Use UUIDs to identify players.

go.mod

@@ -16,6 +16,7 @@ require (
 	github.com/go-playground/universal-translator v0.18.1 // indirect
 	github.com/go-playground/validator/v10 v10.11.2 // indirect
 	github.com/goccy/go-json v0.10.0 // indirect
+	github.com/google/uuid v1.3.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.0.9 // indirect
 	github.com/leodido/go-urn v1.2.1 // indirect

go.sum

@@ -26,6 +26,8 @@ github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaS
 github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
 github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=

main.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/gin-gonic/autotls"
 	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
 	"github.com/gorilla/websocket"
 )
 
@@ -15,8 +16,6 @@ var cert_path = "/etc/letsencrypt/live/chess.sw-gross.de/"
 var cert_file = cert_path + "fullchain.pem"
 var key_file = cert_path + "privkey.pem"
 
-var player_number = 0
-
 var upgrader = websocket.Upgrader{}
 
 // album represents data about a record album.
@@ -55,9 +54,9 @@ func main() {
 }
 
 func playRandomGame(c *gin.Context) {
-	server.GetLobby().RegisterPlayer(server.NewPlayer(player_number))
-	player_number = player_number + 1
-	c.IndentedJSON(http.StatusOK, player_number)
+	player_uuid := uuid.New()
+	server.GetLobby().RegisterPlayer(server.NewPlayer(player_uuid))
+	c.IndentedJSON(http.StatusOK, player_uuid)
 }
 
 // getAlbums responds with the list of all albums as JSON.

server/game.go

@@ -65,7 +65,7 @@ func (game *chessGame) handle() {
 		case CheckPlayerChange:
 
 			if move.realMove {
-				if game.currentTurnPlayer.id == game.players[0].id {
+				if game.currentTurnPlayer.uuid == game.players[0].uuid {
 					game.currentTurnPlayer = game.players[1]
 				} else {
 					game.currentTurnPlayer = game.players[0]
@@ -97,7 +97,7 @@ func (game *chessGame) handle() {
 }
 
 func addPlayersToGame(players [2]Player) {
-	log.Printf("Adding players %d and %d to new game", players[0].id, players[1].id)
+	log.Printf("Adding players %d and %d to new game", players[0].uuid, players[1].uuid)
 	game := NewChessGame(rand.Int(), players)
 
 	go game.handle()

server/player.go

@@ -1,14 +1,17 @@
 package server
 
-import "github.com/gorilla/websocket"
+import (
+	"github.com/google/uuid"
+	"github.com/gorilla/websocket"
+)
 
 type Player struct {
-	id   int
+	uuid uuid.UUID
 	conn *websocket.Conn
 }
 
-func NewPlayer(id int) *Player {
+func NewPlayer(uuid uuid.UUID) *Player {
 	return &Player{
-		id: id,
+		uuid: uuid,
 	}
 }

server/server.go

@@ -28,14 +28,14 @@ func PlayHandler(w http.ResponseWriter, r *http.Request) {
 }
 
 func WriteMessageToPlayer(player *Player, msg []byte, msgType int) error {
-	log.Printf("Writing message: %s (with messagetype %d) to player %d", string(msg), msgType, player.id)
+	log.Printf("Writing message: %s (with messagetype %d) to player %d", string(msg), msgType, player.uuid)
 
 	return player.conn.WriteMessage(msgType, msg)
 }
 
 func ReadMessageFromPlayer(player *Player) (messageType int, p []byte, err error) {
 	msgType, msg, err := player.conn.ReadMessage()
-	log.Printf("Reading message: %s (with messagetype %d) from player %d", string(msg), msgType, player.id)
+	log.Printf("Reading message: %s (with messagetype %d) from player %d", string(msg), msgType, player.uuid)
 
 	return msgType, msg, err
 }