README

This is one of those things that feels like it should already exist, but my cursory search of the interwebs failed to turn it up: an associative array akin to $_GLOBALS that is backed by a persistent datastore (MySQL in this case, because it's the only thing I ever use, because… lazy, I guess).

Usage

Update your composer.json file to include the following.

{
  "requires": {
    "battis/appmetadata": "~1.0"
  }
}

Handy hint: It always annoys me to have the overhead of documentation, unit tests, etc. for other projects included in mine. Per this answer on Stack Overflow, you can actually buy some small improvement by adding the --prefer-dist flag to composer install and composer update, as in:

composer install --prefer-dist

Create an AppMetadata object and treat it as you would any other associative array.

// instantiate a new mysqli database connection
$sql = new mysqli('localhost', 'root', 's00pers3kr3t', 'demo-db');

// first use (create database tables -- only needs to happen once!)
Battis\AppMetadata::prepareDatabase($sql);

// instantiate our metadata array
$metadata = new Battis\AppMetadata($sql, 'my-unique-app-key');

// store something into the database
$metadata['X'] = 'foobar';

// read something out of the database
echo $metadata['X']; // 'foobar'

// use one metadata value to derive another
$metadata['Y'] = '@X again'
echo $metadata['Y']; // 'foobar again';

// derived values update automagically
$metadata['X'] = 'xoxo';
echo $metadata['Y']; // 'xoxo again';

// remove something from the database
unset($metadata['X']);
echo $metadata['Y']; // '@X again', since no value X to derive from

Complete documentation is available within the package.