Caravan

throttle REST request client.

Installation

Via npm

$ npm install caravan --save

var caravan= require('caravan')
console.log(caravan) //function

Via bower

$ bower install caravan --save

<script src="bower_components/caravan/caravan.min.js"></script>
<script>
  console.log(caravan) //function
</script>

Via rawgit.com(the simple way)

<script src="https://cdn.rawgit.com/59naga/caravan/96e63a0476b31e5b724e85bcf2ae6019cc5a1da3/caravan.min.js"></script>
<script>
  console.log(caravan) //function
</script>

API

caravan(urls,options) -> Promise(responses)

Do throttle request to urls. return the bodies and errors. It is handled one by one, but can change at options.concurrency.

var urls= [
  'http://romanize.berabou.me/foo',
  'http://romanize.berabou.me/bar',
  'http://romanize.berabou.me/baz',
  'http://localhost:404/notfound',
]

// do serial (slowly)
caravan(urls).then(console.log.bind(console))
//[
//  'foo',
//  'bar',
//  'baz',
//  {
//    [Error: connect ECONNREFUSED]
//    code: 'ECONNREFUSED',
//    errno: 'ECONNREFUSED',
//    syscall: 'connect'
//  }
//]

// do parallel (quickly)
caravan(urls,{concurrency:4}).then(console.log.bind(console))

// do graceful (wait a ms)
caravan(urls,{delay:2000}).then(console.log.bind(console))

Or, usage follows.

caravan.get('http://romanize.berabou.me/foo').then(console.log.bind(console))
caravan.get(['http://romanize.berabou.me/bar']).then(console.log.bind(console))

caravan.post('http://romanize.berabou.me/baz').then(console.log.bind(console))
caravan.put('http://romanize.berabou.me/beep').then(console.log.bind(console))
caravan.delete('http://romanize.berabou.me/boop').then(console.log.bind(console))

progress notifying

Promise will have a .progress. the registered callback will be Invoked every time the request is fulfilled or rejected.

var urls= [
  'http://romanize.berabou.me/foo',
  'http://romanize.berabou.me/bar',
  'http://romanize.berabou.me/baz',
  'http://localhost:404/notfound',
]

caravan(urls)
.progress((progress)=>{
  console.log('progress: %s / %s',progress.index+1,urls.length)
  console.log(progress.value)
})
.then((results)=>{
  console.log('done')
})
// progress: 1 / 4
// foo
// progress: 2 / 4
// bar
// progress: 3 / 4
// baz
// progress: 4 / 4
// { [Error: connect ECONNREFUSED 127.0.0.1:404]
//   code: 'ECONNREFUSED',
//   errno: 'ECONNREFUSED',
//   syscall: 'connect',
//   address: '127.0.0.1',
//   port: 404,
//   response: undefined }
// done

Customize request

If passing an object to the urls, can switch the verb, and send a header and data.

url/uri: string

method: string (default:'GET')

headers: object (default:null)

data: object (default:null)

It uses as an argument of superagent

caravan([
  {
    url: 'http://superserver.berabou.me/1',
    method: 'GET',
    headers: {foo:'bar'},
    data: {baz:'beep'},
  },
  {
    url: 'http://superserver.berabou.me/2',
    method: 'POST',
    headers: {foo:'bar'},
    data: {baz:'beep'},
  },
  {
    url: 'http://superserver.berabou.me/3',
    method: 'PUT',
    headers: {foo:'bar'},
    data: {baz:'beep'},
  },
  {
    url: 'http://superserver.berabou.me/4',
    method: 'DELETE',
    headers: {foo:'bar'},
    data: {baz:'beep'},
  },
])
.then(results=>{
  console.log(results)
})

Caravan options

delay: number (default:0)

Specify the delay a millsecond for next request.

var urls= [
  'http://example.com/',
  'http://example.com/',
]

console.time('deferred')
caravan(url,{delay:1000})
.then((results)=>{
  console.timeEnd('deferred')
})
// deferred: 1s

concurrency: number (default:1)

Specify the number of throttle requests.

var urls= [
  'http://localhost/ping/1s',
  'http://localhost/ping/2s',
  'http://localhost/ping/3s',
]

console.time('concurrency is 1')
caravan(url,{concurrency:1})
.then((results)=>{
  console.timeEnd('concurrency is 1')
})
// concurrency is 1: 6s

console.time('concurrency is 3')
caravan(url,{concurrency:3})
.then((results)=>{
  console.timeEnd('concurrency is 3')
})
// concurrency is 3: 3s

raw: bool (default:false)

if true, response contains detailed information such as headers, statuscode...

caravan('http://romanize.berabou.me/foo',{raw:true})
.then((responses)=>{
  console.log(responses[0])
  // {
  //   ...
  //   links: {},
  //   text: '"foo"',
  //   body: 'foo',
  //   files: {},
  //   buffered: true,
  //   headers: 
  //    { 'x-powered-by': 'Express',
  //      'access-control-allow-origin': '*',
  //      'access-control-allow-headers': 'Content-Type',
  //      'access-control-allow-methods': 'PUT, GET, POST, DELETE, OPTIONS',
  //      'content-type': 'application/json charset=utf-8',
  //      'content-length': '5',
  //      etag: 'W/"5-DbpSDjNcBrqSQKl46UVYeA"',
  //      date: 'Mon, 26 Oct 2015 07:55:43 GMT',
  //      connection: 'close' },
  //   header: { ... },
  //   statusCode: 200,
  //   status: 200,
  //   statusType: 2,
  //   info: false,
  //   ok: true,
  //   ...
  // }
})

License

MIT