python requests cache dns

Python Requests Cache DNS

If you are using the Python 'requests' library to make HTTP requests, you might have noticed that it takes some time to resolve the DNS of the host you are trying to connect to. This might cause some delay in your application, especially if you are making a lot of requests.

One way to solve this problem is to cache the DNS responses, so that subsequent requests to the same host can use the cached response instead of resolving the DNS again.

Using requests-cache library

The easiest way to cache DNS responses in 'requests' is to use the 'requests-cache' library. This library provides a simple way to cache the responses of your requests. To use it, you need to install the library:

pip install requests-cache

After installing, you need to create a cache object:

import requests_cache

This will create a cache named 'demo_cache' in the current directory. You can now make requests as usual, and the responses will be cached:

import requests
response = requests.get('')

The first request will take some time to resolve the DNS, but subsequent requests will use the cached response:

response = requests.get('')

Using a custom DNS cache

If you want more control over the caching mechanism, you can create a custom DNS cache using the 'dns.resolver' module.

First, install the 'dnspython' library:

pip install dnspython

Then, create a caching resolver:

import dns.resolver
import dns.reversename
resolver = dns.resolver.Resolver(configure=False)
resolver.nameservers = ['', '']
cache = dns.resolver.Cache(dns.rdatatype.ANY)
resolver.cache = cache

This will create a resolver that uses the Google DNS servers and a cache that caches any record type.

Now, you can use this resolver to resolve DNS queries:

hostname = ''
ip_address = None
    answer = resolver.query(hostname)
    ip_address = answer[0].address
except dns.exception.DNSException as e:
    print('Could not resolve DNS for {}: {}'.format(hostname, e))
if ip_address is not None:
    url = 'http://{}'.format(ip_address)
    response = requests.get(url)

This code will first try to resolve the DNS of '', and if successful, it will use the IP address to make a request using 'requests'.