/*
* Storoid worker.
*
* Configure in storoid.config.json.
*/
// global includes
var express = require('express'),
cluster = require('cluster'),
http = require('http'),
fs = require('fs'),
child_process = require('child_process'),
request = require('request'),
querystring = require('querystring');
var config;
// Get the config
try {
config = JSON.parse(fs.readFileSync('./mathoid.config.json', 'utf8'));
} catch ( e ) {
// Build a skeleton localSettings to prevent errors later.
console.error("Please set up your mathoid.config.json from the example " +
"storoid.config.json.example");
process.exit(1);
}
/**
* The name of this instance.
* @property {string}
*/
var instanceName = cluster.isWorker ? 'worker(' + process.pid + ')' : 'master';
console.log( ' - ' + instanceName + ' loading...' );
/*
* Backend setup
*/
var restarts = 10;
var backend,
backendStarting = false,
backendPort,
requestQueue = [];
// forward declaration
var handleRequests;
var backendCB = function () {
backendStarting = false;
handleRequests();
};
var startBackend = function (cb) {
if (backend) {
backend.removeAllListeners();
backend.kill('SIGKILL');
}
backendPort = Math.floor(9000 + Math.random() * 50000);
console.error(instanceName + ': Starting backend on port ' + backendPort);
backend = child_process.spawn('phantomjs', ['main.js', backendPort]);
backend.stdout.pipe(process.stderr);
backend.stderr.pipe(process.stderr);
backend.on('close', startBackend);
backendStarting = true;
// give backend 1 seconds to start up
setTimeout(backendCB, 1000);
};
startBackend();
/* -------------------- Web service --------------------- */
var app = express.createServer();
// Increase the form field size limit from the 2M default.
app.use(express.bodyParser({maxFieldsSize: 25 * 1024 * 1024}));
app.use( express.limit( '25mb' ) );
app.get('/', function(req, res){
res.write('\n');
res.write('Welcome to Mathoid. POST to / with var tex');
res.write('');
res.end('');
});
// robots.txt: no indexing.
app.get(/^\/robots.txt$/, function ( req, res ) {
res.end( "User-agent: *\nDisallow: /\n" );
});
function handleRequest(req, res, tex) {
// do the backend request
var reqbody = new Buffer(querystring.stringify({tex: tex})),
options = {
method: 'POST',
uri: 'http://localhost:' + backendPort.toString() + '/',
body: reqbody,
// Work around https://github.com/ariya/phantomjs/issues/11421 by
// setting explicit upper-case headers (request sends them lowercase
// by default) and manually encoding the body.
headers: {
'Content-Length': reqbody.length,
'Content-Type': 'application/x-www-form-urlencoded'
},
timeout: 2000
};
request(options, function (err, response, body) {
body = new Buffer(body);
if (err || response.statusCode !== 200) {
var errBuf;
if (err) {
errBuf = new Buffer(JSON.stringify({
tex: tex,
log: err.toString(),
success: false
}));
} else {
errBuf = body;
}
res.writeHead(500,
{
'Content-Type': 'application/json',
'Content-Length': errBuf.length
});
res.end(errBuf);
// don't retry the request
requestQueue.shift();
startBackend();
return handleRequests();
}
res.writeHead(200,
{
'Content-Type': 'application/json',
'Content-length': body.length
});
res.end(body);
requestQueue.shift();
handleRequests();
});
}
handleRequests = function() {
// Call the next request on the queue
if (!backendStarting && requestQueue.length) {
requestQueue[0]();
}
};
app.post(/^\/$/, function ( req, res ) {
// First some rudimentary input validation
if (!req.body.tex) {
res.writeHead(400);
return res.end(JSON.stringify({error: "'tex' post parameter is missing!"}));
}
var tex = req.body.tex;
requestQueue.push(handleRequest.bind(null, req, res, tex));
// phantomjs only handles one request at a time. Enforce this.
if (requestQueue.length === 1) {
// Start this process
handleRequests();
}
});
console.log( ' - ' + instanceName + ' ready' );
module.exports = app;