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爬虫基本库的使用之requests库

使用requests

由于处理网页验证和Cookies时，需要写Opener和Handler来处理，为了更方便地实现这些操作，就有了更强大的库requests。requests库功能很强大。能实现Cookies、登录验证、代理设置等操作。

简单使用requests库

import requests
r = requests.get('http://wwww.baidu.com/')
print(type(r), r.status_code, r.text, r.cookies, sep='\n\n')

GET请求

返回相应的请求信息

requests.get(url, params)
# url表示要捕获的页面链接，params表示url的额外参数（字典或字节流格式）

举例1：

import requests
r = requests.get('http://httpbin.org/get')
print(r.text)

# 输出
{
   "args": {}, 
   "headers": {
     "Accept": "*/*", 
     "Accept-Encoding": "gzip, deflate", 
     "Host": "httpbin.org", 
     "User-Agent": "python-requests/2.21.0"
   }, 
   "origin": "120.85.108.192, 120.85.108.192", 
   "url": "https://httpbin.org/get"
 }

举例2

import requests
data = {
     'name': 'LiYihua',
     'age': '21'
 }
r = requests.get('http://httpbin.org/get', params=data)
print(r.text)

# 输出：
{
  "args": {
    "age": "21", 
    "name": "LiYihua"
  }, 
  "headers": {
    "Accept": "*/*", 
    "Accept-Encoding": "gzip, deflate", 
    "Host": "httpbin.org", 
    "User-Agent": "python-requests/2.21.0"
  }, 
  "origin": "120.85.108.92, 120.85.108.92", 
  "url": "https://httpbin.org/get?name=LiYihua&age=21"
}

举例3

import requests
r = requests.get('http://httpbin.org/get')
print(type(r.text), r.json(), type(r.json()), sep='\n\n')

# 输出：
<class 'str'>

{'args': {}, 'headers': {'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'Host': 'httpbin.org', 'User-Agent': 'python-requests/2.21.0'}, 'origin': '120.85.108.92, 120.85.108.92', 'url': 'https://httpbin.org/get'}

<class 'dict'>

举例4

抓取照片

import requests
r = requests.get('https://github.com/favicon.ico')
with open('favicon.ico', 'wb') as f:
    f.write(r.content)

# 运行结束后生成一个名为favicon.ico的图标

POST请求

这是一种比较常见的URL请求方式，举例：

import requests

data = {
    'name': 'LiYihua',
    'age': 21
}
r = requests.post('http://httpbin.org/post', data=data)
print(r.text)


# 输出：
{
  "args": {}, 
  "data": "", 
  "files": {}, 
  "form": {
    "age": "21", 
    "name": "LiYihua"
  }, 
  "headers": {
    "Accept": "*/*", 
    "Accept-Encoding": "gzip, deflate", 
    "Content-Length": "19", 
    "Content-Type": "application/x-www-form-urlencoded", 
    "Host": "httpbin.org", 
    "User-Agent": "python-requests/2.21.0"
  }, 
  "json": null, 
  "origin": "120.85.108.90, 120.85.108.90", 
  "url": "https://httpbin.org/post"
}

# POST请求成功，获得返回结果，form部分为提交的数据

Response

text 和 content 获取响应的内容
status code 属性得到状态码
headers 属性得到响应头
cookies属性得到 Cookies
url属性得到 URL
history属性得到请求历史

举例：

import requests

r = requests.get('https://www.cnblogs.com/liyihua/')

print(type(r.status_code), r.status_code,
      type(r.headers), r.headers,
      type(r.cookies), r.cookies,
      type(r.url), r.url,
      type(r.history), r.history,
      sep='\n\n')


# 输出：
<class 'int'>

200

<class 'requests.structures.CaseInsensitiveDict'>

{'Date': 'Thu, 20 Jun 2019 08:18:00 GMT', 'Content-Type': 'text/html; charset=utf-8', 'Transfer-Encoding': 'chunked', 'Connection': 'keep-alive', 'Vary': 'Accept-Encoding', 'Cache-Control': 'private, max-age=10', 'Expires': 'Thu, 20 Jun 2019 08:18:10 GMT', 'Last-Modified': 'Thu, 20 Jun 2019 08:18:00 GMT', 'X-UA-Compatible': 'IE=10', 'X-Frame-Options': 'SAMEORIGIN', 'Content-Encoding': 'gzip'}

<class 'requests.cookies.RequestsCookieJar'>

<RequestsCookieJar[]>

<class 'str'>

https://www.cnblogs.com/liyihua/

<class 'list'>

[]

requests 的高级用法

文件上传

import requests

files = {
    'file': open('favicon.ico', 'rb')
}
r = requests.post('http://httpbin.org/post', files=files)
print(r.text)


# 输出：
{
  "args": {}, 
  "data": "", 
  "files": {
    "file": "data:application/octetstream;base64,AAABAAIAEBAAAAEAIAAoBQAAJgAAACAgAAABACAAKBQAAE4FAAAoAAAAEAAAACAAAAABACAAAAAAAAAFAAA...
  }, 
  "form": {}, 
  "headers": {
    "Accept": "*/*", 
    "Accept-Encoding": "gzip, deflate", 
    "Content-Length": "6665", 
    "Content-Type": "multipart/form-data; boundary=c1b665273fc73e67e57ac97e78f49110", 
    "Host": "httpbin.org", 
    "User-Agent": "python-requests/2.21.0"
  }, 
  "json": null, 
  "origin": "120.85.108.71, 120.85.108.71", 
  "url": "https://httpbin.org/post"
}

会话维持

Session对象，可以方便的维护一个会话

import requests

requests.get('http://httpbin.org/cookies/set/number/123456789')
r = requests.get('http://httpbin.org/cookies')
print(r.text)


# 输出：
{
  "cookies": {}
}


import requests

s = requests.Session()
s.get('http://httpbin.org/cookies/set/number/123456789')
r = s.get('http://httpbin.org/cookies')
print(r.text)


# 输出：
{
  "cookies": {
    "number": "123456789"
  }
}

SSL证书验证

import requests

r = requests.get('https://www.12306.cn')
print(r.status_code)

# 没有出错会输出：200
# 如果请求一个HTTPS站点，但是证书验证错误的页面时，就会错误。


# 为了避免错误，可以将改例子稍作修改
import requests
from requests.packages import urllib3

urllib3.disable_warnings()
r = requests.get('https://www.12306.cn', verify=False)
print(r.status_code)

代理设置

import requests

proxies = {
    'http': 'socks5://user:password@10.10.1.10:3128',
    'https': 'socks5://user:password@10.10.1.10:1080'
}

requests.get('https://www.taobao.com', proxies=proxies)


# 使用SOCKS协议代理

超时设置

import requests

r = requests.get('https://taobao.com', timeout=(0.1, 1))
print(r.status_code)

# 输出：200

身份验证

import requests
from requests.auth import HTTPBasicAuth

r = requests.get('http://localhost', auth=HTTPBasicAuth('liyihua', 'woshiyihua134'))
print(r.status_code)


# 输出：200


# 也可以使用OAuth1方法
import requests
from requests_oauthlib import OAuth1

url = 'https://api.twitter.com/1.1/account/verify_credentials.json'
auth = OAuth1('YOUR_APP_KEY', 'YOUR_APP_SECRET'
              'USER_OAUTH_TOKEN', 'USER_OAUTH_TOKEN_SECRET')
requests.get(url, auth=auth)

Prepared Request（准备请求

要获取一个带有状态的 Prepared Request， 需要用Session.prepare_request()

from requests import Request, Session

url = 'http://httpbin.org/post'
data = {
    'name': 'LiYihua'
}           # 参数
header = {
    'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537 (KHTML, like Gecko Chrome/53.0.2785.116 Safari/537.36'
}           # 伪装浏览器
s = Session()                       # 会话维持
req = Request('POST', url, data=data, headers=header)

prepped = s.prepare_request(req)            # Session的prepare_request()方法将req转化为一个 Prepared Request对象 
r = s.send(prepped)                 # send() 发送请求
print(r.text)


# 输出：
{
  "args": {}, 
  "data": "", 
  "files": {}, 
  "form": {
    "name": "LiYihua"
  }, 
  "headers": {
    "Accept": "*/*", 
    "Accept-Encoding": "gzip, deflate", 
    "Content-Length": "12", 
    "Content-Type": "application/x-www-form-urlencoded", 
    "Host": "httpbin.org", 
    "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537 (KHTML, like Gecko Chrome/53.0.2785.116 Safari/537.36"
  }, 
  "json": null, 
  "origin": "120.85.108.184, 120.85.108.184", 
  "url": "https://httpbin.org/post"
}

本文来自博客园，作者：LeeHua，转载请注明原文链接：https://www.cnblogs.com/liyihua/p/11050374.html

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原文地址：https://www.cnblogs.com/liyihua/p/11050374.html