midware-pool

midware-pool

midware-pool is a tiny module to create a pool of connect-style domain-agnostic middleware layers for any node.js or browser application. It uses midware behind the scenes.

Supports variadic arguments, stack manipulation and middleware inheritance. It's just ~180 SLOC.

To get started, see the example below or the API usage docs.

Example

var pool = require('midware-pool')()
var message = {}

// Create foo middleware stack
pool.use('foo', function(msg, next) {
  // msg === message
  next()
})

// Create another middleware stack
pool.use('bar', function(msg, next) {
  // msg === message
  next()
})

// Run both middlewares stacks
pool.run('foo', message, function(err) {
  if (err) return console.log(err)
  
  // Run next middleware stack
  pool.run('bar', message, function(err) {
    console.log('End')
  })
})

Installation

Node.js

To install midware-pool in a Node application use npm.

npm install midware-pool

Browser

Via bower:

bower install midware-pool

Via component:

component install h2non/midware-pool

Or loading the script:

<script src="//cdn.rawgit.com/h2non/midware-pool/0.1.2/midware-pool.js"></script>

Testing

$ npm install
$ npm test

Usage

Basic setup

Middleware is useful for creating a plugin system or configuring anything within an application. To use midware just require it and make a call to the module.

var pool = require('midware-pool')()

This will return a use function which when passed a callback will add it a waterfall sequence that will be invoked one after the other whenever the middleware is run.

pool.use('foo', function(next) {
  // mad science here
  next()
})

Callbacks are given a next function which will always be the last argument. Calling next will tell the middleware to call the next callback in the use sequence or will complete its run. To run the callback sequence call the method run on the use function.

pool.run('foo', function (err, end) {
  if (err) return console.log(err)
  if (end) console.log(end)
  // all done professor
})

run takes any amount of parameters that the callbacks will passed whenever run.

pool.use('foo', function (first, last, next) {
  console.log('Hello %s, %s', first, last)
  next()
})

pool.run('foo', 'Chunk', 'Norris')

Stopping

Whenever a callback should throw an exception or wish to stop the middleware from running any more calls. Give next an error or explicitly tell it stop.

pool.use('foo', function(next) {
  next(new Error()) // stops middleware and gives error
  next(null, true) // tells middleware to stop
})

pool.run('foo', function (err, ended) {
  // ...
})

Apply Context

Instead of binding context to callbacks, send the context to midware.

var context = {}
var pool = midwarePool()
pool.useCtx(context)

pool.use('foo', function (next) {
  // this === context
  next()
})

pool.run('foo', function(err) {
  // this === context
})

Removing a function

You can remove registered functions in the middleware via its function name or function reference

var pool = midwarePool()
pool.use('foo', function test(next) {
  next()
})
pool.remove('foo', 'test') // by function name

var pool = midwarePool()
function test(next) {
  next()
}
pool.use('foo', test)
pool.remove('foo', test) // by function reference

API

pool([parent]) => Pool

Pool#use(name, ...middleware)

Pool#remove(name, middlewareName|function)

Pool#run(name, [args...], [done])

Pool#runParent(name, [args...], [done])

Pool#registered(name) => boolean

Pool#useParent(pool)

Pool#useCtx(ctx)

Pool#flush(name)

Pool#flushAll()

Pool#stack(name) => midware

Pool#pool = { ...name: midware }

pool.midware => midware

pool.Pool => Pool

License

MIT

Copyright (c) 2015 Tomas Aparicio