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IOConnector API

Version: 1.0.0

Status: ⚫⚪⚪

IOConnector interface for Thunder framework.

(Defined with IIOConnector in IIOConnector.h)

Table of Contents

Introduction

Scope

This document describes purpose and functionality of the IOConnector interface (version 1.0.0). It includes detailed specification about its methods and properties as well as sent notifications.

Case Sensitivity

All identifiers of the interfaces described in this document are case-sensitive. Thus, unless stated otherwise, all keywords, entities, properties, relations and actions should be treated as such.

Acronyms, Abbreviations and Terms

The table below provides and overview of acronyms used in this document and their definitions.

Acronym Description
API Application Programming Interface
HTTP Hypertext Transfer Protocol
JSON JavaScript Object Notation; a data interchange format
JSON-RPC A remote procedure call protocol encoded in JSON

The table below provides and overview of terms and abbreviations used in this document and their definitions.

Term Description
callsign The name given to an instance of a plugin. One plugin can be instantiated multiple times, but each instance the instance name, callsign, must be unique.

References

Ref ID Description
HTTP HTTP specification
JSON-RPC JSON-RPC 2.0 specification
JSON JSON specification
Thunder Thunder API Reference

Description

IOConnector JSON-RPC interface.

This interface uses legacy lowercase naming convention. With the next major release the naming convention will change to camelCase.

Methods

The following methods are provided by the IOConnector interface:

Built-in methods:

Method Description
exists Checks if a JSON-RPC method or property exists
register Registers for an asynchronous JSON-RPC notification
unregister Unregisters from an asynchronous JSON-RPC notification

exists method

Checks if a JSON-RPC method or property exists.

Description

This method will return True for the following methods/properties: pin, exists, register, unregister.

Parameters

Name Type M/O Description
params object mandatory ...
params.method string mandatory Name of the method or property to look up

Result

Name Type M/O Description
result boolean mandatory Denotes if the method exists or not

Example

Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.exists",
  "params": {
    "method": "methodName"
  }
}

Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": false
}

register method

Registers for an asynchronous JSON-RPC notification.

Description

This method supports the following event names: activity.

Parameters

Name Type M/O Description
params object mandatory ...
params.event string mandatory Name of the notification to register for
params.id string mandatory Client identifier

Result

Name Type M/O Description
result null mandatory Always null

Errors

Message Description
ERROR_FAILED_REGISTERED Failed to register for the notification (e.g. already registered)

Example

Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.register",
  "params": {
    "event": "eventName",
    "id": "myapp"
  }
}

Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": null
}

unregister method

Unregisters from an asynchronous JSON-RPC notification.

Description

This method supports the following event names: activity.

Parameters

Name Type M/O Description
params object mandatory ...
params.event string mandatory Name of the notification to register for
params.id string mandatory Client identifier

Result

Name Type M/O Description
result null mandatory Always null

Errors

Message Description
ERROR_FAILED_UNREGISTERED Failed to unregister from the notification (e.g. not yet registered)

Example

Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.unregister",
  "params": {
    "event": "eventName",
    "id": "myapp"
  }
}

Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": null
}

Properties

The following properties are provided by the IOConnector interface:

IOConnector interface properties:

Property R/W Description
pin read/write GPIO pin value

pin property

Provides access to the GPIO pin value.

The id parameter shall be passed as the index to the property, i.e. pin@<id>.

Index

Name Type M/O Description
id integer mandatory Pin ID

Value

Name Type M/O Description
(property) object mandatory GPIO pin value
(property).value integer mandatory Value of the pin
Name Type M/O Description
(property) integer mandatory GPIO pin value

Errors

Message Description
ERROR_UNKNOWN_KEY Unknown pin ID given

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.pin@189"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": 0
}

Set Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.pin@189",
  "params": {
    "value": 1
  }
}

Set Response

{
    "jsonrpc": "2.0",
    "id": 42,
    "result": "null"
}

Notifications

Notifications are autonomous events triggered by the internals of the implementation and broadcasted via JSON-RPC to all registered observers. Refer to [Thunder] for information on how to register for a notification.

The following events are provided by the IOConnector interface:

IOConnector interface events:

Notification Description
activity Notifies about GPIO pin activity

activity notification

Notifies about GPIO pin activity.

Parameters

The id parameter shall be passed as index to the register call, i.e. register@<id>.

Notification Parameters

Name Type M/O Description
params object mandatory ...
params.value integer mandatory Value of the pin

Example

Registration

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.register@189",
  "params": {
    "event": "activity",
    "id": "myid"
  }
}

Notification

{
  "jsonrpc": "2.0",
  "method": "myid.activity@189",
  "params": {
    "value": 1
  }
}

The client ID parameter is passed within the notification designator, i.e. <client-id>.activity@<id>.

The id parameter is passed as index within the notification designator, i.e. <client-id>.activity@<id>.