python教程:requests库使用方法详解

1.官方文档

requests的具体安装过程请看:http://docs.python-requests.org/en/latest/user/install.html#install
requests的官方指南文档:http://docs.python-requests.org/en/latest/user/quickstart.html
requests的高级指南文档:http://docs.python-requests.org/en/latest/user/advanced.html#advanced

2.什么是Requests

Requests 是⽤imgython语⾔编写,基于urllib,采⽤Apache2 Licensed开源协议的 HTTP 库。它⽐ urllib 更加⽅便,
可以节约我们⼤量的⼯作,完全满⾜HTTP测试需求。

⼀句话——Python实现的简单易⽤的HTTP库

安装Requests库

进入命令行win+R执行

  • 命令:pip install requests

  • 项目导入:import requests

各种请求方式

直接上代码,不明白可以查看我的urllib的基本使用方法

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')

这么多请求方式,都有什么含义,所以问下度娘:

  • GET: 请求指定的页面信息,并返回实体主体。
  • HEAD: 只请求页面的首部。
  • POST: 请求服务器接受所指定的文档作为对所标识的URI的新的从属实体。
  • PUT: 从客户端向服务器传送的数据取代指定的文档的内容。
  • DELETE: 请求服务器删除指定的页面。
  • get 和 post比较常见 GET请求将提交的数据放置在HTTP请求协议头中
  • POST提交的数据则放在实体数据中
基本的GET请求
import requests

response = requests.get('http://httpbin.org/get')
print(response.text)
返回值:

{
    "args": {}, 
    "headers": {
    "Accept": "*/*", 
    "Accept-Encoding": "gzip, deflate", 
    "Connection": "close", 
    "Host": "httpbin.org", 
    "User-Agent": "python-requests/2.18.4"
  }, 
  "origin": "183.64.61.29", 
  "url": "http://httpbin.org/get"
}4)、获取二进制数据

记住返回值.content就ok了

import requests

response = requests.get("https://github.com/favicon.ico")
print(type(response.text), type(response.content))
print(response.text)
print(response.content)
带参数的GET请求

将name和age传进去

import requests

response = requests.get("http://httpbin.org/get?name=germey&age=22")
print(response.text)
{
    "args": {
    "age": "22", 
    "name": "germey"
  }, 
    "headers": {
    "Accept": "*/*", 
    "Accept-Encoding": "gzip, deflate", 
    "Connection": "close", 
    "Host": "httpbin.org", 
    "User-Agent": "python-requests/2.18.4"
  }, 
  "origin": "183.64.61.29", 
  "url": "http://httpbin.org/get?name=germey&age=22"
}
或者使用params的方法:

import requests

data = {
 'name': 'germey',
 'age': 22
}
response = requests.get("http://httpbin.org/get", params=data)
print(response.text)

返回值一样

返回值为二进制不必再进行展示,

解析json

将返回值已json的形式展示:

import requests

import json


response = requests.get("http://httpbin.org/get")

print(type(response.text))

print(response.json())

print(json.loads(response.text))

print(type(response.json()))

返回值:


<class 'str'>

{'args': {}, 'headers': {'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'Connection': 'close', 'Host': 'httpbin.org', 'User-Agent': 'python-requests/2.18.4'}, 'origin': '183.64.61.29', 'url': 'http://httpbin.org/get'}

{'args': {}, 'headers': {'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate', 'Connection': 'close', 'Host': 'httpbin.org', 'User-Agent': 'python-requests/2.18.4'}, 'origin': '183.64.61.29', 'url': 'http://httpbin.org/get'}

<class 'dict'>
添加headers

有些网站访问时必须带有浏览器等信息,如果不传入headers就会报错,如下

import requests

response = requests.get("https://www.zhihu.com/explore")
print(response.text)
返回值:

<html><body><h1>500 Server Error</h1>
An internal server error occured.
</body></html>
当传入headers时:

import requests

headers = {
'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36'
}
response = requests.get("https://www.zhihu.com/explore", headers=headers)
print(response.text)

成功返回网页源代码不做展示

基本POST请求

不明白见urllib的使用方法

import requests

data = {'name': 'germey', 'age': '22'}
response = requests.post("http://httpbin.org/post", data=data)
print(response.text)

返回:

{
   "args": {}, 
   "data": "", 
   "files": {}, 
   "form": {
    "age": "22", 
    "name": "germey"
   }, 
    "headers": {
    "Accept": "*/*", 
    "Accept-Encoding": "gzip, deflate", 
    "Connection": "close", 
    "Content-Length": "18", 
    "Content-Type": "application/x-www-form-urlencoded", 
    "Host": "httpbin.org", 
    "User-Agent": "python-requests/2.18.4"
  }, 
  "json": null, 
  "origin": "183.64.61.29", 
  "url": "http://httpbin.org/post"
}

3.响应

response属性
import requests
response = requests.get('http://www.jianshu.com')
print(type(response.status_code), response.status_code)
print(type(response.headers), response.headers)
print(type(response.cookies), response.cookies)
print(type(response.url), response.url)
print(type(response.history), response.history)
return<class 'int'> 200
<class 'requests.structures.CaseInsensitiveDict'> {'Date': 'Thu, 01 Feb 2018 20:47:08 GMT', 'Server': 'Tengine', 'Content-Type': 'text/html; charset=utf-8', 'Transfer-Encoding': 'chunked', 'X-Frame-Options': 'DENY', 'X-XSS-Protection': '1; mode=block', 'X-Content-Type-Options': 'nosniff', 'ETag': 'W/"9f70e869e7cce214b6e9d90f4ceaa53d"', 'Cache-Control': 'max-age=0, private, must-revalidate', 'Set-Cookie': 'locale=zh-CN; path=/', 'X-Request-Id': '366f4cba-8414-4841-bfe2-792aeb8cf302', 'X-Runtime': '0.008350', 'Content-Encoding': 'gzip', 'X-Via': '1.1 gjf22:8 (Cdn Cache Server V2.0), 1.1 PSzqstdx2ps251:10 (Cdn Cache Server V2.0)', 'Connection': 'keep-alive'}
<class 'requests.cookies.RequestsCookieJar'> <RequestsCookieJar[<Cookie locale=zh-CN for www.jianshu.com/>]>
<class 'str'> https://www.jianshu.com/
<class 'list'> [<Response [301]>]

状态码判断:常见的网页状态码:

100: ('continue',),
101: ('switching_protocols',),
102: ('processing',),
103: ('checkpoint',),
122: ('uri_too_long', 'request_uri_too_long'),
    
200: ('ok', 'okay', 'all_ok', 'all_okay', 'all_good', '\\o/', '✓'),
201: ('created',),
202: ('accepted',),
203: ('non_authoritative_info', 'non_authoritative_information'),
204: ('no_content',),
205: ('reset_content', 'reset'),
206: ('partial_content', 'partial'),
207: ('multi_status', 'multiple_status', 'multi_stati', 'multiple_stati'),
208: ('already_reported',),
226: ('im_used',),
    
# Redirection.
300: ('multiple_choices',),
301: ('moved_permanently', 'moved', '\\o-'),
302: ('found',),
303: ('see_other', 'other'),
304: ('not_modified',),
305: ('use_proxy',),
306: ('switch_proxy',),
307: ('temporary_redirect', 'temporary_moved', 'temporary'),
308: ('permanent_redirect','resume_incomplete', 'resume',), # These 2 to be removed in 3.0
    
# Client Error.
400: ('bad_request', 'bad'),
401: ('unauthorized',),
402: ('payment_required', 'payment'),
403: ('forbidden',),
404: ('not_found', '-o-'),
405: ('method_not_allowed', 'not_allowed'),
406: ('not_acceptable',),
407: ('proxy_authentication_required', 'proxy_auth', 'proxy_authentication'),
408: ('request_timeout', 'timeout'),
409: ('conflict',),
410: ('gone',),
411: ('length_required',),
412: ('precondition_failed', 'precondition'),
413: ('request_entity_too_large',),
414: ('request_uri_too_large',),
415: ('unsupported_media_type', 'unsupported_media', 'media_type'),
416: ('requested_range_not_satisfiable', 'requested_range', 'range_not_satisfiable'),
417: ('expectation_failed',),
418: ('im_a_teapot', 'teapot', 'i_am_a_teapot'),
421: ('misdirected_request',),
422: ('unprocessable_entity', 'unprocessable'),
423: ('locked',),
424: ('failed_dependency', 'dependency'),
425: ('unordered_collection', 'unordered'),
426: ('upgrade_required', 'upgrade'),
428: ('precondition_required', 'precondition'),
429: ('too_many_requests', 'too_many'),
431: ('header_fields_too_large', 'fields_too_large'),
444: ('no_response', 'none'),
449: ('retry_with', 'retry'),
450: ('blocked_by_windows_parental_controls', 'parental_controls'),
451: ('unavailable_for_legal_reasons', 'legal_reasons'),
499: ('client_closed_request',),
    
# Server Error.
500: ('internal_server_error', 'server_error', '/o\\', '✗'),
501: ('not_implemented',),
502: ('bad_gateway',),
503: ('service_unavailable', 'unavailable'),
504: ('gateway_timeout',),
505: ('http_version_not_supported', 'http_version'),
506: ('variant_also_negotiates',),
507: ('insufficient_storage',),
509: ('bandwidth_limit_exceeded', 'bandwidth'),
510: ('not_extended',),
511: ('network_authentication_required', 'network_auth', 'network_authentication'),

4.高级操作

文件上传

使用 Requests 模块,上传文件也是如此简单的,文件的类型会自动进行处理:

实例:

import requests

files = {'file': open('cookie.txt', 'rb')}
response = requests.post("http://httpbin.org/post", files=files)
print(response.text)

这是通过测试网站做的一个测试,返回值如下:

{
"args": {}, 
"data": "", 
"files": {
"file": "#LWP-Cookies-2.0\r\nSet-Cookie3: BAIDUID=\"D2B4E137DE67E271D87F03A8A15DC459:FG=1\"; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; expires=\"2086-02-13 11:15:12Z\"; version=0\r\nSet-Cookie3: BIDUPSID=D2B4E137DE67E271D87F03A8A15DC459; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; expires=\"2086-02-13 11:15:12Z\"; version=0\r\nSet-Cookie3: H_PS_PSSID=25641_1465_21087_17001_22159; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; discard; version=0\r\nSet-Cookie3: PSTM=1516953672; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; expires=\"2086-02-13 11:15:12Z\"; version=0\r\nSet-Cookie3: BDSVRTM=0; path=\"/\"; domain=\"www.baidu.com\"; path_spec; discard; version=0\r\nSet-Cookie3: BD_HOME=0; path=\"/\"; domain=\"www.baidu.com\"; path_spec; discard; version=0\r\n"
}, 
"form": {}, 
"headers": {
"Accept": "*/*", 
"Accept-Encoding": "gzip, deflate", 
"Connection": "close", 
"Content-Length": "909", 
"Content-Type": "multipart/form-data; boundary=84835f570cfa44da8f4a062b097cad49", 
"Host": "httpbin.org", 
"User-Agent": "python-requests/2.18.4"
}, 
"json": null, 
"origin": "183.64.61.29", 
"url": "http://httpbin.org/post"
}
获取cookie

当需要cookie时,直接调用response.cookieimgresponse为请求后的返回值)

import requests

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

输出结果:

<RequestsCookieJar[<Cookie BDORZ=27315 for .baidu.com/>]>
BDORZ=27315

会话维持、模拟登陆

如果某个响应中包含一些Cookie,你可以快速访问它们:

import requests

r = requests.get('http://www.google.com.hk/')
print(r.cookies['NID'])
print(tuple(r.cookies))

要想发送你的cookies到服务器,可以使用 cookies 参数:

import requests

url = 'http://httpbin.org/cookies'
cookies = {'testCookies_1': 'Hello_Python3', 'testCookies_2': 'Hello_Requests'}

# 在Cookie Version 0中规定空格、方括号、圆括号、等于号、逗号、双引号、斜杠、问号、@,冒号,分号等

特殊符号都不能作为Cookie的内容。

r = requests.get(url, cookies=cookies)
print(r.json())
证书验证(SSL Cert Verification)
#证书验证(大部分网站都是https)
import requests
respone=requests.get('https://www.12306.cn') #如果是ssl请求,首先检查证书是否合法,不合法则报错,程序终端


#改进1:去掉报错,但是会报警告
import requests
respone=requests.get('https://www.12306.cn',verify=False) #不验证证书,报警告,返回200
print(respone.status_code)


#改进2:去掉报错,并且去掉警报信息
import requests
from requests.packages import urllib3
urllib3.disable_warnings() #关闭警告
respone=requests.get('https://www.12306.cn',verify=False)
print(respone.status_code)

#改进3:加上证书
#很多网站都是https,但是不用证书也可以访问,大多数情况都是可以携带也可以不携带证书
#知乎\百度等都是可带可不带
#有硬性要求的,则必须带,比如对于定向的用户,拿到证书后才有权限访问某个特定网站
import requests
respone=requests.get('https://www.12306.cn',
                     cert=('/path/server.crt',
                           '/path/key'))
print(respone.status_code)
认证设置
#官网链接:http://docs.python-requests.org/en/master/user/authentication/

#认证设置:登陆网站是,弹出一个框,要求你输入用户名密码(与alter很类似),此时是无法获取html的
# 但本质原理是拼接成请求头发送
#         r.headers['Authorization'] = _basic_auth_str(self.username, self.password)
# 一般的网站都不用默认的加密方式,都是自己写
# 那么我们就需要按照网站的加密方式,自己写一个类似于_basic_auth_str的方法
# 得到加密字符串后添加到请求头
#         r.headers['Authorization'] =func('.....')

#看一看默认的加密方式吧,通常网站都不会用默认的加密设置
import requests
from requests.auth import HTTPBasicAuth
r=requests.get('xxx',auth=HTTPBasicAuth('user','password'))
print(r.status_code)

#HTTPBasicAuth可以简写为如下格式
import requests
r=requests.get('xxx',auth=('user','password'))
print(r.status_code)
代理设置

在进行爬虫爬取时,有时候爬虫会被服务器给屏蔽掉,这时采用的方法主要有降低访问时间,通过代理ip访问,
如下:

import requests

proxies = {
"http": "http://127.0.0.1:9743",
"https": "https://127.0.0.1:9743",
}


response = requests.get("https://www.taobao.com", proxies=proxies)
print(response.status_code)

ip可以从网上抓取,或者某宝购买

如果代理需要设置账户名和密码,只需要将字典更改为如下:

proxies = {
"http":"http://user:[email protected]:9999"
}

如果你的代理是通过sokces这种方式则需要

pip install "requests[socks]"
proxies= {
"http":"socks5://127.0.0.1:9999",
"https":"sockes5://127.0.0.1:8888"
}

超时设置

访问有些网站时可能会超时,这时设置好timeout就可以解决这个问题

import requests
from requests.exceptions import ReadTimeout
try:
response = requests.get("http://httpbin.org/get", timeout = 0.5)
print(response.status_code)
except ReadTimeout:
print('Timeout')

正常访问,状态吗返回200

认证设置

如果碰到需要认证的网站可以通过requests.auth模块实现

import requests

from requests.auth import HTTPBasicAuth

response = requests.get("http://120.27.34.24:9001/",auth=HTTPBasicAuth("user","123"))
print(response.status_code)

当然这里还有一种方式

import requests

response = requests.get("http://120.27.34.24:9001/",auth=("user","123"))
print(response.status_code)
异常处理

遇到网络问题(如:DNS查询失败、拒绝连接等)时,Requests会抛出一个ConnectionError 异常。

遇到罕见的无效HTTP响应时,Requests则会抛出一个 HTTPError 异常。

若请求超时,则抛出一个 Timeout 异常。

若请求超过了设定的最大重定向次数,则会抛出一个 TooManyRedirects 异常。

所有Requests显式抛出的异常都继承自 requests.exceptions.RequestException 。

上传文件
import requests
files={'file':open('a.jpg','rb')}
respone=requests.post('http://httpbin.org/post',files=files)
print(respone.status_code)
带参数的GET请求->headers

通常我们在发送请求时都需要带上请求头,请求头是将自身伪装成浏览器的关键,常见的有用的请求头如下

Host

Referer #大型网站通常都会根据该参数判断请求的来源
User-Agent #客户端
Cookie #Cookie信息虽然包含在请求头里,但requests模块有单独的参数来处理他,headers={}内就不要放它了

添加headers(浏览器会识别请求头,不加可能会被拒绝访问,比如访问https://www.zhihu.com/explore)

import requests
response=requests.get('https://www.zhihu.com/explore')
response.status_code #500

#学习中遇到问题没人解答?小编创建了一个Python学习交流群:711312441
#自己定制headers
headers={
    'User-Agent':'Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.76 Mobile Safari/537.36',

}
respone=requests.get('https://www.zhihu.com/explore',
                     headers=headers)
print(respone.status_code) #200
带参数的GET请求->cookies
import requests

Cookies={   'user_session':'rzNme4L6LTH7QSresq8w0BVYhTNt5GS-asNnkOe7_FZ2CjB6',
}

response=requests.get('https://github.com/settings/emails',
             cookies=Cookies) #github对请求头没有什么限制,我们无需定制user-agent,对于其他网站可能还需要定制


print('********@**.com' in response.text) #True
发送post请求,模拟浏览器的登录行为

对于登录来说,应该输错用户名或密码然后分析抓包流程,用脑子想一想,输对了浏览器就跳转了,还分析个毛线,累死你也找不到包

自动登录gitbub(自己处理cookies))

'''
一 目标站点分析
    浏览器输入https://github.com/login
    然后输入错误的账号密码,抓包
    发现登录行为是post提交到:https://github.com/session
    而且请求头包含cookie
    而且请求体包含:
        commit:Sign in
        utf8:✓
        authenticity_token:lbI8IJCwGslZS8qJPnof5e7ZkCoSoMn6jmDTsL1r/m06NLyIbw7vCrpwrFAPzHMep3Tmf/TSJVoXWrvDZaVwxQ==
        login:egonlin
        password:123


二 流程分析
    先GET:https://github.com/login拿到初始cookie与authenticity_token
    返回POST:https://github.com/session, 带上初始cookie,带上请求体(authenticity_token,用户名,密码等)
    最后拿到登录cookie

    ps:如果密码时密文形式,则可以先输错账号,输对密码,然后到浏览器中拿到加密后的密码,github的密码是明文
'''

import requests
import re

#第一次请求
r1=requests.get('https://github.com/login')
r1_cookie=r1.cookies.get_dict() #拿到初始cookie(未被授权)
authenticity_token=re.findall(r'name="authenticity_token".*?value="(.*?)"',r1.text)[0] #从页面中拿到CSRF TOKEN

#第二次请求:带着初始cookie和TOKEN发送POST请求给登录页面,带上账号密码
data={
    'commit':'Sign in',
    'utf8':'✓',
    'authenticity_token':authenticity_token,
    'login':'********@**.com',
    'password':'alex3714'
}
r2=requests.post('https://github.com/session',
             data=data,
             cookies=r1_cookie
             )


login_cookie=r2.cookies.get_dict()


#第三次请求:以后的登录,拿着login_cookie就可以,比如访问一些个人配置
r3=requests.get('https://github.com/settings/emails',
                cookies=login_cookie)

print('********@**.com' in r3.text) #True

requests.session()自动帮我们保存cookie信息

import requests
import re

session=requests.session()
#第一次请求
r1=session.get('https://github.com/login')
authenticity_token=re.findall(r'name="authenticity_token".*?value="(.*?)"',r1.text)[0] #从页面中拿到CSRF TOKEN

#第二次请求
data={
    'commit':'Sign in',
    'utf8':'✓',
    'authenticity_token':authenticity_token,
    'login':'********@**.com',
    'password':'alex3714'
}
r2=session.post('https://github.com/session',
             data=data,
             )

#第三次请求
r3=session.get('https://github.com/settings/emails')

print('********@**.com' in r3.text) #True

补充json

json的用法

requests.post(url='xxxxxxxx',
              data={'xxx':'yyy'}) #没有指定请求头,#默认的请求头:application/x-www-form-urlencoed

#如果我们自定义请求头是application/json,并且用data传值, 则服务端取不到值
requests.post(url='',
              data={'':1,},
              headers={
                  'content-type':'application/json'
              })


requests.post(url='',
              json={'':1,},
              ) #默认的请求头:application/json

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