Abstract

Interface service to communicate with several arduino or similar microcontroller based on a serial interface

Contents

• Meta
• Global Functions
  • _deriveSubscribesFromCommandMap
  • _deriveSubscribesFromTopicMap
  • lsb
  • prepare
  • serialMessageToString
  • switchMessageToString
• Class SerialDevice
  • Parameters
  • Methods
    • _traceStringSendToSerial
    • close
    • getSubscriptions
    • handleMessage
    • on
    • run

Meta

| | | | --- | --- | | File | index.js | | Abstract | Interface service to communicate with several arduino or similar microcontroller based on a serial interface | | Author | Volker Böhm | | Copyright | Copyright ( c ) 2020 Volker Böhm | | License | This software is licensed under the GNU LESSER GENERAL PUBLIC LICENSE Version 3 . It is furnished "as is" , without any support , and with no warranty , express or implied , as to its usefulness for any purpose . |

Callback definitions

Publish

Callback to publish messages to the mqtt broker

Publish Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | message | Message | message to publish | |

Global functions

_deriveSubscribesFromCommandMap

readonly _deriveSubscribesFromCommandMap (commandMap, topicBegin, qos)

Creates a list of subscribes starting with topicBegin and ending with all strings of the commandMap

_deriveSubscribesFromCommandMap Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | commandMap | Object | map commands to topic end strings | | | topicBegin | string | begin of the topic | | | qos | number | quality of service | |

_deriveSubscribesFromTopicMap

readonly _deriveSubscribesFromTopicMap (topicMap, qos) => {Object.<topic:qos>}

Derives subscriptions from a topic list

_deriveSubscribesFromTopicMap Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | topicMap | Object.<topic:string> | object with topic properties | | | qos | 0, 1, 2 | quality of service for the subscription | |

_deriveSubscribesFromTopicMap returns

| Type | Description | | ---- | ----------- | | Object.<topic:qos> | object with topic : qos entries |

lsb

lsb (value) => {integer}

Returns the number of the least significant bit of an integer

lsb Parameters

| Name | Type | | ---------- | ------------ | | value | integer | |

lsb returns

| Type | Description | | ---- | ----------- | | integer | -1 , if no bit set , else the position of the bit set ( starting with bit 0 ) |

prepare

prepare (config, serialDevice)

Creates a serial device object , if not already available

prepare Parameters

| Name | Type | Attribute | Default | Description | | ---------- | ------------ | ------------ | ------------ | ----------------- | | config | Object | | | serial device configuration settings | | | serialDevice | SerialDevice | optional | null | serial device object | |

serialMessageToString

serialMessageToString (message) => {string}

Converts a serial message to a byte stream

serialMessageToString Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | message | SerialMessage | message to convert | |

serialMessageToString returns

| Type | Description | | ---- | ----------- | | string | string to transmit |

switchMessageToString

switchMessageToString (message)

Calculates the switching string from a switch message

switchMessageToString Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | message | SerialMessage | message to convert | |

message properties

| Name | Type | Description | | ---------- | ------------ | ----------------- | | value | number | value used to identify the switch and the switching value | |

Class SerialDevice

new SerialDevice(options)

Creates a service class to communicate with several arduino over a serial bus

SerialDevice Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | options | Object | configuration options | |

options properties

| Name | Type | Attribute | Default | Description | | ---------- | ------------ | ------------ | ------------ | ----------------- | | serialPortName | string | | | name of the port to use | | | baudrate | integer | optional | 57600 | baud rate to be used | | | qos | 0, 1, 2 | optional | 1 | quality of service to send messages | | | trace | string | optional | 'messages' | trace level , supported : errors , messages , internal | | | keepAliveDelayInSeconds | number | optional | 1 | delay between two keep alive messages to serial | |

SerialDevice Methods

_traceStringSendToSerial

_traceStringSendToSerial (serialString)

Traces a string send to the serial device

_traceStringSendToSerial Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | serialString | string | string send to serial device | |

close

async close ()

Stops the service

getSubscriptions

getSubscriptions () => {topic:qos}

Gets the list of required subscriptions for this service

getSubscriptions returns

| Type | Description | | ---- | ----------- | | topic:qos | list of subscription strings |

handleMessage

handleMessage (mqttMessage)

Processes an incoming mqtt message

handleMessage Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | mqttMessage | Message | mqtt message | |

on

on (event, callback)

Sets a callback .

on Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | event | string | event name ( not case sensitive ) for the callback ( supported : 'publish' ) | | | callback | Publish | function ( . . . parameter ) | |

on throws

| Type | Description | | ---- | ----------- | | Error | if the event is not supported | | Error | if the callback is not 'function' |

run

async run ()

Starts the server