There are several locations where configuration files may be placed. All of them are scanned by the configuration manager during initialization and cascaded into a single configuration tree. The following locations exist (listed in the order they are loaded):

The format of FLOW3's configuration files is YAML. YAML is a well-readable format which is especially well-suited for defining configuration. The full specification among with many examples can be found on the YAML website. All important parts of the YAML specification are supported by the parser used by FLOW3, it might happen though that some exotic features won't have the desired effect. At best you look at the configuration files which come with the FLOW3 distribution for getting more examples.

#                                                                        #
# Settings Configuration for the TYPO3CR Package                         #
#                                                                        #

# $Id: Settings.yaml 1234 2009-01-01 12:00:00Z foobar $

TYPO3CR:

  # The storage backend configuration
  storage:
    backend: 'F3\TYPO3CR\Storage\Backend\Pdo'
    backendOptions:
      dataSourceName: 'sqlite:%FLOW3_PATH_DATA%Persistent/TYPO3CR.db'
      username: 
      password: 

  # The indexing/search backend configuration
  search:
    backend: 'F3\TYPO3CR\Storage\Search\Lucene'
    backendOptions:
      indexLocation: '%FLOW3_PATH_DATA%Persistent/Index/'

Sometimes it is necessary to use values in your configuration files which are defined as PHP constants.These values can be included by special markers which are replaced by the actual value during parse time. The format is %CONSTANT_NAME% where CONSTANT_NAME is the name of a PHP constant. Note that the constant name must be all uppercase. Some examples:

What you usually want to work with are settings. The following example demonstrates how to let FLOW3 inject the settings of a classes' package and output some option value:

namespace F3\Demo;

class SomeClass {

	/**
	 * @var array
	 */
	protected $settings;

	/**
	 * Inject the settings
	 *
	 * @param array $settings
	 * @return void
	 */
	public function injectSettings(array $settings) {
		$this->settings = $settings;
	}

	/**
	 * Outputs some settings of the "Demo" package.
	 *
	 * @return void
	 */
	public function theMethod() {
		echo ($this->settings['administrator']['name']);
		echo ($this->settings['administrator']['email']);
	}
}

There might be situations in which you don't want to get the settings injected. The Configuration Manager provides an API for these cases as you can see in the next example.

namespace F3\Demo;

class SomeClass {

	/**
	 * @var \F3\FLOW3\Configuration\ConfigurationManager
 	 */
	protected $configurationManager;

	/**
	 * Inject the Configuration Manager
	 *
	 * @param \F3\FLOW3\Configuration\ConfigurationManager $configurationManager
	 * @return void
	 */
	public function injectConfigurationManager(\F3\FLOW3\Configuration\ConfigurationManager ⏎
    $configurationManager) {
		$this->configurationManager = $configurationManager;
	}

	/**
	 * Output some settings of the Demo package
	 *
	 * @return void
	 */
	public function theMethod() {
		$mySettings = $this->configurationManager->getConfiguration(\F3\FLOW3\Configuration\ConfigurationManager::CONFIGURATION_TYPE_SETTINGS, 'Demo');
		echo ($mySettings->administrator->name);
		echo ($mySettings->administrator->email);
	}
}

Although infrequently necessary, it is also possible to retrieve options of the more special configuration types. The configuration manager provides a method called getConfiguration() for this purpose. The result this method returns depends on the actual configuration type you are requesting.

Bottom line is that you should be highly aware of what you're doing when working with these special options and that they might change in a later version of FLOW3. Usually there are much better ways to get the desired information (e.g. ask the Object Manager for object configuration).