provide-handler

Convenience wrapper for Express handlers.

Installation

npm i --save provide-handler

Usage

Handler methods are responsible only for processing whatever inputs they need (e.g., req.params, req.body, etc.) and returning a value. That return value will be wrapped in a Promise if it isn't already thenable. The usual Express res, res, next are available within handler methods. However, for most common cases this module does the work of processing the Express response, calling res.status(200).json with the handler's return value on success and next(err) on failure.

You can pass your data model(s) to the constructor for them to be available in handler methods as @Name, where Name is the exported model property (see below).

Example handler (called by Express route):

Handler = require 'provide-handler'

class TicketHandler extends Handler
  proxy: # methods which should be wrapped in Promise
    # here we're dereferencing QUERY from req because it's all we need...
    get: ({ query }) ->
      @Ticket.all query

    # ...and here we only need req.params...
    for_customer: ({ params }) ->
      @Ticket.find_by_customer params.customer_id

module.exports = new TicketHandler require '../models'

If you need to return a status other than the default, you can call res directly from your handler:

  # pass custom response back to Express...
  for_customer: ({ params }, res) ->
    @Ticket.find_by_customer(params.customer_id).then (data) ->
      return res.sendStatus 404 unless data?
      data
    .catch (err) ->
      res.sendStatus 500

Handlers are called from Express app like:

express = require 'express'
handler = require '../handlers/ticket' # the example file above
app = express()

customer = express.Router()
customer.get '/:customer_id/tickets', handler.for_customer
app.use '/customer', customer

ticket = express.Router()
ticket.get '/', handler.get
app.use '/ticket', ticket

Testing

npm test