Does golang have an interceptor?

Golang does not provide built-in interceptors, but you can use language features such as functions, interfaces, and structures to achieve similar functions. The following are commonly used interceptor implementation methods: 1. Functional interceptor, through the request Call functions before and after reaching the handler to implement the interceptor; 2. Interface interceptor, implement the interceptor by defining an interface and implementing the interface before and after the target handler. This method can make the interceptor more Flexible, different interceptor logic can be implemented on different interfaces.

#The operating environment of this article: Windows 10 system, go1.20 version, dell g3 computer.

Interceptor is a common programming pattern, and there are corresponding mechanisms in the Go programming language to implement interceptors. In this article, we will explore the concept of interceptors in Golang and how to use and implement them.

What is an interceptor?

An interceptor is a middleware used to intercept requests and responses, allowing us to perform certain operations before the request reaches the target handler and before the response is sent to the client. Interceptors are often used to handle common logic such as logging, authentication, error handling, etc., thereby reducing code duplication.

Interceptor in Go

In Golang, there is no special interceptor mechanism, but we can use language features such as functions, interfaces and structures to implement it. Similar functionality. Here are some common interceptor patterns implemented in Go.

1. Functional interceptor:

Interceptors are implemented by calling functions before and after the request reaches the handler. We can define a function type to represent the interceptor and then pass it to the concrete function as a parameter of the handler.

type InterceptorFunc func http.Handler http.Handler

Sample code:

func Logger(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
log.Printf("[%s] %s", r.Method, r.URL.Path)
next.ServeHTTP(w, r)
})
}

2. Interface interceptor:

Implement the interceptor by defining an interface and implementing the interface before and after the target handler . This approach can make the interceptor more flexible and can implement different interceptor logic on different interfaces.

type Interceptor interface {
Before(next http.Handler) http.Handler
After(next http.Handler) http.Handler
}

Sample code:

type LoggerInterceptor struct{}
func (l *LoggerInterceptor) Before(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
log.Printf("[%s] %s", r.Method, r.URL.Path)
next.ServeHTTP(w, r)
})
}
func (l *LoggerInterceptor) After(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
next.ServeHTTP(w, r)
log.Printf("Response sent.")
})
}

Using interceptors

Now that we have seen how to implement interceptors in Golang, let’s see How to use them. Let's say we have an HTTP server and want to log requests before processing them. We can use the Logger function or LoggerInterceptor defined in the previous example code to implement the interceptor.

func main() {
// 创建一个HTTP服务器实例
server := http.NewServeMux()
// 注册路由处理程序
server.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
fmt.Fprintf(w, "Hello, World!")
})
// 使用拦截器包装处理程序
serverWithInterceptor := Logger(server)
// 启动服务器
log.Fatal(http.ListenAndServe(":8080", serverWithInterceptor))
}

Advantages and applicable scenarios of interceptors

Interceptors provide a reusable, modular way to handle common logic. They allow us to separate common functionality from a specific handler and apply it to multiple handlers, making the code maintainable and extensible. Interceptors are suitable for various scenarios, including authentication, authorization, caching, logging, error handling, etc.

Conclusion:

Although Golang itself does not provide a built-in interceptor mechanism, we can use language features such as functions, interfaces, and structures to achieve similar functions. Functional and interface interceptors are common ways to implement the interceptor pattern. By using interceptors, we can perform custom actions before the request reaches the target handler and before the response is sent to the client, and improve code reusability and maintainability.

The above is the detailed content of Does golang have an interceptor?. For more information, please follow other related articles on the PHP Chinese website!