An ISystemControllerInterface is the interface between a component and the System controller controlling the component. The interface allows for two-way communication between the component and the system controller by means of sending requests and getting responses. Classes deriving from the ISystemControllerInterface should provide the component side implementation of the communication with the system controller. This interface can be inherited and implemented by developers to connect to custom system controllers, or to directly control a component programmatically, without the need for connecting to a remote server. An ISystemControllerInterface can have a parent-child relationship with other interfaces, where the children are aware of which their parent interface is. This is useful for components that provides extra features for another component, but where the components are still to be considered as two separate entities with separate connections to the System controller.
A response to a request, consists of a status code and an (optional) parameters JSON object.
A struct containing the callbacks that needs to be registered by the component using this interface.

Source code

// Copyright (c) 2022, Edgeware AB. All rights reserved.

#pragma once

#include <functional>
#include <json.hpp>
#include <string>

class ISystemControllerInterface {
    enum class StatusCode : uint32_t {
        SUCCESS = 3001, // Accept / Success

        TOO_MANY_REQUESTS = 3101, // Too many requests, try again later

        UUID_ALREADY_REGISTERED = 3201, // UUID is already registered
        FORMAT_ERROR = 3202,            // Message formatting error
        ALREADY_CONFIGURED = 3203,      // The requested thing to configure is already configured
        OUT_OF_RESOURCES = 3204,  // Out of resources (CPU/GPU close to max utilization, all available slots used, etc.)
        NOT_FOUND = 3205,         // The requested thing was not found
        INTERNAL_ERROR = 3206,    // Internal error when trying to serve the request
        CONNECTION_FAILED = 3207, // Connection failure
        TIMEOUT_EXCEEDED = 3208,  // Timeout exceeded
        KEY_MISMATCH = 3209,      // Key mismatch (might be a timeout, 3007 in the future)
        UNKNOWN_REQUEST = 3210,   // The name of the request was not known
        MALFORMED_REQUEST = 3211, // The request is not correctly formatted
        ALREADY_IN_USE = 3212,    // The requested resource is already in use

        // None, yet

    struct Response {
        StatusCode mCode;
        nlohmann::json mParameters; // Can be empty

    struct Callbacks {
        std::function<Response(const std::string&, const nlohmann::json&)>
            mRequestCallback; // Callback called when then controller has sent a request
        std::function<void(uint32_t, const std::string&, const std::error_code&)>
            mConnectionClosedCallback; // Callback called when the connection to the controller is closed

    virtual ~ISystemControllerInterface() = default;

    virtual Response sendRequest(const std::string& request, const nlohmann::json& parameters) = 0;

    virtual bool registerRequestCallback(const Callbacks& callbacks) = 0;

    virtual bool connect() = 0;

    virtual bool disconnect() = 0;

    virtual bool isConnected() const = 0;

    virtual std::string getUUID() const = 0;

    virtual bool hasParent() const = 0;

    virtual std::shared_ptr<ISystemControllerInterface> getParentInterface() const = 0;

Updated on 2023-10-03 at 14:32:11 +0200