Proxy mode golang implementation

The proxy mode plays an important role in software development. It can indirectly connect the client with the object that actually handles the request, making the software designed in this way more flexible and scalable. In this article, we will implement a simple proxy pattern through golang language.

What is proxy mode?

The proxy pattern is a structural design pattern that adds a proxy layer between the proxy object and the actual object. The proxy layer can control access to the actual object. The purpose of proxy mode is to provide better access control and operational control to visitors.

In the proxy pattern, the proxy object has the same interface as the actual object, so they can be replaced with each other. At the same time, the proxy object also needs to implement some additional functions, which can be triggered before or after accessing the actual object.

The advantages of the proxy mode are:

1. The proxy object and the actual object are independent of each other and can be developed and tested independently.
2. The proxy layer can control access to the actual object.
3. The proxy layer can add, delete, and modify the processing of some requests.

The disadvantages of the proxy mode are:

1. The proxy mode increases the complexity of the code because additional proxy layers need to be added.
2. Proxy mode may increase the execution time of the code because additional operations are required.

How to implement proxy mode?

The implementation of the proxy pattern can be divided into two steps: first, create a proxy object, and then call the method of the actual object in the proxy object.

In golang, we can use interfaces to realize the connection between proxy objects and actual objects. The specific implementation steps are as follows:

1. Create interface

First, we need to create an interface, which contains the methods that the actual object needs to implement, and the methods that the proxy object needs to call. .

type Subject interface {
    Do() string
}

2. Create the actual object

Next, we create an actual object, which implements the interface method mentioned earlier.

type RealSubject struct {}

func (*RealSubject) Do() string {
    return "RealSubject"
}

3. Create proxy object

Next, we create a proxy object. This proxy object needs to have a pointer to the actual object so that it can call the actual object when needed. method.

type ProxySubject struct {
    realSubject *RealSubject
}

func (p *ProxySubject) Do() string {
    if p.realSubject == nil {
        p.realSubject = &RealSubject{}
    }

    result := "Pre-Handler
"
    result += p.realSubject.Do() + "
"
    result += "Post-Handler
"
    return result
}

In this proxy object, we first need to determine whether the actual object already exists. If it does not exist, we need to create it first. Then, we add a preprocessor before calling the method of the actual object, and a postprocessor after calling the method of the actual object.

4. Testing the proxy pattern

Finally, we write test code to verify whether the proxy pattern is implemented correctly.

func main() {
    var subject Subject
    subject = &ProxySubject{}

    result := subject.Do()
    fmt.Println(result)
}

In this test code, we create a proxy object and point it to the actual object. Then we call the Do() method of the proxy object. By observing the output results, we can conclude that the implementation of the proxy pattern is correct.

Summary

Through this article, we understand the definition and working principle of the proxy mode, and implement a simple proxy mode through golang language. In actual development, the proxy mode is widely used, such as caching proxy, security proxy, virtual proxy, etc. Therefore, an in-depth understanding of the usage and characteristics of the proxy pattern can enable us to better respond to the needs and challenges in actual development.

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