cheatbt.py

   1 import logging
   2 import urlparse
   3
   4 from odict import OrderedDict
   5
   6 def load_mappings(fname="trackers"):
   7     """
   8     Initialises tracker to ratio multiple mappings from the specified
   9     file.
  10     """
  11
  12     logger = logging.getLogger("cheatbt")
  13     logger.info('loading mappings from "' + fname + '"')
  14
  15     f = open(fname)
  16     mappings = {}
  17
  18     for l in f:
  19         tracker, multiple = l.split(":")
  20         mappings[tracker.strip()] = int(multiple.strip())
  21
  22     f.close()
  23
  24     if "default" not in mappings:
  25         mappings["default"] = 1
  26
  27     return mappings
  28
  29 def cheat(url, mappings):
  30     """
  31     Modifies BitTorrent tracker URLs, faking the amount of data
  32     uploaded. All other URLs should pass through unimpeded.
  33     """
  34
  35     parsed = urlparse.urlparse(url)
  36
  37     if "=" not in parsed.query:
  38         return url
  39
  40     query = OrderedDict([i.split("=") for i in parsed.query.split("&")])
  41     if "uploaded" not in query or query["uploaded"] == "0":
  42         return url
  43
  44     if parsed.hostname in mappings:
  45         multiple = mappings[parsed.hostname]
  46     else:
  47         if "default" in mappings:
  48             multiple = mappings["default"]
  49         else:
  50             return url
  51
  52     # Don't bother munging the URL if the upload amount isn't going
  53     # to change.
  54     if multiple == 1:
  55         return url
  56
  57     fakeupload = int(query["uploaded"])
  58
  59     logger = logging.getLogger("cheatbt")
  60     logger.debug("%s: %d -> %d" % (parsed.hostname, fakeupload,
  61                                    fakeupload * multiple))
  62
  63     fakeupload = fakeupload * multiple
  64     query["uploaded"] = str(fakeupload)
  65
  66     new_query = ""
  67     for k in query.keys():
  68         new_query += k + "=" + query[k] + "&"
  69     new_query = new_query[:-1] # Remove trailing "&"
  70
  71     # <scheme>://<netloc>/<path>;<params>?<query>#<fragment>
  72     new_url = urlparse.urlunparse((parsed.scheme, parsed.netloc, parsed.path,
  73                                    parsed.params, new_query, parsed.fragment))
  74
  75     return new_url