caddy-hugo2/deltas.go

package caddyhugo

import (
	"fmt"
	"net/http"
	"time"

	"git.stephensearles.com/stephen/acedoc"
	"github.com/gorilla/websocket"
)

const (
	IdleWebsocketTimeout = 10 * time.Minute
	WebsocketFileTicker  = 1 * time.Second
)

func (ch *CaddyHugo) ObserveLTime(ltime uint64) uint64 {
	ch.mtx.Lock()

	if ch.ltime < ltime {
		ch.ltime = ltime
	}

	ch.mtx.Unlock()
	return ch.LTime()
}

func (ch *CaddyHugo) LTime() uint64 {
	ch.mtx.Lock()
	defer ch.mtx.Unlock()
	ch.ltime++
	return ch.ltime
}

func (ch *CaddyHugo) DeltaWebsocket(w http.ResponseWriter, r *http.Request) (int, error) {
	var upgrader = websocket.Upgrader{
		ReadBufferSize:  1024,
		WriteBufferSize: 1024,
	}

	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		fmt.Println(err)
		return http.StatusBadRequest, err
	}

	doc, err := ch.doc(r)
	if err != nil {
		fmt.Println(err)
		return http.StatusBadRequest, err
	}

	const idlePing = 15 * time.Second
	const idlePingShort = 1 * time.Millisecond
	var timer *time.Timer

	timer = time.AfterFunc(idlePing, func() {
		conn.WriteJSON(Message{
			Deltas: []acedoc.Delta{},
			LTime:  ch.LTime(),
		})
		timer.Reset(idlePing)
	})

	client := doc.doc.Client(acedoc.DeltaHandlerFunc(func(ds []acedoc.Delta) error {
		timer.Reset(idlePing)
		err := conn.WriteJSON(Message{
			Deltas: ds,
			LTime:  ch.LTime(),
		})
		return err
	}))

	ch.mtx.Lock()
	doc.clients++
	ch.mtx.Unlock()

	defer func() {
		ch.mtx.Lock()
		client.Close()
		doc.clients--
		ch.mtx.Unlock()
	}()

	for {
		var message Message
		err := conn.ReadJSON(&message)
		if err != nil {
			return http.StatusBadRequest, err
		}

		ch.ObserveLTime(message.LTime)
		timer.Reset(idlePingShort)

		err = client.PushDeltas(message.Deltas...)
		if err != nil {
			return http.StatusBadRequest, err
		}

	}
}

type Message struct {
	Deltas []acedoc.Delta `json:"deltas"`
	LTime  uint64         `json:"ltime"`
}