request-compose

Composable HTTP Client

var compose = require('request-compose')
var Request = compose.Request
var Response = compose.Response

;(async () => {
  try {
    var {res, body} = await compose(
      Request.defaults({headers: {'user-agent': 'request-compose'}}),
      Request.url('https://api.github.com/users/simov'),
      Request.send(),
      Response.buffer(),
      Response.string(),
      Response.parse(),
    )()
    console.log(res.statusCode, res.statusMessage)
    console.log(res.headers['x-ratelimit-remaining'])
    console.log(body)
  }
  catch (err) {
    console.error(err)
  }
})()

Goals

• No dependencies
• No abstraction
• No state

Table of Contents

• Compose
• Bundled Middlewares
• Opinionated Client
  • client / buffer / stream / options / extend
• Errors
• Debug Logs
• Examples

Compose

In computer science, function composition (not to be confused with object composition) is an act or mechanism to combine simple functions to build more complicated ones. Like the usual composition of functions in mathematics, the result of each function is passed as the argument of the next, and the result of the last one is the result of the whole.

var compose = require('request-compose')

Accepts a list of functions to execute and returns a Promise:

var doit = compose(
  (a) => a + 2,
  (a) => a * 2,
)

Then we can call it:

var result = await doit(5) // 14

A more practical example however would be to compose our own HTTP client:

var compose = require('request-compose')
var https = require('https')

var request = compose(
  (options) => {
    options.headers = options.headers || {}
    options.headers['user-agent'] = 'request-compose'
    return options
  },
  (options) => new Promise((resolve, reject) => {
    https.request(options)
      .on('response', resolve)
      .on('error', reject)
      .end()
  }),
  async (res) => await new Promise((resolve, reject) => {
    var body = ''
    res
      .on('data', (chunk) => body += chunk)
      .on('end', () => resolve({res, body}))
      .on('error', reject)
  }),
  ({res, body}) => ({res, body: JSON.parse(body)}),
)

Then we can use it like this:

;(async () => {
  try {
    var {res, body} = await request({
      protocol: 'https:',
      hostname: 'api.github.com',
      path: '/users/simov',
    })
    console.log(res.statusCode, res.statusMessage)
    console.log(res.headers['x-ratelimit-remaining'])
    console.log(body)
  }
  catch (err) {
    console.error(err)
  }
})()

Bundled Middlewares

request-compose comes with a bunch of pre-defined middlewares for transforming the request and the response:

var compose = require('request-compose')
var Request = compose.Request
var Response = compose.Response

We can use these middlewares to compose our own HTTP client:

;(async () => {
  try {
    var {res, body} = await compose(
      Request.defaults({headers: {'user-agent': 'request-compose'}}),
      Request.url('https://api.github.com/users/simov'),
      Request.send(),
      Response.buffer(),
      Response.string(),
      Response.parse(),
    )()
    console.log(res.statusCode, res.statusMessage)
    console.log(res.headers['x-ratelimit-remaining'])
    console.log(body)
  }
  catch (err) {
    console.error(err)
  }
})()

Opinionated Client

request-compose comes with opinionated HTTP client that is composed of the above middlewares.

There are 3 types of composition available based on the returned data type:

client

var request = require('request-compose').client
var {res, body} = await request({options})

The client composition does the following:

• buffers the response body
• decompresses gzip and deflate encoded bodies with valid content-encoding header
• converts the response body to string using utf8 encoding by default
• tries to parse JSON and querystring encoded bodies with valid content-type header

Returns either String or Object.

buffer

var request = require('request-compose').buffer
var {res, body} = await request({options})

The buffer composition does the following:

• buffers the response body
• decompresses gzip and deflate encoded bodies with valid content-encoding header

Returns Buffer.

stream

var request = require('request-compose').stream
var {res} = await request({options})

The stream composition returns the response Stream.

options

The above compositions accept any of the Node's http.request and https.request options:

var {res, body} = await request({
  method: 'GET',
  url: 'https://api.github.com/users/simov',
  headers: {
    'user-agent': 'request-compose'
  }
})

Additionally the following options are available:

Querystring set in the url, and/or in qs and/or in form as 'string' is left untouched, meaning that the proper encoding is left to the user.

When qs and/or form is {object} the querystring is encoded using the Node's querystring module which mirrors the global encodeURIComponent method. Additionally all reserved characters according to RFC3986 are encoded as well. Full list of all reserved characters that are being encoded can be found here.

redirect

extend

Extend or override any of the bundled request and response middlewares:

var request = require('request-compose').extend({
  Request: {
    oauth: require('request-oauth'),
    multipart: require('request-multipart'),
    cookie: require('request-cookie').Request
  },
  Response: {cookie: require('request-cookie').Response},
}).client

Errors

Non 200/300 responses are thrown as Error object with the following properties:

• message - status code + status message
• res - the response object
• body - the parsed response body
• raw - the raw response body

Debug Logs

Fancy request-logs:

npm i --save-dev request-logs

Pick any of the following debug options:

DEBUG=req,res,body,json,nocolor node app.js

Examples

Basics

Compositions

External Middlewares

Stream

Misc

Pipeline

Modules