本文主要介绍如何在C++ Builder中用TServerSocket,TClientSocket来写一个网络间短包，文件传输的程序，这个程序可以支持：1.局域网上的传输。2.局域网与公网的传输（双向传输），在第二篇文章中我将用socket api写一个客户端和服务器，功能和本文中的功能一样。使用通讯协议TCP，这里的客户端和服务器使用的都是阻塞模式---多线程。
Client:
.h File
class ClientThread : public TThread
{
private:
AnsiString File;
TClientSocket* ClientSocket;
TWinSocketStream* WskStream;
protected:
void __fastcall Execute();
public:
__fastcall ClientThread(AnsiString IPAddr,
WORD Port, AnsiString file);
};
.cpp File
void __fastcall ClientThread::Execute()
{
//Send Text or SendFile
UINT TimeOut=60000;
char buf[4096];
//char IPAddress[32];
//GetIPAddress(IPAddress);//IPAddress
WskStream = new TWinSocketStream(ClientSocket->Socket, TimeOut);
if(Form1->CheckBox1->Checked)//Determine whether to send short package or send file.
{
String S=Form1->TxtEdit->Text;
int TxtLen=Form1->TxtEdit->Text.Length();
strncpy(buf,S.c_str(),TxtLen);
ClientSocket->Active=true;
WskStream->Write("TEXT\0",5);//Send Text Flag
WskStream->Write(IPAddress,32);//Send IP Address
WskStream->Write(buf,TxtLen);//Send Text String
WskStream->Write(buf,TxtLen);
if(WskStream->WaitForData(TimeOut))
{
buf[0]='\0';
FlagBuf[0]='\0';
IPAddress[0]='\0';
WskStream->Read(FlagBuf,5);
WskStream->Read(IPAddress,32);
int nSize=0;
nSize=WskStream->Read(buf,TxtLen);
buf[nSize]='\0';
if(!StrPas(buf).IsEmpty())
{
SaveLog("Received a text!");
SaveLog("Client:"+StrPas(IPAddress)+"\r\nStart Time:"+DateTimeToStr(Now()));
SaveLog("Text Content:"+StrPas(buf));
FLASHWINFO FSHINFO;
::ZeroMemory(&FSHINFO,sizeof(FLASHWINFO));
FSHINFO.cbSize=sizeof(FLASHWINFO);
FSHINFO.hwnd=Application->Handle;
FSHINFO.dwFlags=FLASHW_TRAY|FLASHW_CAPTION;
FSHINFO.uCount=10;
FSHINFO.dwTimeout=200;
::FlashWindowEx(&FSHINFO);
Form1->RecEdit->Lines->Add("Received Length:"+String(nSize));
Form1->RecEdit->Lines->Add("Received:"+StrPas(buf));
//SaveLog("Client:"+StrPas(IPAddress)+"\r\nEnd Time:"+DateTimeToStr(Now()));
}
}
}
else
{
int nLen;
int hFile;
int nSize;
char Path[255];//Path Buffer
char FileName[255];//FileName Buffer;
char FileExt[5];//Extension Buffer
char FlagBuf[5];
static int num=0;
AnsiString sFileName=ExtractFileName(File);
for(int k=sFileName.Length();k>0;k--)
{
if(sFileName.SubString(k,1)==".")
{
sFileName=sFileName.SubString(1,k-1);
break;
}
}
AnsiString sPath=ExtractFilePath(File);
AnsiString sExtension=ExtractFileExt(File);
strcpy(FileName,sFileName.c_str());//FileName
strcpy(Path,sPath.c_str()); //Path
strcpy(FileExt,sExtension.c_str()); ://Extension
try {
hFile = -1;
ClientSocket->Active = true;
hFile = FileOpen(File, fmOpenRead);
if (hFile != -1) {
nSize = GetFileSize((HANDLE)
hFile, NULL);
//Send the Flag
WskStream->Write("FILE\0",5);
//Send the name of directory
WskStream->Write(Path,255);
//Send the filename
WskStream->Write(FileName,255);
//Send the extension of file
WskStream->Write(FileExt,5);
//Send client's IP addresss
WskStream->Write(IPAddress,32);
//Send the length
WskStream->Write(&nSize, 4);
//Send the data
for(; nSize>0; nSize-=nLen) {
nLen = min((int)sizeof(
buf), nSize);
nLen = FileRead(hFile, buf,
nLen);
if (nLen<=0) break;
WskStream->Write(buf, nLen);
}
}
FileClose(hFile);//Send Completely
//Client is beginning to read data
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(FlagBuf,5);
}
if(WskStream->WaitForData(TimeOut))//Obtain the directory's name
{
WskStream->Read(Path,255);
}
//If the directory obtained from client doesnot exist,the create it
if(!DirectoryExists(StrPas(Path)))
{
CreateDir(StrPas(Path));
}
//Obtain the FileName
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(FileName,255);
}
//Obtain the extension
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(FileExt,5);
}
//Obtain the client's IPAddress
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(IPAddress,32);
}
AnsiString S=StrPas(Path)+StrPas(FileName)+StrPas(FileExt);
buf[0]='\0';
strcpy(buf,S.c_str());
while(1) {
if (FileExists(buf)) {
S=StrPas(Path)+StrPas(FileName)+"%03d"+StrPas(FileExt);
wsprintf(buf, S.c_str(),
num);
num++;
//Created Susscessfully
} else break;
}
hFile = FileCreate(buf);
if (hFile==-1)
{
Application->MessageBox("Failed to create file!","Error",MB_OK+MB_ICONERROR);
ClientSocket->Active=false;
delete WskStream;
Terminate();
return;
}
SaveLog("Received a file:"+StrPas(buf));
SaveLog("Client:"+StrPas(IPAddress)+"\r\nStart Time:"+DateTimeToStr(Now()));
try {
DWORD dwTick = GetTickCount();
//Obtain the length
if (WskStream->WaitForData(
TimeOut)) {
nLen = WskStream->Read(
&nSize, 4);
if (nLen!=4) nSize = 0;
}
else
nSize = 0;
//Reading data
for(; nSize>0 && !Terminated;
nSize-=nLen) {
if (!WskStream->WaitForData(
5000)) {
if (GetTickCount()-dwTick
<TimeOut)
continue;
::MessageBox(NULL,"Timeout,the thread has been terminated!","Error",MB_OK|MB_ICONERROR);
ClientSocket->Active=false;
break;
}
nLen = WskStream->Read(buf,
sizeof(buf));
dwTick = GetTickCount();
if (nLen <= 0) {
//Read Error
ClientSocket->Active=false;
::MessageBox(NULL,"Read Error，the thread has been terminated!","Error",MB_OK|MB_ICONERROR);
break;
}
//Combine the data
FileWrite(hFile, buf, nLen);
}
Form1->RecEdit->Lines->Add("You got a file from server,which was saved in "+StrPas(Path));
SaveLog("Client:"+StrPas(IPAddress)+"\r\nEnd Time:"+DateTimeToStr(Now()));
FLASHWINFO FSHINFO;
::ZeroMemory(&FSHINFO,sizeof(FLASHWINFO));
FSHINFO.cbSize=sizeof(FLASHWINFO);
FSHINFO.hwnd=Application->Handle;
FSHINFO.dwFlags=FLASHW_TRAY|FLASHW_CAPTION;
FSHINFO.uCount=10;
FSHINFO.dwTimeout=200;
::FlashWindowEx(&FSHINFO);
FileClose(hFile);
}
catch(Exception& e) {
ClientSocket->Active=false;
MessageBox(0, e.Message.c_str(),
"Error", MB_ICONERROR);
}
}
catch(Exception& e) {
ClientSocket->Active=false;
::MessageBox(0, e.Message.c_str(),
"Error", MB_OK|MB_ICONERROR);
}
FileClose(hFile);
}
delete WskStream; // delete ClientSocket;
}
//Begin to send package
void __fastcall TForm1::Button1Click(TObject *Sender)
{
int Port;
AnsiString Addr;
Addr = IPAddr->Text.Trim();
if (Addr.IsEmpty()) {
IPAddr->SetFocus();
Application->MessageBox("Please enter the client's address!","Warning",MB_OK|MB_ICONWARNING);
return;
}
try {
Port = ClientPort->Text.ToInt();
}
catch(Exception& e) {
ShowMessage(e.Message);
ClientPort->SetFocus(); return;
}
if(CheckBox1->Checked) //Send Text
{
if(TxtEdit->Text.IsEmpty())
{
::MessageBox(0,"Please enter the text string which you want to send!","Error",MB_OK+MB_ICONERROR);
return;
}
new ClientThread(Addr,Port,"");
}
else //Send File
{
if (OpenDialog1->Execute())
new ClientThread(Addr, Port,
OpenDialog1->FileName); //Begin to send data
}
}
Server:
.h File
//My Comments:
//At design-time,please place a TServerSocket Component on your form and set its clientype to stThreadBlocking.
//Server Thread Class
//The Server Can not only receives the packages coming from Clients,but also deliver the package to the clients after
processing upon the package.
class SrvThread : public TServerClientThread
{
private:
UINT FTimeOut;
TWinSocketStream* WskStream;
TThread *pThread;
protected:
void __fastcall ClientExecute();
public:
__fastcall SrvThread(TServerClientWinSocket*);
__property UINT TimeOut = { read=FTimeOut, write=FTimeOut };
};
void __fastcall SrvThread::ClientExecute()
{
TimeOut = 60000; file://60 Seconds
WskStream = new TWinSocketStream(ClientSocket, TimeOut);
file://Send Text or File
char FlagBuf[5];
char buf[4096];
char IPAddress[32];
SMS[0]='\0';
RecIPAddr[0]='\0';
if(WskStream->WaitForData(TimeOut)) file://Obtain Flag:File or Text
{
WskStream->Read(FlagBuf,5);
}
file://Save the flag received from clients
strcpy(Flag,FlagBuf);
if(StrPas(FlagBuf)=="TEXT")
{
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(IPAddress,32);
}
file://Save the client's IPAddress
strcpy(RecIPAddr,IPAddress);
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(buf,4096);
}
file://Save the short message received from clients
strcpy(SMS,buf);
SaveLog("Received a text!");
SaveLog("Client:"+StrPas(IPAddress)+"\r\nStart Time:"+DateTimeToStr(Now()));
SaveLog("Text Content:"+StrPas(SMS));
SaveLog("Client:"+StrPas(IPAddress)+"\r\nEnd Time:"+DateTimeToStr(Now()));
Form1->Memo1->Lines->Add("Text Content:"+StrPas(buf));
FLASHWINFO FSHINFO;
::ZeroMemory(&FSHINFO,sizeof(FLASHWINFO));
FSHINFO.cbSize=sizeof(FLASHWINFO);
FSHINFO.hwnd=Application->Handle;
FSHINFO.dwFlags=FLASHW_TRAY|FLASHW_CAPTION;
FSHINFO.uCount=10;
FSHINFO.dwTimeout=200;
::FlashWindowEx(&FSHINFO);
if(Form1->adv->Checked)//Automatically Deliver To Client
{
if(StrPas(Flag).IsEmpty() || StrPas(RecIPAddr).IsEmpty() || StrPas(SMS).IsEmpty())
{
Application->MessageBox("You can't deliver because no data are received!","Error",MB_OK+MB_ICONERROR);
return;
}
WskStream->Write(FlagBuf,5);
WskStream->Write(Form1->ComboBox1->Text.c_str(),32);
WskStream->Write(SMS,4096);
::Sleep(500);//Delay for 500ms
ClientSocket->Close();
}
if(Form1->spt->Checked)//Automatically deliver to serial port on local computer
{
StrCat(SMS,FlagBuf);
StrCat(SMS,Form1->ComboBox1->Text.c_str());
// SaveLog("Write Serial Port "+Form1->Port);
// SaveLog("Start Time:"+DateTimeToStr(Now()));
// SaveLog("End Time:"+DateTimeToStr(Now()));
pThread=new TWriteCommThread(Form1->Port,Form1->BaudRate,(void*)buf,1000);
pThread->Terminate();
}
}
else
{
if(StrPas(FlagBuf).Pos("GET")) file://GPRS
{
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(buf,4096);
}
file://Save the flag to Flag
strcpy(Flag,"GPRS");
file://Save the frame to SMS
strcpy(SMS,buf);
file://Set the destination IP
strcpy(RecIPAddr,"127.0.0.1");
SaveLog("Received a package from GPRS");
SaveLog("Start Time:"+DateTimeToStr(Now()));
SaveLog(StrPas(FlagBuf)+StrPas(buf));
SaveLog("End Time:"+DateTimeToStr(Now()));
Form1->Memo1->Lines->Add(StrPas(FlagBuf)+StrPas(buf));
FLASHWINFO FSHINFO;
::ZeroMemory(&FSHINFO,sizeof(FLASHWINFO));
FSHINFO.cbSize=sizeof(FLASHWINFO);
FSHINFO.hwnd=Application->Handle;
FSHINFO.dwFlags=FLASHW_TRAY|FLASHW_CAPTION;
FSHINFO.uCount=10;
FSHINFO.dwTimeout=200;
::FlashWindowEx(&FSHINFO);
if(Form1->adv->Checked)
{
if(StrPas(Flag).IsEmpty() || StrPas(RecIPAddr).IsEmpty() || StrPas(SMS).IsEmpty())
{
Application->MessageBox("You can't deliver because no data are received!","Error",MB_OK+MB_ICONERROR);
return;
}
WskStream->Write(FlagBuf,5);
WskStream->Write(Form1->ComboBox1->Text.c_str(),32);
WskStream->Write(SMS,4096);
::Sleep(500);//ms
ClientSocket->Close();
}
if(Form1->spt->Checked) file://Automatically deliver to serial port on local computer
{
StrCat(SMS,FlagBuf);
StrCat(SMS,Form1->ComboBox1->Text.c_str());
file://SaveLog("Write Serial Port "+Form1->Port);
file://SaveLog("Start Time:"+DateTimeToStr(Now()));
file://SaveLog("End Time:"+DateTimeToStr(Now()));
pThread=new TWriteCommThread(Form1->Port,Form1->BaudRate,(void*)SMS,4096);
pThread->Terminate();
}
}
else
{
int nLen;
int nSize;
int hFile;
char Path[255]; file://Path
char FileName[255]; file://FileName
char FileExt[5]; file://Extension
static int num=0;
file://Obtain the directory's name
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(Path,255);
}
file://If the directory obtained from client doesnot exist,the create it
if(!DirectoryExists(StrPas(Path)))
{
CreateDir(StrPas(Path));
}
file://Obtain the FileName
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(FileName,255);
}
file://Obtain the extension
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(FileExt,5);
}
file://Obtain the client's IPAddress
if(WskStream->WaitForData(TimeOut))
{
WskStream->Read(IPAddress,32);
}
file://Save the client's IPAddress
strcpy(RecIPAddr,IPAddress);
AnsiString S=StrPas(Path)+StrPas(FileName)+StrPas(FileExt);
strcpy(buf,S.c_str());
while(1) {
if (FileExists(buf)) {
S=StrPas(Path)+StrPas(FileName)+"%03d"+StrPas(FileExt);
wsprintf(buf, S.c_str(),
num);
num++;
file://Created Susscessfully
} else break;
}
hFile = FileCreate(buf);
if (hFile==-1)
{
Application->MessageBox("Failed to create file on server!","Error",MB_OK+MB_ICONERROR);
delete WskStream;
Terminate();
return;
}
file://Save the filename received from clients
strncpy(RecFile,buf,255);
SaveLog("Received a file:"+StrPas(buf));
SaveLog("Client:"+StrPas(IPAddress)+"\r\nStart Time:"+DateTimeToStr(Now()));
try {
DWORD dwTick = GetTickCount();
file://Obtain the length
if (WskStream->WaitForData(
TimeOut)) {
nLen = WskStream->Read(
&nSize, 4);
if (nLen!=4) nSize = 0;
}
else
nSize = 0;
file://Reading data
for(; nSize>0 && !Terminated;
nSize-=nLen) {
if (!WskStream->WaitForData(
5000)) {
if (GetTickCount()-dwTick
<TimeOut)
continue;
::MessageBox(NULL,"Timeout,the thread has been terminated!","Error",MB_OK|MB_ICONERROR);
break;
}
nLen = WskStream->Read(buf,
sizeof(buf));
dwTick = GetTickCount();
if (nLen <= 0) {
file://Read Error
::MessageBox(NULL,"Read Error，the thread has been terminated!","Error",MB_OK|MB_ICONERROR);
break;
}
file://Combine the data
FileWrite(hFile, buf, nLen);
}
SaveLog("Client:"+StrPas(IPAddress)+"\r\nEnd Time:"+DateTimeToStr(Now()));
Form1->Memo1->Lines->Add("You got a file received from client,which was saved in "+StrPas(Path));
file://Application->MessageBox("Server has successfully received the data !","Notification",MB_OK+MB_ICONINFORMATION);
FLASHWINFO FSHINFO;
::ZeroMemory(&FSHINFO,sizeof(FLASHWINFO));
FSHINFO.cbSize=sizeof(FLASHWINFO);
FSHINFO.hwnd=Application->Handle;
FSHINFO.dwFlags=FLASHW_TRAY|FLASHW_CAPTION;
FSHINFO.uCount=10;
FSHINFO.dwTimeout=200;
::FlashWindowEx(&FSHINFO);
FileClose(hFile);//Read Completely
if(Form1->adv->Checked)//Automatically Deliver
{
if(StrPas(Flag).IsEmpty() || StrPas(RecIPAddr).IsEmpty())
{
Application->MessageBox("You can't deliver because no data are received!","Error",MB_OK+MB_ICONERROR);
return;
}
file://Send Data
try
{
buf[0]='\0';
hFile = -1;
hFile = FileOpen(StrPas(RecFile), fmOpenRead);
if (hFile != -1) {
nSize = GetFileSize((HANDLE)
hFile, NULL);
file://Send the Flag
WskStream->Write("FILE\0",5);
file://Send the name of directory
WskStream->Write(Path,255);
file://Send the filename
WskStream->Write(FileName,255);
file://Send the extension of file
WskStream->Write(FileExt,5);
file://Send client's IP addresss
WskStream->Write(Form1->ComboBox1->Text.c_str(),32);
file://Send the length
WskStream->Write(&nSize, 4);
file://Send the data
for(; nSize>0; nSize-=nLen) {
nLen = min((int)sizeof(
buf), nSize);
nLen = FileRead(hFile, buf,
nLen);
if (nLen<=0) break;
WskStream->Write(buf, nLen);
}
}
} //try
catch(Exception& e) {
ClientSocket->Close();
::MessageBox(0, e.Message.c_str(),
"Error", MB_OK|MB_ICONERROR);
}
FileClose(hFile);
}//if
}//catch
catch(Exception& e) {
ClientSocket->Close();
::MessageBox(0, e.Message.c_str(),
"Error", MB_ICONERROR);
}
}
}
delete WskStream;
WskStream=NULL;
::Sleep(100);
}
//At ServerSocket's OnGetThread event to new a thread to communication with the requested client
void __fastcall TForm1::ServerSocket1GetThread(TObject *Sender,
TServerClientWinSocket *ClientSocket,
TServerClientThread *&SocketThread)
{
SocketThread = new SrvThread(ClientSocket);
}
The metioned-written codes is used to test a hardware.It can be run correctly.As many different applications,so you only reference it and could not be copy completely.It is important to know the principle of TServerSocket,TClientSocket and how VCL wraps the socket api.This article only provides the support of TCP protocol.The next article I will write will accomplish TCP and UDP protocol,please pay your attention for it.At this time,I would like to thank jishiping(JSP) and Raptor for their help.Thanks for browsing it.I am can be contacted via e-mail:kingcaiyao@163.com
以上程序可以实现服务器与客户端之间的双向通讯，只用一个端口，其工作原理类似于IE，由客户端主动发起连接，服务器端在收到数据包后进行处理，然后根据已建立起的链路，再将数据回写到客户端。在同处在两台局域网的机器上以及一台处于局域，而另一台处于公网的机器上都测试通过。还有我从去年起开始接触网络编程，中间得到jishiping,Raptor的指点和帮助，在此再次感谢他们。
补充说明一点，我将代码经过Notepad编辑后copy到这里的时，发现所有的注释部分都加了一个file:，因此当你看到file:前缀时，那就是注释，并非代码，特此声明
