[PHP] Is there a referring page or URL variable?

Adnams Drinker · 19 Mar 2006 at 13:08

Is there any global variable - like the superglobals used for handling user input from forms - that holds the page or URL that a browser was showing before visiting the current page? I've had my head in my PHP books for the last ten minutes and haven't found anything yet - although I may well be looking for something that doesn't exist or is named entirely different to what I'm expecting, of course ...

What I'd like to do is have a link to a particular page on all the other pages in a site and show different content on that target page depending on which of the linking pages the user arrived from, or show a 'standard' page if the user arrives from outside the site - is there any simple way of doing that? I can just about grasp how to display that content using an 'if...then' or maybe even a 'case' conditional statement, but it's having a record of the referring page that's got me beat at the moment ...

Thanks in advance gents

paulsheff · 19 Mar 2006 at 13:27

http://uk2.php.net/manual/en/reserved.variables.php

You probably want HTTP_REFERER

$previous_page = $_SERVER['HTTP_REFERER'];

Adnams Drinker · 19 Mar 2006 at 13:38

Excellent - cheers for that ...

Although, according to the PHP site's documentation it says it 'can't be trusted' ... never mind, just have to try it and see ...

lookitsjonno · 19 Mar 2006 at 13:51

Adnams Drinker said:
Although, according to the PHP site's documentation it says it 'can't be trusted' ... never mind, just have to try it and see ...

it can be very easily spoofed and exploited using XSS so be careful.

Beansprout · 19 Mar 2006 at 13:52

In my experience about 90% of browsers send correct referral info

Edit: Ah yeah, the trust thing....don't trust anything, even $_SERVER

robmiller · 19 Mar 2006 at 14:54

Doesn't Opera hide it by default? I seem to remember it doing last time I checked, but that was about 7.x so I don't know if it's still the case.

Augmented · 19 Mar 2006 at 14:54

I tend to browse with it disabled

.
If I need to track internal referrals, I use a session variable or pass the referring page through the url with something like base64_encode(). I generally consider $_SERVER['HTTP_REFERER'] useless and unusable.