Description

Symfony Config component makes it possible to define semantic configuration, exposed to the end developer. This configuration is validated by rules you define, e.g. validating type (string, array, integer, boolean, etc.). Usually, once validated and processed, this semantic configuration is then mapped to internal key/value parameters stored in the ServiceContainer.

eZ Platform uses this for its core configuration, but adds another configuration level, the siteaccess. For each defined siteaccess, we need to be able to use the same configuration tree in order to define siteaccess-specific config. These settings then need to be mapped to siteaccess-aware internal parameters that you can retrieve via the ConfigResolver. For this, internal keys need to follow the format <namespace>.<scope>.<parameter_name>, namespace being specific to your app/bundle, scope being the siteaccess, siteaccess group, default or global, parameter_name being the actual setting identifier.

The goal of this feature is to make it easy to implement a siteaccess-aware semantic configuration and its mapping to internal config for any eZ bundle developer.

Solution

Semantic configuration parsing

An abstract Configuration class has been added, simplifying the way to add a siteaccess settings tree like the following:

Class FQN is eZ\Bundle\EzPublishCoreBundle\DependencyInjection\Configuration\SiteAccessAware\Configuration.
All you have to do is to extend it and use $this->generateScopeBaseNode():

Mapping to internal settings

Semantic configuration must always be mapped to internal key/value settings within the ServiceContainer. This is usually done in the DIC extension.

For siteaccess-aware settings, new ConfigurationProcessor and Contextualizer classes have been introduced to ease the process.

Merging hash values between scopes

When you define a hash as semantic config, you sometimes don't want the siteaccess settings to replace the default or group values, but enrich them by appending new entries. This is made possible by using $processor->mapConfigArray(), which needs to be called outside the closure (before or after), in order to be called only once.

Consider the following default config:

And then this semantic config:

What we want here is that keys defined for foo_setting are merged between default/group/siteaccess:

Merge from second level

In the example above, entries were merged in respect to the scope order of precedence. However, if we define the planets key forsa1, it will completely override the default value since the merge process is done at only 1 level.

You can add another level by passing ContextualizerInterface::MERGE_FROM_SECOND_LEVEL as an option (3rd argument) to$contextualizer->mapConfigArray().

Result of using ContextualizerInterface::MERGE_FROM_SECOND_LEVEL option:

Limitations

A few limitation exist with this scope hash merge:

• Semantic setting name and internal name will be the same (like foo_setting in the examples above).
• Applicable to first level semantic parameter only (i.e. settings right under the siteaccess name).
• Merge is not recursive. Only second level merge is possible by using ContextualizerInterface::MERGE_FROM_SECOND_LEVEL option.

Dedicated mapper object

Instead of passing a callable to $processor->mapConfig(), an instance of eZ\Bundle\EzPublishCoreBundle\DependencyInjection\Configuration\SiteAccessAware\ConfigurationMapperInterface can be passed.

This can be useful if you have a lot of configuration to map and don't want to pollute your DIC extension class (better for maintenance).

Merging hash values between scopes

As specified above, $contextualizer->mapConfigArray() is not to be used within the scope loop, like for simple values. When using a closure/callable, you usually call it before or after $processor->mapConfig(). For mapper objects, a dedicated interface can be used: HookableConfigurationMapperInterface, which defines 2 methods: preMap() and postMap().