Do you know what AOP is?

foreword

AOP full name Aspect Oriented Programming , meaning: Aspect Oriented Programming.

Why is there this article? Because watching Laravel in Pipeline design , we found Pipeline is based AOP an idea implementation.

Speaking of AOP , we have to talk about OOP , what is their relationship and what is the difference?

The difference between AOP and OOP

OOP We all know that the whole process is Object Oriented Programming , which means: object-oriented programming.

First of all, we need to know that AOP and OOP are not in opposition to each other. We can regard AOP OOP . This is the best way to make up for the shortcomings of the other. The combination of the two is the best.

OOP is for business entity and its attributes and behavior abstract encapsulation , for example: user modules, order modules, etc., this is not difficult to understand.

AOP is extracted for the business section, it faced certain process step or phase , in order to achieve low coupling between portions of the logic processing isolation , for example: log Records, authorization verification, etc.

For example, it is easy to understand. If you simply use OOP , you need to perform authorization verification and logging in the log module and order module. Do you want to add code for permission verification and logging before each method? So what if you need to log before and after every method?

At this time, if you use AOP , you can use the proxy to complete these repeated operations, you can not add code for authorization verification and logging before each method, and reduce the coupling between each part.

What can AOP do

In addition to the permission verification and logging mentioned above, AOP can also do data encryption and decryption, request and response data specification...

As long as it is not related to the specific business, and at the same time the business is concerned, then AOP can be used to extract these concerns and maintain them uniformly to improve the reusability of the code.

above business focus sound familiar... In fact, our commonly used 161dab939ba0ec routing middleware is an implementation based on the AOP

An implementation of AOP

Example: Laravel routing middleware in .

/**
 * Send the given request through the middleware / router.
 *
 * @param  \Illuminate\Http\Request  $request
 * @return \Illuminate\Http\Response
 */
protected function sendRequestThroughRouter($request)
{
    $this->app->instance('request', $request);

    Facade::clearResolvedInstance('request');

    $this->bootstrap();

    return (new Pipeline($this->app))
                ->send($request)
                ->through($this->app->shouldSkipMiddleware() ? [] : $this->middleware)
                ->then($this->dispatchToRouter());
}

By the above-described code can be found in the middleware necessary configuration through() process performed after execution then method.

The above code is used in the routing middleware, of course, it can also be used in other places, such as controller , it can be written like this:

// 示例代码

$pipes = [
    LoggingPipeline::class,   // 日志记录
    PermitPipeline::class,    // 权限验证
];

return app(Pipeline::class)
    ->send($request->all())
    ->through($pipes)
    ->then(function ($content) {
        return $content;
    });

The above only Laravel one implementation, of course, in PHP other frame also has a similar implementation, for example: Yii , ThinkPHP like.

AOP is just an idea, of course, there are other language implementations, such as: Golang and Java and so on.

Recommended reading

• Programming is an idea, not a code
• do business system research and development seriously and responsibly?