0.2.1 • Published 5 years ago

@midwest/responder v0.2.1

Weekly downloads
-
License
MIT
Repository
github
Last release
5 years ago

Midwest Responder

One of the main concepts behind Midwest is a global responder middleware. Basically no other middleware should be sending the response, they should simply call next() until the responder is reached. The responder then either send the contents of res.locals as JSON or renders a template.

Only the global responder should ever be terminating a request (ie. send a response).

The responder is a very short and simple middleware that decides what to send back to the client.

Usage

const errorHandler = require('@midwest/error-handler')(config.errorHandler)

server.use([
  require('midwest/middleware/ensure-found'),
  // format and log error
  errorHandler,
  // respond
  require('@midwest/responder')({
    errorHandler,
    logError: require('@midwest/error-handler/log'),
  }),
])

Rendering

When the responder renders, calls the the render method:

res.render(res.master, ...(res.templates || []))

Master vs Template

The master is the template that contains the <html>, <head> and <body> tags. It includes scripts, styles etc.

Prevent Flattening

If there is only a single property on the res.locals object, the responder will send that property directly. Ie. if res.locals = { poopsicle: {...} } {...} will be sent instead of { poopsicle: {...} }.

Caveats

Static routes also matching dynamic routes

Since no middleware except the responder should be sending the response, dynamic routes that match static routes will clash.

Ie. if you have

server.get('/api/users/me', mw.getCurrent)
server.get('/api/users/:id', isAdmin, mw.findById)

and make a request to /api/users/me, the isAdmin and mw.findById middleware will always be called after mw.getCurrent. If the user is not an admin, all requests to /api/users/me will return the 401 response from isAdmin middleware.

To prevent this, create a Express#param function like so:

router.param(':id', (req, res, next, id) => {
  if (id === 'me')
    return next('route')

  next()
})
0.2.1

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