asyncdns - Pure Python asynchronous DNS for asyncio¶
What is this?¶
asyncdns is a pure Python asynchronous DNS resolver implementation written
on top of asyncio. It doesn’t require any external libraries, and it doesn’t
use threads or blocking functions.
asyncdns doesn’t have an equivalent to the widely used
getaddrinfo() functions. Instead, you use it by constructing a
Query object specifying the DNS query you wish to run, then pass it to a
Resolver to actually perform the query.
There are a handful of built-in resolvers, but for demonstration purposes the
easiest one to use is the
SmartResolver, which automatically makes use of
/etc/hosts, multicast DNS and regular DNS as appropriate.
For instance, do a simple lookup for an A record:
>>> import asyncdns, asyncio >>> resolver = asyncdns.SmartResolver() >>> loop = asyncio.get_event_loop() >>> query = asyncdns.Query('www.example.com', asyncdns.A, asyncdns.IN) >>> f = resolver.lookup(query) >>> loop.run_until_complete(f) >>> print(f.result()) ;; No error (RD, RA) ; 1 answers: www.example.com 54950 IN A 220.127.116.11 ; 0 authorities: ; 0 additional:
Note that you may or may not want to use
SmartResolver in your code,
depending on your requirements - it probably isn’t a good idea using multicast
DNS on an untrusted network, for instance.