Go

Here is a basic code example for implementing the server side in Go. In this example, we will create a simple web server with the following functions.

GET / : Returns “Hello, World!”

GET /users : Returns a list of users in JSON format

POST /users : Adds a user (accepts JSON)

```go

package main

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

// User model
type User struct {
    ID   int    `json:"id"`
    Name string `json:"name"`
}

var users = []User{
    {ID: 1, Name: "Alice"},
    {ID: 2, Name: "Bob"},
}

// Handler: "/" → return Hello, World!
func helloHandler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "Hello, World!")
}

// Handler: "/users" (GET) → return user list
func getUsersHandler(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Content-Type", "application/json")
    json.NewEncoder(w).Encode(users)
}

// Handler: "/users" (POST) → add a new user
func createUserHandler(w http.ResponseWriter, r *http.Request) {
    if r.Method != http.MethodPost {
        http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
        return
    }

    var newUser User
    if err := json.NewDecoder(r.Body).Decode(&newUser); err != nil {
        http.Error(w, "Bad Request", http.StatusBadRequest)
        return
    }

    newUser.ID = len(users) + 1
    users = append(users, newUser)

    w.Header().Set("Content-Type", "application/json")
    w.WriteHeader(http.StatusCreated)
    json.NewEncoder(w).Encode(newUser)
}

func main() {
    http.HandleFunc("/", helloHandler)
    http.HandleFunc("/users", func(w http.ResponseWriter, r *http.Request) {
        if r.Method == http.MethodGet {
            getUsersHandler(w, r)
        } else if r.Method == http.MethodPost {
            createUserHandler(w, r)
        } else {
            http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
        }
    })

    fmt.Println("🚀 Server is running at http://localhost:8080")
    log.Fatal(http.ListenAndServe(":8080", nil))
}