feat(backend): websockets with player co-ordination and JWT auto-generation

backend/go.mod

@@ -5,6 +5,7 @@ go 1.20
 require (
 	github.com/charmbracelet/log v0.2.3
 	github.com/golang-jwt/jwt v3.2.2+incompatible
+	github.com/gorilla/websocket v1.5.0
 	github.com/joho/godotenv v1.5.1
 	github.com/mattn/go-sqlite3 v1.14.17
 	golang.org/x/crypto v0.11.0

backend/go.sum

@@ -9,6 +9,8 @@ github.com/go-logfmt/logfmt v0.6.0 h1:wGYYu3uicYdqXVgoYbvnkrPVXkuLM1p1ifugDMEdRi
 github.com/go-logfmt/logfmt v0.6.0/go.mod h1:WYhtIu8zTZfxdn5+rREduYbwxfcBr/Vr6KEVveWlfTs=
 github.com/golang-jwt/jwt v3.2.2+incompatible h1:IfV12K8xAKAnZqdXVzCZ+TOjboZ2keLg81eXfW3O+oY=
 github.com/golang-jwt/jwt v3.2.2+incompatible/go.mod h1:8pz2t5EyA70fFQQSrl6XZXzqecmYZeUEB8OUGHkxJ+I=
+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/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
 github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=

backend/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	_ "github.com/joho/godotenv/autoload"
 	"net/http"
@@ -8,20 +9,92 @@ import (
 
 	// Stylish stuff
 	"github.com/charmbracelet/log"
+
+	// Websockets
+	"github.com/gorilla/websocket"
 )
 
 type App struct {
 	UserHandler *UserHandler
+	clients     map[*websocket.Conn]bool
+	broadcast   chan []byte
+	upgrader    websocket.Upgrader
 }
 
+type Player struct {
+	X int `json:"x"`
+	Y int `json:"y"`
+}
+
+type GameState struct {
+	Players []Player `json:"players"`
+}
+
+func (s *App) handlePlayerMovement(conn *websocket.Conn) {
+	var player Player
+	player.X = 0
+	player.Y = 0
+
+	for {
+		// Read the next message from the client
+		_, message, err := conn.ReadMessage()
+		if err != nil {
+			log.Error("Failed to read message:", err)
+			break
+		}
+
+		// Update the player's position based on the received message
+		switch string(message) {
+		case "up":
+			player.Y--
+		case "down":
+			player.Y++
+		case "left":
+			player.X--
+		case "right":
+			player.X++
+		}
+
+		// Create a JSON representation of the game state
+		gameState := GameState{
+			Players: []Player{player},
+		}
+		gameStateData, err := json.Marshal(gameState)
+		if err != nil {
+			log.Error("Failed to marshal game state:", err)
+			break
+		}
+
+		// Broadcast the game state to all clients
+		s.broadcast <- gameStateData
+	}
+}
+
+func (s *App) handleBroadcasts() {
+	for {
+		// Read the next message from the broadcast channel
+		message := <-s.broadcast
+
+		// Broadcast the message to all clients
+		for client := range s.clients {
+			err := client.WriteMessage(websocket.TextMessage, message)
+			if err != nil {
+				log.Error("Failed to write message:", err)
+			}
+		}
+	}
+}
+
+var upgrader = websocket.Upgrader{}
+
 // Define the serve function
-func (h *App) ServeHTTP(res http.ResponseWriter, req *http.Request) {
+func (s *App) ServeHTTP(res http.ResponseWriter, req *http.Request) {
 	var head string
 	head, req.URL.Path = ShiftPath(req.URL.Path)
 	switch head {
 	// Start the user handler should the requested user be found
 	case "user":
-		h.UserHandler.Handle(res, req)
+		s.UserHandler.Handle(res, req)
 	// Return a `Not Found` if the user is not found
 	default:
 		http.Error(res, "Not Found", http.StatusNotFound)
@@ -29,7 +102,75 @@ func (h *App) ServeHTTP(res http.ResponseWriter, req *http.Request) {
 }
 
 // Run the server
+func (s *App) Run() {
+	http.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
+		// Upgrade the connection to a WebSocket connection
+		conn, err := s.upgrader.Upgrade(w, r, nil)
+		if err != nil {
+			log.Error("Failed to upgrade connection:", err)
+			return
+		}
+
+		// Add the client connection to the clients map
+		s.clients[conn] = true
+
+		// Log when a client connects
+		log.Info("Client connected:", conn.RemoteAddr())
+
+		// Allow the server to handle player movement
+		go s.handlePlayerMovement(conn)
+
+		// Close the connection and remove it from the clients map
+		defer func() {
+			// Log when a client disconnects
+			log.Info("Client disconnected:", conn.RemoteAddr())
+
+			conn.Close()
+			delete(s.clients, conn)
+		}()
+
+		// Handle incoming messages
+		for {
+			_, message, err := conn.ReadMessage()
+			if err != nil {
+				log.Error("Failed to read message:", err)
+				break
+			}
+
+			// Broadcast the received message to all clients
+			s.broadcast <- message
+		}
+	})
+
+	go s.handleBroadcasts()
+
+	http.HandleFunc("/echo", func(w http.ResponseWriter, r *http.Request) {
+		conn, err := upgrader.Upgrade(w, r, nil)
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		for {
+
+			msgType, msg, err := conn.ReadMessage()
+			if err != nil {
+				return
+			}
+
+			fmt.Printf("%s sent: %s\n", conn.RemoteAddr(), string(msg))
+
+			if err = conn.WriteMessage(msgType, msg); err != nil {
+				return
+			}
+		}
+	})
+}
+
 func main() {
+	// Make the jwt_secret file within the server configuration directory
+	makeSecret()
+
 	// Initialise the user handler
 	user_handler, err := NewUserHandler()
 
@@ -49,4 +190,5 @@ func main() {
 	// Log that the program has successfully started listening to the port
 	log.Info(fmt.Sprintf("Ambition backend listening to port %v", port))
 	http.ListenAndServe(":"+port, a)
+
 }

backend/user.go

@@ -7,8 +7,13 @@ import (
 	"io"
 	"os"
 
+	// A cute logging system
+	"github.com/charmbracelet/log"
+
 	// Encryption
+	"crypto/rand"
 	"encoding/json"
+	"math/big"
 	"net/http"
 
 	"github.com/golang-jwt/jwt"
@@ -19,6 +24,11 @@ import (
 	_ "github.com/mattn/go-sqlite3"
 )
 
+// Define the configuration directories
+var userConfigDirectory, err = os.UserConfigDir()
+var serverConfigDirectory = fmt.Sprintf("%v/ambition/server", userConfigDirectory)
+var jwtPath = fmt.Sprintf("%v/jwt_secret", serverConfigDirectory)
+
 // Define the user request struct
 type UserRequest struct {
 	Name     string `json:"name"`
@@ -37,6 +47,30 @@ func (ur *UserRequest) Parse(req *http.Request) error {
 	return nil
 }
 
+// A function to write a randomly-generated cryptographically secure 24-character string to a file
+func makeSecret() {
+	const characters = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-"
+	ret := make([]byte, 24)
+	for i := 0; i < 24; i++ {
+		num, err := rand.Int(rand.Reader, big.NewInt(int64(len(characters))))
+		if err != nil {
+			log.Fatal(err)
+		}
+		ret[i] = characters[num.Int64()]
+	}
+
+	// Check if the Ambition server config folder exists, otherwise make it
+	_, err2 := os.Stat(serverConfigDirectory)
+	if os.IsNotExist(err2) {
+		log.Info("Ambition backend config folder does not exist, creating...")
+		os.MkdirAll(serverConfigDirectory, 0755)
+		log.Info("Made Ambition backend config folder!")
+	}
+
+	// Write the secret to the file
+	os.WriteFile(jwtPath, ret, 0755)
+}
+
 // Define the user handler struct
 type UserHandler struct {
 	db         *sql.DB
@@ -51,8 +85,9 @@ func NewUserHandler() (*UserHandler, error) {
 		return nil, err
 	}
 
-	// Define the JSON web token
+	// Get the JSON web token
-	jwt_secret_str := os.Getenv("JWT_SECRET")
+	jwt_secret_bytes, err := os.ReadFile(jwtPath)
+	jwt_secret_str := string(jwt_secret_bytes)
 	// Return any errors
 	if jwt_secret_str == "" {
 		return nil, errors.New("no JWT_SECRET provided in .env")