BaseCommandHandler.hpp

// SPDX-FileCopyrightText: 2025 Vincent Leroy
// SPDX-License-Identifier: MIT
//
// This file is part of dfx.
//
// Licensed under the MIT License. See the LICENSE file in the project root
// for full license information.
 
#pragma once
 
// Project includes
#include <dfx-utilities/JsonValidator.hpp>
#include <dfx-utilities/SFINAEHelpers.hpp>
 
namespace dfx::Server
{
class UnixRouter;
 
class UnixSession;
using UnixSessionPtr = std::shared_ptr<UnixSession>;
} // !namespace dfx::Server
 
namespace dfx::Server::Api
{
class BaseCommandHandler
{
    using Handler = std::move_only_function<bool (UnixSessionPtr, nlohmann::json, std::string)>;
 
public:
    BaseCommandHandler() = default;
 
protected:
    template<typename PMF>
    void registerNewCommand(UnixRouter & router, std::string command,
                            nlohmann::json const & schema, PMF handler);

    bool validateParams(std::string_view command, nlohmann::json const & params,
                        std::string_view id, UnixSessionPtr session) const;
 
private:
    void _registerNewCommandImpl(UnixRouter & router, std::string command,
                                 nlohmann::json const & schema, Handler handler);
 
private:
    Utils::JsonValidator _validator;
};
 
template<typename PMF>
inline void BaseCommandHandler::registerNewCommand(UnixRouter & router, std::string command,
                                                   nlohmann::json const & schema, PMF handler)
{
    static_assert(std::is_member_function_pointer_v<PMF>, "The handler must be a member function pointer");
    using C = Utils::SFINAE::memberClass_t<PMF>;
    static_assert(std::is_base_of_v<BaseCommandHandler, C>, "The handler must be a member function of a class derived from BaseCommandHandler");
    static_assert(std::is_convertible_v<C, BaseCommandHandler>, "The base class must inherit from BaseCommandHandler publicly");
 
    _registerNewCommandImpl(router, command, schema,
                            [handler, this](UnixSessionPtr session, nlohmann::json params, std::string id)
    { return std::invoke(handler, static_cast<C *>(this), session, std::move(params), std::move(id)); });
}
} // !namespace dfx::Server::Api