Magento 2 - Best practices - Helper vs Model : Which one to get config values?

Question

I cannot seem to find an official information about what is the recommended way to retrieve configuration values in Magento 2.

I am searching for the recommended way to retrieve values from the configuration. Should it be from a Helper, or from a "Config" Model ?

In the Magento official documentation about best practices, they talk about avoiding to create helper classes, but it is more about static methods.

In the Magento code, we can see both are used, and even sometimes the config values are retrieved directly from other classes along with other code logic.

Here are some examples of both usages :

• Data Helpers :
  • \Magento\Wishlist\Helper\Data
  • \Magento\GoogleAdwords\Helper\Data
  • \Magento\Catalog\Helper\Data
  • \Magento\Directory\Helper\Data
  • \Magento\Payment\Helper\Data
• Config Models :
  • \Magento\CatalogImportExport\Model\Export\Product\Stock
  • \Magento\LoginAsCustomer\Model\Config
  • \Magento\CatalogInventory\Model\Configuration
  • \Magento\Weee\Model\Config
  • \Magento\Wishlist\Model\Config

What is your approach on this matter ? And why ?

I will share my own approach about it, and am open to comments to discuss about it.

Answer 1

Helper class usage

Here are some observations about Helper usage to retrieve config :

• They seem to be older, maybe it is a (sometimes bad) habit from Magento 1 with its data helpers, which has been kept at the begining of Magento 2.
• They often had the @api tag early in the Magento project. If I am not mistaken, @api tag means that the class is safe to use, as it should not have backward incompatible changes. This might be another reason why they are still here.
• They are often surrounded by additional code logic, which makes their purpose to other things than just "get the config".
• Helpers also look heavier, because they usually extend "AbstractHelper" which is requiring a lot of dependency injections and goes against the composite reuse principle (Composition over inheritance).

Config Model class usage

Here are some observations about Config Model usage to retrieve config :

• It looks like new config classes tend to be Models instead of Helpers, making it look like it is a preferred solution than the Helper.
• A Config Model has its own purpose about retrieving the configuration values from the database (or cache), which makes sense about what a model is supposed to do.
• They generaly come with their own Inteface, mapped in the di.xml file for an abstract implementation, which is a good thing.
• Using this kind of Model also seems lighter, because it favors composition over inheritence, which is a good practice.

Conclusion

With all those observations in mind, I would tend to use Models instead of Helpers.

It looks cleaner, lighter, and seems to follow more coding standards.