超过请求中URL的最大重试次数

Question

我正在尝试获取App Store > Business的内容

import requests
from lxml import html

page = requests.get("https://itunes.apple.com/in/genre/ios-business/id6000?mt=8")
tree = html.fromstring(page.text)

flist = []
plist = []
for i in range(0, 100):
    app = tree.xpath("//div[@class='column first']/ul/li/a/@href")
    ap = app[0]
    page1 = requests.get(ap)

当我用(0,2)尝试range时，它可以工作，但当我将range放入100s中时，它显示以下错误：

Traceback (most recent call last):
  File "/home/preetham/Desktop/eg.py", line 17, in <module>
    page1 = requests.get(ap)
  File "/usr/local/lib/python2.7/dist-packages/requests/api.py", line 55, in get
    return request('get', url, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/requests/api.py", line 44, in request
    return session.request(method=method, url=url, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/requests/sessions.py", line 383, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/local/lib/python2.7/dist-packages/requests/sessions.py", line 486, in send
    r = adapter.send(request, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/requests/adapters.py", line 378, in send
    raise ConnectionError(e)
requests.exceptions.ConnectionError: HTTPSConnectionPool(host='itunes.apple.com', port=443): Max retries exceeded with url: /in/app/adobe-reader/id469337564?mt=8 (Caused by <class 'socket.gaierror'>: [Errno -2] Name or service not known)

Answer 1

这里发生的事情是itunes服务器拒绝你的连接(你在短时间内从同一个ip地址发送了太多的请求)

重试次数超过了url: /in/app/adobe-reader/id469337564?mt=8

错误跟踪是误导性的，它应该类似于“无法建立连接，因为目标计算机主动拒绝了它”。

在Github的关于python.requests库有一个问题，请查看here

要解决这个问题(这不是一个问题，因为它会误导调试跟踪)，您应该捕获与连接相关的异常，如下所示：

try:
    page1 = requests.get(ap)
except requests.exceptions.ConnectionError:
    r.status_code = "Connection refused"

解决这个问题的另一种方法是，如果你使用足够的时间间隔向服务器发送请求，这可以通过python中的sleep(timeinsec)函数来实现(别忘了导入睡眠)

from time import sleep

所有的请求都是很棒的python库，希望它能解决你的问题。

Answer 2

只需使用requests'功能即可：

import requests
from requests.adapters import HTTPAdapter
from requests.packages.urllib3.util.retry import Retry


session = requests.Session()
retry = Retry(connect=3, backoff_factor=0.5)
adapter = HTTPAdapter(max_retries=retry)
session.mount('http://', adapter)
session.mount('https://', adapter)

session.get(url)

这将GET该URL并在requests.exceptions.ConnectionError的情况下重试3次。backoff_factor将有助于在两次尝试之间应用延迟，以避免在定期请求配额的情况下再次失败。

看看requests.packages.urllib3.util.retry.Retry，它有许多选项来简化重试。

Answer 3

就这么做，

粘贴以下代码以替换page = requests.get(url)

import time

page = ''
while page == '':
    try:
        page = requests.get(url)
        break
    except:
        print("Connection refused by the server..")
        print("Let me sleep for 5 seconds")
        print("ZZzzzz...")
        time.sleep(5)
        print("Was a nice sleep, now let me continue...")
        continue

不客气:)