我有一个简单的客户端-服务器应用程序,用于将文件从客户端发送到服务器。客户端以预定义大小的块(例如 512)发送文件。服务器也以相同大小的块接收文件。客户端的套接字直到服务器在接收到整个文件后发送一个 ack 才会关闭。
会发生什么:
- 客户端设法发送(send() 调用)整个文件,意味着它的所有块。
- 服务器设法仅获取(recv() 调用)第一个块,这意味着 recv() 调用在第一次调用时返回 512,而在第二次调用时它会阻塞。
这种行为的原因可能是什么?
以下是相关部分。
发送\接收功能:
int sendBuf(int sockFd, char* buf, int size){
int bytesSent = 0;
while (bytesSent < size){
bytesSent += send(sockFd, buf, size, 0);
}
return bytesSent;
}
int sendInt(int sockFd, int num){
uint32_t nbo_num = htonl(num);
return sendBuf(sockFd, (char*)&nbo_num, sizeof(nbo_num));
}
int getBuf(int sockFd, char* buf, int size){
int bytesRecv = 0;
while (bytesRecv < size){
bytesRecv += recv(sockFd, buf, size, 0);
}
return bytesRecv;
}
int getInt(int sockFd, int *num){
int temp, bytesRecv;
bytesRecv = getBuf(sockFd, (char*)&temp, sizeof(int));
*num = ntohl(temp);
return bytesRecv;
}
服务器:
printf("%s New file was created.\n",tStr);
/* get file data */
char buf[FILE_READ_CHUNK_SIZE] = {0}; // FILE_READ_CHUNK_SIZE is the maximal read amount
int bytesWritten = 0, bytesLeft = fileSize, _size=0, chunkNo=0;
bytesRecv = 0;
while (bytesLeft > 0){
_size = (bytesLeft > FILE_READ_CHUNK_SIZE) ? FILE_READ_CHUNK_SIZE : bytesLeft;
bytesRecv = getBuf(newsockfd, buf, _size);
int _bytesLeft = bytesRecv;
bytesWritten = 0;
while (_bytesLeft > 0){
bytesWritten = fileInfoWrite(fileInfo, buf, _bytesLeft);
_bytesLeft -= bytesWritten;
}
chunkNo++;
printf("%s chunk #%d: received %d bytes\n",tStr , chunkNo, bytesRecv);
bytesLeft -= bytesRecv;
}
printf("%s Finished getting file #%d.\n",tStr ,i+1);
/* send ack to the client */
bytesSent = sendInt(newsockfd, 1);
printf("%s Sent the client an ack for file #%d.\n",tStr ,i+1);
客户:
/* send the entire data of the file */
printf(" Sending file data\t\t... ");
char buf[FILE_READ_CHUNK_SIZE] = {0}; // FILE_READ_CHUNK_SIZE is the maximal read amount
int numOfChunks=0, bytesRead = 0, bytesLeft = filesArr[i]->fileSize ;
bool eof = false;
bytesSent = 1;
while (bytesLeft > 0){
bytesRead = fileInfoRead(filesArr[i], buf, &eof);
int _bytesLeft = bytesRead;
while (bytesSent < _bytesLeft){
bytesSent = sendBuf(sockFd, buf, _bytesLeft);
_bytesLeft -= bytesSent;
}
//printf(" chunk #%d: sent %d bytes\n", numOfChunks+1, bytesRead);
bytesLeft -= bytesRead;
numOfChunks++;
}
printf("Success.\n");
/* get ack from server */
int ack=0;
bytesRecv = getInt(sockFd, &ack);
if (bytesRecv!=4 || ack!=1){
printf("Server ack is invalid.\n");
}
printf("Finished sending file #%d.\n",i+1);