main.go

package main

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

	"github.com/gorilla/mux"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
)

var DB *gorm.DB
var err error

//used the local database her i.e "mysql"
//passed the url to connect to the data base
//as I'm using mysql db,we have installed mysql driver here
const DNS = "root:admin@tcp(127.0.0.1:3306)/godb?charset=utf8mb4&parseTime=True&loc=Local"

type User struct {
	gorm.Model
	FirstName string `json:"firstname"`
	LastName  string `json:"lastname"`
	Email     string `json:"email"`
}

func InitialMigration() {
	DB, err = gorm.Open(mysql.Open(DNS), &gorm.Config{})
	if err != nil {
		fmt.Println(err.Error())
		panic("Cannot connect to DB")
	}
	DB.AutoMigrate(&User{})
}

func GetUsers(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	var users []User
	DB.Find(&users)
	json.NewEncoder(w).Encode(users)
}

func GetUser(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	params := mux.Vars(r)
	var user User
	DB.First(&user, params["id"])
	json.NewEncoder(w).Encode(user)
}

func CreateUser(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	var user User
	json.NewDecoder(r.Body).Decode(&user)
	DB.Create(&user)
	json.NewEncoder(w).Encode(user)
}

func UpdateUser(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	params := mux.Vars(r)
	var user User
	DB.First(&user, params["id"])
	json.NewDecoder(r.Body).Decode(&user)
	DB.Save(&user)
	json.NewEncoder(w).Encode(user)
}

func DeleteUser(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	params := mux.Vars(r)
	var user User
	DB.Delete(&user, params["id"])
	json.NewEncoder(w).Encode("The USer is Deleted Successfully!")
}

func handleRequest() {
	r := mux.NewRouter()

	r.HandleFunc("/users", GetUsers).Methods("GET")
	r.HandleFunc("/users/{id}", GetUser).Methods("GET")
	r.HandleFunc("/users", CreateUser).Methods("POST")
	r.HandleFunc("/users/{id}", UpdateUser).Methods("PUT")
	r.HandleFunc("/users/{id}", DeleteUser).Methods("DELETE")

	log.Fatal(http.ListenAndServe(":9000", r))
}

func main() {
	InitialMigration()
	handleRequest()
}