创建DataSnap Server

DataSnap REST Application

http://edn.embarcadero.com/article/41305

2017.1.19 官方例子

https://community.embarcadero.com/blogs/entry/in-the-c-builder-of-rad-server-firedac-sqlserver-connection

官方创建datasnapServer的步骤说明

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/DataSnap_Server_Wizard_for_Windows

这个是创建 Datasnap Rest 服务的步骤。

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/DataSnap_REST_Application_Wizard_for_Windows

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Tutorial:_Using_a_REST_DataSnap_Server_with_an_Application

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Tutorial:_Using_a_REST_DataSnap_Server_with_an_Application_and_FireDAC

建立DataSnap/REST服务器，请点选Files|New菜单，在DataSnap Server选项中选择DataSnap Server图像，如下图所示:3个选项都可以选择，创建后都是DataSnap服务器

官方例子参考D:\Users\Public\Documents\Embarcadero\Studio\14.0\Samples\CPP\DataSnap\SimpleDataSnapDemo\CppDataSnapServer\CppDataSnapServerApp.cbproj

注意：TDSTCPServerTransport.poolsize 线程池

TDSTCPServerTransport.maxThreads  并发连接数量

TDSServerClass.LIFECycle,  SESSION/SERVER/INVOCATION

Representational State Transfer (REST) is a new architecture for Web Services that is having a significant impact on the industry

ServerMethodsUnit1.cpp

DSServerModuleCreate是每个客户端连接的时候触发，两个客户端连接就触发两次，所以用到全局指针的话，第二次的触发就可能影响了第一次的指针，必须注意特别小心。

关于数据库操作必须写到ServerMethodsUnit1，包括数据库连接，ServerMethodsUnit1具有线程功能， 一个客户端连接一个线程实例，一个实例就是new一个ServerMethodsUnit1类，各个互不影响。

普通的datamodule无线程功能。

视频教程

http://www.embarcadero.com/rad-in-action/datasnap

服务器可以创建exe，app，也可以是服务；可以是windows 平台，也可以是firemonkey跨平台。

一路完成后会生成控件

TDSServer，TDSTCPServerTransport以及TDSServerClass、TDSHTTPService

USEFORM("MainForm.cpp", Form1);
USEFORM("ServerContainerUnit1.cpp", ServerContainer1); /* TDataModule: File Type */
//---------------------------------------------------------------------------
int WINAPI _tWinMain(HINSTANCE, HINSTANCE, LPTSTR, int)
{
    try
    {
        Application->Initialize();
        Application->MainFormOnTaskBar = true;
        Application->CreateForm(__classid(TForm1), &Form1);
        Application->CreateForm(__classid(TServerContainer1), &ServerContainer1);
        Application->Run();
    }
}

//----------------------------------------------------------------------------

#ifndef ServerMethodsUnit1H
#define ServerMethodsUnit1H
//----------------------------------------------------------------------------
#include <Classes.hpp>
#include <DSServer.hpp>
//----------------------------------------------------------------------------
class DECLSPEC_DRTTI TServerMethods1 : public TComponent
{
private:    // User declarations
public:        // User declarations
    System::UnicodeString EchoString(System::UnicodeString value);
    System::UnicodeString  ReverseString(System::UnicodeString value);
};
#endif

//---------------------------------------------------------------------------

// This software is Copyright (c) 2014 Embarcadero Technologies, Inc.
// You may only use this software if you are an authorized licensee
// of an Embarcadero developer tools product.
// This software is considered a Redistributable as defined under
// the software license agreement that comes with the Embarcadero Products
// and is subject to that software license agreement.

//---------------------------------------------------------------------------
//----------------------------------------------------------------------------
#include <SysUtils.hpp>
#pragma hdrstop

#include "ServerMethodsUnit1.h"
#include <Datasnap.DSProviderDataModuleAdapter.hpp>
//----------------------------------------------------------------------------
#pragma package(smart_init)
//----------------------------------------------------------------------------
System::UnicodeString TServerMethods1::EchoString(System::UnicodeString value)
{
    return value;
}
//----------------------------------------------------------------------------
System::UnicodeString TServerMethods1::ReverseString(System::UnicodeString value)
{
    return ::ReverseString(value);
}
//----------------------------------------------------------------------------

//----------------------------------------------------------------------------

#ifndef ServerContainerUnit1H
#define ServerContainerUnit1H
//---------------------------------------------------------------------------
#include <Classes.hpp>
#include <DSCommonServer.hpp>
#include <DSServer.hpp>
#include <DSTCPServerTransport.hpp>
#include <DSAuth.hpp>
#include <IPPeerServer.hpp>
//----------------------------------------------------------------------------
class TServerContainer1 : public TDataModule
{
__published:    // IDE-managed Components
    TDSServer *DSServer1;
    TDSTCPServerTransport *DSTCPServerTransport1;
    TDSServerClass *DSServerClass1;
    void __fastcall DSServerClass1GetClass(TDSServerClass *DSServerClass, TPersistentClass &PersistentClass);
private:    // User declarations
public:        // User declarations
    __fastcall TServerContainer1(TComponent* Owner);
};
//----------------------------------------------------------------------------
extern PACKAGE TServerContainer1 *ServerContainer1;
//----------------------------------------------------------------------------
#endif

//---------------------------------------------------------------------------

// This software is Copyright (c) 2014 Embarcadero Technologies, Inc.
// You may only use this software if you are an authorized licensee
// of an Embarcadero developer tools product.
// This software is considered a Redistributable as defined under
// the software license agreement that comes with the Embarcadero Products
// and is subject to that software license agreement.

//---------------------------------------------------------------------------
//----------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop
#include <tchar.h>
#include <stdio.h>
#include <memory>
#include "ServerMethodsUnit1.h"

#include "ServerContainerUnit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TServerContainer1 *ServerContainer1;
//---------------------------------------------------------------------------
__fastcall TServerContainer1::TServerContainer1(TComponent* Owner)
    : TDataModule(Owner)
{
}
//----------------------------------------------------------------------------
void __fastcall TServerContainer1::DSServerClass1GetClass(TDSServerClass *DSServerClass,
          TPersistentClass &PersistentClass)
{
    PersistentClass =  __classid(TServerMethods1);
}
//----------------------------------------------------------------------------
//---------------------------------------------------------------------------

多个类文件

ServerMethodsUnit1.cpp文件中就是类 class TServerMethods1 : public TDSServerModule，如果想多个类，例如分模块分业务多个类,File>new>Other>DataSnap Server》选择 Server Module新添加一个类。没有打开任何功能时Server Module是不可见的。只有打开了某个应用服务器的工程，再new的时候才能看见！

https://newsgroups.embarcadero.com/thread.jspa?threadID=229169

https://forums.embarcadero.com/thread.jspa?messageID=833882

ServerMethodsUnit1、ServerMethodsUnit2

DSServerClass1、DSServerClass2

procedure TWebModule1.DSServerClass2GetClass(DSServerClass: TDSServerClass;
  var PersistentClass: TPersistentClass);
begin
 PersistentClass := ServerMethodsUnit2.TDSServerModule2;
end;

这样就注册上第二个单位类，多模块，多个类、多个业务、多个接口、分离