Query string, populating a page from DB or file - php

Question

Is this facebook link populated fully from the DB? Or, is it a physical file with PHP in it? Just, how is this page called?
http://www.facebook.com/profile.php?id=49300915&sk=photos
They probably do something like:
if(isset($_GET['id'], $_GET['sk'])) {
mysql_query("SELECT info, photos FROM users WHERE id = '$id'");
}
I'm trying to ask, how do they include this page? Is it like Drupal / any CMS where the PHP and page is stored in the DB, or is it a physical file on the server? If the latter, what's the best way to get the file (case insensitive URL)?

Answer 1

I would have a class with a single method, which reads 'sk' and runs another method, depending on what it's value is.
One method would be 'photos' which would read 'id' and fetch a photo from the database. It would then run another method, displayPage, which will display a page from that data.
The displayPage method takes a "template" filename and an array of variables to provide to the template. It sets up a smarty object, provides the variables, and instructs it to display the template.
Inside the template, I'd include another template for the global header that's on every page in the site, then i'd have the html page content, using smarty to insert dynamic values, then include a global footer.
Note that i've simplified this system a lot. A real page like that would take me a week to write all the code, since a big website does a lot of stuff just to display a simple page (for example: find out if the logged in user actually has access to the page... i don't have access to the example one you gave).
<?php
// profile.php
class ProfileController
{
public function run()
{
if ($_GET['sk'] == 'photos')
return $this->photosPage();
}
protected function photosPage()
{
$id = (int)$_GET['id'];
$result = mysql_query("select * from photo where id = $id");
$photo = mysql_fetch_object($photo);
$this->displayPage('view-photo.tpl', array('photo' => $photo);
}
protected function displayPage($templateFile, $templateVariables)
{
$smarty = new Smarty();
foreach ($templateVariables as $variableName => $variableValue) {
$smarty->assign($variableName, $variableValue);
}
$smarty->display($templateFile);
}
}
$conntroller = new ProfileController();
$controller->run();
And the smarty code:
<!-- view-photo.tpl -->
{include file='head.tpl'}
<h1>View Photo {$photo->name|escape}</h1>
<img src="{$photo->src|escape}" width="{$photo->width|escape} height="{$photo->height|escape}>
{include file='foot.tpl'}