unbound/libunbound/python/doc/examples/example3.rst

   1 .. _example_asynch:
   2
   3 ==============================
   4 Asynchronous lookup
   5 ==============================
   6
   7 This example performs the name lookup in the background.
   8 The main program keeps running while the name is resolved.
   9
  10 ::
  11
  12         #!/usr/bin/python
  13         import time
  14         import unbound
  15
  16         ctx = unbound.ub_ctx()
  17         ctx.resolvconf("/etc/resolv.conf")
  18
  19         def call_back(my_data,status,result):
  20                 print "Call_back:", my_data
  21                 if status == 0 and result.havedata:
  22                         print "Result:", result.data.address_list
  23                         my_data['done_flag'] = True
  24
  25
  26         my_data = {'done_flag':False,'arbitrary':"object"}
  27         status, async_id = ctx.resolve_async("www.seznam.cz", my_data, call_back, unbound.RR_TYPE_A, unbound.RR_CLASS_IN)
  28
  29         while (status == 0) and (not my_data['done_flag']):
  30                 status = ctx.process()
  31                 time.sleep(0.1)
  32
  33         if (status != 0):
  34                 print "Resolve error:", unbound.ub_strerror(status)
  35
  36 The :meth:`unbound.ub_ctx.resolve_async` method is able to pass on any Python object. In this example, we used a dictionary object `my_data`.