take-five

A minimal REST server that deals solely with JSON payloads that automatically handles CORS requests and limits the size of a POST bodies.

Installation

npm install -S take-five

Usage

const Five = require('take-five')
const five = new Five()
five.get('/', async (req, res, ctx) => ctx.send('Hello, world'))
five.post('/', async (req, res, ctx) => ctx.send(req.body))
five.listen(3000)

curl -X GET localhost:3000
Hello, world
curl -X POST localhost:3000 -H 'content-type: application/json' -d '{"hello": "world"}'
{"hello": "world"}

Routing and route-handlers

In lieu of pre-set middleware, routes handlers can be arrays of functions that will be iterated over asynchronously. To simplify handling of these handlers, it is expected that the handlers will return thenables, or terminate the response stream. This means any promises library should work (including the built in one), as well as using the async function keyword.

If you do not return a thenable, handler processing will stop in that function

e.g.:

function badSetContentHeader (req, res, ctx) {
  res.setHeader('x-no-way', 'this is gonna do nothing')
}
 
function goodSetContentHeader (req, res, ctx) {
  return new Promise((resolve) => {
    res.setHeader('x-yes-way', 'this is gonna do everything!')
    resolve()
  })
}
 
function sendReply (req, res, ctx) {
  ctx.send('beep!')
}
 
five.get('/nope', [badSetContentHeader, sendReply])
five.get('/yup', [goodSetContentHeader, sendReply)

since badSetContentHeader doesn't return a thenable, take-five will not know that it needs to call the sendReply function in the handler list for the /nope route.

If you have either closed the response stream, or rejected the thenable returned from your route handler, the next route will not be called. In the case that you have rejected the thenable, the error handler will be invoked as well. If you have closed the response stream, the server assumes you were done processing the request and will just ignore the remaning functions in the queue.

By default, get, post, put, delete, options and patch will be available for routing, but this can be changed by providing an array of methods on the options hash when instatiating a new TakeFive prototype.

Examples

Using async/await

five.handleError = (err, req, res, ctx) => {
  ctx.err(err.statusCode, err.message)
}
 
five.get('/:secretdata', [
  async (req, res, ctx) => {
    try {
      const session = await isAuthorized(req.headers.Authorization)
      ctx.session = session
    } catch (err) {
      err.statusCode = 401
      throw err
    }
  },
  async (res, res, ctx) => {
    try {
      const data = await getResource(ctx.params.secretdata, ctx.session)
      ctx.send(data)
    } catch (err) {
      err.statusCode = 500
      reject(err)
    }
  }
])

Using a "then"-able

five.get('/:secretdata', [
  (req, res, ctx) => {
    return new Promise((resolve, reject) => {
      isAuthorized(req.headers.Authorization, (err, session) => {
        if (err) {
          ctx.err(401, 'Not Authorized')
          return reject(new Error('Not authorized'))
        }
        ctx.session = session
        resolve()
      })
    })
  },
  (res, res, ctx) => {
    return new Promise((resolve, reject) => {
      getResource(ctx.params.secretdata, ctx.session, (err, data) => {
        if (err) {
          ctx.err(500, 'Server error')
          return reject(new Error('server error'))
        }
        ctx.send(data)
        resolve()
      })
    })
  }
])

API

Five(opts?:object):object

Create and return a new HTTP server object.

• opts.maxPost?:number: the max size for a payload. Default: 512kb
• opts.allowHeaders?:array(string): an array of headers to accept besides the default. Default: Content-Type, Accept, X-Requested-With
• opts.allowOrigin?:string: What origin(s) are accepted. Deafult: *
• opts.allowCredentials?:boolean: Allow or deny credentials. Default: true
• opts.allowContentTypes?:string|string[]: What content types are allowed to be used when sending data to the server. Default: ['application/json']. Note: This is additive, so application/json will ALWAYS be allowed.
• opts.allowMethods?array(string): an array of methods to accept besides the default. Default: PUT, POST, DELETE, GET, OPTIONS, PATCH
• opts.methods?array(string): An array of methods to create route handlers for. Default: PUT, POST, DELETE, GET, OPTIONS, PATCH
• opts.http?object: options for http(s).createServer. If you supply key, cert and ca as options, it will assume you are trying to create an https server`

Access-Control-Allow-Headers and Access-Control-Allow-Methods can also be changed during runtime by setting allowHeaders and allowMethods respectively.

Five#get(route:string, handler:(function|array(function)), routeOpts?:object)

Five#post(route:string, handler:(function|array(function)), routeOpts?:object)

Five#put(route:string, handler:(function|array(function)), routeOpts?:object)

Five#patch(route:string, handler:(function|array(function)), routeOpts?:object)

Five#delete(route:string, handler:(function|array(function)), routeOpts?:object)

Five#options(route:string, handler:(function|array(function)), routeOpts?:object)

Add a new route to the server. Routes may be added after the server has been started. You can supply either a single function or an array of functions to call. The array will be traversed in the order it is supplied

• route:string A wayfarer route definition.
• handler(request:object, response:object, ctx:object):function: The handler for this route.
• routeOpts?:object - overrides for this specific chain of handlers
  • maxPost:number - set the maximum size of a payload for this set of handlers
  • allowedContentTypes:string|string[] - add new allowable content-types for this set of handlers

ctx:object

• query?:object: query parameters from the URL (if any)
• params?:object: Named parameters from the route definition as provided by wayfarer
• body?:object: The parsed JSON body available on POST requests
• send(statusCode?:number, body?:(string|object)):function: Send a response.
• err(statusCode?:number, message?:string):function: Send an error. If no status code is provided it will default to a 500 error. If no message is provided, it will use the default message for that status code. The message will be wrapped in a JSON object under the key message
• next():function: Go to the next handler

The ctx object can also be extended to contain user defined objects, through setting this.ctx to an object. The object will be copied over using Object.assign.

The keys from above will overwrite any keys you provide named the same.

Five#handleError(err:Error, req:Request, res:Response, ctx:Context)

This function is invoked when either an error object is passed to the ctx.next method, or the then-able function's reject handler is invoked.

This is a no-op by default, allowing you to customize it's behavior.

Five#listen(port:number, handle?:function)

Start listening for requests and call the optional callback when you've started listening

Five.addParser(type:string, parser:functon):void

Add a new content parser to the parsers list. By default there is only a single parser (application/json: JSON.parser). This can be overridden with a custom JSON parser if you'd like.

Five#close()

Shutdown the underlying server

Getters/Setters

Five.server

The underlying http(s) server from node can be accessed directly. This is non-writeable

Five.maxPost

Globally control the maximum payload size after creation

Five.allowContentTypes

Add new allowable content types for clients to send data with. You can use either an array of strings or a string

Five.allowHeaders

Set a new allowable header or headers for CORS requests. You can use either an array of strings or a string.

Five.allowMethods

Set a new allowable method for CORS requests.

Five.ctx

Add new keys to the ctx objects

Do we need another REST server?

Probably not, but restify, hapi and express are all over-kill on the types of services I'm building for the most part.

• Setting up CORS is difficult or laborious: most REST services need to support CORS, this should be enabled by default (and easily configurable)
• It has no need to accept anything other than application/json payloads, but you can easily extend it to
• By default it will respond with application/json as well, but allow it be override-able if needed
• Should be trivial to reject large payloads to prevent DOS attacks
• Each route should have the ability to have multiple placeholders, regardless of the payload type
• It shouldn't mutate the built-in request and response objects
• It should be as fast as possible

I found that the other three projects aim to support way more than this, which means supporting these features involves jumping through hoops or installing a ton of various other packages.

License

Copyright © 2018 Scripto LLC, Todd Kennedy. Reuse permitted under the Apache-2.0 license