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.

Usage

asyncdns doesn’t have an equivalent to the widely used gethostbyname() or 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       93.184.216.34
; 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.