Find where a t.co link goes to

问题:

Given a t.co link, how can I find see where the link resolves? For example, if I have t.co/foo, I want a function or process that returns domain.com/bar.

回答1:

I would stay away from external APIs over which you have no control. That will simply introduce a dependency into your application that is a potential point of failure, and could cost you money to use.

CURL can do this quite nicely. Here's how I did it in PHP:

function unshorten_url($url) {
  $ch = curl_init($url);
  curl_setopt_array($ch, array(
    CURLOPT_FOLLOWLOCATION => TRUE,  // the magic sauce
    CURLOPT_RETURNTRANSFER => TRUE,
    CURLOPT_SSL_VERIFYHOST => FALSE, // suppress certain SSL errors
    CURLOPT_SSL_VERIFYPEER => FALSE, 
  ));
  curl_exec($ch); 
  return curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);
}

I'm sure this could be adapted to other languages or even scripted with the curl command on UNIXy systems.

http://jonathonhill.net/2012-05-18/unshorten-urls-with-php-and-curl/

回答2:

curl -s -o /dev/null --head -w "%{url_effective}\n" -L "https://t.co/6e7LFNBv"

• --head or -I only downloads HTTP headers
• -w or --write-out prints the specified string after the output
• -L or --location follows location headers

回答3:

If you want to do it from the command line, curl's verbose option comes to the rescue:

curl -v <url>

gives you the HTTP reply. For t.co it seems to give you an HTTP/301 reply (permanently moved). Then, there's a Location field, which points to the URL behind the shortened one.

回答4:

You could give unshorten.me a go. It has an API.

JSON:

http://api.unshort.me/?r=http://theshorturl.ly/28292&t=json

Would give you:

{
   "requestedURL":"http://theshorturl.ly/28292",
   "success":"true",
   "resolvedURL":"http://thefullurl.com/a-webiste/what-a-long-url"
}

回答5:

Here is a Python solution.

import urllib2

class HeadRequest(urllib2.Request):
    def get_method(self): return "HEAD"

def get_real(url):
    res = urllib2.urlopen(HeadRequest(url))
    return res.geturl()

Tested with an actual twitter t.co link:

url = "http://t.co/yla4TZys"
expanded = get_real(url)

expanded = http://twitter.com/shanselman/status/276958062156320768/photo/1

Wrap it up with a try-except and you are good to go.

回答6:

Another Python solution, this time relying on the requests module instead of urllib2 (and all the rest of those libraries):

#!/usr/bin/env python

import requests

shorturl = raw_input("Enter the shortened URL in its entirety: ")
r = requests.get(shorturl)

print("""
The shortened URL forwards to:

    %s
""" % r.url)

回答7:

Here is an R solution, ported from other answers in this thread, and from example() code of the RCurl Package:

unshorten_url <- function(uri){
        require(RCurl)
        if(RCurl::url.exists(uri)){
                # listCurlOptions()
                opts <- list(
                        followlocation = TRUE,  # resolve redirects
                        ssl.verifyhost = FALSE, # suppress certain SSL errors
                        ssl.verifypeer = FALSE, 
                        nobody = TRUE, # perform HEAD request
                        verbose = FALSE
                );
                curlhandle = getCurlHandle(.opts = opts)
                getURL(uri, curl = curlhandle)
                info <- getCurlInfo(curlhandle)
                rm(curlhandle)  # release the curlhandle!
                info$effective.url
        } else {
                # just return the url as-is
                uri
        }
}

回答8:

You may try this Java code. Such is a code use the HttpURLConnection owned by java. : http://www.srccodes.com/p/article/37/expand-shortened-link-using-java?fb_action_ids=1544985322486585&fb_action_types=og.likes

How this URL Expander will work? Make HttpURLConnection to the shortened url (say http://goo.gl/WT6eFw).

Extract the value of HTTP header field "Location". And this value is nothing but the expanded or actual destination URL.

Close the connection.

回答9:

Twitter expands the URL. Assume you have a single tweet using twitter API encoded as json file.

import json
urlInfo=[]

tweet=json.loads(tweet)
keyList=tweet.keys() # list of all posssible keys
tweet['entities'] # gives us values linked to entities 

You can observe that there is a value called 'urls' tweet['entities']['urls'] # gives values mapped to key urls

urlInfo=tweet['entities']['expanded_url'] # move it to a list
# iterating over the list.. gives shortened URL
# and expanded URL
for item in urlInfo:
  if "url" and "expanded_url" in urlInfo.keys():
    print(item["url"] + " "+item["expanded_url"])