agent-next

#agent-next

The idea is simple:

1. Lets create a function send(req, cb).
2. Lets say that request is .url, .headers and .body
3. Lets say that response is .status, .headers and .body.

Given that:

// cookie support? Easy!
function agent(req, cb) {
  setCookies(req)
  send(req, function(err, res) {
    saveCookies(res)
    cb(err, res)
  })
}

// redirects? Easy!
function aagent(req, cb) {
  agent(req, function(err, res) {
    if (isRedirect(res)) return aagent(redirectRequest(req, res), cb)
    cb(err, res)
  })
}

// Everything is easy.

What this project gives?

1. Middlewares

• cookies
• redirects
• unzip
• body parser
• serialize (support for JSON request bodies)
• timeout
• baseUrl (setup base url for all requests)
• handler (normalize results, i.e. attach req to errors, etc)

1. Request, Response prototypes in the vein of superagent

2. Agent abstraction as an easy way to setup your send function and issueing requests.

What advantages it has over other libs (like request or superagent)?

It is tremendously simpler and far more flexible. For example, you can swap entire http implementation and still have all advanced functionality available.

Examples

basic

var agent = require('agent-next')()
agent
.get('http://google.com/search/q=hello+world')
.end(function(err, res) {
  console.log(err || res.body)
})

advanced

// Setup an agent specifically for the Github API from scratch
var Agent = require('agent-next')
var github = Agent.basic()
  .use(Agent.redirects(10))
  .use(Agent.unzip())
  .use(Agent.parser())
  .use(Agent.serialize())
  .use(Agent.baseUrl('https://api.github.com'))
  .use(function(req, send, cb) {
    req.headers['user-agent'] = 'test application'
    req.headers['accept'] = 'application/vnd.github.preview'
    send(req, function(err, res) {
      if (err) return cb(err)
      if (res.ok) return cb(null, res.body)
      cb(new Error(res.body.message))
    })
  })

// get some info about agent-next
github
.get('/repos/eldargab/agent-next')
.end(function(err, msg) {
  console.log(err || msg.description)
})

setup with options

var Agent = require('agent-next')

// superagent like
var agent = Agent()

// tweak
var agent = Agent({
  cookies: true, // enable cookies
  unzip: false, // disable gzip support
  parser: fn, // set custom body parser
  timeout: 30000,
  baseUrl: 'http://example.com'
})

Notes

• Basic send function accepts strings, buffers and simple streams as an request body.
• Response body is a simple stream (if not overrided by middleware)
• req.url must be an instance of Agent.Url, not a string or an arbitrary object.
• You must always either consume, abort or dump response body, usually via middlewares.
• Middlewares should always pass the response object, even on errors, i.e. always do cb(err, res), not just cb(err).

Installation

via npm

npm install agent-next

License

(The MIT License)

Copyright (c) 2013 Eldar Gabdullin [e-mail]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.