unicornpaint

Server.go (4762B)

---

 // +build ignore
 
 package main
 
 import (
 	"encoding/json"
 	"fmt"
 
 	"io/ioutil"
 	"log"
 	"net/http"
 	"path"
 	"strings"
 
 	"github.com/gorilla/websocket"
 
 	"github.com/MFAshby/unicornpaint/unicorn"
 )
 
 var (
 	un unicorn.Unicorn
 
 	upgrader = websocket.Upgrader{
 		ReadBufferSize:  1024,
 		WriteBufferSize: 1024,
 		CheckOrigin:     func(*http.Request) bool { return true },
 	}
 	delCh       = make(chan *websocket.Conn)
 	addCh       = make(chan *websocket.Conn)
 	broadcastCh = make(chan interface{})
 	clients     = map[*websocket.Conn]bool{}
 )
 
 // Types of commands
 type commandType string
 
 const (
 	noop     commandType = "NO_OP"
 	setPixel commandType = "SET_PIXEL"
 	clear    commandType = "CLEAR"
 	save     commandType = "SAVE"
 	load     commandType = "LOAD"
 )
 
 type Command struct {
 	Type     commandType `json:"type"`
 	X        uint8       `json:"x"`
 	Y        uint8       `json:"y"`
 	R        uint8       `json:"r"`
 	G        uint8       `json:"g"`
 	B        uint8       `json:"b"`
 	SaveName string      `json:"saveName"`
 }
 
 const (
 	savesDir = "saves"
 )
 
 type State struct {
 	Saves  []string     `json:"saves"`
 	Pixels [][]uint8arr `json:"pixels"`
 }
 
 // This is a trick to avoid the JSON serializer from
 // interpreting uint8's as bytes and encoding them in base64
 type uint8arr []uint8
 
 func (u uint8arr) MarshalJSON() ([]byte, error) {
 	var result string
 	if u == nil {
 		result = "null"
 	} else {
 		result = strings.Join(strings.Fields(fmt.Sprintf("%d", u)), ",")
 	}
 	return []byte(result), nil
 }
 
 func getState() *State {
 	infos, err := ioutil.ReadDir(savesDir)
 	if err != nil {
 		log.Printf("Error reading saves dir %v", err)
 	}
 	saveFileNames := make([]string, len(infos))
 	for ix, info := range infos {
 		saveFileNames[ix] = info.Name()
 	}
 
 	// Irritating conversion function
 	pixels := un.GetPixels()
 	width := un.GetWidth()
 	height := un.GetHeight()
 
 	px2 := make([][]uint8arr, width)
 	for x := uint8(0); x < width; x++ {
 		px2[x] = make([]uint8arr, height)
 		for y := uint8(0); y < height; y++ {
 			px2[x][y] = uint8arr(pixels[x][y])
 		}
 	}
 
 	return &State{
 		Pixels: px2,
 		Saves:  saveFileNames,
 	}
 }
 
 func savePic(saveFileName string) {
 	pixels := un.GetPixels()
 	// Save to PNG instead
 	data, err := json.Marshal(pixels)
 	if err != nil {
 		log.Printf("Failed to save picture to JSON %v", err)
 		return
 	}
 	err = ioutil.WriteFile(path.Join(savesDir, saveFileName), data, 0644)
 	if err != nil {
 		log.Printf("Failed to write to save file %v", err)
 		return
 	}
 }
 
 func loadPic(saveFileName string) {
 	data, err := ioutil.ReadFile(path.Join(savesDir, saveFileName))
 	if err != nil {
 		log.Printf("Failed to read file %v", err)
 		return
 	}
 
 	newPixels := [][][]uint8{}
 	err = json.Unmarshal(data, &newPixels)
 	if err != nil {
 		log.Printf("Failed to parse file %v", err)
 		return
 	}
 
 	width := len(newPixels)
 	height := len(newPixels[0])
 	for x := 0; x < width; x++ {
 		for y := 0; y < height; y++ {
 			r, g, b := unicorn.Rgb(newPixels[x][y])
 			un.SetPixel(uint8(x), uint8(y), r, g, b)
 		}
 	}
 	un.Show()
 }
 
 func upgradeHandler(w http.ResponseWriter, r *http.Request) {
 	conn, err := upgrader.Upgrade(w, r, nil)
 	if err != nil {
 		log.Printf("Failed to upgrade someone %v", err)
 		return
 	}
 
 	// Add you to my list, remember to remove later
 	addCh <- conn
 	defer func() { delCh <- conn }()
 
 	// Get you up to speed
 	err = conn.WriteJSON(getState())
 	if err != nil {
 		log.Printf("Failed to send initial state %v", err)
 		return
 	}
 
 	// Read & execute commands in a loop until error
 	for {
 		cmd := Command{}
 		err = conn.ReadJSON(&cmd)
 		if err != nil {
 			log.Printf("Error reading from client %v", err)
 			break
 		}
 
 		switch cmd.Type {
 		case noop:
 			// Don't do anything
 		case setPixel:
 			un.SetPixel(cmd.X, cmd.Y, cmd.R, cmd.G, cmd.B)
 			un.Show()
 		case clear:
 			un.Clear()
 			un.Show()
 		case save:
 			savePic(cmd.SaveName)
 		case load:
 			loadPic(cmd.SaveName)
 		}
 		// Pretty much all commands demand a change of state,
 		// do a broadcast each time
 		broadcastCh <- getState()
 	}
 }
 
 func handleClients() {
 	for {
 		select {
 		case c := <-addCh:
 			clients[c] = true
 		case c := <-delCh:
 			delete(clients, c)
 		case msg := <-broadcastCh:
 			doBroadcast(msg)
 		}
 	}
 }
 
 func main() {
 	uni, err := unicorn.GetUnicorn()
 	if err != nil {
 		log.Fatalf("Couldn't get a unicorn :( %v", err)
 	}
 	un = uni
 
 	log.Println("Starting server on port 3001")
 	http.Handle("/", http.FileServer(http.Dir("build")))
 	http.HandleFunc("/ws", upgradeHandler)
 	go http.ListenAndServe(":3001", nil)
 	go handleClients()
 	un.MainLoop()
 }
 
 func doBroadcast(obj interface{}) {
 	for client := range clients {
 		err := client.WriteJSON(obj)
 
 		if err != nil {
 			log.Printf("Error writing to client, closing %v", err)
 			client.Close()
 			delete(clients, client)
 		}
 	}
 }