python pycurl模块

转自：http://www.cnblogs.com/gide/p/5650655.html

一、pycurl概述

PycURl是一个C语言写的libcurl的python绑定库。libcurl 是一个自由的，并且容易使用的用在客户端的 URL 传输库。它的功能很强大，在PyCURL的主页上介绍的支持的功能有：FTP, FTPS, HTTP, HTTPS, GOPHER, TELNET, DICT, FILE and LDAP. libcurl supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading, kerberos, HTTP form based upload, proxies, cookies, user+password authentication, file transfer resume, http proxy tunneling and more!

由于PycURl 是由C语言原生实现的，所以一般来说会比其会比纯python实现的liburl、liburl2模块快不少，可能也会比Requests的效率更高。特别是使用PycURL的多并发请求时，效率更高。

　 如果机器没有PycURL 通过命令 sudo easy_install pycurl

二、pycurl 的用法

　实例一：

#! /usr/bin/env python
# -*- coding: utf-8 -*-
import sys
import pycurl
import time
class Test:
    def __init__(self):
        self.contents = ""
    def body_callback(self, buf):
        self.contents = self.contents + buf
sys.stderr.write("Testing %sn" % pycurl.version)
start_time = time.time()
url = "http://www.dianping.com/beijing"
t = Test()
c = pycurl.Curl()
c.setopt(c.URL, url)
c.setopt(c.WRITEFUNCTION, t.body_callback)
c.perform()
end_time = time.time()
duration = end_time - start_time
print c.getinfo(pycurl.HTTP_CODE), c.getinfo(pycurl.EFFECTIVE_URL)
c.close()
print "pycurl takes %s seconds to get %s " % (duration, url)
print "lenth of the content is %d" % len(t.contents)
#print(t.contents)

实例二：封装get post函数

import pycurl
import StringIO
import urllib
#------------------------自动处理cookile的函数----------------------------------#
def initCurl():
"""初始化一个pycurl对象，
尽管urllib2也支持 cookie 但是在登录cas系统时总是失败，并且没有搞清楚失败的原因。
这里采用pycurl主要是因为pycurl设置了cookie后，可以正常登录Cas系统
"""
        c = pycurl.Curl()
        c.setopt(pycurl.COOKIEFILE, "cookie_file_name")#把cookie保存在该文件中
        c.setopt(pycurl.COOKIEJAR, "cookie_file_name")
        c.setopt(pycurl.FOLLOWLOCATION, 1) #允许跟踪来源
        c.setopt(pycurl.MAXREDIRS, 5)
        #设置代理 如果有需要请去掉注释，并设置合适的参数
        #c.setopt(pycurl.PROXY, ‘http://11.11.11.11:8080′)
        #c.setopt(pycurl.PROXYUSERPWD, ‘aaa:aaa’)
        return c
#-----------------------------------get函数-----------------------------------#
def GetDate(curl, url):
"""获得url指定的资源，这里采用了HTTP的GET方法
"""
        head = ["Accept:*/*",
                "User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64; rv:32.0) Gecko/20100101 Firefox/32.0"]
        buf = StringIO.StringIO()
        curl.setopt(pycurl.WRITEFUNCTION, buf.write)
        curl.setopt(pycurl.URL, url)
        curl.setopt(pycurl.HTTPHEADER,  head)
        curl.perform()
        the_page =buf.getvalue()
        buf.close()
        return the_page
#-----------------------------------post函数-----------------------------------#
def PostData(curl, url, data):
"""提交数据到url，这里使用了HTTP的POST方法
备注，这里提交的数据为json数据，
如果需要修改数据类型，请修改head中的数据类型声明
"""
        head = ["Accept:*/*",
                "Content-Type:application/xml",
                "render:json",
                "clientType:json",
                "Accept-Charset:GBK,utf-8;q=0.7,*;q=0.3",
                "Accept-Encoding:gzip,deflate,sdch",
                "Accept-Language:zh-CN,zh;q=0.8",
                "User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64; rv:32.0) Gecko/20100101 Firefox/32.0"]
        buf = StringIO.StringIO()
        curl.setopt(pycurl.WRITEFUNCTION, buf.write)
        curl.setopt(pycurl.POSTFIELDS,  data)
        curl.setopt(pycurl.URL, url)
        curl.setopt(pycurl.HTTPHEADER,  head)
        curl.perform()
        the_page = buf.getvalue()
        #print the_page
        buf.close()
        return the_page
#-----------------------------------post函数-----------------------------------#
c = initCurl()
html = GetDate(c, "http://www.baidu.com")
print html

实例三：将短链接转化为实际的url地址

import StringIO
import pycurl
c = pycurl.Curl()
str = StringIO.StringIO()
c.setopt(pycurl.URL, "http://t.cn/Rhevig4")
c.setopt(pycurl.WRITEFUNCTION, str.write)
c.setopt(pycurl.FOLLOWLOCATION, 1)
c.perform()
print c.getinfo(pycurl.EFFECTIVE_URL)