screenshot-service.js

var http = require('http');
var url  = require('url');
var spawn = require('child_process').spawn, child;
var fs = require('fs');
var util = require('util');
var gm = require('gm');
var ssh2 = require('ssh2');
var debug = 1; // increase to increase verbosity
require('systemd');


var conn = new ssh2();
options = {
  "host": "imageserver",
  "port": 22,
  "username": "username",
  "privateKey": fs.readFileSync("/home/username/.ssh/id_rsa")
};
conn.connect(options);
conn.on('error',function (err) {
  if (debug >=1) { console.log( " - ssh connection error" ); };
});
conn.on('close', function() {
  if (debug >= 2) { console.log( " - ssh connection closed, reconnecting in 2 seconds"); };
  setTimeout(function() { conn.connect(options); }, 2000);
});
conn.on('end', function () {
  if (debug >= 2) { console.log( " - ssh connection ended"); };
//  setTimeout(function() { conn.connect(options); }, 2000);
});
conn.on('ready',function () {
  if (debug >= 2) { console.log( "- ssh connection ready for %s"); }
});



/* create a server to receive callbacks from the screenshot service*/

http.createServer(function(req, res) {
  var urldata = url.parse(req.url, true).query;
  var site = urldata.url;
  var id = urldata.id;
  var render = spawn('./node_modules/phantomjs/bin/phantomjs',['screenshot.js', site, id + '.png' ]);

  function sendErr(code) {
    res.writeHead(code, { 'Connection': 'close' });
    res.end();
//    conn.end();
  }
  function sendOk() {
    res.writeHead(200);
    res.end();
//    conn.end();
  }
  
  render.stdout.on("data", function(data) {
    if (debug >= 2) { console.log( " - taking shot of: ==> %s <== to file: %s", site, id ); } 
  });

  // once our rederer exits, the shot was taken
  render.on("exit", function(code) {
    // make sure we get the full file, so read sync
    // if ENOENT, we can assume phantom failed and return 500
    try {
      var src = fs.readFileSync('./'+id+'.png');
    } catch(e) {
      if (e.code === 'ENOENT') {
        if (debug >= 2) { console.log(" - taking shot for: %s to file %s +++FAILED!+++", site, id); };
        console.log(' - %s: for site %s', e.message, site);
      } else { throw e; };
      sendErr('500');
      return;
    };

    gm(src)
    .flatten()
    .background('#ffffff')
    .resize(290, 220, "^")
    .extent(290, 220)
    .gravity('north')
    .quality(100)
    .sharpen(0, 0.8)
    .write(id + '.jpg', function (err) {
      if (!err) {
        if (debug >= 2) { console.log("file: %s written for site: %s", id, site); };
        conn.sftp(function (err, sftp) {
          if (err) {
            if (debug >= 1) {  console.log( "Error, problem starting SFTP for %s", site ); }
            sendErr('500');
          }
          if (debug >= 2) { console.log( "- SFTP started for %s", site ); }
	// setup the two streams
          var readStream = fs.createReadStream( id + ".jpg" );								//local
          var writeStream = sftp.createWriteStream( "/web/screenshots/" + id + ".jpg" );	                	//remote
          writeStream.on('close', function () {		// once the write stream closes, everything ran successfully, return 200 
            if (debug >= 1 ) { console.log( "- file transferred %s for site: %s", id, site ); }
            sftp.end();
            sendOk();
	// clean up our mess
	    fs.unlink(id + '.png', function(err){ if (err && debug >= 1 ) { console.log("could not remove "+id+".png after transfer" ); }; });
            fs.unlink(id + '.jpg', function(err){ if (err && debug >= 1 ) { console.log("could not remove "+id+".jpg after transfer" ); }; });
          });
          readStream.pipe( writeStream );  		// connect the two streams
        });
      } else { 
        if (debug >= 1) { console.log( "something went wrong upon gm .write operation on %s for site %s", id, site ); };
          sendErr('500');
      };
    });
  });

  render.stderr.on("data", function(data) {
    if (debug >= 1) { console.log("error executing phantom.js: ", data); };
      sendErr('500');
  });

}).listen('systemd');