Requests库
什么是Request库
Requests是用Python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
pip3 install requests
request详解
- 实例引入
import requests
response = requests.get('https://www.baidu.com')
print(type(response)) #<class 'requests.models.Response'>
print(response.status_code) #200
print(type(response.text))#class'str'
print(response.text)#响应的内容，返回的页面html
print(response.cookies)#<RequestsCookieJar[<Cookie BDORZ=27315 for .baidu.com/>]>
- 各种请求方法
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')
-
请求
1.基本用法
import requests
#response = requests.get('http://www.baidu.com')
response = requests.get('http://httpbin.org/get')
print(response.text)
2.带参数的get请求
import requests
response = requests.get("http://httpbin.org/get?name=xiexie&age=22")
print(response.text)
这个参数编写起来蛮复杂的，以下是更清楚的做法，使用带参数的requests.get方法
import requests
data = {
'name':'xiexie',
'age':89
}
response = requests.get('http://httpbin.org/get',params=data)
print(response.text)
3.解析Json
import requests
response = requests.get('http://httpbin.org/get')
print(response.text)
print(response.json())
print(type(response.json()))
这在ajax请求时比较常用
4.获取二进制数据
import requests
response = requests.get('https://github.com/favicon.ico')
print(type(response.text),type(response.content))
print(response.text)
print(response.content)
response.text是string类型，而response.content是二进制流
保存二进制流到本地，图片、视频、音频都可以
import requests
response = requests.get('http://github.com/favicon.ico')
with open('favicon.ico','wb') as f:
f.write(response.content)
f.close()
5.添加headers作为爬虫来说，headers非常重要，演戏演全套。不然会被服务器识别出来被禁用。
import requests
response = requests.get('https://www.zhihu.com/explore')
print(response.text)
不用headers，直接返回400 Bad Request ，无法爬取,以下代码添加headers就能爬取了
import requests
headers = {
'user-agent': 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36'
}
response = requests.get('https://www.zhihu.com/explore',headers=headers)
print(response.text)
6.基本POST请求，需要构造formdata
import requests
data = {'name':'xiexie','age':33} #传个字典
response = requests.post('http://httpbin.org/post',data=data)
print(response.text)
response详解
- 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)
import requests
response = requests.get('http://jianshu.com')
exit() if not response.status_code == 403 else print('Forbidden!')
request高级操作
1.文件上传
import requests
files = {'file':open('favicon.ico','rb')}
response = requests.post('http://httpbin.org/post',files=files)
print(response.text)
2.获取cookie
import requests
response = requests.get('https://www.baidu.com')
print(response.cookies)#response.cookies是一个列表
for key,value in response.cookies.items():
print(key + "=" + value)
3.会话维持，用来模拟登陆用的。
模拟登陆 非常常用
import requests
requests.get('http://httpbin.org/cookies/set/number/1234567')
response = requests.get('http://httpbin.org/cookies')
print(response.text)
这里使用set设置了一个cookie，本意是下一句使用requests.get调用时希望返回这个cookie，实际返回cookies为空。实际上调用2次requests.get是互相独立的，相当于用不同的浏览器打开网页。如果想返回刚刚设置的cookie需要保持会话。以下是会话维持的代码，相当于用同一个浏览器打开。
import requests
s = requests.Session()
s.get('http://httpbin.org/cookies/set/number/1234567')
response = s.get('http://httpbin.org/cookies')
print(response.text)
返回值：{
"cookies": {
"number": "1234567"
}
}
证书验证
有时候打开https的网站，而这个网站提供的证书没有通过验证，那么抛出ssl错误导致程序中断。为了防止这种情况，可以用varify参数。
import requests
from requests.packages import urllib3
urllib3.disable_warnings()#调用原生的urllib3中的disable_warnings()可以消除警告信息。
response = requests.get('https://www.12306.cn',verify=False)
print(response.status_code)
也可以手动导入ca证书和key，这样也不会弹出错误
import requests
response = requests.get('https://www.12306.cn',cert={'parth/server.crt','/path/key'})
print(response.status_code)
代理设置
import request
proxies = {
"http":"http://127.0.0.1:9998",
"https":"https://127.0.0.1:9998",
}
response = requests.get("https://www.taobao.com",proxies=proxies)
print(response.status_code)
有用户名密码的代理
import request
proxies = {
"http":"http://user:password@127.0.0.1:9998",
}
response = requests.get("https://www.taobao.com",proxies=proxies)
print(response.status_code)
ssr这种类型的socks代理怎么使用？
安装：pip3 install 'requests[socks]'
import requests
proxies = {
"http":"sock5://127.0.0.1:9998",
"https":"sock5://127.0.0.1:9998",
}
response = requests.get("https://www.taobao.com",proxies=proxies)
print(response.status_code)
}
超时设置
import requests
try:
response = requests.get("http://httpbin.org/get",timeout=1)
print(response.status_code)
except requests.ReadTimeout:
print('Timeout')
认证设置
import requests
response = requests.get("http://httpbin.org/get",auth=HTTPBasicAuth('user','123'))
print(response.status_code)
另一种字典的方式
import requests
response = requests.get("http://httpbin.org/get",auth={'user':'123'})
print(response.status_code)
异常处理，爬虫的异常处理也很有必要
import requests
from requests.exceptions import ReadTimeout,ConnectionError,RequestException
try:
response = requests.get("http://httpbin.org/get",timeout=0.2)
print(response.status_code)
except ReadTimeout:
print('Timeout')
except ConnectionError:
print("Con error")
except RequestException:
print('Error')
