database (#4)

Co-authored-by: Evan Burkey <dev@fputs.com>
Reviewed-on: https://git.fputs.com/fputs/protohackers/pulls/4

cmd/budgetchat/main.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+
+	"protohackers/pkg/conn"
+)
+
+func main() {
+	l, err := net.Listen(conn.Type, conn.Port)
+	if err != nil {
+		panic(err)
+	}
+	defer l.Close()
+
+	fmt.Println(fmt.Sprintf("Listening on port %s", conn.Port))
+
+	r := createRoom()
+	for {
+		c, err := l.Accept()
+		if err != nil {
+			break
+		}
+		go handleConn(r, c)
+	}
+}
+
+func handleConn(r *room, c net.Conn) {
+	u := newUser(c)
+	defer c.Close()
+	go u.sendMessage()
+
+	u.write("Welcome to budgetchat! What shall I call you?")
+
+	s := bufio.NewScanner(u.conn)
+	for s.Scan() {
+		input := s.Text()
+		if !u.online {
+			r.sendToRest(r.joinMsg(u), u)
+			u.write(r.connectMsg())
+			r.joinUser(u)
+		} else {
+			r.sendToRest(msgWrap(input, u), u)
+		}
+		if s.Err() != nil {
+			return
+		}
+	}
+}
+
+func msgWrap(msg string, u *user) string {
+	return fmt.Sprintf("[%s] %s", u.nick, msg)
+}

cmd/budgetchat/room.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+type room struct {
+	users []*user
+}
+
+func createRoom() *room {
+	return &room{
+		users: make([]*user, 16),
+	}
+}
+
+func (r *room) joinUser(u *user) {
+	for _, usr := range r.users {
+		if usr.nick == u.nick {
+
+		}
+	}
+	r.users = append(r.users, u)
+	u.online = true
+}
+
+func (r *room) sendToAll(msg string) {
+	for _, u := range r.users {
+		if u.online {
+			u.write(msg)
+		}
+	}
+}
+
+func (r *room) sendToRest(msg string, skip *user) {
+	for _, u := range r.users {
+		if u.online && u != skip {
+			u.write(msg)
+		}
+	}
+}
+
+func (r *room) connected() (nicks []string) {
+	for _, u := range r.users {
+		if u.online {
+			nicks = append(nicks, u.nick)
+		}
+	}
+	return nicks
+}
+
+func (r *room) joinMsg(u *user) string {
+	return fmt.Sprintf("* %s has joined the channel", u.nick)
+}
+
+func (r *room) connectMsg() string {
+	return fmt.Sprintf("* The room contains: %s", strings.Join(r.connected(), ", "))
+}

cmd/budgetchat/user.go

@@ -0,0 +1,27 @@
+package main
+
+import "net"
+
+type user struct {
+	conn   net.Conn
+	nick   string
+	online bool
+	output chan string
+}
+
+func newUser(conn net.Conn) *user {
+	return &user{
+		conn:   conn,
+		output: make(chan string),
+	}
+}
+
+func (u *user) write(s string) {
+	u.output <- s + "\n"
+}
+
+func (u *user) sendMessage() {
+	for line := range u.output {
+		u.conn.Write([]byte(line))
+	}
+}

cmd/unusualdatabase/main.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"strings"
+
+	"protohackers/pkg/conn"
+)
+
+var (
+	db map[string]string
+)
+
+func init() {
+	db = make(map[string]string)
+	db["version"] = "0.1.1"
+}
+
+func main() {
+	err := conn.StartSimpleUDP(handler, 1024)
+	if err != nil {
+		log.Fatalln(err)
+	}
+}
+
+func handler(c *net.UDPConn, addr *net.UDPAddr, data []byte) {
+	if strings.Contains(string(data), "version=") {
+		return
+	} else if strings.Contains(string(data), "=") {
+		sp := strings.SplitN(string(data), "=", 2)
+		db[sp[0]] = sp[1]
+	} else {
+		out := fmt.Sprintf("%s=", string(data))
+		if v, ok := db[string(data)]; ok {
+			out += v
+		}
+		c.WriteTo([]byte(out), addr)
+	}
+}

pkg/conn/conn.go

@@ -8,17 +8,16 @@ import (
 
 const (
 	Port = ":3030"
-	Type = "tcp4"
 )
 
 func StartSimple(handler func(conn net.Conn)) error {
-	l, err := net.Listen(Type, Port)
+	l, err := net.Listen("tcp4", Port)
 	if err != nil {
 		return err
 	}
 	defer l.Close()
 
-	fmt.Println(fmt.Sprintf("Listening on port %s", Port))
+	fmt.Println(fmt.Sprintf("Listening TCP on port %s", Port))
 
 	for {
 		c, err := l.Accept()
@@ -26,9 +25,30 @@ func StartSimple(handler func(conn net.Conn)) error {
 			return err
 		}
 		go handler(c)
+	}
+}
+
+func StartSimpleUDP(handler func(*net.UDPConn, *net.UDPAddr, []byte), buffSize int) error {
+	srv, err := net.ResolveUDPAddr("udp4", Port)
+	if err != nil {
+		return err
+	}
+
+	c, err := net.ListenUDP("udp4", srv)
+	if err != nil {
+		return err
+	}
+	defer c.Close()
+
+	fmt.Println(fmt.Sprintf("Listening UDP on port %s", Port))
+
+	buf := make([]byte, buffSize)
+	for {
+		n, addr, err := c.ReadFromUDP(buf)
 		if err != nil {
 			return err
 		}
+		go handler(c, addr, buf[:n])
 	}
 }