websocket checkboxes

src/main.go

@@ -4,10 +4,14 @@ import (
 	"html/template"
 	"io"
 	"net/http"
+	"strconv"
+	"sync"
 
 	"github.com/labstack/echo/v4"
 	"github.com/labstack/echo/v4/middleware"
 	"github.com/labstack/gommon/log"
+	"github.com/russross/blackfriday/v2"
+	"golang.org/x/net/websocket"
 )
 
 type Templates struct {
@@ -25,22 +29,42 @@ func NewTemplates() *Templates {
 }
 
 type Page struct {
+	Boxes map[int]bool
 }
 
-func newPage() Page {
-	return Page{}
+func newPage(boxes map[int]bool) Page {
+	return Page{
+		Boxes: boxes,
+	}
 }
 
 type Article struct {
-	Content string
+	Content template.HTML
 }
 
-func newArticle(content string) Article {
+func newArticle(content template.HTML) Article {
 	return Article{
 		Content: content,
 	}
 }
 
+var (
+	wsConnections = make(map[*websocket.Conn]bool)
+	wsMutex       sync.Mutex
+	boxes         = make(map[int]bool, 1000)
+)
+
+func broadcastMessage(message string) {
+	wsMutex.Lock()
+	defer wsMutex.Unlock()
+	for conn := range wsConnections {
+		if err := websocket.Message.Send(conn, message); err != nil {
+			conn.Close()
+			delete(wsConnections, conn)
+		}
+	}
+}
+
 func main() {
 	e := echo.New()
 	e.Renderer = NewTemplates()
@@ -48,7 +72,11 @@ func main() {
 	e.Logger.SetLevel(log.DEBUG)
 	e.Use(middleware.Logger())
 
-	page := newPage()
+	for i := 0; i < 1000; i++ {
+		boxes[i] = false
+	}
+
+	page := newPage(boxes)
 
 	e.Static("/images", "images")
 	e.Static("/css", "css")
@@ -57,16 +85,64 @@ func main() {
 		return c.Render(200, "index", page)
 	})
 
-	e.GET("/we-are-here", func(c echo.Context) error {
+	e.GET("/blog", func(c echo.Context) error {
 		// Log a test message
 		e.Logger.Info("Test log: /we-are-here endpoint called")
 
 		msg := getNotes(c, e.Logger)
 		e.Logger.Info(msg)
 
-		article := newArticle(" content")
+		htmlContent := blackfriday.Run([]byte(msg))
+
+		article := newArticle(template.HTML(string(htmlContent)))
 		return c.Render(http.StatusOK, "article", article)
 	})
 
+	e.POST("/box/:id", updateBoxes)
+	e.GET("/ws", initWs)
+
 	e.Logger.Fatal(e.Start(":54321"))
 }
+
+func updateBoxes(c echo.Context) error {
+	id := c.Param("id")
+	checked := c.FormValue("checked") == "on"
+
+	index, err := strconv.Atoi(id)
+	if err != nil {
+		return c.String(http.StatusBadRequest, "Invalid ID")
+	}
+
+	boxes[index] = checked
+
+	message := strconv.Itoa(index)
+	if checked {
+		message += ":+"
+	} else {
+		message += ":-"
+	}
+
+	broadcastMessage(message)
+
+	return c.JSON(200, "[]")
+}
+
+func initWs(c echo.Context) error {
+	websocket.Handler(func(ws *websocket.Conn) {
+		wsMutex.Lock()
+		wsConnections[ws] = true
+		wsMutex.Unlock()
+
+		for {
+			var msg string
+			if err := websocket.Message.Receive(ws, &msg); err != nil {
+				wsMutex.Lock()
+				delete(wsConnections, ws)
+				wsMutex.Unlock()
+				ws.Close()
+				break
+			}
+		}
+	}).ServeHTTP(c.Response(), c.Request())
+	return nil
+}