1 /**

     2  * Relational pipes

     3  * Copyright © 2022 František Kučera (Frantovo.cz, GlobalCode.info)

     4  *

     5  * This program is free software: you can redistribute it and/or modify

     6  * it under the terms of the GNU General Public License as published by

     7  * the Free Software Foundation, version 3 of the License.

     8  *

     9  * This program is distributed in the hope that it will be useful,

    10  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

    12  * GNU General Public License for more details.

    13  *

    14  * You should have received a copy of the GNU General Public License

    15  * along with this program. If not, see <http://www.gnu.org/licenses/>.

    16  */

    17 #pragma once

    18 

    19 #include <mqueue.h>

    20 #include <string>

    21 #include <stdexcept>

    22 #include <cstring>

    23 

    24 namespace relpipe {

    25 namespace in {

    26 namespace amqp {

    27 

    28 class AMQP {

    29 private:

    30 	const static size_t MSG_SIZE = 8192; // TODO: configurable/dynamic

    31 	std::string queueName;

    32 	mqd_t handle = -2;

    33 	bool unlinkOnClose = false;

    34 

    35 	AMQP(std::string queueName, mqd_t handle, bool unlinkOnClose) : queueName(queueName), handle(handle), unlinkOnClose(unlinkOnClose) {

    36 	}

    37 

    38 public:

    39 

    40 	virtual ~AMQP() {

    41 		if (handle >= 0) mq_close(handle);

    42 		if (unlinkOnClose) mq_unlink(queueName.c_str());

    43 	}

    44 

    45 	static AMQP* open(std::string queueName, bool unlinkOnClose = false) {

    46 		mqd_t handle = mq_open(queueName.c_str(), O_RDONLY | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);

    47 		if (handle >= 0) return new AMQP(queueName, handle, unlinkOnClose);

    48 		else throw std::logic_error("Unable to open AMQP: " + queueName + " error: " + strerror(errno));

    49 	}

    50 

    51 	void send(std::string message) {

    52 		int result = mq_send(handle, message.c_str(), message.size(), 0);

    53 		if (result) throw std::logic_error("Unable to send message to" + queueName + " error: " + strerror(errno));

    54 	}

    55 

    56 	std::string receive() {

    57 		char buffer[MSG_SIZE + 1];

    58 		memset(buffer, 0, MSG_SIZE + 1);

    59 		ssize_t msgSize = mq_receive(handle, buffer, MSG_SIZE, nullptr);

    60 

    61 		if (msgSize > sizeof (buffer))throw std::logic_error("Invalid AMQP message size.");

    62 		else if (msgSize >= 0) return std::string(buffer, msgSize);

    63 		else throw std::logic_error("Unable to receive AMQP message from " + queueName + " error: " + strerror(errno));

    64 	}

    65 

    66 };

    67 

    68 }

    69 }

    70 }