Python爬虫requests的使用

一些请求方式

import requests
requests.post("http://httpbin.org/post")
requests.put("http://httpbin.org/put")
requests.delete("http://httpbin.org/delete")
requests.head("http://httpbin.org/get")
requests.options("http://httpbin.org/get")

基本GET的使用

import requests
 
url = 'https://www.baidu.com/'
response = requests.get(url)
print(response.text)

带参数的GET请求

如果想查询http://httpbin.org/get页面的具体参数，需要在url里面加上，例如我想看有没有Host=httpbin.org这条数据，url形式应该是http://httpbin.org/get?Host=httpbin.org

下面提交的数据是往这个地址传送data里面的数据。

import requests
 
url = 'http://httpbin.org/get'
data = {
    'name':'zhangsan',
    'age':'25'
}
response = requests.get(url,params=data)
print(response.url)
print(response.text)

添加header

首先说，为什么要加header（头部信息）呢？例如下面，我们试图访问知乎的登录页面（当然大家都你要是不登录知乎，就看不到里面的内容），我们试试不加header信息会报什么错。

import requests
 
url = 'https://www.zhihu.com/'
response = requests.get(url)
response.encoding = "utf-8"
print(response.text)

提示发生内部服务器错误（也就说你连知乎登录页面的html都下载不下来）。

如果想访问就必须得加headers信息。

import requests
 
url = 'https://www.zhihu.com/'
headers = {
    'User-Agent':'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36'
}
response = requests.get(url,headers=headers)
print(response.text)

基本POST请求

通过post把数据提交到url地址，等同于一字典的形式提交form表单里面的数据

import requests
 
url = 'http://httpbin.org/post'
data = {
    'name':'jack',
    'age':'23'
    }
response = requests.post(url,data=data)
print(response.text)

结果如下:

{
  "args": {},
  "data": "",
  "files": {},
  "form": {
    "age": "23",
    "name": "jack"
  },
  "headers": {
    "Accept": "*/*",
    "Accept-Encoding": "gzip, deflate",
    "Connection": "close",
    "Content-Length": "16",
    "Content-Type": "application/x-www-form-urlencoded",
    "Host": "httpbin.org",
    "User-Agent": "python-requests/2.13.0"
  },
  "json": null,
  "origin": "118.144.137.95",
  "url": "http://httpbin.org/post"
}

requests的高级操作

会话维持

cookie的一个作用就是可以用于模拟登陆，做会话维持

import requests
session = requests.session()
session.get('http://httpbin.org/cookies/set/number/12456')
response = session.get('http://httpbin.org/cookies')
print(response.text)

获取cookie

import requests
response = requests.get('https://www.baidu.com')
print(response.cookies)
for key,value in response.cookies.items():
    print(key,'==',value)

文件上传

import requests
url = "http://httpbin.org/post"
files= {"files":open("test.jpg","rb")}
response = requests.post(url,files=files)
print(response.text)

更多具体以后补上，先看看这个

更多的用法