Micro Action

Tools to help build Micro-Action server using Zeit Micro.

Usage

Install package

npm i -S micro-action

Basic usage

// server.js
const {route} = require('micro-action')

module.exports = route({
  'add': ({a, b}) => a + b,
  'add?async': async ({a, b}) => await Promise.resolve(a + b)
})

// client.js
const fetch = require('node-fetch')

const res = await fetch('http://server-path', {
  method: 'POST',
  headers: {'content-type': 'application/json'},
  body: JSON.stringify({cmd: 'add', input: {a: 1, b: 2}})
})
const body = await res.json()
const sum = body.output // sum=3

const res = await fetch('http://server-path', {
  method: 'POST',
  headers: {'content-type': 'application/json'},
  body: JSON.stringify({cmd: 'add?async', input: {a: 2, b: 3}})
})
const body = await res.json()
const sum = body.output // sum=5

Ok with code

If you have multiple possible success cases, use code to distinguish them.

// server.js
const {route, ok, fail} = require('micro-action')

module.exports = {
  'magicNumber': (number) => {
    if (number % 2 === 0) return ok('even', number / 2)
    else return ok('odd', number * 2)
  },
}

// client.js
const fetch = require('node-fetch')

const res = await fetch('http://server-path', {
  method: 'POST',
  headers: {'content-type': 'application/json'},
  body: JSON.stringify({cmd: 'magicNumber', input: 4})
})
const body = await res.json() // body1={ok: true, code:'even', output:2}

const res = await fetch('http://server-path', {
  method: 'POST',
  headers: {'content-type': 'application/json'},
  body: JSON.stringify({cmd: 'magicNumber', input: 5})
})
const body = await res.json() // body={ok: true, code:'odd', output:10}

Fail with code

You should always give a code for known failure cases.

The output is optional and can be used for further details of this failure case.

// server.js
const {route, ok, fail} = require('micro-action')

module.exports = {
  'divide': ({a, b}) => {
    if (b === 0) return fail('zero-denominator', {msg: 'b cannot be 0'})
    else return a / b
  },
}

// client.js
const fetch = require('node-fetch')

const res = await fetch('http://server-path', {
  method: 'POST',
  headers: {'content-type': 'application/json'},
  body: JSON.stringify({cmd: 'divide', input: {a: 1, b: 2}})
})
const body = await res.json() // body={ok: true, output: 0.5}

const res = await fetch('http://server-path', {
  method: 'POST',
  headers: {'content-type': 'application/json'},
  body: JSON.stringify({cmd: 'divide', input: {a: 1, b: 0}})
})
const body = await res.json() // body={ok: false, code:'zero-denominator', output: {msg: 'b cannot be 0'}}

Uncatched error

You can ignore if you don't care the unknown errors. It will be caught and properly composed into response.

// server.js
const {route, ok, fail} = require('micro-action')

module.exports = {
  'parse/jsonString': (json) => {
    return JSON.parse(json)
  },
}

// client.js
const fetch = require('node-fetch')

const res = await fetch('http://server-path', {
  method: 'POST',
  headers: {'content-type': 'application/json'},
  body: JSON.stringify({cmd: 'parse/jsonString', input: '{invalidJsonString'})
})
const body = await res.json() // body1={ok: false, error: {name: 'SyntaxError', message: 'Unexpected token i in JSON at position 1'}}

APIs

route

func(handlers, options) => [microRequestHandler][micro-request-handler]

• handlers - object, key is cmd pattern, value is the handler.
• handler - async func(input) => any | handlerResult
• options
  • errorLogger - async func(err)
  • errorHandler - async func(err, res, input) => any | handlerResult
  • otherRequestHandler - [microRequestHandler][micro-request-handler]
  • unmatchedCmdHandler - async func(cmd, input) => any | handlerResult

ok

async func(code, output) => handlerResult

fail

async func(code, output, err) => handlerResult

Related Projects

• micro-action-protocol
• micro-action-callers

License

ISC