r_place/go/server.go

158 lines
3.4 KiB
Go

package main
import (
"encoding/json"
"flag"
"fmt"
"io/ioutil"
"log"
"net/http"
"os"
"strconv"
"time"
"github.com/gorilla/websocket"
)
var upgrader = websocket.Upgrader{
ReadBufferSize: 4096,
WriteBufferSize: 4096,
}
const (
// Time allowed to write a message to the peer.
writeWait = 10 * time.Second
// Time allowed to read the next pong message from the peer.
pongWait = 60 * time.Second
// Send pings to peer with this period. Must be less than pongWait.
pingPeriod = (pongWait * 9) / 10
// Maximum message size allowed from peer.
maxMessageSize = 512
)
var img = GetImage(1000, 1000)
var tmpImage = GetImage(img.Width, img.Height)
func get(w http.ResponseWriter, r *http.Request) {
c, err := upgrader.Upgrade(w, r, nil)
if err != nil {
log.Print("error while upgrading", err)
return
}
c.SetReadLimit(maxMessageSize)
c.SetPongHandler(func(string) error { c.SetReadDeadline(time.Now().Add(pongWait)); return nil })
defer c.Close()
ticker := time.NewTicker(1 * time.Second)
for range ticker.C {
diff := tmpImage.GetDiff(&img)
for i := 0; i < int(diff.Width*diff.Height); i++ {
pix := diff.Pixels[i]
if pix.Pixel.UserID != 0 {
x := i / int(diff.Width)
y := i % int(diff.Height)
msg := Message{X: uint32(x), Y: uint32(y), Timestamp: pix.Pixel.Timestamp, UserID: pix.Pixel.UserID, Color: pix.Pixel.Color}
marshalMsg, err := json.Marshal(msg)
if err != nil {
log.Println("error while writing image", err)
break
}
err = c.WriteMessage(1, marshalMsg)
_, msg2, _ := c.ReadMessage()
_ = msg2
}
}
if err := c.WriteMessage(websocket.PingMessage, []byte{}); err != nil {
return
}
copy(tmpImage.Pixels, img.Pixels)
}
}
func getAll(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(img)
}
func set(w http.ResponseWriter, r *http.Request) {
c, err := upgrader.Upgrade(w, r, nil)
if err != nil {
log.Print("error while upgrading", err)
return
}
c.SetReadLimit(maxMessageSize)
c.SetPongHandler(func(string) error { c.SetReadDeadline(time.Now().Add(pongWait)); return nil })
defer c.Close()
for {
mt, msg, err := c.ReadMessage()
if err != nil {
log.Println("read:", err)
break
}
if mt == websocket.PingMessage {
continue
}
message := Message{}
json.Unmarshal(msg, &message)
status := img.SetPixel(message)
err = c.WriteMessage(1, []byte(strconv.Itoa(status)))
}
}
func loadState(img *image, path string) {
stateJSON, err := os.Open(path)
if err != nil {
fmt.Println(err)
return
}
defer stateJSON.Close()
byteValue, _ := ioutil.ReadAll(stateJSON)
json.Unmarshal(byteValue, &img)
}
func saveState(img *image, path string, period time.Duration) {
ticker := time.NewTicker(period * time.Second)
for range ticker.C {
imgJSON, _ := json.Marshal(img)
file, err := os.Create(path)
if err != nil {
return
}
defer file.Close()
file.WriteString(string(imgJSON))
if err != nil {
fmt.Println("Could not save state")
fmt.Println(err)
}
}
}
func main() {
var addr = flag.String("addr", "localhost:8080", "http service address")
flag.Parse()
log.SetFlags(0)
log.Println("starting server on", *addr)
cachePath := "./state.json"
loadState(&img, cachePath)
go saveState(&img, cachePath, 10)
http.HandleFunc("/get", get)
http.HandleFunc("/getAll", getAll)
http.HandleFunc("/set", set)
log.Fatal(http.ListenAndServe(*addr, nil))
}