Simple DNS resolver for asyncio

https://secure.travis-ci.org/saghul/aiodns.png?branch=master

aiodns provides a simple way for doing asynchronous DNS resolutions with a synchronous looking interface by using pycares.

Example

import asyncio
import aiodns

loop = asyncio.get_event_loop()
resolver = aiodns.DNSResolver(loop=loop)
f = resolver.query('google.com','A')
result = loop.run_until_complete(f)
print(result)

The following query types are supported: A, AAAA, CNAME, MX, NAPTR, NS, PTR, SOA, SRV, TXT.

The library supports both asyncio and Trollius.

If you use use Python 3.5+, you can use the async and await statements:

import asyncio
import aiodns

loop = asyncio.get_event_loop()
resolver = aiodns.DNSResolver(loop=loop)

async def query(name, query_type):
    return await resolver.query(name, query_type)

coro = query('google.com', 'A')
result = loop.run_until_complete(coro)

If you use Python 3.3/3.4 you may use yield from statement:

@asyncio.coroutine
def func():
    result = yield from resolver.query('google.com','A')

For Trollius you should use another syntax like:

@trollius.coroutine
def func():
     result = yield trollius.From(resolver.query('google.com','A'))

API

The API is pretty simple, three functions are provided in the DNSResolver class:

query(host, type): Do a DNS resolution of the given type for the given hostname. It returns an instance of asyncio.Future. The actual result of the DNS query is taken directly from pycares. As of version 1.0.0 of aiodns (and pycares, for that matter) results are always namedtuple-like objects with different attributes. Please check the documentation for the result fields.
gethostbyname(host, socket_family): Do a DNS resolution for the given hostname and the desired type of address family (i.e. socket.AF_INET). While query() always performs a request to a DNS server, gethostbyname() first looks into /etc/hosts and thus can resolve local hostnames (such as localhost). Please check the documentation for the result fields. The actual result of the call is a asyncio.Future.
cancel(): Cancel all pending DNS queries. All futures will get DNSError exception set, with ARES_ECANCELLED errno.

Running the test suite

To run the test suite: python test_aiodns.py

Author

Saúl Ibarra Corretgé <saghul@gmail.com>

License

aiodns uses the MIT license, check LICENSE file.

Python versions

Python >= 3.4 is natively supported. Python 3.3 supported using the asyncio package. Older Python versions(2.6 - 3.2) are supported using trollius.

Contributing

If you'd like to contribute, fork the project, make a patch and send a pull request. Have a look at the surrounding code and please, make yours look alike :-)

Jerusalemsbell/aiodns