Finding paths with PHP

I’m worling on web apps and need to do two things that require knowing where you are in the file hierarchy. When a user clicks on an app that I am charging for, I need them to log in. But when they are done with the login, I want to send them back to the app that they want to use. So what I do is use the server variable PHP_SELF to get the complete URL of the file they clicked on. I need to make sure that there is a active session and then add a session variable, calledFileName. Once the user has finished the login or signup process, I redirect them to the app they want to use.

// if user is not logged in, restrict what they can do
$calledFileName = $_SERVER['PHP_SELF'];
$_SESSION['calledFileName'] = $calledFileName;

When they hit the submit button, I call a bunch of validation code and reload the form page. Before any HTML is sent, I check to see how they got to the login/signup page and then send them to the appropriate page.

$startlocation = $_SESSION['calledFileName'];
if ($passwordIsValid) {
  if ( strlen($startlocation) > 0 ) {
    header("Location: $startlocation");
  } else {
    header("Location: /exercises/overview.php");

Most of my web pages have been fairly simple so I the past I have done live editing to fix mistakes or update text. When I converted one of my sites to responsive HTML5, I created a beta subdomain, e.g., and did all the changes there and them rsynced the whole thing to the original site. That worked because I used hard coded paths and one global variable for the site domain name.

I have active users of the exercises and I don’t want to break things for them so live editing is out. I am developing on a beta subdomain, but I want to be extra careful that nothing breaks. I also want to make the site robust enough that I can easily move it to another domain if someone wants to license the apps. So rather than absolute paths, I’ve been using relative paths. This mostly works, but there are some instances where I want to use the same file in different locations and the images that file calls need a fixed path.

I have been using git to sync the files and it seems to work as well as rsync. Because I want to be extra careful about breaking the site for active users, I created a test folder for the exercises on the live site, exercises_test, and synched it with the beta content. Then renamed it when I was sure everything was working. The relative paths work fine but hard coded paths won’t work in this case since the files are not located in /exercises/folder but are located in /exercises_test/folder. One case where it doesn’t work is when I redirect the user to the login page if they haven’t yet logged in. In this case, I use another server variable and grab the root directory. The variable looks like this: /exercises_test/apptype/index.php so when I grab the root folder with explode, the first element of the array is empty, so I need to get the second element of the array.

if ($_SESSION['userID'] == '') {
  header("HTTP/1.1 302 Found");
  $curRoot = explode("/", $_SERVER['REQUEST_URI']);
    header("Location: /$curRoot[1]/login.php");

I can use this same trick for path names in my header files.

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