Python爬虫基础（四）Requests库的使用

requests文档

首先需要安装：pip install requests

get请求

最基本的get：

# -*- coding: utf-8 -*-
import requests
response = requests.get("http://www.baidu.com/")

添加headers及查询参数：

# -*- coding: utf-8 -*-
import requests

kw = {'wd':'秦时明月'}
headers = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36"}

# params 接收一个字典或者字符串的查询参数，字典类型自动转换为url编码，不需要urlencode()
response = requests.get("http://www.baidu.com/s?", params = kw, headers = headers)

# 查看响应内容，response.text 返回的是Unicode格式的数据
print response.text

# 查看响应内容，response.content返回的字节流数据
print respones.content

# 查看完整url地址
print response.url

# 查看响应头部字符编码
print response.encoding

# 查看响应码
print response.status_code

post请求

最基本的post：

# -*- coding: utf-8 -*-
import requests
response = requests.post("http://www.baidu.com/", data = data)

传入查询参数：

使用有道翻译的例子

# -*- coding: utf-8 -*-
import requests

formdata = {
    "i":" python",
    "from":"AUTO",
　　 "to":"AUTO",
    "smartresult":" dict",
　　 "client":" fanyideskweb",
　　 "salt":"",
　　 "sign":" 2a6d78290492d163dbd6803b29e2489c",
    "doctype":"json",
    "version":"2.1",
    "keyfrom":"fanyi.web",
    "action":"FY_BY_ENTER",
    "typoResult":"true"
}

url = "http://fanyi.youdao.com/translate?smartresult=dict&smartresult=rule"

headers={ "User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36"}

response = requests.post(url, data = formdata, headers = headers)

print response.text

# 如果是json文件可以直接显示
print response.json()

设置代理

# -*- coding: utf-8 -*-
import requests

# 根据协议类型，选择不同的代理
proxies = {
  "http": "http://12.34.56.79:9527",
  "https": "http://12.34.56.79:9527",
}
# 私密代理
# proxy = { "http": "账户:密码@61.158.163.130:16816" }
response = requests.get("http://www.baidu.com", proxies = proxies)
print response.text

web客户端验证

# -*- coding: utf-8 -*-
import requests

auth=('账户', '密码')

response = requests.get('http://192.168.23.19', auth = auth)

print response.text

比urllib2简单很多

cookie

如果一个响应中包含了cookie，那么我们可以利用 cookies参数拿到：

# -*- coding: utf-8 -*-
import requests

response = requests.get("http://www.baidu.com/")

#  返回CookieJar对象:
cookiejar = response.cookies

#  将CookieJar转为字典：
cookiedict = requests.utils.dict_from_cookiejar(cookiejar)

print cookiejar

print cookiedict

模拟登录：

# -*- coding: utf-8 -*-
import requests

# 创建session对象，可以保存Cookie值
ssion = requests.session()
# 需要登录的用户名和密码
data = {"email":"账户", "password":"密码"}  

# 发送附带用户名和密码的请求，并获取登录后的Cookie值，保存在ssion里
ssion.post("http://www.renren.com/PLogin.do", data = data)

# ssion包含用户登录后的Cookie值，可以直接访问那些登录后才可以访问的页面
response = ssion.get("http://www.renren.com/410046543/profile")

print response.text

处理SSL验证

# -*- coding: utf-8 -*-
import requests
response = requests.get("https://www.baidu.com/", verify=True)

# 也可以省略不写
# response = requests.get("https://www.baidu.com/")
# 如果SSL证书验证不通过，或者不信任服务器的安全证书，则会报出SSLError
print response.text

# 如果我们想跳过 12306 的证书验证，把 verify 设置为 False 就可以正常请求了
import requests
response = requests.get("https://www.12306.cn/mormhweb/", verify = False)
print response.text