Restling NPM | npm.io

Restling

Restling is a lightweight Node.js module for building promise-based asynchronous HTTP requests. Under the hood it uses restler to make HTTP calls and bluebird to transform it in promises.

Avoid callback hell

Working on an asynchronous environment you have probably seen this:

Traditional callback approach

User.logIn("user", "pass", {
  success: function(user) {
    query.find({
      success: function(results) {
        results[0].save({ key: value }, {
          success: function(result) {
            // the object was saved.
          }
        });
      }
    });
  }
});

With Restling

User.logIn("user", "pass").then(function(user) {
  return query.find();
}).then(function(results) {
  return results[0].save({ key: value });
}).then(function(result) {
  // the object was saved.
});

Installing

npm install restling

Basic Usage

var rest = require('restling');

rest.get('http://google.com').then(function(result){
  console.log(result.data);
}, function(error){
  console.log(error.message);
});

The result passed into the success callback is an object with two keys: data and response. Example: {'data': 3, 'response': res}

The error passed into the error callback is an instance of Error with the attributes below:

Example:

  {
    'message'   : 'getaddrinfo ENOTFOUND',
    'statusCode': 404,
    'response:' : res,
    'data'      : result.data
  }

Parallel Request Basic Usage

Run requests in parallel, without waiting until the previous requests has completed.

To make this we will use a myRequest object which contains two keys:

url : Path to make the request.
options : OPTIONAL - Some extra params and settings of the request.

Example of myRequest object: {'url': 'http://path/to/api', options:{timeout: 5000}}

Passing an object

Each property must be a myRequest object that will be executed. The return is a promise with a value that is a object containing each property of the object passed with their respective value.

var rest = require('restling');
var obj  = {'google':{'url':'http://google.com'},
            'api':{'url':'http://some/rest/api'}}

rest.settleAsync(obj).then(function(result){
  // handle result here
  // result is {google: responseFromGoogle, api: responseFromApi}
},function(err){
  // handle error here
});

Passing an array

It is also possible pass an array of myRequest object. THe return is a promise with a value a array which each index contain it respective value in order.

var rest  = require('restling');
var array = [{'url':'http://google.com'},
             {'url':'http://some/rest/api'}]

rest.settleAsync(array).then(function(result){
  // handle results here
  // result is [responseFromGoogle, responseFromApi]
},function(err){
  // handle error here
});

Using the `allAsync` instead `settleAsync`

If you want to reject the return promise for the whole if one of the parallel request is rejected use allAsync instead of settleAsync.

Features

Easy interface for common operations via http.request
Automatic serialization of post data
Automatic serialization of query string data
Automatic deserialization of XML, JSON and YAML responses to JavaScript objects
Provide your own deserialization functions for other datatypes
Automatic following of redirects
Send files with multipart requests
Transparently handle SSL (just specify https in the URL)
Deals with basic auth for you, just provide username and password options
Simple service wrapper that allows you to easily put together REST API libraries
Transparently handle content-encoded responses (gzip, deflate)
Transparently handle different content charsets via iconv-lite

API

request(url, options)

Basic method to make a request of any type. The function returns a promise object:

get(url, options)

Create a GET request.

post(url, options)

Create a POST request.

put(url, options)

Create a PUT request.

del(url, options)

Create a DELETE request.

head(url, options)

Create a HEAD request.

patch(url, options)

Create a PATCH request.

json(url, data, options)

Send json data via GET method.

postJson(url, data, options)

Send json data via POST method.

putJson(url, data, options)

Send json data via PUT method.

settleAsync(requestObjects, callback)

Run the requestObjects array/object in parallel, without waiting until the previous request has completed.

Parsers

You can give any of these to the parsers option to specify how the response data is deserialized. In case of malformed content, parsers emit error event. Original data returned by server is stored in response.raw.

parsers.auto

Checks the content-type and then uses parsers.xml, parsers.json or parsers.yaml. If the content type isn't recognised it just returns the data untouched.

parsers.json, parsers.xml, parsers.yaml

All of these attempt to turn the response into a JavaScript object. In order to use the YAML and XML parsers you must have yaml and/or xml2js installed.

Options

method Request method, can be get, post, put, delete. Defaults to "get".
query Query string variables as a javascript object, will override the querystring in the URL. Defaults to empty.
data The data to be added to the body of the request. Can be a string or any object. Note that if you want your request body to be JSON with the Content-Type: application/json, you need to JSON.stringify your object first. Otherwise, it will be sent as application/x-www-form-urlencoded and encoded accordingly. Also you can use json() and postJson() methods.
parser A function that will be called on the returned data.
encoding The encoding of the request body. Defaults to "utf8".
decoding The encoding of the response body. For a list of supported values see Buffers. Additionally accepts "buffer" - returns response as Buffer. Defaults to "utf8".
headers A hash of HTTP headers to be sent. Defaults to { 'Accept': '*/*', 'User-Agent': 'Restling for node.js' }.
username Basic auth username. Defaults to empty.
password Basic auth password. Defaults to empty.
accessToken OAuth Bearer Token. Defaults to empty.
multipart If set the data passed will be formated as multipart/form-encoded. See multipart example below. Defaults to false.
client A http.Client instance if you want to reuse or implement some kind of connection pooling. Defaults to empty.
followRedirects If set will recursively follow redirects. Defaults to true.
timeout If set, will emit the timeout event when the response does not return within the said value (in ms)
rejectUnauthorized If true, the server certificate is verified against the list of supplied CAs. An 'error' event is emitted if verification fails. Verification happens at the connection level, before the HTTP request is sent. Default true.

Example usage

var rest = require('./restling');

var successCallback = function(result){
console.log('Data: ' + result.data);
console.log('Response: ' + result.response);
};

var errorCallback = function(error){
  console.log('Error: ' + error.message);
  if (error.response) {
    console.log('Response: ' + error.response);
  }
};

rest.get('http://google.com').then(successCallback, errorCallback);

// auto convert json to object
rest.get('http://twaud.io/api/v1/users/danwrong.json')
  .then(successCallback, errorCallback);

// auto convert xml to object
rest.get('http://twaud.io/api/v1/users/danwrong.xml')
  .then(successCallback, errorCallback);

rest.get('http://someslowdomain.com',{timeout: 10000})
  .then(successCallback, errorCallback);

rest.post('http://user:pass@service.com/action', {
  data: { id: 334 },
}).then(function(result) {
  if (result.response.statusCode == 201) {
    result.data;// you can get at the raw response like this...
  }
},
errorCallback);

// multipart request sending a 321567 byte long file using https
rest.post('https://twaud.io/api/v1/upload.json', {
  multipart: true,
  username: 'danwrong',
  password: 'wouldntyouliketoknow',
  data: {
    'sound[message]': 'hello from restling!',
    'sound[file]': rest.file('doug-e-fresh_the-show.mp3', null, 321567, null, 'audio/mpeg')
  }
}).then(successCallback, errorCallback);

// post JSON
var jsonData = { id: 334 };
rest.postJson('http://example.com/action', jsonData).then(successCallback, errorCallback);

// put JSON
var jsonData = { id: 334 };
rest.putJson('http://example.com/action', jsonData).then(successCallback, errorCallback);