第一种方法

headers = Dict()

url = 'https://www.baidu.com'

try:

proxies = None

response = requests.get(url, headers=headers, verify=False, proxies=None, timeout=3)

except:

# logdebug('requests failed one time')

try:

proxies = None

response = requests.get(url, headers=headers, verify=False, proxies=None, timeout=3)

except:

# logdebug('requests failed two time')

print('requests failed two time')

总结 ：代码比较冗余，重试try的次数越多，代码行数越多，但是打印日志比较方便

第二种方法

def requestDemo(url，):

headers = Dict()

trytimes = 3 # 重试的次数

for i in range(trytimes):

try:

proxies = None

response = requests.get(url, headers=headers, verify=False, proxies=None, timeout=3)

# 注意此处也可能是302等状态码

if response.status_code == 200:

break

except:

# logdebug(f'requests failed {i}time')

print(f'requests failed {i} time')

总结 ：遍历代码明显比第一个简化了很多，打印日志也方便

第三种方法

def requestDemo(url， times=1):

headers = Dict()

try:

proxies = None

response = requests.get(url, headers=headers, verify=False, proxies=None, timeout=3)

html = response.text()

# todo 此处处理代码正常逻辑

pass

return html

except:

# logdebug(f'requests failed {i}time')

trytimes = 3 # 重试的次数

if times < trytimes:

times += 1

return requestDemo(url， times)

return 'out of maxtimes'

总结 ：迭代 显得比较高大上，中间处理代码时有其它错误照样可以进行重试； 缺点 不太好理解，容易出错，另外try包含的内容过多时，对代码运行速度不利。

第四种方法

@retry(3) # 重试的次数 3

def requestDemo(url):

headers = Dict()

proxies = None

response = requests.get(url, headers=headers, verify=False, proxies=None, timeout=3)

html = response.text()

# todo 此处处理代码正常逻辑

pass

return html

def retry(times):

def wrapper(func):

def inner_wrapper(*args, **kwargs):

i = 0

while i < times:

try:

print(i)

return func(*args, **kwargs)

except:

# 此处打印日志 func.__name__ 为say函数

print("logdebug: {}()".format(func.__name__))

i += 1

return inner_wrapper

return wrapper

总结 ：装饰器优点 多种函数复用，使用十分方便

第五种方法

#!/usr/bin/python

# -*-coding='utf-8' -*-

import requests

import time

import json

from lxml import etree

import warnings

warnings.filterwarnings("ignore")

def get_xiaomi():

try:

# for n in range(5): # 重试5次

# print("第"+str(n)+"次")

for a in range(5): # 重试5次

print(a)

url = "https://www.mi.com/"

headers = {

"Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3",

"Accept-Encoding": "gzip, deflate, br",

"Accept-Language": "zh-CN,zh;q=0.9,en;q=0.8",

"Connection": "keep-alive",

# "Cookie": "xmuuid=XMGUEST-D80D9CE0-910B-11EA-8EE0-3131E8FF9940; Hm_lvt_c3e3e8b3ea48955284516b186acf0f4e=1588929065; XM_agreement=0; pageid=81190ccc4d52f577; lastsource=www.baidu.com; mstuid=1588929065187_5718; log_code=81190ccc4d52f577-e0f893c4337cbe4d|https%3A%2F%2Fwww.mi.com%2F; Hm_lpvt_c3e3e8b3ea48955284516b186acf0f4e=1588929099; mstz=||1156285732.7|||; xm_vistor=1588929065187_5718_1588929065187-1588929100964",

"Host": "www.mi.com",

"Upgrade-Insecure-Requests": "1",

"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.90 Safari/537.36"

}

response = requests.get(url,headers=headers,timeout=10,verify=False)

html = etree.HTML(response.text)

# print(html)

result = etree.tostring(html)

# print(result)

print(result.decode("utf-8"))

title = html.xpath('//head/title/text()')[0]

print("title==",title)

if "左左" in title:

# print(response.status_code)

# if response.status_code ==200:

break

return title

except:

result = "异常"

return result

if __name__ == '__main__':

print(get_xiaomi())

第六种方法

Python重试模块retrying

# 设置最大重试次数

@retry(stop_max_attempt_number=5)

def get_proxies(self):

r = requests.get('代理地址')

print('正在获取')

raise Exception("异常")

print('获取到最新代理 = %s' % r.text)

params = dict()

if r and r.status_code == 200:

proxy = str(r.content, encoding='utf-8')

params['http'] = 'http://' + proxy

params['https'] = 'https://' + proxy

# 设置方法的最大延迟时间，默认为100毫秒(是执行这个方法重试的总时间)

@retry(stop_max_attempt_number=5,stop_max_delay=50)

# 通过设置为50，我们会发现，任务并没有执行5次才结束！

# 添加每次方法执行之间的等待时间

@retry(stop_max_attempt_number=5,wait_fixed=2000)

# 随机的等待时间

@retry(stop_max_attempt_number=5,wait_random_min=100,wait_random_max=2000)

# 每调用一次增加固定时长

@retry(stop_max_attempt_number=5,wait_incrementing_increment=1000)

# 根据异常重试，先看个简单的例子

def retry_if_io_error(exception):

return isinstance(exception, IOError)

@retry(retry_on_exception=retry_if_io_error)

def read_a_file():

with open("file", "r") as f:

return f.read()

read_a_file函数如果抛出了异常，会去retry_on_exception指向的函数去判断返回的是True还是False，如果是True则运行指定的重试次数后，抛出异常，False的话直接抛出异常。

当时自己测试的时候网上一大堆抄来抄去的，意思是retry_on_exception指定一个函数，函数返回指定异常，会重试，不是异常会退出。真坑人啊！

来看看获取代理的应用(仅仅是为了测试retrying模块)