我试图使用winsock实现一个简单的FTP客户端。我在尝试下载文件时遇到问题。下面是我使用的时刻代码:recv()只读取1个字节(使用winsock实现FTP)
bool FTPHandler::downloadFile(const char * remoteFilePath, const char * filePath) {
if (!isConnected()) {
setErrorMsg("Not connected, imposible to upload file...");
return false;
}
if (usePasiveMode) {
this->pasivePort = makeConectionPasive();
if (this->pasivePort == -1) {
//error msg will be setted by makeConectionPasive()
return false;
}
} else {
setErrorMsg("Unable to upload file not in pasive mode :S");
return false;
}
char * fileName = new char[500];
getFileName(remoteFilePath,fileName);
// Default name and path := current directory and same name as remote.
if (filePath == NULL) {
filePath = fileName;
}
if (!setDirectory(remoteFilePath)) {
return false;
}
char msg[OTHER_BUF_SIZE];
char serverMsg[SERVER_BUF_SIZE];
sprintf(msg,"%s%s\n",RETR_MSG,fileName);
send(sock, msg, strlen(msg), 0);
SOCKET passSocket;
SOCKADDR_IN passServer;
passSocket = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
if (passSocket == INVALID_SOCKET) {
WSACleanup();
sprintf(errorMsg,"Error trying to create socket (WSA error code: %d)",WSAGetLastError());
return false;
}
passServer.sin_family = PF_INET;
passServer.sin_port = htons(this->pasivePort);
passServer.sin_addr = *((struct in_addr *)gethostbyname(this->host)->h_addr);
memset(server.sin_zero,0,8);
int errorCode = connect(passSocket, (LPSOCKADDR) &passServer, sizeof(struct sockaddr));
int tries = 0;
while (errorCode == SOCKET_ERROR) {
tries++;
if (tries >= MAX_TRIES) {
closesocket(passSocket);
sprintf(errorMsg,"Error trying to create socket");
WSACleanup();
return false;
}
}
char * buffer = (char *) malloc(CHUNK_SIZE);
ofstream f(filePath);
Sleep(WAIT_TIME);
while (int readBytes = ***recv(passSocket, buffer, CHUNK_SIZE, 0)***>0) {
buffer[readBytes] = '\0';
f.write(buffer,readBytes);
}
f.close();
Sleep(WAIT_TIME);
recv(sock, serverMsg, OTHER_BUF_SIZE, 0);
if (!startWith(serverMsg, FILE_STATUS_OKEY_CODE)) {
sprintf(errorMsg,"Bad response: %s",serverMsg);
return false;
}
return true;
}
这最后的recv()返回1个字节几次,然后该方法结束这应该是各地的1Kb的文件仅仅是23个字节。
为什么不recv读洞文件?
什么是23字节?另外,在打开与服务器的数据连接之前,我并不确定是否发布了RETR。数据端口被打开后,服务器是否应该发送一些ACK消息,也就是说,客户端应该在发布RETR之前收听ACK? – 2012-07-30 17:36:00
这23个字节看起来很像。如果我尝试下载一个小文件(如50字节),那么它只能读取1个字节。我不认为服务器应该发送任何ACK消息。 – 2012-07-30 18:08:01
好的,也许你是对的 - 自从我做这些东西以来,有一段时间了。接下来,'buffer [readBytes] ='\ 0'是什么';'做?它似乎在数据的末尾放置了空值,然后不会写入文件,所以它是多余的。接下来,调试 - 到目前为止你做了什么?如果您在f.write中断,readBytes的值和缓冲区中的值是什么? – 2012-07-30 19:18:01