requests是python实现的简单易用的HTTP库，使用起来比urllib简洁很多
因为是第三方库，所以使用前需要cmd安装
pip install requests
安装完成后import一下，正常则说明可以开始使用了。
基本用法：
requests.get()用于请求目标网站，类型是一个HTTPresponse类型
import requestsresponse = requests.get('http://www.baidu.com')
print(response.status_code) # 打印状态码
print(response.url) # 打印请求url
print(response.headers) # 打印头信息
print(response.cookies) # 打印cookie信息
print(response.text) #以文本形式打印网页源码
print(response.content) #以字节流形式打印
运行结果：
状态码：200
url：www.baidu.com
headers信息
各种请求方式：
import requests
requests.get('http://httpbin.org/get')
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')
基本的get请求
import requests
response = requests.get('http://httpbin.org/get')
print(response.text)
结果
带参数的GET请求：
第一种直接将参数放在url内
import requests response = requests.get(http://httpbin.org/get?name=gemey&age=22) print(response.text)
结果
另一种先将参数填写在dict中，发起请求时params参数指定为dict
import requests
data = {
'name': 'tom',
'age': 20
}
response = requests.get('http://httpbin.org/get', params=data)
print(response.text)
结果同上
解析json
import requests
response = requests.get('http://httpbin.org/get')
print(response.text)
print(response.json()) #response.json()方法同json.loads(response.text)
print(type(response.json()))
结果
简单保存一个二进制文件
二进制内容为response.content
import requests
response = requests.get('http://img.ivsky.com/img/tupian/pre/201708/30/kekeersitao-002.jpg')
b = response.content
with open('F://fengjing.jpg','wb') as f:
f.write(b)
为你的请求添加头信息
import requests
heads = {}
heads['User-Agent'] = 'Mozilla/5.0 ' \
'(Macintosh; U; Intel Mac OS X 10_6_8; en-us) AppleWebKit/534.50 ' \
'(KHTML, like Gecko) Version/5.1 Safari/534.50'
response = requests.get('http://www.baidu.com',headers=headers)
使用代理
同添加headers方法，代理参数也要是一个dict
这里使用requests库爬取了IP代理网站的IP与端口和类型
因为是免费的，使用的代理地址很快就失效了。
import requests
import re
def get_html(url):
proxy = {
'http': '120.25.253.234:812',
'https' '163.125.222.244:8123'
}
heads = {}
heads['User-Agent'] = 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.221 Safari/537.36 SE 2.X MetaSr 1.0'
req = requests.get(url, headers=heads,proxies=proxy)
html = req.text
return html
def get_ipport(html):
regex = r'(.+) '
iplist = re.findall(regex, html)
regex2 = '(.+) '
portlist = re.findall(regex2, html)
regex3 = r'(.+) '
typelist = re.findall(regex3, html)
sumray = []
for i in iplist:
for p in portlist:
for t in typelist:
pass
pass
a = t+','+i + ':' + p
sumray.append(a)
print('高匿代理')
print(sumray)
if __name__ == '__main__':
url = 'http://www.kuaidaili.com/free/'
get_ipport(get_html(url))
结果：
基本POST请求：
import requests
data = {'name':'tom','age':'22'}
response = requests.post('http://httpbin.org/post', data=data)
获取cookie
#获取cookie
import requests
response = requests.get('http://www.baidu.com')
print(response.cookies)
print(type(response.cookies))
for k,v in response.cookies.items():
print(k+':'+v)
结果：
会话维持
import requests
session = requests.Session()
session.get('http://httpbin.org/cookies/set/number/12345')
response = session.get('http://httpbin.org/cookies')
print(response.text)
结果：
证书验证设置
import requests
from requests.packages import urllib3
urllib3.disable_warnings() #从urllib3中消除警告
response = requests.get('https://www.12306.cn',verify=False) #证书验证设为FALSE
print(response.status_code)打印结果：200
超时异常捕获
import requests
from requests.exceptions import ReadTimeout
try:
res = requests.get('http://httpbin.org', timeout=0.1)
print(res.status_code)
except ReadTimeout:
print(timeout)
异常处理
在你不确定会发生什么错误时，尽量使用try...except来捕获异常
所有的requests exception：
Exceptions
import requests
from requests.exceptions import ReadTimeout,HTTPError,RequestException
try:
response = requests.get('http://www.baidu.com',timeout=0.5)
print(response.status_code)
except ReadTimeout:
print('timeout')
except HTTPError:
print('httperror')
except RequestException:
print('reqerror')
25行代码带你爬取4399小游戏数据
import requests
import parsel
import csv
f = open('4399游戏.csv', mode='a', encoding='utf-8-sig', newline='')
csv_writer = csv.DictWriter(f, fieldnames=['游戏地址', '游戏名字'])
csv_writer.writeheader()
for page in range(1, 106):
url = 'http://www.4399.com/flash_fl/5_{}.htm'.format(page)
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36'
}
response = requests.get(url=url, headers=headers)
response.encoding = response.apparent_encoding
selector = parsel.Selector(response.text)
lis = selector.css('#classic li')
for li in lis:
dit ={}
data_url = li.css('a::attr(href)').get()
new_url = 'http://www.4399.com' + data_url.replace('http://', '/')
dit['游戏地址'] = new_url
title = li.css('img::attr(alt)').get()
dit['游戏名字'] = title
print(new_url, title)
csv_writer.writerow(dit)
f.close()
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