src/backend/resolver.py

   1 #!/usr/bin/python
   2
   3 import ipaddress
   4 import pycares
   5 import tornado.gen
   6 import tornado.platform.caresresolver
   7
   8 class Resolver(tornado.platform.caresresolver.CaresResolver):
   9         def initialize(self, **kwargs):
  10                 super().initialize()
  11
  12                 # Overwrite Channel
  13                 self.channel = pycares.Channel(sock_state_cb=self._sock_state_cb, **kwargs)
  14
  15         async def query(self, name, type=pycares.QUERY_TYPE_A):
  16                 # Create a new Future
  17                 fut = tornado.gen.Future()
  18
  19                 # Perform the query
  20                 self.channel.query(name, type, lambda result, error: fut.set_result((result, error)))
  21
  22                 # Wait for the response
  23                 result, error = await fut
  24
  25                 # Handle any errors
  26                 if error:
  27                         # NXDOMAIN
  28                         if error == pycares.errno.ARES_ENOTFOUND:
  29                                 return
  30
  31                         # Ignore responses with no data
  32                         elif error == pycares.errno.ARES_ENODATA:
  33                                 return
  34
  35                         raise IOError(
  36                                 "C-Ares returned error %s: %s while resolving %s"
  37                                 % (error, pycares.errno.strerror(error), name)
  38                         )
  39
  40                 # Return the result
  41                 return result