArgs=(path, d), errbackArgs=(path, d))
  49         findDefer.addErrback(log.err)
  50         return d
  51
  52     def findHash_error(self, failure, path, d):
  53         log.err(failure)
  54         self.findHash_done(HashObject(), path, d)
  55
  56     def findHash_done(self, hash, path, d):
  57         if hash.expected() is None:
  58             log.msg('Hash for %s was not found' % path)
  59             self.download_file([path], hash, path, d)
  60         else:
  61             log.msg('Found hash %s for %s' % (hash.hexexpected(), path))
  62             # Lookup hash from DHT
  63             key = hash.normexpected(bits = config.getint(config.get('DEFAULT', 'DHT'), 'HASH_LENGTH'))
  64             lookupDefer = self.dht.getValue(key)
  65             lookupDefer.addCallback(self.lookupHash_done, hash, path, d)
  66
  67     def lookupHash_done(self, locations, hash, path, d):
  68         if not locations:
  69             log.msg('Peers for %s were not found' % path)
  70             self.download_file([path], hash, path, d)
  71         else:
  72             log.msg('Found peers for %s: %r' % (path, locations))
  73             # Download from the found peers
  74             self.download_file(locations, hash, path, d)
  75
  76     def download_file(self, locations, hash, path, d):
  77         getDefer = self.peers.get(locations)
  78         getDefer.addCallback(self.mirrors.save_file, hash, path)
  79         getDefer.addErrback(self.mirrors.save_error, path)
  80         getDefer.addCallbacks(d.callback, d.errback)
  81
  82     def download_complete(self, hash, url, file_path):
  83         assert file_path.startswith(config.get('DEFAULT', 'cache_dir'))
  84         directory = file_path[:len(config.get('DEFAULT', 'cache_dir'))]
  85         url_path = file_path[len(config.get('DEFAULT', 'cache_dir')):]
  86         if url_path[0] == '/':
  87             url_path = url_path[1:]
  88         top_directory = url_path.split('/',1)[0]
  89         url_path = url_path[len(top_directory):]
  90         http_dir = os.path.join(directory, top_directory)
  91         new_top = self.http_server.addDirectory(http_dir)
  92         url_path = '/' + new_top + url_path
  93         log.msg('now avaliable at %s: %s' % (url_path, url))