presence-button-web/main.go

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net"
	"net/http"
	"os"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"time"

	"github.com/matrix-org/gomatrix"
)

type Status struct {
	FuzIsOpen      bool      `json:"fuzIsOpen"`
	LastSeenAsOpen bool      `json:"lastSeenAsOpen"`
	LastSeen       time.Time `json:"lastSeen"`
	LastOpened     time.Time `json:"lastOpened"`
	LastClosed     time.Time `json:"lastClosed"`
	ProcessUptime  string    `json:"processUptime"`
}

type Config struct {
	PORT                 string
	MATRIXROOM           string
	MATRIXOPENINGMESSAGE string
	MATRIXCLOSINGMESSAGE string
	MATRIXACCESSTOKEN    string
	MATRIXUSERNAME       string
	ESPUSERNAME          string
	ESPPASSWORD          string
}

const (
	dbPath                = "./.data/data.json"
	defaultClosingTimeout = 1 * time.Minute
	espMaxBlinkDuration   = 5 * time.Minute
)

var (
	status Status
	config = Config{
		PORT: "8080",
	}
	startTime = time.Now()
	imgs      = map[bool]string{
		// https://www.iconfinder.com/icons/1871431/online_open_shop_shopping_sign_icon
		// formerly https://www.flaticon.com/free-icon/open_1234189, maybe try https://flaticons.net/customize.php?dir=Miscellaneous&icon=Open.png without attribution
		true: `<?xml version="1.0" ?><svg viewBox="0 0 128 128" xmlns="http://www.w3.org/2000/svg"><defs><style>.cls-1{fill:#5bc9e1;}.cls-2{fill:#fd0;}.cls-3{fill:#314967;}</style></defs><title/><g data-name="15 Open Sign" id="_15_Open_Sign"><rect class="cls-1" height="36" rx="6" ry="6" width="96" x="16" y="64"/><circle class="cls-2" cx="64" cy="28" r="6"/><path class="cls-3" d="M92.73,98H22a4,4,0,0,1-4-4V70a4,4,0,0,1,4-4H42.54a2,2,0,0,0,0-4H32.83L59.93,34.89a8,8,0,0,0,8.13,0L81.71,48.54a2,2,0,0,0,2.83-2.83L70.88,32.06A8,8,0,0,0,64,20a2,2,0,0,0,0,4,4,4,0,1,1-3.49,2,2,2,0,0,0-3.49-2,8,8,0,0,0,.09,8L27.17,62H22a8,8,0,0,0-8,8V94a8,8,0,0,0,8,8H92.73A2,2,0,0,0,92.73,98Z"/><path class="cls-3" d="M106,62h-5.17L88.09,49.26a2,2,0,0,0-2.83,2.83L95.17,62H76a2,2,0,0,0,0,4h30a4,4,0,0,1,4,4V94a4,4,0,0,1-4,4H98.51a2,2,0,0,0,0,4H106a8,8,0,0,0,8-8V70A8,8,0,0,0,106,62Z"/><path class="cls-3" d="M70,62H49.22a2,2,0,0,0,0,4H70A2,2,0,0,0,70,62Z"/><path class="cls-3" d="M54.86,73.62a2.2,2.2,0,0,0-2.19,2.19v12.8a2.2,2.2,0,0,0,4.41,0V84.91h1.67a5.64,5.64,0,1,0,0-11.29ZM60,79.27c0,1.49-1.64,1.23-2.93,1.23V78C58.42,78,60,77.78,60,79.27Z"/><path class="cls-3" d="M77,78c2.86,0,2.93-4.41,0-4.41H69.92a2.17,2.17,0,0,0-2.19,2.19v12.8a2.2,2.2,0,0,0,1.25,2v.21h8c2.91,0,2.87-4.41,0-4.41H72.13v-2h4.06a2.2,2.2,0,0,0,0-4.41H72.13V78Z"/><path class="cls-3" d="M96.63,76c0-2.83-4.37-2.9-4.37,0v5.85l-5.19-7.19A2.18,2.18,0,0,0,83.13,76V88.62a2.18,2.18,0,0,0,4.37,0V82.71l5.1,7.08a2.19,2.19,0,0,0,4-1.17Z"/><path class="cls-3" d="M39.84,73.19a8.82,8.82,0,0,0,0,17.62A8.69,8.69,0,0,0,48.22,82C48.22,77.31,44.49,73.19,39.84,73.19Zm0,13.15c-5.3,0-5.26-8.68,0-8.68a4.36,4.36,0,0,1,0,8.68Z"/></g></svg>`,
		// https://www.iconfinder.com/icons/1871435/closed_online_shop_shopping_sign_icon
		// formerly https://www.flaticon.com/free-icon/closed_1234190, maybe try https://flaticons.net/customize.php?dir=Miscellaneous&icon=Closed.png without attribution
		false: `<?xml version="1.0" ?><svg viewBox="0 0 128 128" xmlns="http://www.w3.org/2000/svg"><defs><style>.cls-1{fill:#f8991d;}.cls-2{fill:#fd0;}.cls-3{fill:#314967;}</style></defs><title/><g data-name="18 Closed Sign" id="_18_Closed_Sign"><rect class="cls-1" height="36" rx="6" ry="6" width="96" x="16" y="64"/><circle class="cls-2" cx="64" cy="28" r="6"/><path class="cls-3" d="M71.85,77.83a4.37,4.37,0,0,1,2.34,1,1.93,1.93,0,1,0,2.08-3.25A7.94,7.94,0,0,0,71.85,74c-3.13,0-5.55,2.06-5.55,4.58,0,2.74,2.64,4.21,5.35,4.58.55.11,2,.45,2.26,1,0,.57-1.38,1-2,1a5.25,5.25,0,0,1-2.79-1.16,1.93,1.93,0,1,0-2.42,3,8.73,8.73,0,0,0,5.23,2c3.12,0,5.88-2,5.88-4.82s-2.88-4.4-5.66-4.78c-1.6-.31-2-.77-2-.77C70.15,78.39,70.8,77.83,71.85,77.83Z"/><path class="cls-3" d="M40,76.34V87a2,2,0,0,0,2,2h5.83a2,2,0,0,0,0-4H44V76.34A2,2,0,0,0,40,76.34Z"/><path class="cls-3" d="M50,81.48A7.16,7.16,0,1,0,57.23,74,7.32,7.32,0,0,0,50,81.48Zm10.26,0c0,2.89-3.21,4.64-5.27,2.43-1.94-2-.71-5.86,2.2-5.86A3.29,3.29,0,0,1,60.3,81.48Z"/><path class="cls-3" d="M34.44,78.82a2,2,0,0,0,2.49-3.21A7.7,7.7,0,0,0,32.15,74a7.6,7.6,0,0,0-7.6,7.48h0c0,6.3,7.44,9.7,12.39,5.86a2,2,0,0,0-2.51-3.2,3.52,3.52,0,1,1,0-5.31Z"/><path class="cls-3" d="M87.69,78.35a2,2,0,0,0,0-4H81.8a2,2,0,0,0-2,2V87a2,2,0,0,0,1,1.75V89h6.83a2,2,0,0,0,0-4H83.81V83.65H87a2,2,0,0,0,0-4h-3.2V78.35Z"/><path class="cls-3" d="M103.09,81.64a7.29,7.29,0,0,0-7.28-7.28H93.69a2,2,0,0,0-2,2V87a2,2,0,0,0,2,2h2.13A7.31,7.31,0,0,0,103.09,81.64ZM95.81,85h-.12V78.35h.12C100.14,78.35,100.18,84.93,95.81,85Z"/><path class="cls-3" d="M92.73,98H22a4,4,0,0,1-4-4V70a4,4,0,0,1,4-4H42.55a2,2,0,0,0,0-4H32.83L59.93,34.89a8,8,0,0,0,8.13,0L81.71,48.54a2,2,0,0,0,2.83-2.83L70.88,32.06A8,8,0,0,0,64,20a2,2,0,0,0,0,4,4,4,0,0,1,2.79,6.86C63.58,34,58.24,30.08,60.51,26a2,2,0,0,0-3.49-2,8,8,0,0,0,.09,8L27.17,62H22a8,8,0,0,0-8,8V94a8,8,0,0,0,8,8H92.73A2,2,0,0,0,92.73,98Z"/><path class="cls-3" d="M106,62h-5.17L88.09,49.26a2,2,0,0,0-2.83,2.83L95.17,62H76a2,2,0,0,0,0,4h30a4,4,0,0,1,4,4V94a4,4,0,0,1-4,4H98.51a2,2,0,0,0,0,4H106a8,8,0,0,0,8-8V70A8,8,0,0,0,106,62Z"/><path class="cls-3" d="M70,62H49.22a2,2,0,0,0,0,4H70A2,2,0,0,0,70,62Z"/></g></svg>`,
	}
	db               *os.File
	matrix           *gomatrix.Client
	espIP            string
	espBlinkDeadline = time.Now().Add(-espMaxBlinkDuration)
)

func init() {
	port := os.Getenv("PORT")
	if val, _ := strconv.Atoi(port); val > 0 {
		config.PORT = port
	}

	config.MATRIXUSERNAME = os.Getenv("MATRIXUSERNAME")
	config.MATRIXACCESSTOKEN = os.Getenv("MATRIXACCESSTOKEN")

	config.MATRIXROOM = os.Getenv("MATRIXROOM")
	config.MATRIXOPENINGMESSAGE = os.Getenv("MATRIXOPENINGMESSAGE")
	config.MATRIXCLOSINGMESSAGE = os.Getenv("MATRIXCLOSINGMESSAGE")

	config.ESPUSERNAME = os.Getenv("ESPUSERNAME")
	config.ESPPASSWORD = os.Getenv("ESPPASSWORD")

	if config.MATRIXUSERNAME == "" {
		panic("MATRIXUSERNAME is empty")
	}
	if config.MATRIXACCESSTOKEN == "" {
		panic("MATRIXACCESSTOKEN is empty")
	}
	var err error
	matrix, err = gomatrix.NewClient(fmt.Sprintf("https://%s", config.MATRIXUSERNAME[strings.Index(config.MATRIXUSERNAME, ":")+1:]), config.MATRIXUSERNAME, config.MATRIXACCESSTOKEN)
	if err != nil {
		panic(fmt.Sprintf("error creating matrix client: %s", err))
	}
	if _, err := matrix.GetOwnStatus(); err != nil { // a way to quickly check if access token is valid
		panic(fmt.Sprintf("error getting matrix status: %s", err))
	}

	if config.MATRIXROOM == "" {
		panic("MATRIXROOM is empty")
	}
	if config.MATRIXOPENINGMESSAGE == "" {
		panic("MATRIXOPENINGMESSAGE is empty")
	}
	if config.MATRIXCLOSINGMESSAGE == "" {
		panic("MATRIXCLOSINGMESSAGE is empty")
	}

	if config.ESPUSERNAME == "" {
		panic("ESPUSERNAME is empty")
	}
	if config.ESPPASSWORD == "" {
		panic("ESPPASSWORD is empty")
	}

	err = os.MkdirAll(filepath.Dir(dbPath), 0755)
	if err != nil {
		panic(err)
	}
	db, err = os.OpenFile(dbPath, os.O_RDWR|os.O_CREATE, 0600)
	if err != nil && !os.IsNotExist(err) {
		panic(err)
	}
	err = json.NewDecoder(db).Decode(&status)
	if err != nil {
		fmt.Println("error unmarshalling db:", err)
	}
}

func updateUptime() {
	for range time.Tick(time.Second) {
		status.ProcessUptime = time.Since(startTime).Truncate(time.Second).String()
	}
}

func checkClosure() {
	time.Sleep(time.Minute) // give some time for presence button to show up
	for {
		if status.LastSeen.Add(defaultClosingTimeout).Before(time.Now()) && status.LastClosed.Before(status.LastSeen) {
			// the Fuz is newly closed, notify on matrix and write file to survive reboot
			fmt.Println("the Fuz is newly closed, notify on matrix and write file to survive reboot")
			msg := config.MATRIXCLOSINGMESSAGE
			if !status.FuzIsOpen {
				msg = fmt.Sprintf("%s : passage bref", msg)
			}
			_, err := matrix.SendText(config.MATRIXROOM, msg)
			if err != nil {
				fmt.Println("err:", err)
				time.Sleep(10 * time.Second)
				continue
			}

			status.LastClosed = time.Now()
			status.FuzIsOpen = false
			db.Truncate(0)
			db.Seek(0, 0)
			e := json.NewEncoder(db)
			e.SetIndent("", "    ")
			e.Encode(status)
		}
		time.Sleep(10 * time.Second)
	}
}

func rootHandler(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		http.NotFound(w, r)
		return
	}
	fmt.Fprintf(w, `Fuz presence button public API

This API provides the current opening status of the hackerspace. This server also posts messages on Matrix to notify when the space opens and closes.

Usage:

/         Shows help
/api      Serves some JSON with lax CORS headers to get the current opening status programatically. The properties are the following:
            * fuzIsOpen: (boolean) reflects if the space is currently open
            * lastSeenAsOpen: (boolean) reflects if the last ping by the ESP was after being pushed (space officially opened)
            * lastSeen: (date) last ESP ping timestamp
            * lastOpened: (date) last space opening timestamp
            * lastClosed: (date) last space closing timestamp
            * processUptime: (duration) API process uptime
/img      Serves an svg image showing if the space is open or closed.
/status   Private endpoint used by the ESP (physical button) to regularly ping/update the opening status.


Source code:        https://github.com/Lomanic/presence-button-web
Source code mirror: https://git.interhacker.space/Lomanic/presence-button-web
Documentation:      https://wiki.fuz.re/doku.php?id=projets:fuz:presence_button`)
}

func apiHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	w.Header().Set("Access-Control-Allow-Origin", "*")
	w.Header().Set("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept")
	e := json.NewEncoder(w)
	e.SetIndent("", "    ")
	e.Encode(status)
}

func imgHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "image/svg+xml")
	w.Header().Set("Cache-Control", "no-store, no-cache, must-revalidate, proxy-revalidate")
	w.Header().Set("Pragma", "no-cache")
	w.Header().Set("Expires", "0")
	fmt.Fprintf(w, imgs[status.FuzIsOpen])
}

func statusHandler(w http.ResponseWriter, r *http.Request) {
	user, pass, ok := r.BasicAuth()
	fmt.Printf("status notification by button... ")
	if !ok || user != config.ESPUSERNAME || pass != config.ESPPASSWORD {
		fmt.Printf("bad authentication: user:%v pass:%v\n", user, pass)
		w.Header().Set("WWW-Authenticate", `Basic realm="Authentication required"`)
		http.Error(w, "Authentication required", 401)
		return
	}

	// handle being behind proxy https://stackoverflow.com/a/33301173
	espIP, _, _ = net.SplitHostPort(r.RemoteAddr)
	for _, ifaceIP := range ifacesIPs() {
		if espIP == ifaceIP {
			for _, header := range []string{"X-Real-Ip", "X-Forwarded-For"} {
				if r.Header.Get(header) != "" {
					espIP = strings.Split(r.Header.Get(header), ", ")[0]
				}
			}
		}
	}
	fmt.Printf("espIP %s ", espIP)


	q := r.URL.Query()
	fuzIsOpen := q.Get("fuzisopen") == "1"
	fmt.Printf("button pushed: %v\n", fuzIsOpen)
	status.FuzIsOpen = fuzIsOpen
	status.LastSeenAsOpen = fuzIsOpen
	status.LastSeen = time.Now()
	fmt.Fprintf(w, "OK")

	db.Truncate(0)
	db.Seek(0, 0)
	e := json.NewEncoder(db)
	e.SetIndent("", "    ")
	e.Encode(status)
	if status.FuzIsOpen && (status.LastOpened.Equal(status.LastClosed) || status.LastOpened.Before(status.LastClosed)) {
		// the Fuz is newly opened, notify on matrix and write file to survive reboot
		fmt.Println("the Fuz is newly opened, notify on matrix and write file to survive reboot")
		_, err := matrix.SendText(config.MATRIXROOM, config.MATRIXOPENINGMESSAGE)
		if err != nil {
			fmt.Println("err:", err)
			return
		}

		status.LastOpened = time.Now()
		db.Truncate(0)
		db.Seek(0, 0)
		e := json.NewEncoder(db)
		e.SetIndent("", "    ")
		e.Encode(status)
	}
}

// https://github.com/qbit/mcchunkie/blob/53eb25ae3394f326e24782f273584e3e6a4c0e8c/plugins/plugins.go#L52-L66
// NameRE matches the "friendly" name. This is typically used in tab
// completion.
var nameRE = regexp.MustCompile(`@(.+):.+$`)

// ToMe returns true of the message pertains to the bot
func toMe(user, message string) bool {
	u := nameRE.ReplaceAllString(user, "$1")
	return strings.Contains(message, u)
}

// RemoveName removes the friendly name from a given message
func removeName(user, message string) string {
	n := nameRE.ReplaceAllString(user, "$1")
	return strings.ReplaceAll(message, n+": ", "")
}

func syncMatrix() {
	syncer := matrix.Syncer.(*gomatrix.DefaultSyncer)
	syncer.OnEventType("m.room.message", func(ev *gomatrix.Event) {
		if ev.Sender != matrix.UserID {
			matrix.MarkRead(ev.RoomID, ev.ID)
			if body, ok := ev.Body(); ok && toMe(config.MATRIXUSERNAME, body) {
				cmd := strings.Fields(removeName(config.MATRIXUSERNAME, body))
				if len(cmd) >= 2 {
					switch cmd[0] {
					case "blink":
						switch cmd[1] {
						case "on":
							if status.FuzIsOpen {
								matrix.SendFormattedText(config.MATRIXROOM, fmt.Sprintf("%s: let's make it **blink**! (%s max)", ev.Sender, espMaxBlinkDuration), fmt.Sprintf("%s: let's make it <b>blink</b>! (%s max)", ev.Sender, espMaxBlinkDuration))
								espBlinkDeadline = time.Now().Add(espMaxBlinkDuration)
							} else {
								matrix.SendText(config.MATRIXROOM, fmt.Sprintf("%s: can't do that, space is closed", ev.Sender))
							}
						case "off":
							if status.FuzIsOpen {
								matrix.SendFormattedText(config.MATRIXROOM, fmt.Sprintf("%s: OK it's time to **STOP**!", ev.Sender), fmt.Sprintf("%s: OK it's time to <b>STOP</b>!", ev.Sender))
								espBlinkDeadline = time.Now()
							} else {
								matrix.SendText(config.MATRIXROOM, fmt.Sprintf("%s: can't do that, space is closed", ev.Sender))
							}
						case "status":
							if time.Now().Before(espBlinkDeadline) {
								matrix.SendText(config.MATRIXROOM, fmt.Sprintf("%s: yes it's still blinking!", ev.Sender))
							} else {
								matrix.SendFormattedText(config.MATRIXROOM, fmt.Sprintf("%s: it's **not** blinking", ev.Sender), fmt.Sprintf("%s: it's <b>not</b> blinking", ev.Sender))
							}
						default:
							matrix.SendFormattedText(config.MATRIXROOM, fmt.Sprintf("%s: command is `blink (status|on|off)`", ev.Sender), fmt.Sprintf("%s: command is <code>blink (status|on|off)</code>", ev.Sender))
						}
						return
					}
				}
				matrix.SendText(config.MATRIXROOM, fmt.Sprintf("%s: huh?", ev.Sender))
			}
		}
	})

	go func() { // set online status every 15 seconds
		for {
			if err := matrix.SetStatus("online", "up and running"); err != nil {
				fmt.Println("error setting matrix status:", err)
			}
			time.Sleep(15 * time.Second)
		}
	}()

	for {
		if err := matrix.Sync(); err != nil {
			fmt.Println("error syncing with matrix:", err)
		}
	}
}

func espBlinkLoop() {
	client := &http.Client{}
	for {
		time.Sleep(time.Second)
		if espIP == "" {
			continue
		}
		if time.Now().Before(espBlinkDeadline) {
			// http.get request to espIP to have it light up
			req, err := http.NewRequest(http.MethodGet, fmt.Sprintf("http://%s/admin?enablerotatinglight", espIP), nil)
			if err != nil {
				fmt.Println("error creating request in espBlinkLoop:", err)
				continue
			}
			req.SetBasicAuth(config.ESPUSERNAME, config.ESPPASSWORD)
			fmt.Print("admin?enablerotatinglight ")
			fmt.Println(client.Do(req))
			time.Sleep(7 * time.Second)

			// http.get request to espIP to shut down light
			req, err = http.NewRequest(http.MethodGet, fmt.Sprintf("http://%s/admin?disablerotatinglight", espIP), nil)
			if err != nil {
				fmt.Println("error creating request in espBlinkLoop:", err)
				continue
			}
			req.SetBasicAuth(config.ESPUSERNAME, config.ESPPASSWORD)
			fmt.Print("admin?disablerotatinglight ")
			fmt.Println(client.Do(req))
			time.Sleep(3 * time.Second)
		}
	}
}

func ifacesIPs() []string { // from https://stackoverflow.com/a/23558495 linked playground
	var ips []string
	ifaces, err := net.Interfaces()
	if err != nil {
		return ips
	}
	for _, iface := range ifaces {
		if iface.Flags&net.FlagUp == 0 {
			continue // interface down
		}
		/*if iface.Flags&net.FlagLoopback != 0 {
			continue // loopback interface
		}*/
		addrs, err := iface.Addrs()
		if err != nil {
			return ips
		}
		for _, addr := range addrs {
			var ip net.IP
			switch v := addr.(type) {
			case *net.IPNet:
				ip = v.IP
			case *net.IPAddr:
				ip = v.IP
			}
			if ip == nil || ip.IsLoopback() {
				continue
			}
			ip = ip.To4()
			if ip == nil {
				continue // not an ipv4 address
			}
			ips = append(ips, ip.String())
		}
	}
	return ips
}

func main() {
	fmt.Println(ifacesIPs())
	go updateUptime()
	go checkClosure()
	go syncMatrix()
	go espBlinkLoop()
	http.HandleFunc("/", rootHandler)
	http.HandleFunc("/api", apiHandler)
	http.HandleFunc("/img", imgHandler)
	http.HandleFunc("/status", statusHandler)
	log.Fatal(http.ListenAndServe(":"+config.PORT, nil))
}