How to identify if referrer is a 301 redirect

Question

I'm implementing a slug system for my website at the moment. I plan to redirect invalid slugs to the correct on that is stored in the database. E.g.

http://example.com/11/wrong-slug

Hit db, check if 11's slug is wrong-slug if not do 301 redirect

http://example.com/11/right-slug

Detect 301 and inform user that they followed an invalid link

Is it possible to identify the 301 redirect preferably using PHP so I can ask the user to update there bookmark etc.

Thanks, Jamie.

Answer 1

Several solutions come to mind:

1. You could try with get_headers() ah no, it dispatches a request to the URL, which is not what you want

2. Since you are redirecting and testing for the redirect from the same machine anyway, you could simply write a message about the wrong slug into the user's session and display it the next time the view template is rendered. Many frameworks have a flash messenger component, that allow you do that easily, e.g. with Zend Framework you would use the following code in your controller action

   $flashMessenger = $this->_helper->getHelper('FlashMessenger'); $flashMessenger->addMessage('We did something in the last request');

3. Instead of redirecting immediately when a wrong slug is found, you just render a View template that tells your user about the wrong slug and then use a meta or javascript redirect from the template. Optionally, you'd also write a plain link with the right slug to the template.

4. And finally, you could also inject a custom header into the redirect via header(), which can then be read from your script. won't work either, because they will be lost once the browser got the redirect from the server