How to use golang to implement http forwarding

In the Internet era, the design and application of Web service architecture has become a very common topic. For most applications today, the HTTP(S) protocol has become mainstream. Therefore, http reverse proxy and forwarding have become crucial in the web application architecture. This article will mainly introduce how to use golang to implement http forwarding.

1. Introduction to HTTP reverse proxy and forwarding

Reverse proxy and forwarding technology play a very important role in Web applications. The main function of a reverse proxy is to solve the load balancing problem and make requests more evenly distributed among multiple servers. In contrast, http forwarding is to transfer the client's request from one Web service to another Web service. HTTP forwarding can be used to solve a variety of problems, such as application overload, spam request filtering, redirection, etc.

2. Use golang to implement http forwarding

Golang can not only implement the reverse proxy function, but also implement http forwarding very conveniently. Below, we will introduce in detail how to use golang to implement http forwarding.

1. The first step is to establish an http server

First, establish an http server to listen for client requests. In this example, we will use golang's built-in http.Server library to build a simple server:

package main

import (
    "fmt"
    "log"
    "net/http"
)

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        log.Printf("Receive a request: %s %s%s", r.Method, r.Host, r.URL)
        w.Write([]byte("Hello, World!"))
    })

    log.Println("Listening on :8080")
    if err := http.ListenAndServe(":8080", nil); err != nil {
        log.Fatal(err)
    }
}

2. The second step is to set the forwarding address

Set the forwarding address to make http requests can be redirected to the corresponding address. Here you can use the http.NewRequest() method to generate a new http request, use the http.Transport() library to execute the request, and finally get the response to the request.

package main

import (
    "fmt"
    "log"
    "net/http"
    "net/http/httputil"
    "net/url"
)

func main() {
    addr, err := url.Parse("http://localhost:9090")
    if err != nil {
        log.Fatal(err)
    }

    proxy := httputil.NewSingleHostReverseProxy(addr)

    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        log.Printf("Receive a request: %s %s%s", r.Method, r.Host, r.URL)

        proxy.ServeHTTP(w, r)
    })

    log.Println("Listening on :8080")
    if err := http.ListenAndServe(":8080", nil); err != nil {
        log.Fatal(err)
    }
}

In this example, the http request is sent from the local port 8080 to port 9090 and is forwarded to the forwarding address where the addr object is located. Through a single host reverse proxy, elastic scaling needs can be achieved as the number of services changes.

3. Summary

A simple http forwarding server is implemented through golang's http library, http.Transport() library and http.NewRequest() method. High-performance languages ​​like golang are very handy for implementing such services, and provide developers with rich support. They can quickly and stably implement http forwarding and reverse proxy technology to meet the needs of various web applications today.

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