How to detect 301 redirect using php

Question

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How to identify if referrer is a 301 redirect

Using htaccess Im doing a 301 redirect to redirect old urls to the new urls, the issue is the url contains the id that is stored in the db. But I have a new db with new ids so now when the old url redirects to the new url a different record loads on the page. So what I did was store the old ids along with the new ids so I know what old id belongs to the new id. However how can I detect someone is trying to access the old url? Is there a way in php to detect the person coming to the page is being redirected via a 301? I dont want to add anything new to the url due to SEO reasons so I really need to know if I can detect if they came to this page via 301 redirect. Hope this makes sense.

you can work with $_SERVER['HTTP_REFERER']; but this is not really reliable — Florian Kasper, Dec 08 '12 at 19:50
@FlorianKasper: even if `HTTP_REFERER` is set it will point to the page where the link was clicked, not the script that sent 301. Such is the case with 301s. — Salman A, Dec 08 '12 at 19:52
http://stackoverflow.com/questions/9496522/php-code-to-determine-if-a-user-was-301-redirected-to-my-site/9496657#9496657 — Salman A, Dec 08 '12 at 19:54

score 2 · Accepted Answer · answered Dec 08 '12 at 19:54

2

Add another parameter to the redirect like redirect=true, check the param to let your app know it was a redirect, start the session, and then redirect again to the final, unaltered url, compare the session to know, that a user came from the redirected url.

Or do what Salman says, use a canonical url.

answered Dec 08 '12 at 19:54

markus

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As mentioned in my original notes I cant due to SEO reasons. – John Dec 08 '12 at 19:55
That's why you redirect again! For the SEO reasons, the final url will have no additional param but your app will know. – markus Dec 08 '12 at 19:56
4

You can tell search engines about your canonical URL via ``. Use this to tell search engines that `?redirect=true` can be ignored. – Salman A Dec 08 '12 at 19:57
What's the point of the session? Besides that this is exactly the same concept as my answer. – Mike Dec 08 '12 at 20:01
The point of the session is to actually transfer the knowledge about the redirect into the app. Otherwise it's just another redirect and can come from whoever. – markus Dec 08 '12 at 20:33
@markus-tharkun I gotcha. I assumed that the point of letting the application know that it was a redirect was to pull the correct product from the database. – Mike Dec 08 '12 at 21:27

score 0 · Answer 2 · answered Dec 08 '12 at 19:51

0

A script won't know that something has been redirected to it or not. Instead of redirecting to, say index.php?id=12345 add an intermediate redirect where you can determine the proper URL.

First, redirect in your .htaccess using a temporary variable name, e.g. index.php?oldid=12345 and then in that script do:

if (isset($_POST['oldid'])) {
    $id = fetch_new_id();
    header("Location: index.php?id=$id");
}

answered Dec 08 '12 at 19:51

Mike

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how does this affect SEO and passing the "juice" via 301 redirects twice? As I would need to do 2 301 redirects in your suggestion. – John Dec 08 '12 at 19:54
An extra 301 redirect isn't going to affect your SEO at all. – Mike Dec 08 '12 at 19:57

score 0 · Answer 3 · answered Dec 08 '12 at 19:53

0

i think you cannot detect http status that was set, but using .htaccess you can add additional variable to redirected urls or rename id to another variable name.

answered Dec 08 '12 at 19:53

Константин Рекунов

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score 0 · Answer 4 · answered Dec 09 '12 at 00:49

0

Why not handle all the old URLs via php plus a rewrite and make the code directly 301 redirect to the new URL with the new id?

answered Dec 09 '12 at 00:49

Tony McCreath

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How to detect 301 redirect using php

4 Answers4