app.js

'use strict'

var compression = require('compression')
var debug = require('debug')('apiembed')
var express = require('express')
var HTTPSnippet = require('httpsnippet')
var morgan = require('morgan')
var unirest = require('unirest')

module.exports = function (callback) {
  var availableTargets = HTTPSnippet.availableTargets().reduce(function (targets, target) {
    if (target.clients) {
      targets[target.key] = target.clients.reduce(function (clients, client) {
        clients[client.key] = false
        return clients
      }, {})
    } else {
      targets[target.key] = false
    }

    return targets
  }, {})

  var namedTargets = HTTPSnippet.availableTargets().reduce(function (targets, target) {
    if (target.clients) {
      targets[target.key] = target

      targets[target.key].clients = target.clients.reduce(function (clients, client) {
        clients[client.key] = client
        return clients
      }, {})
    } else {
      targets[target.key] = target
    }

    return targets
  }, {})

  var APIError = function (code, message) {
    this.name = 'APIError'
    this.code = code || 500
    this.message = message || 'Oops, something went wrong!'
  }

  APIError.prototype = Error.prototype

  // express setup
  var app = express()
  app.set('view engine', 'jade')
  app.disable('x-powered-by')

  if (!process.env.NOCACHE) {
    app.enable('view cache')
  }

  // logging
  app.use(morgan('dev'))

  // add 3rd party middlewares
  app.use(compression())

  // useful to get info in the view
  app.locals.HTTPSnippet = HTTPSnippet
  app.locals.namedTargets = namedTargets

  // enable CORS
  app.use(function (req, res, next) {
    res.header('Access-Control-Allow-Origin', '*')
    res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept')
    next()
  })

  // static middleware does not work here
  app.use('/favicon.ico', function (req, res) {
    res.sendFile(__dirname + '/static/favicon.ico')
  })

  // static middleware does not work here
  app.use('/targets', function (req, res) {
    res.json(HTTPSnippet.availableTargets())
  })

  app.get('/', function (req, res, next) {
    var source = decodeURIComponent(req.query.source)
    var targets = req.query.targets || 'all'

    if (!source) {
      return next(new APIError(400, 'Invalid input'))
    }

    debug('received request for source: %s & targets: %s', source, targets)

    // parse the requested targets
    // TODO this needs optimization
    var requestedTargets = targets.split(',').reduce(function (requested, part) {
      var i = part.split(':')

      var target = i[0] || 'all'
      var client = i[1] || 'all'

      // all targets
      if (target === 'all') {
        // set all members to true
        return Object.keys(availableTargets).reduce(function (requested, target) {
          if (typeof availableTargets[target] === 'object') {
            requested[target] = Object.keys(availableTargets[target]).reduce(function (clients, client) {
              clients[client] = true
              return clients
            }, {})
          } else {
            requested[target] = true
          }

          return requested
        }, {})
      }

      // all clients?
      if (availableTargets.hasOwnProperty(target)) {
        if (typeof availableTargets[target] === 'object') {
          if (client === 'all') {
            requested[target] = Object.keys(availableTargets[target]).reduce(function (clients, client) {
              clients[client] = true
              return clients
            }, {})
          } else {
            if (availableTargets[target].hasOwnProperty(client)) {
              requested[target] = requested[target] ? requested[target] : {}
              requested[target][client] = true
            }
          }
        } else {
          requested[target] = true
        }

        return requested

      }

      return requested
    }, {})

    unirest.get(source)
      .headers({'Accept': 'application/json'})
      .end(function (response) {
        if (response.error) {
          debug('failed to load source over http: %s %s', response.code || response.error.code, response.status || response.error.message)

          return next(new APIError(400, 'Could not load JSON source'))
        }

        var snippet
        var output = {}

        if (typeof response.body !== 'object') {
          try {
            response.body = JSON.parse(response.body)
          } catch (err) {
            debug('failed to parse content of %s, with error: %s', source, err.message)

            return next(new APIError(400, 'Invalid JSON source'))
          }
        }

        try {
          snippet = new HTTPSnippet(response.body)
        } catch (err) {
          debug('failed to generate snippet object: %s', err.message)

          return next(new APIError(400, err))
        }

        Object.keys(requestedTargets).map(function (target) {
          if (typeof requestedTargets[target] === 'object') {
            output[target] = {}

            return Object.keys(requestedTargets[target]).map(function (client) {
              output[target][client] = snippet.convert(target, client)
            })
          }

          output[target] = snippet.convert(target)
        })

        if (Object.keys(output).length === 0) {
          debug('no matching targets found')

          return next(new APIError(400, 'Invalid Targets'))
        }

        res.render('main', {
          output: output
        })

        res.end()
      })
  })

  // error handler
  app.use(function errorHandler (error, req, res, next) {
    if (error.code === 400) {
      error.message += ', please review the <a href="https://apiembed.com/#docs" target="_blank">documentation</a> and try again'
    }

    // never show a 40x
    res.status(200)
    res.render('error', error)
  })

  app.listen(process.env.PORT || process.env.npm_package_config_port)

  if (typeof callback === 'function') {
    callback()
  }
}