Creating middleware

One of the great things about JsonMapper is that it is highly extensible. If the out-of-the-box middleware don't meet your specific needs, it's very easy to create your own custom middleware to handle your specific use case.

To create your own middleware, you need to define a class that implements JsonMapper\Middleware\MiddlewareInterface. The easiest way to do so is to extend JsonMapper\Middleware\AbstractMiddleware, which leaves you a single method to implement: handle(). It receives the JSON data, the object being mapped, the property map built so far, and the mapper itself, and amends them in place rather than returning anything.

Here's an example of how to create a simple middleware that converts a JSON string to an array before it's mapped to a PHP class:

use JsonMapper\Middleware\AbstractMiddleware;
use JsonMapper\JsonMapperInterface;
use JsonMapper\ValueObjects\PropertyMap;
use JsonMapper\Wrapper\ObjectWrapper;
 
class CustomMiddleware extends AbstractMiddleware
{
    public function handle(
        \stdClass $json,
        ObjectWrapper $object,
        PropertyMap $propertyMap,
        JsonMapperInterface $mapper
    ): void
    {
        // Custom logic goes here.
    }
}

Once you've created your custom middleware, you can add it to the middleware stack with the builder's withMiddleware method, like this:

$mapper = \JsonMapper\JsonMapperBuilder::new()
    ->withDocBlockAnnotationsMiddleware()
    ->withTypedPropertiesMiddleware()
    ->withMiddleware(new CustomMiddleware())
    ->build();