Gangway

A client-side API abstraction layer.

Gangway is our general purpose tool for working with APIs on the client-side. It is a thin layer on top of superagent with specific opinions related to how we work.

Getting started

Gangway is a factory function that progressively layers configuration options for building an AJAX request with superagent.

The returned value of all endpoints follow the Promise interface. Invocations of that interface return real Promises. This means you'll need to include your own polyfill for Promise (depending on your environment). We recommend then/promise as it includes additional methods like .done() and .nodeify() that improve interoperability and debugging:

require('promise/polyfill')
// Continue with the rest of your code

Alternatively, provide Promise as a configuration option (see below):

Create an instance of Gangway

var Gangway = require('gangway')
 
var API = Gangway({
  baseURL: 'http://example.com',
  headers: {
    'x-api-key': 'your-token-for-every-request'
  },
  Promise: require('promise') // Optional, if Promise is not polyfilled
})

Add routes

API.route({
    getUser: {
      method : 'GET',
      path   : '/users/{id?}' // ? indicates that the parameter is optional
    }
  }
})

API.getUser() will now perform a GET request to /users/{id}. The ? in the path option specifies that it is optional. This is useful when using the same route for index and show endpoints for resources.

Add namespaces

Most APIs break down endpoints into discrete resources. Gangway provides a namespace method for this purpose. All routes will be prefixed with a provided URL segment:

API.namespace('users').route({
    read: {
      method : 'GET',
      path   : '{id?}' // ? indicates that the parameter is optional
    }
  }
})

API.users.read({ params: { id: 2 }}) will perform a GET request to /users/2.

Add routes in bulk with .resource

For RESTful resources, adding routes this way can become tedious. Gangway provides another method for quickly building routes for RESTful resources:

// This is equivalent to creating a create, read, update, and destroy
// route. Options are folded into every route.
API.resource("comments", {})

Sending requests

Assuming the previous steps have been followed, Gangway is ready for use!

// This will send a request to GET http://example.com/users
API.users.read()
 
// This will send a request to GET http://example.com/users/10
API.users.read({ params: { id: '10' } })
 
// The same is true for routes added via API.resource
API.comments.read({ params: { id: '2' }})

Accessing the original request object

It is some times useful to access the unwrapped superagent request object. The value returned from endpoints contains a request property that grants access to this instance:

let fetch = API.users.read({ params: { id: '10' } })
 
fetch.request.abort()

Documentation

Checkout the ./docs folder and the available options below. Or consider working through the Hello Gangway guide.

Available options

baseURL    : The base URL prepended to all requests
body       : The request body
headers    : Request headers,
method     : Request method (GET, POST, PUT, PATCH, DELETE, etc...)
beforeSend : Configure an instance of superagent before the request is sent
onResponse : Run before resolving a request to preprocessing data
onError    : Run before rejecting a request to preprocessing errors
buildQuery : Run before a query string stringifies.
params     : Populate bindings in paths and are sent as request bodies. Defaults to body.
Promise    : The Promise implementation. Defaults to global.Promise.
path       : The path fragment of the endpoint, appended to baseURL
type       : Content type, defaults to JSON
query      : An object of query parameters. Gangway will automatically stringify this into the URL.
timeout    : Request timeout in milliseconds. Defaults to 15 seconds.

Responses

Gangway wraps around superagent, leaning on it to build a response object. This object is documented within superagent, however the important parts are:

{
  "text": "...", // The unparsed response body string
  "body": {},    // The parsed response body
  "status": 200  // The HTTP status code for the request
}

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