Я настроил TCP-клиент в C # и сервер в C. Когда я хочу передать файл, некоторые пакеты теряются и файл не сохраняется должным образом.
Я сравнил файл PDF, который пыталсяпередача и половина пакетов не были сохранены, поэтому я не смог открыть его на другом компьютере.
код клиента:
public void SendFile(string file, string destPath = "C:\\")
{
int bufferSize = 1024;
byte[] filebuff = new byte[bufferSize];
string fileName = destPath + file;
//send to TcpServer request to send file
stream.Write(textToBytes("RECEIVEFILE"), 0, 11);
try
{
FileStream streamFile = new FileStream(fileName, FileMode.Open, FileAccess.Read);
BinaryReader binReader = new BinaryReader(streamFile);
//send file name to TcpServer
stream.Write(textToBytes(file), 0, file.Length);
//get file size
long filesize = streamFile.Length;
//send file size to TcpServer
//sendData(stream, BitConverter.GetBytes(filesize));
//if file doesn't exist
if (file == null)
{
Console.WriteLine("Error.");
}
//if file is empty
if (filesize == 0)
{
Console.WriteLine("File size: 0");
return;
}
int totalLength = Convert.ToInt32(filesize);
Console.WriteLine("Totallength: " + totalLength);
long numberOfPackets = Convert.ToInt32(Math.Ceiling(Convert.ToDouble(streamFile.Length) / bufferSize));
int currentPacketLength;
for (int i = 0; i < numberOfPackets; i++)
{
if (filesize > bufferSize)
{
currentPacketLength = bufferSize;
totalLength = totalLength - currentPacketLength;
}
else
currentPacketLength = totalLength;
filebuff = new byte[currentPacketLength];
//streamFile.Read(filebuff, 0, currentPacketLength);
binReader.Read(filebuff, 0, currentPacketLength);
stream.Write(filebuff, 0, filebuff.Length);
}
streamFile.Close();
}
catch
{
Console.WriteLine("There's no file...");
}
}
public void DownloadFile(string fileName)
{
byte[] recBuffer = new byte[1024];
byte[] fileNameBytes;
long received = 0;
long receivedAll = 0;
byte[] fileData = new byte[1024];
stream.Write(textToBytes("SENDFILE"), 0, 8);
fileNameBytes = Encoding.UTF8.GetBytes(fileName);
stream.Write(fileNameBytes, 0, fileNameBytes.Length);
byte[] fileSizeBytes = new byte[4];
stream.Read(fileSizeBytes, 0, fileSizeBytes.Length);
int bytes = BitConverter.ToInt32(fileSizeBytes, 0);
Console.WriteLine("I'm downloading file...");
while (receivedAll < bytes)
{
received = stream.Read(fileData, 0, fileData.Length);
if (received < 0)
{
Console.WriteLine("Error");
break;
}
BinaryWriter bWrite = new BinaryWriter(File.Open("C:\\" + fileName, FileMode.Append));
bWrite.Write(fileData);
bWrite.Close();
receivedAll += received;
}
if(receivedAll == bytes)
{
Console.WriteLine("File downloaded successfuly.");
}
}
код сервера:
void ReceiveFile(int client_socket)
{
const int buffsize = 1024;
char buff[buffsize];
long filesize, received = 0, receivedall;
char filenamechar[512];
std::string filename, fullFilename;
memset(filenamechar, 0, 512);
/*
if(recv(client_socket, filenamechar, 512, 0) != 512)
{
printf("Error - filename.\n");
return;
}
fullFilename = "/Users/xxx/" + std::string(filenamechar);
*
if(recv(client_socket, &filesize, sizeof(long), 0) != sizeof(long))
{
printf("Child process: error.\n");
return;
}*/
filesize = 331776;
std::fstream fileFromClient;
fullFilename = "/Users/xxx/sockets.pdf";
fileFromClient.open(fullFilename, std::ios::binary | std::ios::out);
receivedall = 0;
while (receivedall < filesize)
{
memset(buff, 0, 1024);
received = recv(client_socket, buff, 1024, 0);
if(received <= 0)
{
std::cout << "error" << std::endl;
break;
}
receivedall += received;
fileFromClient << buff;
fputs(buff, stdout);
}
fileFromClient.close();
std::cout << "\nreceivedall: " << receivedall << std::endl;
std::cout << "filesize: " << filesize << std::endl;
if(receivedall != filesize)
printf("Error\n");
else
printf("File saved successfuly\n");
}
void SendFile(int client_socket)
{
char path[512];
char fileName[512];
char fullFileName[512];
long fileLen, sent, sentAll, read;
struct stat fileinfo;
FILE* file;
unsigned char bufor[1024];
memset(path, 0, 512);
strcpy(path, "/Users/xxxx/");
if (recv(client_socket, fileName, 512, 0) <= 0)
{
printf("Child process: error\n");
return;
}
strcpy(fullFileName, strcat(path, fileName));
printf("Child process: client wants file: %s\n", fullFileName);
if (stat(fullFileName, &fileinfo) < 0)
{
printf("Child process: can't get file info\n");
return;
}
if (fileinfo.st_size == 0)
{
printf("Child process: file size: 0\n");
return;
}
fileLen = fileinfo.st_size;
if (send(client_socket, &fileLen, sizeof(long), 0) != sizeof(long))
{
printf("Child process: error\n");
return;
}
sentAll = 0;
file = fopen(fullFileName, "rb");
if (file == NULL)
{
printf("Error\n");
return;
}
while (sentAll < fileLen)
{
read = fread(bufor, 1, 1024, file);
sent = send(client_socket, bufor, read, 0);
if (read != sent)
break;
sentAll += sent;
printf("Child process: sent %ld bytes\n", sentAll);
}
if (sentAll == fileLen)
printf("Child process: file sent successfuly\n");
else
printf("Child process: error\n");
fclose(file);
return;
}
Как гарантировать, что каждый пакет будет сохранен правильно?