repo_description: Fast and low overhead web framework, for Node.js
repo_topics: hacktoberfest nodejs performance speed webframework
code: 'use strict'
  
  const FindMyWay = require('find-my-way')
  
  const Reply = require('./reply')
  const Request = require('./request')
  const Context = require('./context')
  const {
    kRoutePrefix,
    kCanSetNotFoundHandler,
    kFourOhFourLevelInstance,
    kFourOhFourContext,
    kHooks,
    kErrorHandler
  } = require('./symbols.js')
  const { lifecycleHooks } = require('./hooks')
  const { buildErrorHandler } = require('./error-handler.js')
  const {
    FST_ERR_NOT_FOUND
  } = require('./errors')
  const { createChildLogger } = require('./logger-factory')
  const { getGenReqId } = require('./req-id-gen-factory.js')
  
  /**
   * Each fastify instance have a:
   * kFourOhFourLevelInstance: point to a fastify instance that has the 404 handler set
   * kCanSetNotFoundHandler: bool to track if the 404 handler has already been set
   * kFourOhFour: the singleton instance of this 404 module
   * kFourOhFourContext: the context in the reply object where the handler will be executed
   */
  function fourOhFour (options) {
    const { logger, disableRequestLogging } = options
  
    // 404 router, used for handling encapsulated 404 handlers
    const router = FindMyWay({ onBadUrl: createOnBadUrl(), defaultRoute: fourOhFourFallBack })
    let _onBadUrlHandler = null
  
    return { router, setNotFoundHandler, setContext, arrange404 }
  
    function arrange404 (instance) {
      // Change the pointer of the fastify instance to itself, so register + prefix can add new 404 handler
      instance[kFourOhFourLevelInstance] = instance
      instance[kCanSetNotFoundHandler] = true
      // we need to bind instance for the context
      router.onBadUrl = router.onBadUrl.bind(instance)
      router.defaultRoute = router.defaultRoute.bind(instance)
    }
  
    function basic404 (request, reply) {
      const { url, method } = request.raw
      const message = `Route ${method}:${url} not found`
      const resolvedDisableRequestLogging = typeof disableRequestLogging === 'function' ? disableRequestLogging(request.raw) : disableRequestLogging
      if (!resolvedDisableRequestLogging) {
        request.log.info(message)
      }
      reply.code(404).send({
        message,
        error: 'Not Found',
        statusCode: 404
      })
    }
  
    function createOnBadUrl () {
      return function onBadUrl (path, req, res) {
        const fourOhFourContext = this[kFourOhFourLevelInstance][kFourOhFourContext]
        const id = getGenReqId(fourOhFourContext.server, req)
        const childLogger = createChildLogger(fourOhFourContext, logger, req, id)
        const request = new Request(id, null, req, null, childLogger, fourOhFourContext)
        const reply = new Reply(res, request, childLogger)
  
        _onBadUrlHandler(request, reply)
      }
    }
  
    function setContext (instance, context) {
      const _404Context = Object.assign({}, instance[kFourOhFourContext])
      _404Context.onSend = context.onSend
      context[kFourOhFourContext] = _404Context
    }
  
    function setNotFoundHandler (opts, handler, avvio, routeHandler) {
      // First initialization of the fastify root instance
      if (this[kCanSetNotFoundHandler] === undefined) {
        this[kCanSetNotFoundHandler] = true
      }
      if (this[kFourOhFourContext] === undefined) {
        this[kFourOhFourContext] = null
      }
  
      const _fastify = this
      const prefix = this[kRoutePrefix] || '/'
  
      if (this[kCanSetNotFoundHandler] === false) {
        throw new Error(`Not found handler already set for Fastify instance with prefix: '${prefix}'`)
      }
  
      if (typeof opts === 'object') {
        if (opts.preHandler) {
          if (Array.isArray(opts.preHandler)) {
            opts.preHandler = opts.preHandler.map(hook => hook.bind(_fastify))
          } else {
            opts.preHandler = opts.preHandler.bind(_fastify)
          }
        }
  
        if (opts.preValidation) {
          if (Array.isArray(opts.preValidation)) {
            opts.preValidation = opts.preValidation.map(hook => hook.bind(_fastify))
          } else {
            opts.preValidation = opts.preValidation.bind(_fastify)
          }
        }
      }
  
      if (typeof opts === 'function') {
        handler = opts
        opts = undefined
      }
      opts = opts || {}
  
      if (handler) {
        this[kFourOhFourLevelInstance][kCanSetNotFoundHandler] = false
        handler = handler.bind(this)
        // update onBadUrl handler
        _onBadUrlHandler = handler
      } else {
        handler = basic404
        // update onBadUrl handler
        _onBadUrlHandler = basic404
      }
  
      this.after((notHandledErr, done) => {
        _setNotFoundHandler.call(this, prefix, opts, handler, avvio, routeHandler)
        done(notHandledErr)
      })
    }
  
    function _setNotFoundHandler (prefix, opts, handler, avvio, routeHandler) {
      const context = new Context({
        schema: opts.schema,
        handler,
        config: opts.config || {},
        server: this
      })
  
      avvio.once('preReady', () => {
        const context = this[kFourOhFourContext]
        for (const hook of lifecycleHooks) {
          const toSet = this[kHooks][hook]
            .concat(opts[hook] || [])
            .map(h => h.bind(this))
          context[hook] = toSet.length ? toSet : null
        }
        context.errorHandler = opts.errorHandler
          ? buildErrorHandler(this[kErrorHandler], opts.errorHandler)
          : this[kErrorHandler]
      })
  
      if (this[kFourOhFourContext] !== null && prefix === '/') {
        Object.assign(this[kFourOhFourContext], context) // Replace the default 404 handler
        return
      }
  
      this[kFourOhFourLevelInstance][kFourOhFourContext] = context
  
      router.all(prefix + (prefix.endsWith('/') ? '*' : '/*'), routeHandler, context)
      router.all(prefix, routeHandler, context)
    }
  
    function fourOhFourFallBack (req, res) {
      // if this happen, we have a very bad bug
      // we might want to do some hard debugging
      // here, let's print out as much info as
      // we can
      const fourOhFourContext = this[kFourOhFourLevelInstance][kFourOhFourContext]
      const id = getGenReqId(fourOhFourContext.server, req)
      const childLogger = createChildLogger(fourOhFourContext, logger, req, id)
  
      childLogger.info({ req }, 'incoming request')
  
      const request = new Request(id, null, req, null, childLogger, fourOhFourContext)
      const reply = new Reply(res, request, childLogger)
  
      request.log.warn('the default handler for 404 did not catch this, this is likely a fastify bug, please report it')
      request.log.warn(router.prettyPrint())
      reply.code(404).send(new FST_ERR_NOT_FOUND())
    }
  }
  
  module.exports = fourOhFour
  