✨ feat: Add streaming support (#125)

This adds:
- [x] Keyboard and mouse handling on the frontend
- [x] Video and audio streaming from the backend to the frontend
- [x] Input server that works with Websockets

Update - 17/11
- [ ] Master docker container to run this
- [ ] Steam runtime
- [ ] Entrypoint.sh

---------

Co-authored-by: Kristian Ollikainen <14197772+DatCaptainHorse@users.noreply.github.com>
Co-authored-by: Kristian Ollikainen <DatCaptainHorse@users.noreply.github.com>

packages/relay/internal/websocket.go

@@ -0,0 +1,114 @@
+package relay
+
+import (
+	"github.com/gorilla/websocket"
+	"log"
+	"sync"
+)
+
+// SafeWebSocket is a websocket with a mutex
+type SafeWebSocket struct {
+	*websocket.Conn
+	sync.Mutex
+	binaryCallbacks map[string]OnMessageCallback // MessageBase type -> callback
+}
+
+// NewSafeWebSocket creates a new SafeWebSocket from *websocket.Conn
+func NewSafeWebSocket(conn *websocket.Conn) *SafeWebSocket {
+	ws := &SafeWebSocket{
+		Conn:            conn,
+		binaryCallbacks: make(map[string]OnMessageCallback),
+	}
+
+	// Launch a goroutine to handle binary messages
+	go func() {
+		for {
+			// Read binary message
+			kind, data, err := ws.Conn.ReadMessage()
+			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure, websocket.CloseNoStatusReceived) {
+				// If unexpected close error, break
+				if GetFlags().Verbose {
+					log.Printf("Unexpected WebSocket close error, reason: %s\n", err)
+				}
+				break
+			} else if websocket.IsCloseError(err, websocket.CloseNormalClosure, websocket.CloseGoingAway, websocket.CloseAbnormalClosure, websocket.CloseNoStatusReceived) {
+				// If closing, just break
+				if GetFlags().Verbose {
+					log.Printf("WebSocket closing\n")
+				}
+				break
+			} else if err != nil {
+				log.Printf("Failed to read WebSocket message, reason: %s\n", err)
+				break
+			}
+
+			switch kind {
+			case websocket.TextMessage:
+				// Ignore, we use binary messages
+				continue
+			case websocket.BinaryMessage:
+				// Decode message
+				var msg MessageBase
+				if err = DecodeMessage(data, &msg); err != nil {
+					log.Printf("Failed to decode binary WebSocket message, reason: %s\n", err)
+					continue
+				}
+
+				// Handle message type callback
+				if callback, ok := ws.binaryCallbacks[msg.PayloadType]; ok {
+					callback(data)
+				} // TODO: Log unknown message type?
+			default:
+				log.Printf("Unknown WebSocket message type: %d\n", kind)
+			}
+		}
+	}()
+
+	return ws
+}
+
+// SendJSON writes JSON to a websocket with a mutex
+func (ws *SafeWebSocket) SendJSON(v interface{}) error {
+	ws.Lock()
+	defer ws.Unlock()
+	return ws.Conn.WriteJSON(v)
+}
+
+// SendBinary writes binary to a websocket with a mutex
+func (ws *SafeWebSocket) SendBinary(data []byte) error {
+	ws.Lock()
+	defer ws.Unlock()
+	return ws.Conn.WriteMessage(websocket.BinaryMessage, data)
+}
+
+// RegisterMessageCallback sets the callback for binary message of given type
+func (ws *SafeWebSocket) RegisterMessageCallback(msgType string, callback OnMessageCallback) {
+	ws.Lock()
+	defer ws.Unlock()
+	if ws.binaryCallbacks == nil {
+		ws.binaryCallbacks = make(map[string]OnMessageCallback)
+	}
+	ws.binaryCallbacks[msgType] = callback
+}
+
+// UnregisterMessageCallback removes the callback for binary message of given type
+func (ws *SafeWebSocket) UnregisterMessageCallback(msgType string) {
+	ws.Lock()
+	defer ws.Unlock()
+	if ws.binaryCallbacks != nil {
+		delete(ws.binaryCallbacks, msgType)
+	}
+}
+
+// RegisterOnClose sets the callback for websocket closing
+func (ws *SafeWebSocket) RegisterOnClose(callback func()) {
+	ws.SetCloseHandler(func(code int, text string) error {
+		// Clear our callbacks
+		ws.Lock()
+		ws.binaryCallbacks = nil
+		ws.Unlock()
+		// Call the callback
+		callback()
+		return nil
+	})
+}