python利用pycurl做get

import urllib2
import pycurl
import cStringIO as _StringIO
import sys
import shutil
import lxml.html as H
import threading
# http transfer limits
accept_type = "*/*"
connection_timeout = 500 
timeout = 800
low_speed = 200
low_speed_time = 120
max_size = 20485760 # 10MB

def get_curl(user_agent="MSIE"):
    "initialize curl handle"
    dev_null = _StringIO.StringIO()
    curl_handle = pycurl.Curl()
    curl_handle.setopt(pycurl.FOLLOWLOCATION, 1)
    curl_handle.setopt(pycurl.MAXREDIRS, 5)
    curl_handle.setopt(pycurl.CONNECTTIMEOUT, connection_timeout)
    curl_handle.setopt(pycurl.TIMEOUT, timeout)
    curl_handle.setopt(pycurl.NOSIGNAL, 1)
    curl_handle.setopt(pycurl.LOW_SPEED_LIMIT, 100)
    curl_handle.setopt(pycurl.LOW_SPEED_TIME, low_speed_time)
    curl_handle.setopt(pycurl.HTTPHEADER, ["User-Agent: %s" % "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0)", accept_type])
    curl_handle.setopt(pycurl.MAXFILESIZE, max_size)
    curl_handle.setopt(pycurl.COOKIEFILE, 'cookies.txt')
    curl_handle.setopt(pycurl.COOKIEJAR, 'cookies.txt')
    curl_handle.setopt(pycurl.WRITEFUNCTION, dev_null.write)
    
    return curl_handle


def curl_fetch(curl_handle, url):
    "retrieve url, return the content, http code, time, effective url"
    fp = _StringIO.StringIO()
    curl_handle.setopt(pycurl.URL, url)
    curl_handle.setopt(pycurl.WRITEFUNCTION, fp.write)
    
    # perform the transfer
    try:
        curl_handle.perform()
    except pycurl.error, e:
        print e
        return (-1,0,0)
    content_type = curl_handle.getinfo(pycurl.CONTENT_TYPE)
    print curl_handle.getinfo(pycurl.CONTENT_TYPE)
    print curl_handle.getinfo(pycurl.HTTP_CODE)
    return (0,fp.getvalue(), content_type)