golang：RPC服务的简单登录验证

《GO语言高级编程》设计中案例，仅作为笔记进行收藏。基于上下⽂可以针对不同客户端提供定制化的RPC服务，同时可以方便地为RPC服务增加简单的登陆状态的验证。

1.server/main.go

package main

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

type HelloService struct {
    // 增加了对应链接的conn成员
	conn    net.Conn
	isLogin bool
}

func ServeHelloService(conn net.Conn) {
	p := rpc.NewServer()
	p.Register(&HelloService{conn: conn})
	p.ServeConn(conn)
}

func (p *HelloService) Login(request string, reply *string) error {
	if request != "user:password" {
		log.Println("login failed")
		return fmt.Errorf("auth failed")
	}

	log.Println("login ok")
	p.isLogin = true
	return nil
}

func (p *HelloService) Hello(request string, reply *string) error {
	if !p.isLogin {
		return fmt.Errorf("please login")
	}
    // 可以根据conn成员识别不同链接的RPC调用
	*reply = "hello:" + request + ", from " + p.conn.RemoteAddr().String()
	return nil
}

func main() {
	listener, err := net.Listen("tcp", ":1234")
	if err != nil {
		log.Fatal("ListenTCP error:", err)
	}

	for {
		conn, err := listener.Accept()
		if err != nil {
			log.Fatal("Accept error:", err)
		}

		go ServeHelloService(conn)
	}
}

2.client/main.go

package main

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

func main(){
	client,err:=rpc.Dial("tcp","localhost:1234")
	if err!=nil{
		log.Fatal("dialing:",err)
	}

	var reply string
	err=client.Call("HelloService.Login","abc",&reply)
	if err!=nil{
		log.Println(err)
	}else{
		log.Println("login ok")
	}

	err=client.Call("HelloService.Login","user:password",&reply)
	if err!=nil{
		log.Println(err)
	}else{
		log.Println("login ok")
	}

	err = client.Call("HelloService.Hello", "hello,world", &reply)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(reply)
}