balena-request

Balena HTTP client.


Role

The intention of this module is to provide an exclusive client to make HTTP requests to the balena servers.

THIS MODULE IS LOW LEVEL AND IS NOT MEANT TO BE USED BY END USERS DIRECTLY.

Unless you know what you're doing, use the balena SDK instead.

Installation

Install balena-request by running:

$ npm install --save balena-request

Documentation

The module returns a factory function that you use to get an instance of the auth module.

It accepts the following params:

Param	Type	Description
options	Object	options
options.auth	Object	An instantiated balena-auth instance
options.debug	boolean	when set to true will log the request details in case of error.
options.isBrowser	boolean	set to true if the runtime is the browser.
options.interceptors	Array<Interceptor>	An initial array of interceptors

Example

var request = require('balena-request')({
    auth: auth,
    debug: false,
    isBrowser: false
})

• request
  • ~getRequest(options)
    • ~interceptors : Array.<Interceptor>
    • ~send(options) ⇒ Promise.<Object>
    • ~stream(options) ⇒ Promise.<NodeJS.ReadableStream>
    • ~refreshToken(options) ⇒ Promise.<String>
  • ~Interceptor : object

request~getRequest(options)

Kind: inner method of request
Summary: Creates a new balena-request instance.

Param	Type
options	object
options.auth	object
options.debug	boolean
options.retries	number
options.isBrowser	boolean
options.interceptors	array

• ~getRequest(options)
  • ~interceptors : Array.<Interceptor>
  • ~send(options) ⇒ Promise.<Object>
  • ~stream(options) ⇒ Promise.<NodeJS.ReadableStream>
  • ~refreshToken(options) ⇒ Promise.<String>

getRequest~interceptors : Array.<Interceptor>

The current array of interceptors to use. Interceptors intercept requests made by calls to .stream() and .send() (some of which are made internally) and are executed in the order they appear in this array for requests, and in the reverse order for responses.

Kind: inner constant of getRequest
Summary: Array of interceptor
Access: public
Example

request.interceptors.push(
    requestError: (error) ->
        console.log(error)
        throw error
)

getRequest~send(options) ⇒ Promise.<Object>

This function automatically handles authorization with balena.

The module scans your environment for a saved session token. Alternatively, you may pass the apiKey option. Otherwise, the request is made anonymously.

Requests can be aborted using an AbortController (with a polyfill like https://www.npmjs.com/package/abortcontroller-polyfill if necessary). This is not well supported everywhere yet, is on a best-efforts basis, and should not be relied upon.

Kind: inner method of getRequest
Summary: Perform an HTTP request to balena
Returns: Promise.<Object> - response
Access: public

Param	Type	Default	Description
options	Object		options
[options.method]	String	'GET'	method
options.url	String		relative url
[options.apiKey]	String		api key
[options.responseFormat]	String		explicit expected response format, can be one of 'blob', 'json', 'text', 'none'. Defaults to sniffing the content-type
[options.signal]	AbortSignal		a signal from an AbortController
[options.body]	*		body
[options.timeout]	number		body

Example

request.send
    method: 'GET'
    baseUrl: 'https://api.balena-cloud.com'
    url: '/foo'
.get('body')

Example

request.send
    method: 'POST'
    baseUrl: 'https://api.balena-cloud.com'
    url: '/bar'
    data:
        hello: 'world'
.get('body')

getRequest~stream(options) ⇒ Promise.<NodeJS.ReadableStream>

This function emits a progress event, passing an object with the following properties:

• Number percent: from 0 to 100.
• Number total: total bytes to be transmitted.
• Number received: number of bytes transmitted.
• Number eta: estimated remaining time, in seconds.

The stream may also contain the following custom properties:

• String .mime: Equals the value of the Content-Type HTTP header.

See request.send() for an explanation on how this function handles authentication, and details on how to abort requests.

Kind: inner method of getRequest
Summary: Stream an HTTP response from balena.
Returns: Promise.<NodeJS.ReadableStream> - response
Access: public

Param	Type	Default	Description
options	Object		options
[options.method]	String	'GET'	method
options.url	String		relative url
[options.body]	*		body

Example

request.stream
    method: 'GET'
    baseUrl: 'https://img.balena-cloud.com'
    url: '/download/foo'
.then (stream) ->
    stream.on 'progress', (state) ->
        console.log(state)

    stream.pipe(fs.createWriteStream('/opt/download'))

getRequest~refreshToken(options) ⇒ Promise.<String>

This function automatically refreshes the authentication token.

Kind: inner method of getRequest
Summary: Refresh token on user request
Returns: Promise.<String> - token - new token
Access: public

Param	Type	Description
options	object
options.baseUrl	String	relative url

Example

request.refreshToken
    baseUrl: 'https://api.balena-cloud.com'

request~Interceptor : object

An interceptor implements some set of the four interception hook callbacks. To continue processing, each function should return a value or a promise that successfully resolves to a value.

To halt processing, each function should throw an error or return a promise that rejects with an error.

Kind: inner typedef of request
Properties

Name	Type	Description
[request]	function	Callback invoked before requests are made. Called with the request options, should return (or resolve to) new request options, or throw/reject.
[response]	function	Callback invoked before responses are returned. Called with the response, should return (or resolve to) a new response, or throw/reject.
[requestError]	function	Callback invoked if an error happens before a request. Called with the error itself, caused by a preceeding request interceptor rejecting/throwing an error for the request, or a failing in preflight token validation. Should return (or resolve to) new request options, or throw/reject.
[responseError]	function	Callback invoked if an error happens in the response. Called with the error itself, caused by a preceeding response interceptor rejecting/throwing an error for the request, a network error, or an error response from the server. Should return (or resolve to) a new response, or throw/reject.

Support

If you're having any problem, please raise an issue on GitHub and the balena team will be happy to help.

Tests

Run the test suite by doing:

$ npm test

Contribute

• Issue Tracker: github.com/balena-io-modules/balena-request/issues
• Source Code: github.com/balena-io-modules/balena-request

Before submitting a PR, please make sure that you include tests, and that coffeelint runs without any warning:

$ gulp lint

License

The project is licensed under the Apache 2.0 license.