aiohttp-asyncmdnsresolver

Introduction

This module provides an aiohttp resolver that supports mDNS, which uses the zeroconf library to resolve mDNS queries.

For full documentation please read https://aiohttp-asyncmdnsresolver.readthedocs.io.

Installation

$ pip install aiohttp-asyncmdnsresolver

Quick start

import asyncio
import aiohttp
from aiohttp_asyncmdnsresolver.api import AsyncMDNSResolver

async def main():
    # aiohttp does not own a resolver passed to TCPConnector, so use the
    # resolver as an async context manager to close it on exit.
    async with AsyncMDNSResolver() as resolver:
        connector = aiohttp.TCPConnector(resolver=resolver)
        async with aiohttp.ClientSession(connector=connector) as session:
            async with session.get('http://example.com') as response:
                print(response.status)
            async with session.get('http://xxx.local.') as response:
                print(response.status)

asyncio.run(main())

Resolving with both mDNS and DNS

AsyncDualMDNSResolver is a variant that resolves .local names over mDNS and regular DNS concurrently, returning the first successful result. Use it when a .local name may be served by a unicast DNS server as well as mDNS.

import asyncio
import aiohttp
from aiohttp_asyncmdnsresolver.api import AsyncDualMDNSResolver

async def main():
    # aiohttp does not own a resolver passed to TCPConnector, so use the
    # resolver as an async context manager to close it on exit.
    async with AsyncDualMDNSResolver() as resolver:
        connector = aiohttp.TCPConnector(resolver=resolver)
        async with aiohttp.ClientSession(connector=connector) as session:
            async with session.get('http://printer.local.') as response:
                print(response.status)

asyncio.run(main())

Security note

mDNS resolution of .local names is not authenticated; any host on the same local link can answer for any .local name, so the resolved address should not be treated as a trust boundary. When connecting to sensitive .local services, use HTTPS with certificate verification, and consider certificate pinning or mTLS. Passing mdns_timeout=0 or mdns_timeout=None restricts mDNS resolution to the existing zeroconf cache and avoids sending new queries on the network, though cached entries may themselves originate from on-link responses.

API documentation

The documentation is located at https://aiohttp-asyncmdnsresolver.readthedocs.io.

Source code

The project is hosted on GitHub

Please file an issue on the bug tracker if you have found a bug or have some suggestion in order to improve the library.

Authors and License

It's Apache 2 licensed and freely available.