Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

package main

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

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

var users = []User{
    {1, "Alice"},
    {2, "Bob"},
    {3, "Carol"},
}

func listUsers(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Content-Type", "application/json")
    json.NewEncoder(w).Encode(users)
}

func getUser(w http.ResponseWriter, r *http.Request) {
    idStr := r.PathValue("id") // Go 1.22+
    id, err := strconv.Atoi(idStr)
    if err != nil {
        http.Error(w, "invalid id", http.StatusBadRequest)
        return
    }
    for _, u := range users {
        if u.ID == id {
            w.Header().Set("Content-Type", "application/json")
            json.NewEncoder(w).Encode(u)
            return
        }
    }
    http.NotFound(w, r)
}

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("GET /users", listUsers)
    mux.HandleFunc("GET /users/{id}", getUser)
    mux.HandleFunc("GET /health", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintln(w, `{"status":"ok"}`)
    })

addr := ":8080"
    log.Printf("listening on %s
", addr)
    if err := http.ListenAndServe(addr, mux); err != nil {
        log.Fatal(err)
    }
}