python请求模块重定向过多的问题

Question

I am trying to unshorten a list of roughly 150,000 t.co links and my code works for the most part, however, I have a bunch of t.co links that all redirect here , and for some reason requests is getting too many redirects.

def expand_url(url):
  s = requests.Session()
  try:
     r = s.head(url.rstrip(), allow_redirects=True,verify=False)
     return r.url.rstrip()
  except requests.exceptions.ConnectionError as e:
    print(e)

I tried using the line s.headers['User-Agent'] = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.131 Safari/537.36' as suggested in another thread. I also tried increasing the max re-directs and that didn't really help.

Here are some of the t.co links that are causing the issue:

https://t dot co/5FXvHY1Rbx

https://t dot co/L3Ytnz2916

Any suggestions on what to do?

Thanks

Answer 1

Set the max redirects times that you can bear.

http://docs.python-requests.org/en/master/api/#requests.Session.max_redirects

s = requests.Session()
s.max_redirects = 3

the reason why you fall into deadloop because WH did not support head method, it keeps sending you 302 Moved Temporarily . But actually you have redirected finished (from short url to WH). Try to use r.history to see all response

import requests

def expand_url(url):
  s = requests.Session()
  #s.allow_redirects = -1
  try:
     r = s.get(url.rstrip(),allow_redirects=3,verify=False)
     print([resp.url for resp in r.history])
     return r.url.rstrip()
  except requests.exceptions.ConnectionError as e:
    print(e)

print(expand_url("https://t<dot>co/5FXvHY1Rbx"))

Also you can write your own max_redirects.

import requests

def expand_url(url,times):
    s = requests.Session()
    times -= 1
    if not times:
        return url
    try:
        r = s.head(url.rstrip(),verify=False)
        location = r.headers.get("location").rstrip()
        if url.find(location) > 0:
            # in case redirect to same page
            return url 
        next_step = expand_url(location,times) if location else url
        return next_step
    except requests.exceptions.ConnectionError as e:
        print(e)

print(expand_url("https://t<dot>co/5FXvHY1Rbx",4))