homebridge-http-outlet Plugin

homebridge-http-outlet is a Homebridge plugin with which you can configure
HomeKit outlets which forward any requests to a defined http server. This comes in handy when you already have home
automated equipment which can be controlled via http requests. Or you have built your own equipment, for example some sort
of outlet controlled with an wifi enabled Arduino board which than can be integrated via this plugin into Homebridge.

Installation

First of all you need to have Homebridge installed. Refer to the repo for
instructions.
Then run the following command to install homebridge-http-outlet

``
sudo npm install -g homebridge-http-outlet
`

Updating the outlet state in HomeKit

All characteristic from the _'outlet'_ service have the permission to notify the HomeKit controller of state
changes. homebridge-http-outlet supports two concepts to send state changes to HomeKit.

$3

The 'pull' way is probably the easiest to set up and supported in every scenario. homebridge-http-outlet requests the
state of the outlet in an specified interval (pulling) and sends the value to HomeKit.
However the pull way is currently only supported for the _'On'_ characteristic!
Look for pullInterval in the list of configuration options if you want to configure it.

$3

When using the 'push' concept, the http device itself sends the updated value to homebridge-http-outlet whenever
values change. This is more efficient as the new value is updated instantly and homebridge-http-outlet does not
need to make needless requests when the value didn't actually change.
However because the http device needs to actively notify the homebridge-http-outlet there is more work needed
to implement this method into your http device.

#### Using MQTT:

MQTT (Message Queuing Telemetry Transport) is a protocol widely used by IoT devices. IoT devices can publish messages
on a certain topic to the MQTT broker which then sends this message to all clients subscribed to the specified topic.
In order to use MQTT you need to setup a broker server (mosquitto is a solid
open source MQTT broker running perfectly on a device like the Raspberry Pi) and then instruct all clients to
publish/subscribe to it.

#### Using 'homebridge-http-notification-server':

For those of you who are developing the http device by themselves I developed a pretty simple 'protocol' based on http
to send push-updates.
How to implement the protocol into your http device can be read in the chapter
Notification Server

Configuration:

The configuration can contain the following properties:

##### Basic configuration options:

- accessory \ required: Defines the plugin used and must be set to "HTTP-OUTLET" for this plugin.
- name \ required: Defines the name which is later displayed in HomeKit

* onUrl \urlObject\> required: Defines the url (and other properties when using
an urlObject) which is called when you turn on the outlet.
* offUrl \urlObject\> required: Defines the url (and other properties when using
an urlObject) which is called when you turn off the outlet.
* statusUrl \urlObject\> required: Defines the url (and other properties when using
an urlObject) to query the current power state from the outlet. By default it expects the http server to
return '1' for ON and '0' for OFF leaving out any html markup.
You can change this using statusPattern option (see below).
* statusPattern \ optional \(Default: "1"\): Defines a regex pattern which is compared to the
body of the http response from the statusUrl. When matching the status of the outlet is set to ON otherwise OFF.
More about regex pattern.

- outletInUse \ optional: Defines everything related to the _'OutletInUse'_ characteristic:
- statusUrl \urlObject\> required: Defines the url (and other properties when using
and urlObject) to query if the outlet is currently in use. By default it expects the http server
to '1' for IN USE and '0' for NOT IN USE.
- statusPattern \ optional \(Default: "1"): Defines a regex pattern which is compared to the
body of the http response from the outletInUse.statusUrl.
When matching the status of the outlet is set to IN USE otherwise NOT IN USE.

##### Advanced configuration options:

* auth \ optional: If your http server requires authentication, you can specify your credential in this
object. It uses those credentials for all http requests and thus overrides all possibly specified credentials inside
an urlObject for any characteristic.
The object can contain the following properties:
* username \ required
* password \ required
* sendImmediately \ optional \(Default: true\): When set to true the plugin will send the
credentials immediately to the http server. This is best practice for basic authentication.
When set to false the plugin will send the proper authentication header after receiving an 401 error code
(unauthenticated). The response from the http server must include a proper WWW-Authenticate header.
Digest authentication requires this property to be set to false!

- statusCache \ optional \(Default: 0\): Defines the amount of time in milliseconds a queried value
of the _On_ characteristic is cached before a new request is made to the http device.
Default is 0 which indicates no caching. A value of -1 will indicate infinite caching.
- outletInUseCache \ optional \(Default: 0\): Same as above, but for the _OutletInUse_
characteristic

* pullInterval \ optional: The property expects an interval in milliseconds in which the plugin
pulls updates from your http device. For more information read pulling updates.
(This option is currently only supported for the _'On'_ characteristic!)
* mqtt \<mqttObject\> optional: Defines all properties used for mqtt connection (More on MQTT).
For configuration see mqttObject.

- debug \ optional: If set to true debug mode is enabled and the plugin prints more detailed information.

In the Examples section are some example configurations to get you started.

#### UrlObject

A urlObject can have the following properties:
* url \ required: Defines the url pointing to your http server
* method \ optional \(Default: "GET"\): Defines the http method used to make the http request
* body \ optional: Defines the body sent with the http request. If value is not a string it will be
converted to a JSON string automatically.
* strictSSL \ optional \(Default: false\): If enabled the SSL certificate used must be valid and
the whole certificate chain must be trusted. The default is false because most people will work with self signed
certificates in their homes and their devices are already authorized since being in their networks.
* auth \ optional: If your http server requires authentication you can specify your credential in this
object. When defined the object can contain the following properties:
* username \ required
* password \ required
* sendImmediately \ optional \(Default: true\): When set to true the plugin will send the
credentials immediately to the http server. This is best practice for basic authentication.
When set to false the plugin will send the proper authentication header after receiving an 401 error code
(unauthenticated). The response must include a proper WWW-Authenticate header.
Digest authentication requires this property to be set to false!
* headers \ optional: Using this object you can define any http headers which are sent with the http
request. The object must contain only string key value pairs.

Below is an example of an urlObject containing all properties:
`json
{
"url": "http://example.com:8080",
"method": "GET",
"body": "exampleBody",

"strictSSL": false,

"auth": {
"username": "yourUsername",
"password": "yourPassword"
},

"headers": {
"Content-Type": "text/html"
}
}
`

#### MQTTObject

A mqttObject can have the following properties:

##### Basic configuration options:

* host \ required: Defines the host of the mqtt broker.
* port \ optional \(Default: 1883\): Defines the port of the mqtt broker.
* credentials \ optional: Defines the credentials used to authenticate with the mqtt broker.
* username \ required
* password \ optional
- subscriptions \