homebridge-http-temperature-sensor Plugin

This Homebridge plugin can be used integrate your temperature sensor which has a http api into HomeKit.

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-temperature-sensor

sudo npm install -g homebridge-http-temperature-sensor

Updating the temperature in HomeKit

The 'CurrentTemperature' characteristic has the permission to notify the HomeKit controller of state changes. homebridge-http-temperature-sensor supports two concepts to send temperature changes to HomeKit.

The 'pull' way:

The 'pull' way is probably the easiest to set up and supported in every scenario. homebridge-http-temperature-sensor requests the temperature of the sensor in an specified interval (pulling) and sends the value to HomeKit.
Look for pullInterval in the list of configuration options if you want to configure it.

The 'push' way:

When using the 'push' concept, the http device itself sends the updated value to homebridge-http-temperature-sensor whenever values change. This is more efficient as the new value is updated instantly and homebridge-http-temperature-sensor 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-temperature-sensor 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 <string> required: Defines the plugin used and must be set to "HTTP-TEMPERATURE" for this plugin.
• name <string> required: Defines the name which is later displayed in HomeKit
• getUrl <string | urlObject> required: Defines the url (and other properties when using and urlObject) to query the current temperature (in celsius) from the sensor. By default it expects the http server to return the temperature as a float ranging from 0-100 (step 0.1).
• unit <string> optional (Default: "celsius): Defines unit expected from the http server. The following are available:
  • "celsius": Using celsius to calculate temperature
  • "fahrenheit": Using fahrenheit to calculate temperature

Advanced configuration options:

• statusPattern <string> optional (Default: "(-?[0-9]{1,3}(.[0-9]))"): Defines a regex pattern with which the temperature is extracted from the body of the http response from the getUrl. The group which should be extracted can be configured with the patternGroupToExtract property.
  More about regex pattern.
• patternGroupToExtract <number> optional (Default: 1): Defines the regex group of which the temperature is extracted.
• statusCache <number> optional (Default: 0): Defines the amount of time in milliseconds a queried value of the CurrentTemperature 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.

• pullInterval <integer> optional: The property expects an interval in milliseconds in which the plugin pulls updates from your http device. For more information read pulling updates.

• mqtt <mqttObject> optional: Defines all properties used for mqtt connection (More on MQTT).
  For configuration see mqttObject.

• debug <boolean> optional: Enable debug mode and write more logs.

Below are two example configurations. One is using a simple string url and the other is using a simple urlObject.
Both configs can be used for a basic plugin configuration.

{
    "accessories": [
        {
          "accessory": "HTTP-TEMPERATURE",
          "name": "Temperature Sensor",
          
          "getUrl": "http://localhost/api/getTemperature"
        }   
    ]
}

{
    "accessories": [
        {
          "accessory": "HTTP-TEMPERATURE",
          "name": "Temperature Sensor",
          
          "getUrl": {
            "url": "http://localhost/api/getTemperature",
            "method": "GET"
          }
        }   
    ]
}

UrlObject

A urlObject can have the following properties:

• url <string> required: Defines the url pointing to your http server
• method <string> optional (Default: "GET"): Defines the http method used to make the http request
• body <any> 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 <boolean> 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 <object> 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 <string> required
  • password <string> required
  • sendImmediately <boolean> 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 <object> 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.
• requestTimeout <number> optional (Default: 20000): Time in milliseconds specifying timeout (Time to wait for http response and also setting socket timeout).

Below is an example of an urlObject containing the basic properties:

{
  "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 <string> required: Defines the host of the mqtt broker.
• port <number> optional (Default: 1883): Defines the port of the mqtt broker.
• credentials <object> optional: Defines the credentials used to authenticate with the mqtt broker.
  • username <string> required
  • password <string> optional

• subscriptions <object | array> required: Defines an array (or one single object) of subscriptions.
  • topic <string> required: Defines the topic to subscribe to.
  • characteristic <string> required: Defines the characteristic this subscription updates.
  • messagePattern <string> optional: Defines a regex pattern. If messagePattern is not specified the message received will be used as value. If the characteristic expects a boolean value it is tested if the specified regex is contained in the received message. Otherwise the pattern is matched against the message and the data from regex group can be extracted using the given patternGroupToExtract.
  • patternGroupToExtract <number> optional (Default: 1): Defines the regex group of which data is extracted.

Advanced configuration options:

• protocol <string> optional (Default: "mqtt"): Defines protocol used to connect to the mqtt broker
• qos <number> optional (Default: 1): Defines the Quality of Service (Notice, the QoS of the publisher must also be configured accordingly).
  In contrast to most implementations the default value is 1.
  • 0: 'At most once' - the message is sent only once and the client and broker take no additional steps to acknowledge delivery (fire and forget).
  • 1: 'At least once' - the message is re-tried by the sender multiple times until acknowledgement is received (acknowledged delivery).
  • 2: 'Exactly once' - the sender and receiver engage in a two-level handshake to ensure only one copy of the message is received (assured delivery).
• clientId <string> optional (Default: 'mqttjs_' + Math.random().toString(16).substr(2, 8)): Defines clientId
• keepalive <number> optional (Default: 60): Time in seconds to send a keepalive. Set to 0 to disable.
• clean <boolean> optional (Default: true): Set to false to receive QoS 1 and 2 messages while offline.
• reconnectPeriod <number> optional (Default: 1000): Time in milliseconds after which a reconnect is tried.
• connectTimeout <number> optional (Default: 30000): Time in milliseconds the client waits until the CONNECT needs to be acknowledged (CONNACK).

Note: Updating values over mqtt is currently only supported for the default unit (celsius).

Below is an example of an mqttObject containing the basic properties for a temperature service:

{
  "host": "127.0.0.1",
  "port": "1883",
  
  "credentials": {
    "username": "yourUsername",
    "password": "yourPassword"
  },
  
  "subscriptions": [
    {
      "topic": "your/topic/here",
      "characteristic": "CurrentTemperature",
      "messagePattern": "(-?[0-9]{1,3}(\\.[0-9]))"
    }
  ]
}

Notification Server

homebridge-http-temperature-sensor can be used together with homebridge-http-notification-server in order to receive updates when the state changes at your external program. For details on how to implement those updates and how to install and configure homebridge-http-notification-server, please refer to the README of the repository.

Down here is an example on how to configure homebridge-http-temperature-sensor to work with your implementation of the homebridge-http-notification-server.

{
    "accessories": [
        {
          "accessory": "HTTP-TEMPERATURE",
          "name": "Temperature Sensor",
          
          "notificationID": "my-temperature-sensor",
          "notificationPassword": "superSecretPassword",
          
          "getUrl": "http://localhost/api/getTemperature"
        }   
    ]
}

• notificationID is an per Homebridge instance unique id which must be included in any http request.
• notificationPassword is optional. It can be used to secure any incoming requests.

To get more details about the configuration have a look at the README.

Available characteristics (for the POST body)

Down here are all characteristics listed which can be updated with an request to the homebridge-http-notification-server

• characteristic "CurrentTemperature": expects an float value in a range of 0-100 (step 0.1)