qabstractgrpcclient.h

/*
 * MIT License
 *
 * Copyright (c) 2019 Alexey Edelev <semlanik@gmail.com>
 *
 * This file is part of QtProtobuf project https://git.semlanik.org/semlanik/qtprotobuf
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and
 * to permit persons to whom the Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies
 * or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
 
#pragma once //QAbstractGrpcClient
 
#include <memory>
#include <functional>
#include <type_traits>
 
#include <QObject>
#include <QPointer>
#include <QByteArray>
 
#include <qtprotobuflogging.h>
#include <qabstractprotobufserializer.h>
 
#include "qabstractgrpcchannel.h"
 
#include "qtgrpcglobal.h"
 
namespace QtProtobuf {
 
class QGrpcAsyncReply;
class QGrpcSubscription;
class QGrpcAsyncOperationBase;
class QAbstractGrpcChannel;
class QAbstractGrpcClientPrivate;
 
using SubscriptionHandler = std::function<void(const QByteArray&)>;
 
class Q_GRPC_EXPORT QAbstractGrpcClient : public QObject
{
    Q_OBJECT
public:
    void attachChannel(const std::shared_ptr<QAbstractGrpcChannel> &channel);
 
signals:
    void error(const QGrpcStatus &status);
 
protected:
    QAbstractGrpcClient(const QString &service, QObject *parent = nullptr);
    virtual ~QAbstractGrpcClient();
 
    template<typename A, typename R>
    QGrpcStatus call(const QString &method, const A &arg, const QPointer<R> &ret) {
        QGrpcStatus status{QGrpcStatus::Ok};
        if (ret.isNull()) {
            static const QString errorString("Unable to call method: %1. Pointer to return data is null");
            status = QGrpcStatus{QGrpcStatus::InvalidArgument, errorString.arg(method)};
            error(status);
            qProtoCritical() << errorString.arg(method);
            return status;
        }
 
        QByteArray retData;
        status = call(method, arg.serialize(serializer()), retData);
        if (status == QGrpcStatus::StatusCode::Ok) {
            return tryDeserialize(*ret, retData);
        }
        return status;
    }
 
    template<typename A>
    QGrpcAsyncReplyShared call(const QString &method, const A &arg) {
        return call(method, arg.serialize(serializer()));
    }
 
    template<typename A>
    QGrpcSubscriptionShared subscribe(const QString &method, const A &arg) {
        return subscribe(method, arg.serialize(serializer()));
    }
 
    template<typename A, typename R>
    QGrpcSubscriptionShared subscribe(const QString &method, const A &arg, const QPointer<R> &ret) {
        if (ret.isNull()) {
            static const QString nullPointerError("Unable to subscribe method: %1. Pointer to return data is null");
            error({QGrpcStatus::InvalidArgument, nullPointerError.arg(method)});
            qProtoCritical() << nullPointerError.arg(method);
            return nullptr;
        }
 
        return subscribe(method, arg.serialize(serializer()), [ret, this](const QByteArray &data) {
            if (!ret.isNull()) {
                tryDeserialize(*ret, data);
            } else {
                static const QLatin1String nullPointerError("Pointer to return data is null while subscription update received");
                error({QGrpcStatus::InvalidArgument, nullPointerError});
                qProtoCritical() << nullPointerError;
            }
        });
    }
 
    void cancel(const QString &method);
 
    QAbstractProtobufSerializer *serializer() const;
 
    friend class QGrpcAsyncOperationBase;
private:
    QGrpcStatus call(const QString &method, const QByteArray &arg, QByteArray &ret);
 
    QGrpcAsyncReplyShared call(const QString &method, const QByteArray &arg);
 
    QGrpcSubscriptionShared subscribe(const QString &method, const QByteArray &arg, const QtProtobuf::SubscriptionHandler &handler = {});
 
    template<typename R>
    QGrpcStatus tryDeserialize(R &ret, const QByteArray &retData) {
        QGrpcStatus status{QGrpcStatus::Ok};
        try {
            ret.deserialize(serializer(), retData);
        } catch (std::invalid_argument &) {
            static const QLatin1String invalidArgumentErrorMessage("Response deserialization failed invalid field found");
            status = {QGrpcStatus::InvalidArgument, invalidArgumentErrorMessage};
            error(status);
            qProtoCritical() << invalidArgumentErrorMessage;
        } catch (std::out_of_range &) {
            static const QLatin1String outOfRangeErrorMessage("Invalid size of received buffer");
            status = {QGrpcStatus::OutOfRange, outOfRangeErrorMessage};
            error(status);
            qProtoCritical() << outOfRangeErrorMessage;
        } catch (...) {
            status = {QGrpcStatus::Internal, QLatin1String("Unknown exception caught during deserialization")};
            error(status);
        }
        return status;
    }
 
    Q_DISABLE_COPY_MOVE(QAbstractGrpcClient)
 
    std::unique_ptr<QAbstractGrpcClientPrivate> dPtr;
};
}