server.js

/**
  * This server is only intended for development so that we can be sure the 
  * static assets will all be refreshed at request time. With just gulp, there 
  * are times when refreshing happens before gulp has finished rendering out all
  * static resources.
  */

'use strict'

var fs = require('fs')
var path = require('path')
var mkdirp = require('mkdirp')
var express = require('express')
var bundlers = require('./bundlers')
var app = express()
var jade = require('jade')
var localsStore = require('./localsStore')
var locals = localsStore.refresh()
var argv = require('minimist')(process.argv.slice(2))
var minify = true
var debug = true

app.set('etag', 'strong')

app.get('/ev/:slug/', function(req, res, next) {
  var slug = req.params.slug
  if (!locals.explanationsHash[slug]) return next()
  var filename = path.join(__dirname, locals.src, 'explanations', slug,
    'index.jade')
  var file = fs.readFileSync(filename)
  var fn = jade.compile(file.toString(), {filename: filename, pretty: true})
  var myLocals = localsStore.forSlug(slug)
  myLocals.dev = argv.dev || myLocals.dev
  res.send(fn(myLocals))
})

function explanationResource(slug, resource) {
  return path.join(__dirname, locals.src, 'explanations', slug, resource)
}

// Old individual script file version...
app.get(/\/ev\/([^\/]*)\/(.*)/, function(req, res, next) {
  var slug = req.params[0] // Explanation slug.
  if (!locals.explanationsHash[slug]) return next()
  var resource = req.params[1] // Explanation specific resource.
  var filename = explanationResource(slug, resource)
  fs.exists(filename, function(exists) {
    if (!exists) next()
    else res.sendFile(filename)
  })
})

// New browserify friendly commonJS and es6 enabled version!
app.get('/ev/:slug/_bundle.js', function(req, res, next) {
  res.type('.js')
  var slug = req.params.slug
  if (!locals.explanationsHash[slug]) return next()
  var explanationDir = path.join('client', 'explanations', slug)
  var entryPoint = path.join(__dirname, explanationDir, 'src/main.js')
  fs.exists(entryPoint, function(exists) {
    if (!exists) {
      return next(new Error('Request for bundle without entry point. Path: \n'
        + entryPoint))
    }
    var bundle = bundlers.js.explanationMain({
      debug: debug,
      watchify: true,
      minify: minify,
    }).require(entryPoint, {entry: true})
      .on('error', function(err) {
        console.error(err.message)
        res.status(500).send(err.message)
        this.emit('end')
      })
      .bundle()
      .pipe(res)
  })
})

app.use(express.static(__dirname + '/_static'))

;(function commonSharedRequestHandler() {
  var relative = '/ev/_build/js/common-shared.js'
  var output = path.join(__dirname, locals.staticOutputDir, relative)
  mkdirp.sync(path.dirname(output))
  fs.exists(output, function(exists) {
    if (exists) fs.unlink(output, function(err) {
      if (err) throw err
    })
  })
  console.log('rebuilding third party modules')
  app.get(relative, function(req, res) {
    res.type('.js') // Set Content-Type: text/javascript
    var bundle = bundlers.js.commonSharedModules({
      debug: debug,
      minify: minify,
    }).bundle()
    bundle.pipe(res)
    bundle.pipe(fs.createWriteStream(output))
  })
})()


var server = app.listen(argv.port || 3000)