server/middlewares/async.ts

   1 import Bluebird from 'bluebird'
   2 import { NextFunction, Request, RequestHandler, Response } from 'express'
   3 import { ValidationChain } from 'express-validator'
   4 import { ExpressPromiseHandler } from '@server/types/express-handler'
   5 import { retryTransactionWrapper } from '../helpers/database-utils'
   6
   7 // Syntactic sugar to avoid try/catch in express controllers/middlewares
   8
   9 export type RequestPromiseHandler = ValidationChain | ExpressPromiseHandler
  10
  11 function asyncMiddleware (fun: RequestPromiseHandler | RequestPromiseHandler[]) {
  12   return (req: Request, res: Response, next: NextFunction) => {
  13     if (Array.isArray(fun) === true) {
  14       return Bluebird.each(fun as RequestPromiseHandler[], f => {
  15         return new Promise<void>((resolve, reject) => {
  16           return asyncMiddleware(f)(req, res, err => {
  17             if (err) return reject(err)
  18
  19             return resolve()
  20           })
  21         })
  22       }).then(() => next())
  23         .catch(err => next(err))
  24     }
  25
  26     return Promise.resolve((fun as RequestHandler)(req, res, next))
  27       .catch(err => next(err))
  28   }
  29 }
  30
  31 function asyncRetryTransactionMiddleware (fun: (req: Request, res: Response, next: NextFunction) => Promise<any>) {
  32   return (req: Request, res: Response, next: NextFunction) => {
  33     return Promise.resolve(
  34       retryTransactionWrapper(fun, req, res, next)
  35     ).catch(err => next(err))
  36   }
  37 }
  38
  39 // ---------------------------------------------------------------------------
  40
  41 export {
  42   asyncMiddleware,
  43   asyncRetryTransactionMiddleware
  44 }