server/middlewares/async.ts

   1 import { eachSeries } from 'async'
   2 import { NextFunction, Request, RequestHandler, Response } from 'express'
   3 import { ValidationChain } from 'express-validator'
   4 import { ExpressPromiseHandler } from '@server/types/express'
   5 import { retryTransactionWrapper } from '../helpers/database-utils'
   6 import { HttpMethod, HttpStatusCode } from '@shared/core-utils'
   7
   8 // Syntactic sugar to avoid try/catch in express controllers
   9 // Thanks: https://medium.com/@Abazhenov/using-async-await-in-express-with-node-8-b8af872c0016
  10
  11 export type RequestPromiseHandler = ValidationChain | ExpressPromiseHandler
  12
  13 function asyncMiddleware (fun: RequestPromiseHandler | RequestPromiseHandler[]) {
  14   return (req: Request, res: Response, next: NextFunction) => {
  15     if (Array.isArray(fun) === true) {
  16       return eachSeries(fun as RequestHandler[], (f, cb) => {
  17         Promise.resolve(f(req, res, err => cb(err)))
  18           .catch(err => next(err))
  19       }, next)
  20     }
  21
  22     return Promise.resolve((fun as RequestHandler)(req, res, next))
  23       .catch(err => next(err))
  24   }
  25 }
  26
  27 function asyncRetryTransactionMiddleware (fun: (req: Request, res: Response, next: NextFunction) => Promise<any>) {
  28   return (req: Request, res: Response, next: NextFunction) => {
  29     return Promise.resolve(
  30       retryTransactionWrapper(fun, req, res, next)
  31     ).catch(err => next(err))
  32   }
  33 }
  34
  35 // ---------------------------------------------------------------------------
  36
  37 export {
  38   asyncMiddleware,
  39   asyncRetryTransactionMiddleware
  40 }