gistfile1.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');

/* 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;
  // ignore missing link entries 
  var muell = site.match(/kein-link/i);
  if (muell !== null) { res.writeHead(400, { 'Connection': 'close' }); res.end();  }

  var render = spawn('./node_modules/phantomjs/bin/phantomjs',['screenshot.js', site, id + '.png' ]);
  
  var conn = new ssh2();
  conn.connect({
    "host": "imageserver",
    "port": 22,
    "username": "webshot",
    "privateKey": fs.readFileSync("/web/.ssh/id_rsa")
  });

  conn.on('error',function (err) {
    if (debug >=1) { console.log( "- ssh connection error for " ); }
    res.writeHead(500, { 'Connection': 'close' });
    res.end();
    conn.end();	// always end the connection
  });

  conn.on('close', function() {
    if (debug >= 2) { console.log( " - ssh connection closed "); }
    conn.end();
  });

  conn.on('end', function () {
    if (debug >= 2) { console.log( " - ssh connection ended "); }
    conn.end();		// always end the connection
  });

  conn.on('ready',function () {
    if (debug >= 2) {  console.log( "- ssh connection ready" ); }
  });

  render.stdout.on("data", function(data) {
    gm( id + '.png')
    .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 " ); }
	    res.writeHead(500, { 'Connection': 'close' });
	    res.end();
            conn.end();
          }
          if (debug >= 2) { console.log( "- SFTP started" ); }
          // setup the two streams
          var readStream = fs.createReadStream( id + ".jpg" );				                                //local
          var writeStream = sftp.createWriteStream( "/web/images.city-map.de/www/screenshots/" + id + ".jpg" );		//remote
          writeStream.on('close', function () {		// once the write stream closes, everything
							// ran successfully, return 200 
							// and remove the temp files
            if (debug >= 1 ) { console.log( "- file transferred %s for site: %s", id, site ); }
	    res.writeHead(200);
	    res.end();					// end http connection
            sftp.end();					// end sftp 
	    conn.end();					// always end the connection
	    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 ); };
        res.writeHead(500, { 'Connection': 'close' }); 	// whoopsie, something went wrong
        res.end();
        conn.end();
      };
    });
  });

  render.stderr.on("data", function(data) {
    if (debug >= 1) { console.log("error executing phantom.js: ", data); };
    res.writeHead(500, { 'Connection': 'close' });
    res.end();
    conn.end();
  });
  render.on("exit", function(code) {
    if (debug >= 2) { console.log("phantom exited"); };
  });

}).listen('systemd');