trailsjs/trailpack-repl

/* eslint no-process-env: 0 */
const fs = require('fs')
const path = require('path')
const repl = require('repl')
const Trailpack = require('trailpack')
const lib = require('./lib')

/**
 * @class REPL
 *
 * Provide an interactive Javascript shell for Trails applications
 *
 * @see {@link https://nodejs.org/api/repl.html#repl_repl}
 */
module.exports = class REPL extends Trailpack {

  validate() {

  }

  configure() {
    lib.Inspect.configureApp(this.app)
    lib.Inspect.configureApi(this.app.api)
    lib.Inspect.configurePacks(this.app.packs)
    lib.Http.init(this.app)

    if (!this.config.historyFileName) {
      this.config.historyFileName = process.env.NODE_REPL_HISTORY || '.node_repl_history'
    }

    if (!this.config.historySize) {
      this.config.historySize = process.env.NODE_REPL_HISTORY_SIZE || 1000
    }

    this.historyFile = path.resolve(
      this.app.config.get('main.paths.temp'),
      this.config.historyFileName
    )

    this.app.log.debug('historyFile', this.historyFile)
  }

  async initialize () {
    // https://nodejs.org/api/process.html#process_tty_terminals_and_process_stdout
    if (!process.stdout.isTTY) {
      this.app.log.info('trailpack-repl: No text terminal available. ')

      if (!this.app.config.get('repl.allowNoTTY')) {
        this.app.log.info('trailpack-repl: REPL not started. Continuing.')
        this.app.log.debug('trailpack-repl: Set config.repl.allowNoTTY=true to override')
        return
      }
      else {
        this.app.log.warn('trailpack-repl: allowNoTTY is enabled, Launching REPL anyway.')
      }
    }

    try {
      this.server = repl.start({
        prompt: '',
        useColors: true,
        replMode: repl.REPL_MODE_STRICT,
        historySize: this.config.historySize
      })
      this.server.pause()
      this.app.once('trails:ready', () => {
        // green prompt
        this.server.setPrompt('\u001b[1;32mtrails > \u001b[0m')
        this.server.resume()
        this.server.write('', { name: 'return' })
      })
    }
    catch (e) {
      this.app.log.error(e)
      this.app.log.warn('trailpack-repl: Disabling REPL.')
      return
    }

    try {
      fs.statSync(this.historyFile)
      fs.readFileSync(this.historyFile).toString()
        .split('\n')
        .reverse()
        .slice(0, this.config.historySize)
        .filter(line => line.trim())
        .map(line => this.server.history.push(line))
    }
    catch (e) {
      this.app.log.silly('Could not read REPL history file at', this.historyFile)
      this.app.log.silly('No problem, a history file will be created on shutdown')
    }

    this.server.once('exit', () => {
      this.app.stop().then(() => process.exit())
    })

    this.server.context.app = this.app

    // TODO https://github.com/trailsjs/trailpack-repl/issues/33
    this.server.context.get = lib.Http.get.bind(lib.Http)
    this.server.context.post = lib.Http.post.bind(lib.Http)
    this.server.context.put = lib.Http.put.bind(lib.Http)
    this.server.context.delete = lib.Http.delete.bind(lib.Http)
    this.server.context.patch = lib.Http.patch.bind(lib.Http)
    this.server.context.head = lib.Http.head.bind(lib.Http)
    this.server.context.options = lib.Http.options.bind(lib.Http)
  }

  addCommand(command, handler) {
    if (this.server) {
      this.server.context[command] = handler
    }
  }

  unload () {
    if (!process.stdout.isTTY && !this.app.config.get('repl.allowNoTTY')) {
      return
    }

    this.server.removeAllListeners('exit')
    this.server.close()

    try {
      const lines = (this.server.history || [])
        .reverse()
        .filter(line => line.trim())
        .join('\n')

      fs.writeFileSync(this.historyFile, lines)
    }
    catch (e) {
      this.app.log.debug(e)
      this.app.log.warn('Could not create REPL history file at', this.historyFile)
      this.app.log.warn('This is strange, but not fatal. Set loglevel to "debug" for more info')
    }

    lib.Inspect.unconfigureApp(this.app)
    lib.Inspect.unconfigureApi(this.app.api)
    lib.Inspect.unconfigurePacks(this.app.packs)
  }

  constructor(app) {
    super(app, {
      config: require('./config'),
      pkg: require('./package')
    })
  }
}