So I've wondered for awhile what this is called, when you can link to a page that doesn't exist but use PHP (or maybe htaccess does it) to retrieve the URL and build a page based on it.

For instance, if I request "mywebsite.com/account/register", what would I have to do in order to manage the "register" part of this without actually having a folder called register?

I've seen websites do this, many blogging websites do this and store all kinds of data this way (/blog/2011/05/21/This_is_a_blog). What is it called? How is it done? Where should I go to read about this?

My theory would be to exploit a 404-error page, and turn around and give it a real page instead of an error. But I'm pretty sure that would still give the user a 404 error to their browser, which could cause problems. I don't know, just thinking out loud.

EDIT: I have many times before used GET methods to accomplish this, but it just seems clunky. I would like to use the directory method I tried to describe, and possibly still be able to use GET methods with it.

This kind of thing is called mod_rewrite. You use it in .htaccess files.

Something like (not tested)

RewriteEngine On
RewriteRule ^account/(.*)$ account.php?action=$1

as your .htaccess file would allow something like mywebsite.com/account/register to work, because it's actually showing you mywebsite.com/account.php?action=register. With this example, it's taking whatever you put after account/ and 'showing' (not redirecting) you action.php?(string). So mywebsite.com/account/blahblah would 'show' you account.php?action=blahblah.

To use this as a '404' page, you'd find ErrorDocument useful.

ErrorDocument 404 404.php

I'll also be moving this to the Website and Server Administration board, where it's more at home

Originally Posted by RadGH

My theory would be to exploit a 404-error page, and turn around and give it a real page instead of an error. But I'm pretty sure that would still give the user a 404 error to their browser, which could cause problems. I don't know, just thinking out loud.

EDIT: I have many times before used GET methods to accomplish this, but it just seems clunky. I would like to use the directory method I tried to describe, and possibly still be able to use GET methods with it.

I would not advise to use a 404 php page to do this kind of redirection.
Instead of "404 Header", use 301 permanent redirect or 302 ( Temporary Redirect)
Use an intermediate page as physicsguy has given to do this kind of redirection.

As vivekar said, my solution will not just redirect. It keeps the URL the same, and no redirection happens behind the scenes. The server just 'serves' a different page. You can also use ErrorDocument 503 for server errors. Any HTTP Status code can be ErrorDoument-ed, but obviously some, like 200 OK, shouldn't be

I would not advise to use a 404 php page to do this kind of redirection.
Instead of "404 Header",

Why not??

You can make the "404" page return any HTTP status code you want.