$${\color{red}\textbf{WARNING:}}$$ The fpsockets unit has been added to the FCL and will be shipped with the next version of the FPC. All future development will take place in that context. This repository will probably not be updated anymore.

PasSimpleSockets

Simple socket API wrapper for FreePascal. Provides access to the socket API in a less C-ish way.

Features:

Provides the base functionality of the berkley socket API in a more modern manner. Also transparently handles IP-address conversion and IPv6/IPv4 dual stack.

Functions (Delphi Notation):

function TCPSocket(AType: TSocketType): TSocket; 
function UDPSocket(AType: TSocketType): TSocket; 

procedure CloseSocket(const ASocket: TSocket); 

procedure Bind(const ASocket: TSocket; const AAddress: TNetworkAddress; APort: Word);

procedure Listen(const ASocket: TSocket; Backlog: Integer); 
function AcceptConnection(const ASocket: TSocket): TSocketConnection; 

procedure Connect(const ASocket: TSocket; const AAddress: TNetworkAddress; APort: Word); 

function Receive(const ASocket: TSocket; ABuffer: Pointer; MaxSize: SizeInt; AFlags: Integer = 0): SizeInt; 
function ReceiveFrom(const ASocket: TSocket; ABuffer: Pointer; MaxSize: SizeInt; AFlags: Integer = 0): TReceiveFromResult;
function Send(const ASocket: TSocket; ABuffer: Pointer; ASize: SizeInt; AFlags: Integer = 0): SizeInt; 
function SendTo(const ASocket: TSocket; const ReceiverAddr: TNetworkAddress;
                  ReceiverPort: Word; ABuffer: Pointer; ASize: SizeInt; AFlags: Integer = 0): SizeInt; 

function ReceiveStr(const ASocket: TSocket; MaxLength: SizeInt; AFlags: Integer = 0): String; 
function ReceiveStrFrom(const ASocket: TSocket; MaxLength: SizeInt = MaxUDPPackageSize; AFlags: Integer = 0): TReceiveFromStringMessage; 
function SendStr(const ASocket: TSocket; const AData: String; AFlags: Integer = 0): SizeInt; 
function SendStrTo(const ASocket: TSocket; const ReceiverAddr: TNetworkAddress; ReceiverPort: Word; const AData: String; AFlags: Integer = 0): SizeInt; 
 
function Receive<T>(const ASocket: TSocket; AFlags: Integer = 0): T; 
function ReceiveFrom<T>(const ASocket: TSocket; AFlags: Integer = 0): TReceiveFromMessage<T>; 
function Send<T>(const ASocket: TSocket; constref AData: T; AFlags: Integer = 0): SizeInt; 
function SendTo<T>(const ASocket: TSocket; constref ReceiverAddr: TNetworkAddress; ReceiverPort: Word; const AData: T; AFlags: Integer = 0): SizeInt; 

function ReceiveArray<T>(const ASocket: TSocket; MaxCount: SizeInt; AFlags: Integer = 0): TArray<T>; 
function ReceiveArrayFrom<T>(const ASocket: TSocket; MaxCount: SizeInt; AFlags: Integer = 0): TReceiveFromMessage<TArray<T>>; 
function SendArray<T>(const ASocket: TSocket; const AData: TArray<T>; AFlags: Integer = 0): SizeInt; 
function SendArrayTo<T>(const ASocket: TSocket; const ReceiverAddr: TNetworkAddress; ReceiverPort: Word; const AData: TArray<T>; AFlags: Integer = 0): SizeInt; 

// Timeout in MS
function DataAvailable(const SocketArray: TSocketArray; TimeOut: Integer = 0): TSocketArray; 
function DataAvailable(const ASocket: TSocket; TimeOut: Integer = 0): Boolean; 
function DataAvailable(const SocketArray: array of TSocket; TimeOut: Integer = 0): TSocketArray;  

Example

program example;

{$mode objfpc}{$H+}

uses
  SimpleSockets;

var
  Sock: TSocket;
  Msg: TUDPStringMessage;
begin
  Sock := UDPSocket(stDualStack);
  try
    Bind(Sock, '127.0.0.1', 1337);
    // Simple echo server: Receive message and answer with same message
    Msg := ReceiveStrFrom(Sock);
    WriteLn('Received from Client at ', Msg.FromAddr.Address, ':', Msg.FromPort,' message: ', Msg.Data);
    SendStrTo(Sock, Msg.FromAddr, Msg.FromPort, Msg.Data);
  finally
    CloseSocket(Sock);
  end;
  ReadLn;
end.

DualStack

Sockets created with type stDualStack will support both IPv4 and IPv6 connections. The wrapper will transparently handle this and will convert IPv6 mapped IPv4 addresses to the common IPv4 notation