heos-api

A zero-dependency low level Node.js api-wrapper for communicating with HEOS devices. It enables developers to find, connect to, and communicate with HEOS devices.

Features

• 🔎 Discover devices: Dead simple discovery of HEOS devices.
• 🎯 Send any command: Send commands with a simple api.
• 🛰 Event handling: React to anything that happens to your HEOS control system, by binding any event to one or more callbacks.
• 🚫 Zero dependency: Don't worry about any left-pad or event-stream vulnerabilities, with this zero-dependency library.
• ✨ Intellisense: Really nice intellisense suggestions.

Table of Contents

• Example
• Installation
• Usage
  • Connecting to devices
    • heos.discoverDevices(timeout, onDiscover[, onTimeout])
    • heos.discoverOneDevice([timeout])
    • heos.discoverAndConnect([timeout])
    • heos.connect(address)
  • HeosConnection
    • connection.write(commandGroup, command[, attributes])
    • connection.on(event, listener)
    • connection.once(event, listener)
    • connection.onAll(listener)
    • connection.onClose(listener)
    • connection.onError(listener)
    • HeosEvent and HeosResponse
• Documentation
• Contributing

Example

const heos = require('heos-api')

heos.discoverAndConnect().then(connection =>
    connection
        .onAll(saveToLog)
        .on(
            {
                commandGroup: 'event',
                command: 'player_volume_changed'
            },
            console.log
        )
        .write('system', 'prettify_json_response', { enable: 'on' })
        .write('system', 'heart_beat')
        .write('player', 'set_volume', { pid: 1, level: 20 })
)

Installation

Install heos-api using npm:

npm install heos-api

Usage

The library is very simple and easy to use. There exists three functions to discover HEOS devices and establish a connection with a HEOS device. When a connection is established the HeosConnection object provides three methods to communicate with a HEOS device.

Connecting to devices

The heos object has two ways of finding devices and one way to connect to a device:

• heos.discoverDevices()
• heos.discoverOneDevice()
• heos.connect()

heos.discoverDevices(options, onDiscover[, onTimeout])

• options: { timeout?: number, port?: number, address?: string } || number
• onDiscover: (address: string) => void
• onTimeout: (addresses: string[]) => void

Tries to discover all available HEOS devices in the network. port and address of options is for connecting to a user specified network interface. When options.timeout or options (type number) milliseconds have passed the search will end. Every time a HEOS device is discovered onDiscover(address) will be triggered, where address is the ip-address of the device found. When the search ends onTimeout(addresses[]) will be triggered with an array with all the devices found.

The function does not return a value.

heos.discoverDevices({ timeout: 3000 }, console.log, () => {})
// Logs out the addresses of every HEOS device in the network, and will end search after 3 seconds

heos.discoverOneDevice([options])

• options: { timeout?: number, port?: number, address?: string } || number

Finds one HEOS device in the network. port and address of options is for connecting to a user specified network interface. A promise is returned that will resolve when the first device is found, or reject if no devices are found before options.timeout or options (type number) milliseconds have passed. If the function resolves it will resolve with the address of the HEOS device found.

heos.discoverDevices() is used under the hood

heos.discoverOneDevice().then(console.log)
// Logs out the address of a HEOS device

heos.discoverAndConnect([options])

• options: { timeout?: number, port?: number, address?: string } || number

Finds one HEOS device in the network, and connects to it. port and address of options is for connecting to a user specified network interface. A promise is returned that will resolve when the first device is found, or reject if no devices are found before options.timeout or options (type number) milliseconds have passed. If the function resolves it will resolve with a HeosConnection.

heos.discoverAndConnect().then(console.log)
// Logs out the HeosConnection object

heos.connect(address)

• address: string

Establishes a connection with a HEOS device, and will return a promise. The promise resolves with a HeosConnection that can be used to communicate with a HEOS device.

Use this function when you know the address of a HEOS device. It is recommended to use heos.discoverOneDevice() to find out an address, or simply use heos.discoverAndConnect().

heos.discoverOneDevice().then(address => heos.connect(address))
// Connects to a HEOS device

HeosConnection

HeosConnection is an object representing a connection with a HEOS device, and provides methods to communicate with the connected HEOS device. All the methods returns a HeosConnection which means that they are chainable.

• connection.write()
• connection.on()
• connection.once()

connection.write(commandGroup, command[, attributes])

• commandGroup: string
• command: string
• attributes: object

Sends a command to the connected HEOS device. A command consists of a commandGroup and a command. Some commands take attributes as well. Check the HEOS CLI Protocol Specification to learn all the commands that can be sent.

connection.write('player', 'set_volume', { pid: 2, level: 15 })
// Sends heos://player/set_volume?pid=2&level=15

connection.on(event, listener)

• event: { command: string, commandGroup: string }
• listener: (message: HeosEvent | HeosResponse) => void

Adds listener to event listener in HeosConnection. When the event happens the listener will be triggered with the response.

connection.on({ commandGroup: 'event', command: 'player_volume_changed' }, console.log)
// If the player volume is changed on the connected HeosDevice the event will be logged

connection.once(event, listener)

• event: { command: string, commandGroup: string }
• listener: (message: HeosEvent | HeosResponse) => void

Exactly like connection.on() but will only trigger the listener the first time the event happens.

connection.onAll(listener)

• listener: (message: HeosEvent | HeosResponse) => void

Exactly like connection.on() but will trigger the listener for every response or event. It is useful for logging or debugging purposes. These listeners are triggered before any other as they can be useful for understanding why other listeners might be faulty.

connection.onClose(listener)

• listener: (hadError: boolean) => void

Adds an event listener for when the connection is closed. hadError is true if there was a transmission error.

connection.onClose(hadError => {
    if (hadError) {
        console.error('There was a transmission error and the connection closed.')
    } else {
        console.log('Connection closed')
    }
})

connection.onError(listener)

• listener: (error: Error) => void

Adds an event listener for when an error occurs.

connection.onError(error => {
    console.error(error)
})

HeosEvent and HeosResponse

The responses to commands are objects like this example:

{
  heos: {
    command: {
      commandGroup: 'system',
      command: 'heart_beat'
    },
    result: 'success',
    message: {
      unparsed: ''
    }
  },
  payload: {},
  options: {}
}

Sometimes there is no payload or options depending on the command. The responses sent from HEOS devices are JSON formatted and are very similar to HeosResponse with the only difference being that the command is differently formatted.

If you subscribe to Unsolicited Responses (by sending the system/register_for_change_events command) you will receive them as a HeosEvent. They are formatted like this example:

  heos: {
    command: {
      commandGroup: 'event',
      command: 'player_now_playing_changed'
    },
    message: {
      unparsed: 'pid=5458',
      parsed: {
        pid: 5458
      }
    }
  }

message can also be {} or have only unparsed attribute.

export type HeosResponse = {
    heos: {
        command: {
            commandGroup: string
            command: string
        }
        result: string
        message: {
            unparsed: string,
            parsed?: {
                [key: string]: string | number
            }
        } | {}
    }
    payload?: object | any[]
    options?: object
}

export type HeosEvent = {
    heos: {
        command: {
            commandGroup: string
            command: string
        }
        message: {
            unparsed: string,
            parsed?: {
                [key: string]: string | number
            }
        } | {}
    }
}

Documentation

Learn more about using heos-api at:

• The GitHub page
• HEOS CLI Protocol Specification

Contributing

Please send issues and pull requests with your problems or ideas!