pb-server.js

//--------------------------------------------------
// Photo-booth service
// by: Alexander Terczka <alex@mail.at>
//--------------------------------------------------

// --- settings
var slideshowdir = "images/slideshow/";
var inactive_slideshowdir = "images/inactive_slideshow/";
var port = 8082;
var use_gphoto2_as_webcam = true;

// --- requires
var fs = require('fs');
var express = require('express');
var exec = require('child_process').exec;
var spawn = require('child_process').spawn;

var app = express();

function read_slideshow_dir(dir,callback)
{
    fs.readdir(dir,function (err,files) {
	if (err) { throw new Error(err); }
	callback(files);
    });
}

//
// ---------- webcam process controll
// this process streams gphoto2 to webcam v4l2
// and is stopped for taking photos
// 
var webcam_process=false;
var webcam_mode=false;
var last_attempt=0;

function start_webcam_mode()
{
    if (!use_gphoto2_as_webcam) return;
    webcam_mode=true;
    keep_webcam_running();
}

function keep_webcam_running()
{
    if (webcam_mode==false) return;

    var now=new Date().getTime();
    if (now-last_attempt<5000) // 5s
    {       // try later again
	setTimeout(keep_webcam_running,5000);
	return;
    }
    last_attempt=now;
    webcam_process=spawn("./start_webcam.sh",[],{ "stdio":"inherit" });
    webcam_process.on("error",function (e) { console.log("Could not start webcam_process\n"); keep_webcam_running(); });
    webcam_process.on("close",function (c) { console.log("Webcam_process terminated with "+c+"\n"); keep_webcam_running(); });
}

function stop_webcam_mode()
{
    if (!use_gphoto2_as_webcam) return;
    webcam_mode=false;
    webcam_process=spawn("./stop_webcam.sh",[],{ "stdio":"inherit" });
}

//
// ----  API URLs
//
    app.get("/capture",function(req,res) {
        // Capture a photo using die capture shell script
	// and send the name to the browser or error text
	stop_webcam_mode();
	setTimeout(function () {
	    console.log("Taking photo\n");
            exec('./capture-photo.sh', function (error, stdout, stderr) {
  	        if (error) res.send({error: "Capture Script Fehler"});
  	        else if (stdout.trim()=="ERROR") res.send({error: "Kamera Fehler"});
  	        else res.send({image:stdout.trim()});
		start_webcam_mode();
	    });
	},100);
    });

    app.get("/images.json",function(req,res) {
        read_slideshow_dir(slideshowdir,function (data) { res.send(data); });
    });

    app.get("/inactive.images.json",function(req,res) {
        read_slideshow_dir(inactive_slideshowdir,function (data) { res.send(data); });
    });

    app.get("/deactivate",function(req,res) {
	var img=req.query.img;
	if (img.match("^[a-zA-Z0-9][a-zA-Z.0-9_-]+$")==null) { res.send("invalid filename"); return; }
	fs.renameSync(slideshowdir+img,inactive_slideshowdir+img);
  	res.send("OK");
    });

    app.get("/reactivate",function(req,res) {
	var img=req.query.img;
	if (img.match("^[a-zA-Z0-9][a-zA-Z.0-9_-]+$")==null) { res.send("invalid filename"); return; }
	fs.renameSync(inactive_slideshowdir+img,slideshowdir+img);
  	res.send("OK");
    });
//
// ---- Client Libraries
//
    app.use("/jquery",express.static('node_modules/jquery/dist/'));

//
// ----  serve static files from "htdocs" files
//
    app.get('/', function (req, res) { res.sendFile(__dirname+"/htdocs/index.html"); });
    app.get('/admin', function (req, res) { res.sendFile(__dirname+"/htdocs/admin.html"); });

    app.use(express.static('htdocs'));
    app.use("/images",express.static('images/slideshow/'));
    app.use("/inactive-images",express.static('images/inactive_slideshow/'));

//
// ---- Startup
//


// 
// ---- GO!
// 
    app.listen(port, function () { console.log("Photo-booth service listening on port "+port+"!"); });
    start_webcam_mode();