class mrpt::comms::CClientTCPSocket

Overview

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

#include <mrpt/comms/CClientTCPSocket.h>

class CClientTCPSocket: public mrpt::io::CStream
{
public:
    // fields

    static unsigned int DNS_LOOKUP_TIMEOUT_MS = 3000;

    // construction

    CClientTCPSocket();

    // methods

    void connect(
        const std::string& remotePartAddress,
        unsigned short remotePartTCPPort,
        unsigned int timeout_ms = 0
        );

    bool isConnected();
    void close();
    void sendString(const std::string& str);
    uint64_t Seek(int64_t off, CStream::TSeekOrigin org = sFromBeginning);
    virtual uint64_t getTotalBytesCount() const;
    virtual uint64_t getPosition() const;

    size_t readAsync(
        void* Buffer,
        size_t Count,
        const int timeoutStart_ms = -1,
        const int timeoutBetween_ms = -1
        );

    size_t writeAsync(const void* Buffer, size_t Count, const int timeout_ms = -1);

    template <class MESSAGE>
    bool sendMessage(
        const MESSAGE& outMsg,
        const int timeout_ms = -1
        );

    template <class MESSAGE>
    bool receiveMessage(
        MESSAGE& inMsg,
        const unsigned int timeoutStart_ms = 100,
        const unsigned int timeoutBetween_ms = 1000
        );

    size_t getReadPendingBytes();
    int setTCPNoDelay(int newValue);
    int getTCPNoDelay();
    int setSOSendBufffer(int newValue);
    int getSOSendBufffer();
    virtual size_t ReadBufferImmediate(void* Buffer, size_t Count);
};

Inherited Members

public:
    // methods

    virtual size_t Read(void* Buffer, size_t Count) = 0;
    virtual size_t Write(const void* Buffer, size_t Count) = 0;
    virtual uint64_t getTotalBytesCount() const = 0;
    virtual uint64_t getPosition() const = 0;

Fields

static unsigned int DNS_LOOKUP_TIMEOUT_MS = 3000

See description of CClientTCPSocket.

Construction

CClientTCPSocket()

Default constructor.

See also:

connect

Methods

void connect(
    const std::string& remotePartAddress,
    unsigned short remotePartTCPPort,
    unsigned int timeout_ms = 0
    )

Establishes a connection with a remote part.

Parameters:

remotePartAddress	This string can be a host name, like “server” or “www.mydomain.org”, or an IP address “11.22.33.44”.
remotePartTCPPort	The port on the remote machine to connect to.
timeout_ms	The timeout to wait for the connection (0: NO TIMEOUT)
This	method raises an exception if an error is found with a textual description of the error.

bool isConnected()

Returns true if this objects represents a successfully connected socket.

void close()

Closes the connection.

void sendString(const std::string& str)

Writes a string to the socket.

Parameters:

std::exception

On communication errors

uint64_t Seek(int64_t off, CStream::TSeekOrigin org = sFromBeginning)

This virtual method has no effect in this implementation over a TCP socket, and its use raises an exception.

virtual uint64_t getTotalBytesCount() const

This virtual method has no effect in this implementation over a TCP socket, and its use raises an exception.

virtual uint64_t getPosition() const

This virtual method has no effect in this implementation over a TCP socket, and its use raises an exception.

size_t readAsync(
    void* Buffer,
    size_t Count,
    const int timeoutStart_ms = -1,
    const int timeoutBetween_ms = -1
    )

A method for reading from the socket with an optional timeout.

Parameters:

Buffer	The destination of data.
Cound	The number of bytes to read.
timeoutStart_ms	The maximum timeout (in milliseconds) to wait for the starting of data from the other side.
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.

Returns:

The number of actually read bytes.

size_t writeAsync(const void* Buffer, size_t Count, const int timeout_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.

Parameters:

Buffer	The data.
Cound	The number of bytes to write.
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.

Returns:

The number of actually written bytes.

template <class MESSAGE>
bool sendMessage(
    const MESSAGE& outMsg,
    const int timeout_ms = -1
    )

Send a message through the TCP stream.

Parameters:

outMsg	The message to be shown.
timeout_ms	The maximum timeout (in milliseconds) to wait for the socket in each write operation.
MESSAGE	can be mrpt::serialization::CMessage

Returns:

Returns false on any error, or true if everything goes fine.

template <class MESSAGE>
bool receiveMessage(
    MESSAGE& inMsg,
    const unsigned int timeoutStart_ms = 100,
    const unsigned int timeoutBetween_ms = 1000
    )

Waits for an incoming message through the TCP stream.

Parameters:

inMsg	The received message is placed here.
timeoutStart_ms	The maximum timeout (in milliseconds) to wait for the starting of data from the other side.
timeoutBetween_ms	The maximum timeout (in milliseconds) to wait for a chunk of data after a previous one.
MESSAGE	can be mrpt::serialization::CMessage

Returns:

Returns false on any error (or timeout), or true if everything goes fine.

size_t getReadPendingBytes()

Return the number of bytes already in the receive queue (they can be read without waiting)

int setTCPNoDelay(int newValue)

Set the TCP no delay option of the protocol (Nagle algorithm).

Parameters:

newValue

New value (0 enable Nagle algorithm, 1 disable).

Returns:

Return a number lower than 0 if any error occurred.

int getTCPNoDelay()

Return the value of the TCPNoDelay option.

int setSOSendBufffer(int newValue)

Set the size of the SO send buffer.

This buffer is used to store data, and is sended when is full.

Parameters:

newValue

New size of the SO send buffer.

Returns:

Return a number lower than 0 if any error occurred.

int getSOSendBufffer()

Return the current size of the SO send buffer.

virtual size_t ReadBufferImmediate(void* Buffer, size_t Count)

Reads a block of bytes from the stream into Buffer, and returns the amound of bytes actually read, without waiting for more extra bytes to arrive (just those already enqued in the stream).

Note that this method will fallback to ReadBuffer() in most CStream classes but in some hardware-related classes.

Parameters:

std::exception

On any error, or if ZERO bytes are read.