plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/tcp/protocol/ModbusTcpProtocolLogic.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
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package org.apache.plc4x.java.modbus.tcp.protocol;

import org.apache.plc4x.java.api.exceptions.PlcRuntimeException;
import org.apache.plc4x.java.api.messages.PlcReadRequest;
import org.apache.plc4x.java.api.messages.PlcReadResponse;
import org.apache.plc4x.java.api.messages.PlcWriteRequest;
import org.apache.plc4x.java.api.messages.PlcWriteResponse;
import org.apache.plc4x.java.api.model.PlcField;
import org.apache.plc4x.java.api.types.PlcResponseCode;
import org.apache.plc4x.java.api.value.PlcValue;
import org.apache.plc4x.java.modbus.base.field.ModbusField;
import org.apache.plc4x.java.modbus.base.protocol.ModbusProtocolLogic;
import org.apache.plc4x.java.modbus.readwrite.*;
import org.apache.plc4x.java.modbus.rtu.config.ModbusRtuConfiguration;
import org.apache.plc4x.java.modbus.tcp.config.ModbusTcpConfiguration;
import org.apache.plc4x.java.spi.configuration.HasConfiguration;
import org.apache.plc4x.java.spi.generation.ParseException;
import org.apache.plc4x.java.spi.messages.DefaultPlcReadRequest;
import org.apache.plc4x.java.spi.messages.DefaultPlcReadResponse;
import org.apache.plc4x.java.spi.messages.DefaultPlcWriteRequest;
import org.apache.plc4x.java.spi.messages.DefaultPlcWriteResponse;
import org.apache.plc4x.java.spi.messages.utils.ResponseItem;
import org.apache.plc4x.java.spi.transaction.RequestTransactionManager;

import java.time.Duration;
import java.util.Collections;
import java.util.concurrent.CompletableFuture;

public class ModbusTcpProtocolLogic extends ModbusProtocolLogic<ModbusTcpADU> implements HasConfiguration<ModbusTcpConfiguration> {

    public ModbusTcpProtocolLogic() {
        super(DriverType.MODBUS_TCP);
    }

    @Override
    public void setConfiguration(ModbusTcpConfiguration configuration) {
        this.requestTimeout = Duration.ofMillis(configuration.getRequestTimeout());
        this.unitIdentifier = (short) configuration.getUnitIdentifier();
        this.tm = new RequestTransactionManager(1);
    }

    @Override
    public CompletableFuture<PlcReadResponse> read(PlcReadRequest readRequest) {
        CompletableFuture<PlcReadResponse> future = new CompletableFuture<>();
        DefaultPlcReadRequest request = (DefaultPlcReadRequest) readRequest;

        // 1. Sort all items by type:
        //      - DiscreteInput     (read-only)     --> ModbusPduReadDiscreteInputsRequest
        //      - Coil              (read-write)    --> ModbusPduReadCoilsRequest
        //      - InputRegister     (read-only)     --> ModbusPduReadInputRegistersRequest
        //      - HoldingRegister   (read-write)    --> ModbusPduReadHoldingRegistersRequest
        //      - FifoQueue         (read-only)     --> ModbusPduReadFifoQueueRequest
        //      - FileRecord        (read-write)    --> ModbusPduReadFileRecordRequest
        // 2. Split up into multiple sub-requests

        // Example for sending a request ...
        if (request.getFieldNames().size() == 1) {
            String fieldName = request.getFieldNames().iterator().next();
            ModbusField field = (ModbusField) request.getField(fieldName);
            final ModbusPDU requestPdu = getReadRequestPdu(field);

            int transactionIdentifier = transactionIdentifierGenerator.getAndIncrement();
            // If we've reached the max value for a 16 bit transaction identifier, reset back to 1
            if (transactionIdentifierGenerator.get() == 0xFFFF) {
                transactionIdentifierGenerator.set(1);
            }
            ModbusTcpADU modbusTcpADU = new ModbusTcpADU(transactionIdentifier, unitIdentifier, requestPdu, false);
            RequestTransactionManager.RequestTransaction transaction = tm.startRequest();
            transaction.submit(() -> context.sendRequest(modbusTcpADU)
                .expectResponse(ModbusTcpADU.class, requestTimeout)
                .onTimeout(future::completeExceptionally)
                .onError((p, e) -> future.completeExceptionally(e))
                .check(p -> ((p.getTransactionIdentifier() == transactionIdentifier) &&
                    (p.getUnitIdentifier() == unitIdentifier)))
                .unwrap(ModbusTcpADU::getPdu)
                .handle(responsePdu -> {
                    // Try to decode the response data based on the corresponding request.
                    PlcValue plcValue = null;
                    PlcResponseCode responseCode;
                    // Check if the response was an error response.
                    if (responsePdu instanceof ModbusPDUError) {
                        ModbusPDUError errorResponse = (ModbusPDUError) responsePdu;
                        responseCode = getErrorCode(errorResponse);
                    } else {
                        try {
                            plcValue = toPlcValue(requestPdu, responsePdu, field.getDataType());
                            responseCode = PlcResponseCode.OK;
                        } catch (ParseException e) {
                            // Add an error response code ...
                            responseCode = PlcResponseCode.INTERNAL_ERROR;
                        }
                    }

                    // Prepare the response.
                    PlcReadResponse response = new DefaultPlcReadResponse(request,
                        Collections.singletonMap(fieldName, new ResponseItem<>(responseCode, plcValue)));

                    // Pass the response back to the application.
                    future.complete(response);

                    // Finish the request-transaction.
                    transaction.endRequest();
                }));
        } else {
            future.completeExceptionally(new PlcRuntimeException("Modbus only supports single filed requests"));
        }
        return future;
    }

    @Override
    public CompletableFuture<PlcWriteResponse> write(PlcWriteRequest writeRequest) {
        CompletableFuture<PlcWriteResponse> future = new CompletableFuture<>();
        DefaultPlcWriteRequest request = (DefaultPlcWriteRequest) writeRequest;

        // 1. Sort all items by type:
        //      - DiscreteInput     (read-only)     --> Error
        //      - Coil              (read-write)    --> ModbusPduWriteSingleCoilRequest / ModbusPduWriteMultipleCoilsRequest
        //      - InputRegister     (read-only)     --> Error
        //      - HoldingRegister   (read-write)    --> ModbusPduWriteSingleRegisterRequest / ModbusPduWriteMultipleRegistersRequest
        //      - FifoQueue         (read-only)     --> Error
        //      - FileRecord        (read-write)    --> ModbusPduWriteFileRecordRequest
        // 2. Split up into multiple sub-requests
        if (request.getFieldNames().size() == 1) {
            String fieldName = request.getFieldNames().iterator().next();
            PlcField field = request.getField(fieldName);
            final ModbusPDU requestPdu = getWriteRequestPdu(field, writeRequest.getPlcValue(fieldName));
            int transactionIdentifier = transactionIdentifierGenerator.getAndIncrement();
            // If we've reached the max value for a 16 bit transaction identifier, reset back to 1
            if (transactionIdentifierGenerator.get() == 0xFFFF) {
                transactionIdentifierGenerator.set(1);
            }
            ModbusTcpADU modbusTcpADU = new ModbusTcpADU(transactionIdentifier, unitIdentifier, requestPdu, false);
            RequestTransactionManager.RequestTransaction transaction = tm.startRequest();
            transaction.submit(() -> context.sendRequest(modbusTcpADU)
                .expectResponse(ModbusTcpADU.class, requestTimeout)
                .onTimeout(future::completeExceptionally)
                .onError((p, e) -> future.completeExceptionally(e))
                .check(p -> p.getTransactionIdentifier() == transactionIdentifier)
                .unwrap(ModbusTcpADU::getPdu)
                .handle(responsePdu -> {
                    // Try to decode the response data based on the corresponding request.
                    PlcResponseCode responseCode;

                    // Check if the response was an error response.
                    if (responsePdu instanceof ModbusPDUError) {
                        ModbusPDUError errorResponse = (ModbusPDUError) responsePdu;
                        responseCode = getErrorCode(errorResponse);
                    } else {
                        responseCode = PlcResponseCode.OK;
                        // TODO: Check the correct number of elements were written.
                        if (responsePdu instanceof ModbusPDUWriteSingleCoilResponse) {
                            ModbusPDUWriteSingleCoilResponse response = (ModbusPDUWriteSingleCoilResponse) responsePdu;
                            ModbusPDUWriteSingleCoilRequest requestSingleCoil = (ModbusPDUWriteSingleCoilRequest) requestPdu;
                            if (!((response.getValue() == requestSingleCoil.getValue()) && (response.getAddress() == requestSingleCoil.getAddress()))) {
                                responseCode = PlcResponseCode.REMOTE_ERROR;
                            }
                        }
                    }

                    // Prepare the response.
                    PlcWriteResponse response = new DefaultPlcWriteResponse(request,
                        Collections.singletonMap(fieldName, responseCode));

                    // Pass the response back to the application.
                    future.complete(response);

                    // Finish the request-transaction.
                    transaction.endRequest();
                }));

        } else {
            future.completeExceptionally(new PlcRuntimeException("Modbus only supports single filed requests"));
        }
        return future;
    }

}