added Image and Pixel Obejcts

go/server.go

@@ -11,17 +11,15 @@ import (
 	"flag"
 	"log"
 	"net/http"
-	"time"
 
 	"github.com/gorilla/websocket"
 )
 
-var addr = flag.String("addr", "localhost:8080", "http service address")
-
 var upgrader = websocket.Upgrader{
 	ReadBufferSize:  2048,
 	WriteBufferSize: 2048,
 }
+var img = GetImage(10, 10)
 
 func serve(w http.ResponseWriter, r *http.Request) {
 	c, err := upgrader.Upgrade(w, r, nil)
@@ -31,16 +29,17 @@ func serve(w http.ResponseWriter, r *http.Request) {
 	}
 	defer c.Close()
 	for {
-		mt, message, err := c.ReadMessage()
+		mt, msg, err := c.ReadMessage()
 		if err != nil {
-			//log.Println("read:", err)
+			log.Println("read:", err)
 			break
 		}
-		pixel := JsonToStruct(message)
 
-		tm := time.Unix(pixel.Timestamp, 0)
+		message := Message{}
-		log.Println(tm)
+		message.JsonToStruct(msg)
-		err = c.WriteMessage(mt, message)
+		img.SetPixel(message)
+
+		err = c.WriteMessage(mt, msg)
 		if err != nil {
 			//log.Println("write:", err)
 			break
@@ -49,6 +48,8 @@ func serve(w http.ResponseWriter, r *http.Request) {
 }
 
 func main() {
+	var addr = flag.String("addr", "localhost:8080", "http service address")
+
 	flag.Parse()
 	log.SetFlags(0)
 	http.HandleFunc("/", serve)

go/util.go

@@ -2,9 +2,11 @@ package main
 
 import (
 	"encoding/json"
+	"fmt"
+	"sync"
 )
 
-type Pixel struct {
+type Message struct {
 	X         uint16 `json:"x"`
 	Y         uint16 `json:"y"`
 	Color     uint8  `json:"color"`
@@ -12,8 +14,52 @@ type Pixel struct {
 	UserID    uint64 `json:"userid"`
 }
 
-func JsonToStruct(input []byte) Pixel {
+func (message *Message) JsonToStruct(input []byte) *Message {
-	pixel := Pixel{}
+	json.Unmarshal(input, message)
-	json.Unmarshal(input, &pixel)
+	return message
-	return pixel
+}
+
+type pixel struct {
+	Color     uint8  `json:"color"`
+	Timestamp int64  `json:"timestamp"`
+	UserID    uint64 `json:"userid"`
+	Mutex     sync.Mutex
+}
+
+type image struct {
+	width  uint16
+	height uint16
+	pixels []pixel
+}
+
+func GetImage(w uint16, h uint16) image {
+	pixels := make([]pixel, w*h)
+	for i := 0; i < int(w*h); i++ {
+		pixels[i] = pixel{Color: 0, Timestamp: 0, UserID: 0, Mutex: sync.Mutex{}}
+	}
+	return image{width: w, height: h, pixels: pixels}
+}
+
+func (p *pixel) setColor(color uint8, timestamp int64, userid uint64) {
+	p.Mutex.Lock()
+	defer p.Mutex.Unlock()
+	if timestamp > p.Timestamp {
+		p.Color = color
+		p.Timestamp = timestamp
+		p.UserID = userid
+	}
+}
+
+func (img *image) SetPixel(message Message) *image {
+	if message.X >= img.width || message.Y >= img.height || message.X < 0 || message.Y < 0 {
+		fmt.Printf("User %d tried accessing out of bounds \n", message.UserID)
+		return img
+	}
+	if message.Color >= 16 || message.Color < 0 {
+		fmt.Printf("User %d tried setting non existent color \n", message.UserID)
+		return img
+	}
+	pos := uint32(message.X)*uint32(img.width) + uint32(message.Y)
+	img.pixels[pos].setColor(message.Color, message.Timestamp, message.UserID)
+	return img
 }

python/clients.py

@@ -21,11 +21,11 @@ class pixel:
 
 async def main():
     message = pixel(
-        x=0,
+        x=11,
-        y=1,
+        y=0,
-        color=0,
+        color=15,
         timestamp=int(time.time()),
-        userid=0,
+        userid=1,
     )
     async with websockets.connect("ws://localhost:8080") as websocket:
         print(message)