reconnectingwebsocket

ReconnectingWebSocket
=====================

A small JavaScript library that decorates the WebSocket API to provide a WebSocket connection that will automatically reconnect if the connection is dropped.

It is API compatible, so when you have:

``javascript
var ws = new WebSocket('ws://....');
`

you can replace with:

`javascript
var ws = new ReconnectingWebSocket('ws://....');
`

Minified library with gzip compression is less than 600 bytes.

How reconnections occur
-----------------------

With the standard WebSocket API, the events you receive from the WebSocket instance are typically:

onopen
onmessage
onmessage
onmessage
onclose // At this point the WebSocket instance is dead.

With a ReconnectingWebSocket, after an onclose event is called it will automatically attempt to reconnect. In addition, a connection is attempted repeatedly (with a small pause) until it succeeds. So the events you receive may look something more like:

onopen
onmessage
onmessage
onmessage
onclose
// ReconnectingWebSocket attempts to reconnect
onopen
onmessage
onmessage
onmessage
onclose
// ReconnectingWebSocket attempts to reconnect
onopen
onmessage
onmessage
onmessage
onclose

This is all handled automatically for you by the library.

Parameters

`javascript
var socket = new ReconnectingWebSocket(url, protocols, options);
`

#### url
- The URL you are connecting to.
- http://dev.w3.org/html5/websockets/#the-websocket-interface

#### protocols
- Optional string or array of protocols per the WebSocket spec.
- http://dev.w3.org/html5/websockets/#refsWSP

#### options
- Options (see below)

Options

Options can either be passed as the 3rd parameter upon instantiation or set directly on the object after instantiation:

`javascript
var socket = new ReconnectingWebSocket(url, null, {debug: true, reconnectInterval: 3000});
`

or

`javascript
var socket = new ReconnectingWebSocket(url);
socket.debug = true;
socket.timeoutInterval = 5400;
`

#### debug
- Whether this instance should log debug messages or not. Debug messages are printed to console.debug().
- Accepts true or false
- Default value: false

#### automaticOpen
- Whether or not the websocket should attempt to connect immediately upon instantiation. The socket can be manually opened or closed at any time using ws.open() and ws.close().
- Accepts true or false
- Default value: true

#### reconnectInterval
- The number of milliseconds to delay before attempting to reconnect.
- Accepts integer
- Default: 1000

#### maxReconnectInterval
- The maximum number of milliseconds to delay a reconnection attempt.
- Accepts integer
- Default: 30000

####reconnectDecay
- The rate of increase of the reconnect delay. Allows reconnect attempts to back off when problems persist.
- Accepts integer or float
- Default: 1.5

#### timeoutInterval
- The maximum time in milliseconds to wait for a connection to succeed before closing and retrying.
- Accepts integer
- Default: 2000

#### maxReconnectAttempts
- The maximum number of reconnection attempts that will be made before giving up. If null, reconnection attempts will be continue to be made forever.
- Accepts integer or null.
- Default: null

---

Methods

#### ws.open()
- Open the Reconnecting Websocket

#### ws.close(code, reason)
- Closes the WebSocket connection or connection attempt, if any. If the connection is already CLOSED, this method does nothing.
- code is optional the closing code (default value 1000). [https://tools.ietf.org/html/rfc6455#section-7.4.1
- reason is the optional reason that the socket is being closed. https://tools.ietf.org/html/rfc6455#section-7.1.6

#### ws.refresh()
- Refresh the connection if still open (close and then re-open it).

#### ws.send(data)`
- Transmits data to the server over the WebSocket connection.
- Accepts @param data a text string, ArrayBuffer or Blob

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