Framework Documentation - Registry Package

Overview

The Registry package provides an indexed key-value data store and an API for importing/exporting this data to several
formats.

Basic usage

The following demonstrates basic usage for storing and retrieving data from the store.

use Joomla\Registry\Registry;

$registry = new Registry;

// Set a value in the registry.
$registry->set('foo', 'bar');

// Get a value from the registry;
$value = $registry->get('foo');

Format Support

A Registry supports import/export in several formats, including:

• INI
• JSON (requires ext-json. As of PHP 8.0.0, the JSON extension is a core PHP extension, so it is always enabled.
• PHP
• XML
• YAML (requires Symfony's Yaml Component)

Export to file

To export the registry to a file, you first convert it to a string with the toString() method or typecast it (
i.e. (string) $registry).
The method accepts two parameters; a format type (defaulting to JSON) and an options array to pass to the formatter.
The result of this conversion can then be written to the filesystem.

use Joomla\Registry\Registry;

$registry = new Registry(['foo' => 'bar']);

// Dump the registry to a file
file_put_contents(__DIR__ . '/registry.json', $registry->toString());

Import from file

Likewise, a registry can be imported from a file by the loadFile() method. The method accepts three parameters; the
file name (required), a format type (defaulting to JSON), and an options array to pass to the formatter.

use Joomla\Registry\Registry;

$registry = new Registry;

// Load the previously dumped registry
$registry->loadFile(__DIR__ . '/registry.json');

XML Structure

Keep in mind that due to XML complexity, a special format must be kept when loading into Registry. By default, the
parent XML element should be named "registry" and all child elements should be named "node". The nodes should include
a "name" attribute, for the name of the value.
The nodes can be optionally filtered with a "type" attribute. Valid types are:

• array
• boolean
• double
• integer
• object (default)
• string

Example XML Document

<?xml version="1.0"?>
<registry>
    <node name="foo_1" type="string">bar</node>
    <node name="foo_2" type="boolean">1</node>
    <node name="foo_3" type="integer">42</node>
    <node name="foo_4" type="double">3.1415</node>
    <node name="foo_5" type="object">
        <node name="foo_5_a" type="string">value</node>
    </node>
    <node name="foo_6" type="array">
        <node name="foo_6_a" type="string">value</node>
    </node>
</registry>

The names of the XML import nodes can be customised using options. For example:

$registry = new Registry(
    [
        'name' => 'data',
        'nodeName' => 'value'
    ]
);

$registry->loadString('<data><value name="foo" type="string">bar</value></data>, 'xml');

Custom Formats

To load a custom format you must implement the Joomla\Registry\FormatInterface. This can then be loaded through
the Joomla\Registry\Factory
class. To load a custom format not provided by Joomla then you can load it by
using Factory::getFormat($type, $options). In this scenario
$type contains the format name, from which the class name is built.

By default, formats use the Joomla\Registry\Format namespace. For a custom format class, the format_namespace key
should be passed in the
$options array which contains the namespace that the format is in. This will also allow you to create a custom format
for one of the format
types provided by this package.

Accessing a Registry as an array

The Registry class implements ArrayAccess so the properties
of the registry can be accessed as an array. Consider the following examples:

use Joomla\Registry\Registry;

$registry = new Registry();

// Set a value in the registry.
$registry['foo'] = 'bar';

// Get a value from the registry;
$value = $registry['foo'];

// Check if a key in the registry is set.
if (isset($registry['foo']))
{
    echo 'Say bar.';
}