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