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https://github.com/supereg/homebridge-http-notification-server

An http/https server inside Homebridge to receive notifications from external programs
https://github.com/supereg/homebridge-http-notification-server

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An http/https server inside Homebridge to receive notifications from external programs

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README 

        
# homebridge-http-notification-server



`homebridge-http-notification-server` can be used together with [Homebridge](https://github.com/homebridge/homebridge) 

http accessories. Http accessories are Homebridge plugins, which forward HomeKit requests to another program over a 

http request. An example for such an accessory would be my 

[homebridge-http-switch](https://github.com/Supereg/homebridge-http-switch).



The problem with such accessories is when 

the state of the external program changes it cannot be directly reflected in HomeKit. So one solution would be that 

every http accessory packs its own http server to receive state changes. But with multiple switches this becomes a mess 

very fast.



This is where the `homebridge-http-notification-server` comes in. It is basically a Homebridge plugin, which is loaded by 

Homebridge like any other plugin but doesn't register any accessories or platforms. Instead it starts ONE http or https 

server. Http accessories can register with an unique id. Any request the external program will send to the notification 

server will be forwarded to the accessory which specified the respective `notificationID`.



## Installation



`sudo npm install -g homebridge-http-notification-server`



## Configuration



The configuration file is located in the homebridge directory and needs to be called `notification-server.json`



Example:

```json

{

    "hostname": "127.0.0.1",

    "port": 8080,



    "ssl": {

        "privateKey": "/path/to/private-key.prm",

        "certificate": "/path/to/certificate.cert"

    }

}

```



* `hostname` is optional, default value is `0.0.0.0`

* `port` is required, default value is `8080`

* `ssl` is optional. When specified notification-server will create an https server with the specified `privateKey` and 

`certificate`. Otherwise a default unsecured http server is started.



## How to implement 'homebridge-http-notification-server' into your project



### Implementation in the homebridge accessory (receiver)



First of all you need to specify a handler function in your homebridge accessory. `homebridge-http-notification-server` 

locates its registration function in the `global` variable `notificationRegistration` at plugin initialization time.



In order to be sure, that `homebridge-http-notification-server` was already loaded by homebridge, you listen on the event 

`didFinishLaunching` of the homebridge api.



`notificationRegistration(notificationId, handlerFunction[, password])`

notificationRegistration function has three parameters, the first two are required.

* `notificationId`: this is id needs to be unique per homebridge instance. It is later used to identify the accessory when 

a request is made to the notification-server

* `handlerFunction`: function which is called when the notification-server received a request for the specified `notificationId`.

It needs to have one parameter, which is the json body from the http request.

* `password`: this parameter is fully optional. If specified every request to the notification-server must be authenticated 

with the specified password. Later more on how a request is constructed.



Example http accessory:

```javascript

let api;



module.exports = function (homebridgeAPI) {

    api = homebridgeAPI;



    homebridgeAPI.registerAccessory("homebridge-http-example-accessory", "HTTP-ACCESSORY", HTTP_ACCESSORY);

};



function HTTP_ACCESSORY(log, config) {

    // Some initialization

    this.name = config.name;

    

    this.service = new Service.Switch(this.name);

    this.service.getCharacteristic(Characteristic.On)

            .on("get", this.getStatus.bind(this))

            .on("set", this.setStatus.bind(this));



    api.on('didFinishLaunching', function() {

        // check if notificationRegistration is set, if not 'notificationRegistration' is probably not installed on the system

        if (global.notificationRegistration && typeof global.notificationRegistration === "function") {

            try {

                global.notificationRegistration("accessory-identifier", this.handleNotification.bind(this), "top-secret-password");

            } catch (error) {

                // notificationID is already taken

            }

        }

    }.bind(this));

}



HTTP_ACCESSORY.prototype = {

    

    identify: function (callback) {

        this.log("Identify requested!");

        callback();

    },



    getServices: function () {

        return [this.service];

    },

    

    handleNotification: function (jsonRequest) {

        const service = jsonRequest.service; // value is optional and only relevant if your accessory exposes multiple services

        

        const characteristic = jsonRequest.characteristic;

        const value = jsonRequest.value;

        

        // #testCharacteristic returns true if the service was added the specified characteristic.

        //  you could ad additional checks to adjust for your needs

        const validCharacteristic = this.service.testCharacteristic(characteristic);

        

        if (!validCharacteristic) {

            this.log("Encountered unknown characteristic when handling notification: " + characteristic);

            return; // in this example we ignore invalid requests

        }

        

        this.service.updateCharacteristic(characteristic, value);

    },

    

    getStatus: function(callback) {

        // request

    },

    

    setStatus: function(on, callback) {

        // request

    }

    

};

```



### Implementation in the http application (sender)



The http application sends a request to the notification-server (inside of homebridge) to update a value of a HomeKit 

characteristic. The http request must be a `POST` request. The url would be constructed as follows:



`http://:/` (`https://...` if ssl is turned on)



In our example the url would look like the following:

`http://127.0.0.1:8080/accessory-identifier`



The POST body would look like the following:

```json5

{

    "characteristic": "On",

    "value": true,

    "password": "your-top-secret-password",

    

    "accessory": "example-accessory", // optional, plugin defined 

    "service": "switch-service", // optional, plugin defined

}

```

**Common properties**: 

* `characteristic` is required. It represents the name of the characteristic which is going to be updated. Value must be 

a string. Of course this only works with characteristics which have the `notify` permissions in the HAP specifications. 

* `value` is required. 

* `password` optional, but required if your accessory defined a password



**Plugin defined properties**:

* `accessory` is fully optional. The type and usage is up to be defined by the plugin. This project just suggest

    this property to be used to identify a given accessory, if your plugin exposes multiple accessories.

* `service` is fully optional. The type and usage is up to be defined by the plugin. This project just suggest

    this property to be used to identify a given service, if your plugin exposes multiple services.



## Some compatible http accessories



* [homebridge-http-switch](https://github.com/Supereg/homebridge-http-switch)

* [homebridge-http-lightbulb](https://github.com/Supereg/homebridge-http-lightbulb)

* [homebridge-http-outlet](https://github.com/Supereg/homebridge-http-outlet)

* [homebridge-http-humidity-sensor](https://github.com/Supereg/homebridge-http-humidity-sensor)

* [homebridge-http-temperature-sensor](https://github.com/Supereg/homebridge-http-temperature-sensor)



- [homebridge-http-rgb-push](https://github.com/QuickSander/homebridge-http-rgb-push) by Sander van Woensel

- [homebridge-http-ambient-light-sensor](https://github.com/QuickSander/homebridge-http-ambient-light-sensor) by Sander van Woensel

- [homebridge-http-moisture-sensor](https://github.com/Pythonaire/homebridge-http-moisture-sensor) by Phytonaire



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