问题
How can you get the HTTP Referrer when redirected from another website, not when they click on a link since it would work for $_SERVER['HTTP_REFERER'], but it doesn't work when a user has been redirected a website and the referrer would be empty.
What will be the method to get the referrer?
回答1:
How can you get the HTTP Referrer when redirected from another website
You can't. If the redirection takes place under your control, you can add the original referer as a parameter, but if the external redirector doesn't do that, you have no way to get hold of the information.
回答2:
An example of how I did it. Say we have 3 pages, one calling the next.
page1.com -> page2.com -> page3.com.
in page2.com get the page1.com using:
$referrer = $_SERVER['HTTP_REFERER'];//=page1.com
when redirecting to page3, send $referrer as a GET parameter
page3.com?referrer=$referrer
in page3 read the $referrer from the get.
$initialReferrer = $_GET['referrer'];//=page1.com
来源：https://stackoverflow.com/questions/4043196/get-http-referrer-on-redirection