CClientTCPSocket.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
#pragma once
 
#include <mrpt/config.h>  // MRPT_WORD_SIZE
#include <mrpt/io/CStream.h>
#include <mrpt/system/os.h>
#include <cstdint>
#include <string>
#include <cstring>  // strlen()
 
namespace mrpt
{
/** Serial and networking devices and utilities */
namespace comms
{
class CServerTCPSocket;
 
/** A TCP socket that can be connected to a TCP server, implementing MRPT's
 * CStream interface for passing objects as well as generic read/write methods.
 *  Unless otherwise noticed, operations are blocking.
 *
 *  Note that for convenience, DNS lookup is performed with a timeout
 * (default=3000ms), which can be changed by the static member
 * CClientTCPSocket::DNS_LOOKUP_TIMEOUT_MS
 * \ingroup mrpt_comms_grp
 */
class CClientTCPSocket : public mrpt::io::CStream
{
        friend class CServerTCPSocket;
 
   public:
        /** See description of CClientTCPSocket */
        static unsigned int DNS_LOOKUP_TIMEOUT_MS;
 
   protected:
#ifdef _WIN32
/** The handle for the connected TCP socket, or INVALID_SOCKET
 */
#if MRPT_WORD_SIZE == 64
        uint64_t m_hSock;
#else
        uint32_t m_hSock;
#endif
#else
        /** The handle for the connected TCP socket, or -1 */
        int m_hSock;
#endif
        /** The IP address of the remote part of the connection. */
        std::string m_remotePartIP;
        /** The TCP port of the remote part of the connection. */
        unsigned short m_remotePartPort;
 
        /** Introduces a virtual method responsible for reading from the stream
         * (This method BLOCKS)
         * This method is implemented as a call to "readAsync" with infinite
         * timeouts.
         * \sa readAsync */
        size_t Read(void* Buffer, size_t Count) override;
 
        /** Introduces a virtual method responsible for writing to the stream.
         *  Write attempts to write up to Count bytes to Buffer, and returns the
         * number of bytes actually written.
         *  This method is implemented as a call to "writeAsync" with infinite
         * timeouts.
         * \sa writeAsync */
        size_t Write(const void* Buffer, size_t Count) override;
 
        /** Returns a description of the last Sockets error */
        std::string getLastErrorStr();
 
   public:
        /** Default constructor \sa connect  */
        CClientTCPSocket();
 
        /** Destructor */
        ~CClientTCPSocket();
 
        /** Establishes a connection with a remote part.
         * \param remotePartAddress This string can be a host name, like "server"
         * or "www.mydomain.org", or an IP address "11.22.33.44".
         * \param remotePartTCPPort The port on the remote machine to connect to.
         * \param timeout_ms  The timeout to wait for the connection (0: NO
         * TIMEOUT)
         * \exception This method raises an exception if an error is found with a
         * textual description of the error.
         */
        void connect(
                const std::string& remotePartAddress, unsigned short remotePartTCPPort,
                unsigned int timeout_ms = 0);
 
        /** Returns true if this objects represents a successfully connected socket
         */
        bool isConnected();
 
        /** Closes the connection */
        void close();
 
        /** Writes a string to the socket.
         * \exception std::exception On communication errors
         */
        void sendString(const std::string& str);
 
        /** This virtual method has no effect in this implementation over a TCP
         * socket, and its use raises an exception */
        uint64_t Seek(
                int64_t off, CStream::TSeekOrigin org = sFromBeginning) override;
 
        /** This virtual method has no effect in this implementation over a TCP
         * socket, and its use raises an exception */
        uint64_t getTotalBytesCount() const override;
 
        /** This virtual method has no effect in this implementation over a TCP
         * socket, and its use raises an exception */
        uint64_t getPosition() const override;
 
        /** A method for reading from the socket with an optional timeout.
         * \param Buffer The destination of data.
         * \param Cound The number of bytes to read.
         * \param timeoutStart_ms The maximum timeout (in milliseconds) to wait for
         * the starting of data from the other side.
         * \param timeoutBetween_ms The maximum timeout (in milliseconds) to wait
         * for a chunk of data after a previous one.
         *  Set timeout's to -1 to block until the desired number of bytes are
         * read, or an error happens.
         *  \return The number of actually read bytes.
         */
        size_t readAsync(
                void* Buffer, const size_t Count, const int timeoutStart_ms = -1,
                const int timeoutBetween_ms = -1);
 
        /** A method for writing to the socket with optional timeouts.
         *  The method supports writing block by block as the socket allows us to
         * write more data.
         * \param Buffer The data.
         * \param Cound The number of bytes to write.
         * \param timeout_ms The maximum timeout (in milliseconds) to wait for the
         * socket to be available for writing (for each block).
         *  Set timeout's to -1 to block until the desired number of bytes are
         * written, or an error happens.
         *  \return The number of actually written bytes.
         */
        size_t writeAsync(
                const void* Buffer, const size_t Count, const int timeout_ms = -1);
 
        /** Send a message through the TCP stream.
         * \param outMsg The message to be shown.
         * \param timeout_ms The maximum timeout (in milliseconds) to wait for the
         * socket in each write operation.
         * \return Returns false on any error, or true if everything goes fine.
         * \tparam MESSAGE can be mrpt::serialization::CMessage
         */
        template <class MESSAGE>
        bool sendMessage(const MESSAGE& outMsg, const int timeout_ms = -1)
        {
                // (1) Send a "magic word":
                const char* magic = "MRPTMessage";
                uint32_t toWrite = strlen(magic);
                uint32_t written = writeAsync(magic, toWrite, timeout_ms);
                if (written != toWrite) return false;  // Error!
                // (2) Send the message type:
                toWrite = sizeof(outMsg.type);
                written = writeAsync(&outMsg.type, toWrite, timeout_ms);
                if (written != toWrite) return false;  // Error!
                // (3) Send the message's content length:
                uint32_t contentLen = outMsg.content.size();
                toWrite = sizeof(contentLen);
                written = writeAsync(&contentLen, toWrite, timeout_ms);
                if (written != toWrite) return false;  // Error!
                // (4) Send the message's contents:
                toWrite = contentLen;
                written = writeAsync(&outMsg.content[0], toWrite, timeout_ms);
                if (written != toWrite) return false;  // Error!
                return true;
        }
 
        /** Waits for an incoming message through the TCP stream.
         * \param inMsg The received message is placed here.
         * \param timeoutStart_ms The maximum timeout (in milliseconds) to wait for
         * the starting of data from the other side.
         * \param timeoutBetween_ms The maximum timeout (in milliseconds) to wait
         * for a chunk of data after a previous one.
         * \return Returns false on any error (or timeout), or true if everything
         * goes fine.
         * \tparam MESSAGE can be mrpt::serialization::CMessage
         */
        template <class MESSAGE>
        bool receiveMessage(
                MESSAGE& inMsg, const unsigned int timeoutStart_ms = 100,
                const unsigned int timeoutBetween_ms = 1000)
        {
                // (1) Read the "magic word":
                char magic[20];
                uint32_t toRead = 11;
                uint32_t actRead =
                        readAsync(magic, toRead, timeoutStart_ms, timeoutBetween_ms);
                if (actRead != toRead) return false;  // Error!
                magic[actRead] = 0;  // Null-term string
                // Check magic:
                if (0 != ::strcmp("MRPTMessage", magic)) return false;
                // (2) Read the message type:
                toRead = sizeof(inMsg.type);
                actRead = readAsync(
                        &inMsg.type, toRead, timeoutBetween_ms, timeoutBetween_ms);
                if (actRead != toRead) return false;  // Error!
                // (3) Read the message's content length:
                uint32_t contentLen;
                toRead = sizeof(contentLen);
                actRead = readAsync(
                        &contentLen, toRead, timeoutBetween_ms, timeoutBetween_ms);
                if (actRead != toRead) return false;  // Error!
                inMsg.content.resize(contentLen);
                // (4) Read the message's contents:
                toRead = contentLen;
                actRead = readAsync(
                        &inMsg.content[0], toRead, timeoutBetween_ms, timeoutBetween_ms);
                if (actRead != toRead) return false;  // Error!
                return true;
        }
 
        /** Return the number of bytes already in the receive queue (they can be
         * read without waiting) */
        size_t getReadPendingBytes();
 
        /** Set the TCP no delay option of the protocol (Nagle algorithm).
         * \param newValue New value (0 enable Nagle algorithm, 1 disable).
         * \return Return a number lower than 0 if any error occurred.
         */
        int setTCPNoDelay(const int& newValue);
 
        /** Return the value of the TCPNoDelay option. */
        int getTCPNoDelay();
 
        /** Set the size of the SO send buffer. This buffer is used to store data,
         * and is sended when is full.
         * \param newValue New size of the SO send buffer.
         * \return Return a number lower than 0 if any error occurred.
         */
        int setSOSendBufffer(const int& newValue);
 
        /** Return the current size of the SO send buffer. */
        int getSOSendBufffer();
 
};  // End of class def.
 
}  // namespace comms
}  // namespace mrpt