How to change different configuration settings between environments in PHP?

Question

I have a a few php files which I call via AJAX calls. They all have a URL to my config.php. Now I've the problem that I always have to change the URLs to that config file by hand when I deploy a new version on my server.

Local Path:

define('__ROOT__', $_SERVER["DOCUMENT_ROOT"].'/mywebsite');

Server Path:

define('__ROOT__', $_SERVER["DOCUMENT_ROOT"].'/../dev.my-website.tld/Modules/');

I want to track changes in all of these PHP files. I'm searching for a solution to automatically change this path.

E.g. This is my current workflow:

Local Environment:

• (path version A)
• do changes in the code
• git add, git commit, git merge, git push to my server

Server:

• git reset --hard
• change path to version B

Answer 1

You are trying to run different code bases between development and live, which is not recommended -- they should be identical. The way I tackle this is to use an environment variable to specify which of several config files should be loaded.

In my Apache vhost I do something like this:

SetEnv ENVIRONMENT_NAME local

And then I use a function to read the environment name:

function getEnvironmentName()
{
    $envKeyName = 'ENVIRONMENT_NAME';
    $envName = isset($_SERVER[$envKeyName]) ? $_SERVER[$envKeyName] : null;
    if (!$envName)
    {
        throw new \Exception('No environment name found, cannot proceed');
    }

    return $envName;
}

That environment name can then be used in a config file to include, or to retrieve values from a single array keyed on environment.

I often keep environment-specific settings in a folder called configs/, but you can store them anywhere it makes sense in your app. So for example you could have this file:

// This is /configs/local.php

return array(
    'path' => '/mywebsite',
    // As many key-values as you want
);

You can then do this (assuming your front controller is one level deep in your project, e.g. in /web/index.php):

$root = dirname(__DIR__);
$config = include($root . '/configs/' . getEnvironmentName() . '.php');

You'll then have access to the appropriate per-environment settings in $config.

Answer 2

A pure git way to achieve this would be filters. Filters are quite cool but often overlooked. Think of filters as a git way of keyword expansion that you could fully control.

The checked in version of your file would for example look like this:

define('__ROOT__', 'MUST_BE_REPLACED_BY_SMUDGE');

Then set up two filters:

• on your local machine, you'd set up a smudge filter that replaces
  'MUST_BE_REPLACED_BY_SMUDGE'
  with
  $_SERVER["DOCUMENT_ROOT"].'/mywebsite'

• on your server, you'd set up a smudge filter that replaces
  'MUST_BE_REPLACED_BY_SMUDGE'
  with
  $_SERVER["DOCUMENT_ROOT"].'/../dev.my-website.tld/Modules/'

• on both machines, the clean filter would restore the line to be
  define('__ROOT__', 'MUST_BE_REPLACED_BY_SMUDGE');

Further information about filters could be found in this answer and in the Git Book.