Introduction to the OpenCart framework operation process

Introduction to framework operation process

What happened to such a get request http://hostname/index.php?route=common/home?

1. Start executing the entry file index.php.

2. require_once(DIR_SYSTEM . 'startup.php');

Do some PHP configuration and load some class declarations, including the system main framework file (file under system/engine), some necessary helpers and libraries.

The main framework files of the system include:

　Registry: Save global variables, using the registrant mode. The base class of the controller, the base class of the model, the loader, etc. all save references to this object. It is not written in singleton mode, maybe because I want to make this class more versatile. You can create an additional registry instance and share it among several objects;

　Loader: used to dynamically load other files, providing the ability to load model, library, helper, database, config and language. Loading model and database will create a new instance and save it into the registry object. For data classes, only one instance is needed ;

　Controller, model: the base class of the controller and the base class of the data model class, the function is very simple;

Action: A request from the user, corresponding to an action, initialize the action with the request query parameter route;

　front: request distributor, dispatch action;

The following framework process will introduce what these classes do specifically.

3. Initialize the registry, loader, db, error handling function and some libraries used later, and save the references of these library instances into the registry object, and then provide them for direct use by the controller and model objects.

4. Initialize the front and action objects. At this time, the action is constructed from the value "common/home" of the query parameter route in the URL. The action parses out the corresponding controller file name, class name, and the method and parameters to be executed.

5. The front dispatches the action. According to the class name attribute of the action, new the controller object ControllerCommonHome (catalog/controller/common/home.php), initialize it with the registry, and then use the action method index (if no method is passed, the default is index ) and parameter attributes (none), execute ControllerCommonHome->index(), in the index method, process business logic, load templates, etc., and finally save the content to be output to the browser in the response. Note that the controller's magic methods __get and __set both take and assign values ​​​​from registry objects, so you can use objects saved in the registry just like using your own attributes. For example: $this->load->model('catalog/category'), calls the model method of the loader object.

6. The last line in index.php, $response->output(), returns the content to the user.

At this point, the framework has processed the user's request.

See also an opencart plug-in written by me, opencart Baidu login and Baidu wallet payment plug-in, responsive and adaptable to pc/mobile