While extracting data from websites most probably you will notice some kind of access limiting for a single IP address. In that case it is good to use proxies. In my scraping projects I've been using both http and socks proxies.

http proxies

In my opinion the most easy and powerful python tool that supports http proxies is requests library. To use http proxy you just need to do something like this:

import requests
my_proxy = { 
              "http"  : "http://127.0.0.1:8080", 
              "https" : "http://127.0.0.1:8081"
            }
r = requests.get("http://google.com", proxies=my_proxy)

socks proxies

Using socks proxies while web scraping in python is a bit more tricky. The problem is that latest version of requests doesn't support socks proxies. But I found another good solution - you can use urllib2 with additional "PySocks" library. So first of all you need to install PySocks:

pip install PySocks

After that you can use socks proxies to crawl web pages (both http and https) in your python code. Below is a basic example:

import urllib2
import socks
from sockshandler import SocksiPyHandler

socks_host = "127.0.0.1"
socks_port = 8080

opener = urllib2.build_opener(
             SocksiPyHandler(socks.PROXY_TYPE_SOCKS5, socks_host, socks_port)
         )
req = opener.open("http://google.com", timeout=10)
content = req.read()

P.S. If you know better solution how to scrape data with proxies in python, feel free to share it in comments.