Configuration Extras

The configuration extras are the way to get varying configuration information.

There are two types of the configuration extras:

  • A configuration extra used to request additional configuration options for existing configuration sections. This extra is represented by Oro\Bundle\ApiBundle\Config\ConfigExtraInterface.
  • A configuration extra used to request additional configuration sections. This extra is represented by Oro\Bundle\ApiBundle\Config\ConfigExtraSectionInterface.

Both types of the configuration extras works in the following way:

  • The actions like get, get_list or delete register the configuration extras in the Context using the addConfigExtra method. All required extras must be registered before any of the getConfig, getConfigOf, getConfigOfFilters or getConfigOfSorters methods of the Context is called. Typically the registration happens in processors from initialize group. For example InitializeConfigExtras.
  • When a processor needs a configuration, it calls the appropriate method of the Context. For example getConfig, getConfigOf, getConfigOfFilters or getConfigOfSorters. The first call of any of these methods causes loading of the configuration.
  • The loading of the configuration is performed by the get_config action. Any of processors registered for this action can check which configuration data is requested. There are two ways of how a processor can find out which configuration data is requested. The first one is to use the processor conditions. The second one is to use the hasExtra method of the ConfigContext.

For more details on the config structure, sections, properties, etc., see the Configuration Reference.

ConfigExtraInterface

The ConfigExtraInterface has the following methods:

  • getName - Returns a string which is used as unique identifier of configuration data.
  • getCacheKeyPart - Returns a string to add to a cache key used by the configuration providers. In most cases this method returns the same value as the getName method. However, more complicated extras can build the cache key part based on other properties, e.g. MaxRelatedEntitiesConfigExtra.
  • configureContext - Adds additional values into the ConfigContext. For example, the mentioned above MaxRelatedEntitiesConfigExtra adds the maximum number of related entities into the context of the get_config action and this value is used by the SetMaxRelatedEntities processor to make necessary modifications to the configuration.
  • isPropagable - Indicates whether this config extra should be used when a configuration of related entities is built. For example, DescriptionsConfigExtra is propagable and and so we will get human-readable descriptions of the main entity and all the related entities. When this extra is not propagable, only the descriptions of the main entity are returned.

ConfigExtraSectionInterface

The ConfigExtraSectionInterface extends ConfigExtraInterface and has one additional method:

  • getConfigType - Returns the configuration type that should be loaded into the corresponding section. The ConfigLoaderFactory uses the return value of this method to find the appropriate loader.

There is a list of existing configuration extras that implement this interface:

Example of configuration extra

The DescriptionsConfigExtra is used to request human-readable descriptions of entities and their fields:

<?php

namespace Oro\Bundle\ApiBundle\Config;

use Oro\Bundle\ApiBundle\Processor\Config\ConfigContext;

class DescriptionsConfigExtra implements ConfigExtraInterface
{
    const NAME = 'descriptions';

    public function getName()
    {
        return self::NAME;
    }

    public function configureContext(ConfigContext $context)
    {
        // no modifications of the ConfigContext are required
    }

    public function isPropagable()
    {
        return true;
    }

    public function getCacheKeyPart()
    {
        return self::NAME;
    }
}

Usually configuration extras are added to the context by the InitializeConfigExtras processors which belong to the initialize group, e.g., the InitializeConfigExtras processor for the get action. However, the data API documentation requires human-readable descriptions. Therefore, DescriptionsConfigExtra is added by RestDocHandler.

The CompleteDescriptions processor adds descriptions for entity, fields, and filters. This processor is registered as a service in processors.get_config.yml. Please note, the processor tag contains the extra attribute with descriptions&definition value. This means that the processor will be executed only if the extra configuration (in this case description and definition) were requested. For more details see processor conditions.