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GNet::Client Class Referenceabstract

A class for making an outgoing connection to a remote server, with support for socket-level protocols such as TLS/SSL and SOCKS 4a. More...

`#include <gclient.h>`

Inheritance diagram for GNet::Client:

## Classes
struct | Config
| A structure containing GNet::Client configuration parameters. More...

## Public Member Functions
| Client (ExceptionSink, const Location &remote_location, const Config &)
| Constructor. More...
void | connect ()
| Initiates a connection to the remote server. More...
bool | connected () const
| Returns true if connected to the peer. More...
bool | hasConnected () const
| Returns true if ever connected(). More...
void | disconnect ()
| Aborts the connection and destroys the object's internal state, resulting in a zombie object. More...
std::pair< bool, Address > | localAddress () const override
| Override from Connection. More...
std::pair< bool, Address > | peerAddress () const override
| Override from Connection. More...
std::string | connectionState () const override
| Returns the connection state display string. More...
std::string | peerCertificate () const override
| Returns the peer's TLS certificate. More...
Location | remoteLocation () const
| Returns a Location structure, including the result of name lookup if available. More...
bool | send (const std::string &data, std::size_t offset=0)
| Sends data to the peer and starts the response timer (if configured). More...
bool | send (const std::vector< G::string_view > &data, std::size_t offset=0)
| Overload for scatter/gather segments. More...
G::Slot::Signal< const std::string &, const std::string &, const std::string & > & | eventSignal () noexcept
| Returns a signal that indicates that something interesting has happened. More...
void | doOnDelete (const std::string &reason, bool done)
| Called by ClientPtr (or equivalent) to call onDelete(), just before this client object is deleted. More...
bool | finished () const
| Returns true if finish()ed or disconnect()ed. More...
LineBufferState | lineBuffer () const
| Returns information about the state of the internal line-buffer. More...
| ~Client () override
| Destructor. More...
| Client (const Client &)=delete
| Client (Client &&)=delete
void | operator= (const Client &)=delete
void | operator= (Client &&)=delete
Public Member Functions inherited from GNet::Connection
virtual | ~Connection ()=default
| Destructor.
virtual std::pair< bool, Address > | localAddress () const =0
| Returns the connection's local address. More...
virtual std::pair< bool, Address > | peerAddress () const =0
| Returns the connection's peer address. More...
virtual std::string | connectionState () const =0
| Returns the connection state as a display string. More...
virtual std::string | peerCertificate () const =0
| Returns the peer's TLS certificate. More...
Public Member Functions inherited from GNet::ExceptionSource
virtual std::string | exceptionSourceId () const
| Returns an identifying string for logging purposes, or the empty string. More...
virtual | ~ExceptionSource ()
| Destructor. More...
| ExceptionSource (const ExceptionSource &)=delete
| ExceptionSource (ExceptionSource &&)=delete
void | operator= (const ExceptionSource &)=delete
void | operator= (ExceptionSource &&)=delete

## Protected Member Functions
StreamSocket & | socket ()
| Returns a reference to the socket. Throws if not connected. More...
const StreamSocket & | socket () const
| Returns a const reference to the socket. Throws if not connected. More...
void | finish (bool with_socket_shutdown)
| Indicates that the last data has been sent and the client is expecting a peer disconnect. More...
void | clearInput ()
| Clears the input LineBuffer and cancels the response timer if running. More...
virtual bool | onReceive (const char *data, std::size_t size, std::size_t eolsize, std::size_t linesize, char c0)=0
| Called with received data. More...
virtual void | onConnect ()=0
| Called once connected.
virtual void | onSendComplete ()=0
| Called when all residual data from send() has been sent.
virtual void | onDelete (const std::string &reason)=0
| Called just before ClientPtr destroys the Client as the result of handling an exception. More...
void | secureConnect ()
| Starts TLS/SSL client-side negotiation. More...

## Detailed Description

A class for making an outgoing connection to a remote server, with support for socket-level protocols such as TLS/SSL and SOCKS 4a.

The class handles name-to-address resolution, deals with connection issues, reads incoming data, and manages flow-control when sending. The implementation uses the SocketProtocol class in order to do TLS/SSL; see secureConnect().

Name-to-address lookup is performed if the supplied Location object does not contain an address. This can be done synchronously or asynchronously. The results of the lookup can be obtained via the remoteLocation() method and possibly fed back to the next Client that connects to the same host/service in order to implement name lookup cacheing.

Received data is delivered through a virtual method onReceive(), with optional line-buffering.

Clients should normally be instantiated on the heap and managed by a ClientPtr so that the onDelete() mechanism works as advertised: the ExceptionHandler passed to the Client constructor via the ExceptionSink object should be the ClientPtr instance. Clients that decide to terminate themselves cleanly should call Client::finish() and then throw a GNet::Done exception.

Definition at line 74 of file gclient.h.

## Constructor & Destructor Documentation

## ◆ Client()

GNet::Client::Client | ( | ExceptionSink | es,
|  | const Location & | remote_location,
|  | const Config & | config
| ) |  |

Constructor.

If not auto-starting then connect() is required to start connecting. The ExceptionSink should delete this Client object when an exception is delivered to it, otherwise the the underlying socket might continue to raise events.

Definition at line 37 of file gclient.cpp.

## ◆ ~Client()

GNet::Client::~Client | ( |  | ) |
| override

Destructor.

Definition at line 63 of file gclient.cpp.

## Member Function Documentation

## ◆ clearInput()

void GNet::Client::clearInput | ( |  | ) |
| protected

Clears the input LineBuffer and cancels the response timer if running.

Definition at line 110 of file gclient.cpp.

## ◆ connect()

void GNet::Client::connect | ( |  | ) |

Initiates a connection to the remote server.

Calls back to onConnect() when complete (non-reentrantly). Throws on immediate failure.

Definition at line 122 of file gclient.cpp.

## ◆ connected()

bool GNet::Client::connected | ( |  | ) | const

Returns true if connected to the peer.

Definition at line 402 of file gclient.cpp.

## ◆ connectionState()

std::string GNet::Client::connectionState | ( |  | ) | const
| override virtual

Returns the connection state display string.

Override from GNet::Connection.

Implements GNet::Connection.

Definition at line 449 of file gclient.cpp.

## ◆ disconnect()

void GNet::Client::disconnect | ( |  | ) |

Aborts the connection and destroys the object's internal state, resulting in a zombie object.

After disconnect() only calls to hasConnected(), finished() and the dtor are allowed.

Definition at line 68 of file gclient.cpp.

## ◆ doOnDelete()

void GNet::Client::doOnDelete | ( | const std::string & | reason,
|  | bool | done
| ) |  |

Called by ClientPtr (or equivalent) to call onDelete(), just before this client object is deleted.

Definition at line 237 of file gclient.cpp.

## ◆ eventSignal()

G::Slot::Signal< const std::string &, const std::string &, const std::string & > & GNet::Client::eventSignal | ( |  | ) |
| noexcept

Returns a signal that indicates that something interesting has happened.

The first signal parameter is one of "resolving", "connecting", or "connected", but other classes may inject the own events into this channel.

Definition at line 86 of file gclient.cpp.

## ◆ finish()

void GNet::Client::finish | ( | bool | with_socket_shutdown | ) |
| protected

Indicates that the last data has been sent and the client is expecting a peer disconnect.

Any subsequent onDelete() callback from doOnDelete() will have an empty reason string.

Definition at line 215 of file gclient.cpp.

## ◆ finished()

bool GNet::Client::finished | ( |  | ) | const

Returns true if finish()ed or disconnect()ed.

Definition at line 227 of file gclient.cpp.

## ◆ hasConnected()

bool GNet::Client::hasConnected | ( |  | ) | const

Returns true if ever connected().

Definition at line 232 of file gclient.cpp.

## ◆ lineBuffer()

GNet::LineBufferState GNet::Client::lineBuffer | ( |  | ) | const

Returns information about the state of the internal line-buffer.

Definition at line 490 of file gclient.cpp.

## ◆ localAddress()

std::pair< bool, GNet::Address > GNet::Client::localAddress | ( |  | ) | const
| override virtual

Override from Connection.

Returns the local address. Pair.first is false on error. Override from GNet::Connection.

Implements GNet::Connection.

Definition at line 433 of file gclient.cpp.

## ◆ onDelete()

virtual void GNet::Client::onDelete | ( | const std::string & | reason | ) |
| protected pure virtual

Called just before ClientPtr destroys the Client as the result of handling an exception.

The reason is the empty string if caused by a GNet::Done exception, or after finish() or disconnect(). Consider making the implementation non-throwing, in the spirit of a destructor, since the Client object is about to be deleted.

## ◆ onReceive()

virtual bool GNet::Client::onReceive | ( | const char * | data,
|  | std::size_t | size,
|  | std::size_t | eolsize,
|  | std::size_t | linesize,
|  | char | c0
| ) |  |
| protected pure virtual

Called with received data.

If configured with no line buffering then only the first two parameters are relevant. The implementation should return false if it needs to stop further onReceive() calls being generated from data already received and buffered.

## ◆ peerAddress()

std::pair< bool, GNet::Address > GNet::Client::peerAddress | ( |  | ) | const
| override virtual

Override from Connection.

Returns the peer address. Pair.first is false on error. Override from GNet::Connection.

Implements GNet::Connection.

Definition at line 441 of file gclient.cpp.

## ◆ peerCertificate()

std::string GNet::Client::peerCertificate | ( |  | ) | const
| override virtual

Returns the peer's TLS certificate.

Override from GNet::Connection.

Implements GNet::Connection.

Definition at line 462 of file gclient.cpp.

## ◆ remoteLocation()

GNet::Location GNet::Client::remoteLocation | ( |  | ) | const

Returns a Location structure, including the result of name lookup if available.

Definition at line 91 of file gclient.cpp.

## ◆ secureConnect()

void GNet::Client::secureConnect | ( |  | ) |
| protected

Starts TLS/SSL client-side negotiation.

Uses a profile called "client"; see GSsl::Library::addProfile(). The callback GNet::SocketProtocolSink::onSecure() is triggered when the secure session is established.

Definition at line 467 of file gclient.cpp.

## ◆ send() [1/2]

bool GNet::Client::send | ( | const std::string & | data,
|  | std::size_t | offset = `0`
| ) |  |

Sends data to the peer and starts the response timer (if configured).

Returns true if all sent. Returns false if flow control was asserted, in which case the unsent portion is copied internally and onSendComplete() called when complete. Throws on error.

Definition at line 474 of file gclient.cpp.

## ◆ send() [2/2]

bool GNet::Client::send | ( | const std::vector< G::string_view > & | data,
|  | std::size_t | offset = `0`
| ) |  |

Overload for scatter/gather segments.

Definition at line 481 of file gclient.cpp.

## ◆ socket() [1/2]

GNet::StreamSocket & GNet::Client::socket | ( |  | ) |
| protected

Returns a reference to the socket. Throws if not connected.

Definition at line 96 of file gclient.cpp.

## ◆ socket() [2/2]

const GNet::StreamSocket & GNet::Client::socket | ( |  | ) | const
| protected

Returns a const reference to the socket. Throws if not connected.

Definition at line 103 of file gclient.cpp.

The documentation for this class was generated from the following files:

- /usr/src/slapt-src-x86_64/network/emailrelay/emailrelay-2.3/src/gnet/gclient.h
- /usr/src/slapt-src-x86_64/network/emailrelay/emailrelay-2.3/src/gnet/gclient.cpp