The Kernel
The Kernel is a central component that acts as the entry point and the core of the application. It manages the bootstrapping process, initializes various subsystems, and handles the request/response lifecycle. Here's an explanation of what the Kernel does in Symfony:
Bootstrap and Configuration: The Kernel is responsible for bootstrapping the application. During the bootstrapping process, it loads the configuration files. The configuration files include settings for services, routing, security, and other application-specific parameters.
Request Handling: When a request arrives at the application, the Kernel receives the request object and triggers the request handling process. It manages the routing system, matching the request to the appropriate controller and action. The Kernel delegates the request to the controller for further processing.
HTTP Response: The Kernel receives the data from the Controller, then returns an HTTP responses.
Termination: Once the request has been processed and the response has been generated, the Kernel performs any necessary cleanup tasks, finalizes the response, and sends it back to the client. It releases any allocated resources and gracefully terminates the application.