python爬蟲---requests庫(kù)的用法詳解

更新時(shí)間：2020年09月28日 21:46:07 作者：AGENTFITZ

requests是python實(shí)現(xiàn)的簡(jiǎn)單易用的HTTP庫(kù)，使用起來(lái)比urllib簡(jiǎn)潔很多，這里就為大家分享一下

requests是python實(shí)現(xiàn)的簡(jiǎn)單易用的HTTP庫(kù)，使用起來(lái)比urllib簡(jiǎn)潔很多

因?yàn)槭堑谌綆?kù)，所以使用前需要cmd安裝

pip install requests

安裝完成后import一下，正常則說(shuō)明可以開始使用了。

基本用法：

requests.get()用于請(qǐng)求目標(biāo)網(wǎng)站，類型是一個(gè)HTTPresponse類型

import requestsresponse = requests.get('http://www.baidu.com')
print(response.status_code) # 打印狀態(tài)碼
print(response.url) # 打印請(qǐng)求url
print(response.headers) # 打印頭信息
print(response.cookies) # 打印cookie信息
print(response.text) #以文本形式打印網(wǎng)頁(yè)源碼
print(response.content) #以字節(jié)流形式打印

運(yùn)行結(jié)果：

狀態(tài)碼：200

url：www.baidu.com

headers信息

各種請(qǐng)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請(qǐng)求

import requests

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

結(jié)果

帶參數(shù)的GET請(qǐng)求：

第一種直接將參數(shù)放在url內(nèi)

import requests

response = requests.get(http://httpbin.org/get?name=gemey&age=22)
print(response.text)

結(jié)果

另一種先將參數(shù)填寫在dict中，發(fā)起請(qǐng)求時(shí)params參數(shù)指定為dict

import requests

data = {
  'name': 'tom',
  'age': 20
}

response = requests.get('http://httpbin.org/get', params=data)
print(response.text)

結(jié)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()))

結(jié)果

簡(jiǎn)單保存一個(gè)二進(jìn)制文件

二進(jìn)制內(nèi)容為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)

為你的請(qǐng)求添加頭信息

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，代理參數(shù)也要是一個(gè)dict

這里使用requests庫(kù)爬取了IP代理網(wǎng)站的IP與端口和類型

因?yàn)槭敲赓M(fèi)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'<td data-title="IP">(.+)</td>'
  iplist = re.findall(regex, html)
  regex2 = '<td data-title="PORT">(.+)</td>'
  portlist = re.findall(regex2, html)
  regex3 = r'<td data-title="類型">(.+)</td>'
  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))

結(jié)果：

基本POST請(qǐng)求：

import requests

data = {'name':'tom','age':'22'}

response = requests.post('http://httpbin.org/post', data=data)

獲取cookie

#獲取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)

結(jié)果：

會(huì)話維持

import requests

session = requests.Session()
session.get('http://httpbin.org/cookies/set/number/12345')
response = session.get('http://httpbin.org/cookies')
print(response.text)

結(jié)果：

證書驗(yàn)證設(shè)置

import requests
from requests.packages import urllib3

urllib3.disable_warnings() #從urllib3中消除警告
response = requests.get('https://www.12306.cn',verify=False) #證書驗(yàn)證設(shè)為FALSE
print(response.status_code)打印結(jié)果：200

超時(shí)異常捕獲

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)

異常處理

在你不確定會(huì)發(fā)生什么錯(cuò)誤時(shí)，盡量使用try...except來(lái)捕獲異常

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行代碼帶你爬取4399小游戲數(shù)據(jù)

import requests
import parsel
import csv
f = open('4399游戲.csv', mode='a', encoding='utf-8-sig', newline='')

csv_writer = csv.DictWriter(f, fieldnames=['游戲地址', '游戲名字'])
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['游戲地址'] = new_url
    title = li.css('img::attr(alt)').get()
    dit['游戲名字'] = title
    print(new_url, title)
    csv_writer.writerow(dit)
f.close()

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