Tip: An implementation solution for the plug-in mechanism in PHP.
The starting point of this article is my understanding of the plug-in mechanism and its implementation in PHP. This solution is only one of the implementation solutions of the plug-in mechanism in PHP. I will write it down and share it with you. Everyone is welcome to discuss it together.
Plug-in, or Plug-in, refers to a specific functional module (usually implemented by third-party developers). Its characteristics are: activate it when you need it, and disable/delete it when you do not need it; and whether it is activated or disabled, it will not affect the operation of the system's core module. That is to say, the plug-in is a non-invasive modular design, which realizes the loose coupling between core programs and plug-in programs. A typical example is the numerous third-party plug-ins in Wordpress, such as the Akimet plug-in, which is used to spam filter users' comments.
A robust plug-in mechanism, I think it must have the following characteristics:
Dynamic listening and loading of plug-ins (Lookup)
Dynamic triggering of plug-ins
The implementation of the above two points will not affect the operation of the core program.
To implement plug-ins in a program, the first thing we should think of is to define different hooks (hooks); "hooks" are a very vivid logical concept, and you can think of it as a plug-in trigger condition reserved by the system. Its logical principle is as follows: when the system executes a certain hook, it will determine whether the conditions of the hook are satisfied; if they are satisfied, it will first call the functions formulated by the hook, and then return to continue to execute the remaining programs; if they are not satisfied, just skip. This is a bit like the "interrupt protection" logic in assembly.
Some hooks may be designed in advance by the system, such as the comments Spam filtering hook I mentioned before, which has been designed by the core system developers into the comment processing logic; another type of hook may be customized by the user (designed by third-party developers) and usually exists in the presentation layer, such as an ordinary PHP form display page.
Maybe you feel that the above words are boring and make you sleepy; but to understand the code I wrote below, it is essential to understand the above principles.
The following is the core implementation of the plug-in mechanism in PHP, and the entire mechanism core is divided into three major parts:
A plug-in manager class: This is the core of the core. It is an application global global object. It has three main responsibilities:
Responsible for listening to all registered plugins and instantiating these plugin objects.
Responsible for registering all plugins.
When the hook condition is satisfied, the corresponding object method is triggered.
Functional implementation of plug-in: Most of this is done by third-party developers, but certain rules need to be followed. This rule is stipulated by the plug-in mechanism and varies depending on the plug-in mechanism. You will see this rule in the following code displayed.
Plugin trigger: that is, the trigger condition of the hook. Specifically, this is a small piece of code that is placed where you need the plugin implementation to trigger this hook.
The starting point of this article is my understanding of the plug-in mechanism and its implementation in PHP. This solution is only one of the implementation solutions of the plug-in mechanism in PHP. I will write it down and share it with you. Everyone is welcome to discuss it together.
Plug-in, or Plug-in, refers to a specific functional module (usually implemented by third-party developers). Its characteristics are: activate it when you need it, and disable/delete it when you do not need it; and whether it is activated or disabled, it will not affect the operation of the system's core module. That is to say, the plug-in is a non-invasive modular design, which realizes the loose coupling between core programs and plug-in programs. A typical example is the numerous third-party plug-ins in Wordpress, such as the Akimet plug-in, which is used to spam filter users' comments.
A robust plug-in mechanism, I think it must have the following characteristics:
Dynamic listening and loading of plug-ins (Lookup)
Dynamic triggering of plug-ins
The implementation of the above two points will not affect the operation of the core program.
To implement plug-ins in a program, the first thing we should think of is to define different hooks (hooks); "hooks" are a very vivid logical concept, and you can think of it as a plug-in trigger condition reserved by the system. Its logical principle is as follows: when the system executes a certain hook, it will determine whether the conditions of the hook are satisfied; if they are satisfied, it will first call the functions formulated by the hook, and then return to continue to execute the remaining programs; if they are not satisfied, just skip. This is a bit like the "interrupt protection" logic in assembly.
Some hooks may be designed in advance by the system, such as the comments Spam filtering hook I mentioned before, which has been designed by the core system developers into the comment processing logic; another type of hook may be customized by the user (designed by third-party developers) and usually exists in the presentation layer, such as an ordinary PHP form display page.
Maybe you feel that the above words are boring and make you sleepy; but to understand the code I wrote below, it is essential to understand the above principles.
The following is the core implementation of the plug-in mechanism in PHP, and the entire mechanism core is divided into three major parts:
A plug-in manager class: This is the core of the core. It is an application global global object. It has three main responsibilities:
Responsible for listening to all registered plugins and instantiating these plugin objects.
Responsible for registering all plugins.
When the hook condition is satisfied, the corresponding object method is triggered.
Functional implementation of plug-in: Most of this is done by third-party developers, but certain rules need to be followed. This rule is stipulated by the plug-in mechanism and varies depending on the plug-in mechanism. You will see this rule in the following code displayed.
Plugin trigger: that is, the trigger condition of the hook. Specifically, this is a small piece of code that is placed where you need the plugin implementation to trigger this hook.