I'm trying to code an application which has to upload/download files to an FTP server. Until now, it used to do those operations in sync mode using Wininet. My goal is to improove so it can do everything in async mode. Thanks to another question on the subject I've come up with a solution to list all the files in the server in async. Now, say I've got a list of all the remote files I want to download and all the local files I want to upload to the server. I know how Callback functions and all this stuff works, but I'm pretty new to async mode in WinAPI. How can I implement this application in C++ using Wininet? Of course, I would like to merge that code with the one I already have to list files. Here's a snippet of it:
enum FTPState {ftpConnect, ftpWaitingForConnect, ftpFindFirstFile, ftpWaitingForFirstFind, ftpFindNextFile, ftpWaitingForNextFind, ftpProcessFile, ftpWaitingForDownload, ftpDisconnect};
struct REQ_CONTEXT
{
FTPState State;
WIN32_FIND_DATAA data;
HINTERNET hConnect;
HINTERNET hServer;
HINTERNET hFile;
HANDLE hDoneEvent;
BOOL DownloadState;
BOOL UploadState;
};
void LogError(const char *Op, DWORD err)
{
if (err == ERROR_INTERNET_EXTENDED_ERROR)
{
LPSTR szBuffer;
DWORD dwLength = 0;
InternetGetLastResponseInfoA(&err, NULL, &dwLength);
if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
{
printf("%s. Unknown Inet Error. OS Error: %u", Op, GetLastError());
return;
}
szBuffer = new char[dwLength+1];
InternetGetLastResponseInfoA(&err, szBuffer, &dwLength);
szBuffer[dwLength] = 0;
printf("%s. Inet Error: %u %s", Op, err, szBuffer);
delete[] szBuffer;
}
else
{
LPSTR lpBuffer = NULL;
DWORD dwLen = FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_ARGUMENT_ARRAY | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, err, 0, (LPSTR)&lpBuffer, 0, NULL);
if (lpBuffer)
{
printf("%s. OS Error: %u %s", Op, err, lpBuffer);
LocalFree(lpBuffer);
}
else
printf("%s. OS Error: %u", Op, err);
}
printf("\n");
}
void LogError(const char *Op)
{
LogError(Op, GetLastError());
}
void DoNextStep(REQ_CONTEXT *ctx)
{
do
{
if ((ctx->State == ftpConnect) && (!f[FLAG_FTP_ITERATE]))
{
printf("Done!\n");
SetEvent(ctx->hDoneEvent);
return;
}
switch (ctx->State)
{
case ftpConnect:
{
printf("Connecting to Server\n");
HINTERNET hServer = InternetConnect(ctx->hConnect, D_ftp_url.c_str(), INTERNET_DEFAULT_FTP_PORT, D_ftp_user.c_str(), D_ftp_pass.c_str(), INTERNET_SERVICE_FTP, NULL, (DWORD_PTR)ctx);
if (hServer != NULL)
{
if (ctx->hServer == NULL)
{
ctx->hServer = hServer;
printf("Server handle: %p\n", ctx->hServer);
}
printf("Connected to Server\n");
ctx->State = ftpFindFirstFile;
}
else if (GetLastError() == ERROR_IO_PENDING)
{
if (ctx->hServer == NULL)
printf("Waiting for Server handle\n");
printf("Waiting for Server connect to complete\n");
ctx->State = ftpWaitingForConnect;
}
else
LogError("Unable to connect to Server");
break;
}
case ftpWaitingForConnect:
return;
case ftpFindFirstFile:
{
printf("Finding first file\n");
HINTERNET hFile = FtpFindFirstFileA(ctx->hServer, D_ftp_base.c_str(), &ctx->data, INTERNET_FLAG_NO_CACHE_WRITE, (DWORD_PTR)ctx);
if (hFile != NULL)
{
if (ctx->hFile == NULL)
{
ctx->hFile = hFile;
printf("Find handle: %p\n", ctx->hFile);
}
ctx->State = ftpProcessFile;
}
else if (GetLastError() == ERROR_IO_PENDING)
{
if (ctx->hFile == NULL)
printf("Waiting for Find handle\n");
printf("Waiting for Find to complete\n");
ctx->State = ftpWaitingForFirstFind;
}
else
{
if (GetLastError() == ERROR_NO_MORE_FILES)
printf("No files were found\n");
else
LogError("Unable to find first file");
ctx->State = ftpDisconnect;
}
break;
}
case ftpWaitingForFirstFind:
case ftpWaitingForNextFind:
return;
case ftpProcessFile:
{
/*Process file*/
printf("Finding next file\n");
if (!InternetFindNextFileA(ctx->hFile, &ctx->data))
{
if (GetLastError() == ERROR_IO_PENDING)
{
printf("Waiting for next file to complete\n");
ctx->State = ftpWaitingForNextFind;
}
else
{
if (GetLastError() == ERROR_NO_MORE_FILES)
printf("No more files were found\n");
else
LogError("Unable to find next file");
ctx->State = ftpDisconnect;
}
}
break;
}
case ftpDisconnect:
{
printf("Disconnecting\n");
if (ctx->hFile != NULL)
{
InternetCloseHandle(ctx->hFile);
ctx->hFile = NULL;
}
if (ctx->hServer != NULL)
{
InternetCloseHandle(ctx->hServer);
ctx->hServer = NULL;
}
ctx->State = ftpConnect;
break;
}
}
}
while (true);
}
void CALLBACK CallbackFunction(HINTERNET hInternet, DWORD_PTR dwContext, DWORD dwInternetStatus, LPVOID lpvStatusInformation, DWORD dwStatusInformationLength)
{
REQ_CONTEXT *ctx = (REQ_CONTEXT*) dwContext;
switch (dwInternetStatus)
{
case INTERNET_STATUS_HANDLE_CREATED:
{
LPINTERNET_ASYNC_RESULT Result = (LPINTERNET_ASYNC_RESULT) lpvStatusInformation;
switch (ctx->State)
{
case ftpConnect:
case ftpWaitingForConnect:
ctx->hServer = (HINTERNET) Result->dwResult;
printf("Server handle: %p\n", ctx->hServer);
break;
case ftpFindFirstFile:
case ftpWaitingForFirstFind:
ctx->hFile = (HINTERNET) Result->dwResult;
printf("Find handle: %p\n", ctx->hFile);
break;
}
break;
}
case INTERNET_STATUS_REQUEST_COMPLETE:
{
LPINTERNET_ASYNC_RESULT Result = (LPINTERNET_ASYNC_RESULT) lpvStatusInformation;
switch (ctx->State)
{
case ftpWaitingForConnect:
{
if (!Result->dwResult)
{
LogError("Unable to connect to Server", Result->dwError);
ctx->State = ftpDisconnect;
}
else
{
printf("Connected to Server\n");
ctx->State = ftpFindFirstFile;
}
break;
}
case ftpWaitingForFirstFind:
case ftpWaitingForNextFind:
{
if (!Result->dwResult)
{
if (Result->dwError == ERROR_NO_MORE_FILES)
printf("No %sfiles were found\n", (ctx->State == ftpWaitingForNextFind) ? "more " : "");
else if (ctx->State == ftpWaitingForFirstFind)
LogError("Unable to find first file", Result->dwError);
else
LogError("Unable to find next file", Result->dwError);
ctx->State = ftpDisconnect;
}
else
ctx->State = ftpProcessFile;
break;
}
}
DoNextStep(ctx);
break;
}
}
}
void FTPIterate()
{
REQ_CONTEXT ctx;
ctx.State = ftpConnect;
ctx.hDoneEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (ctx.hDoneEvent == NULL)
{
LogError("Unable to Create Done Event");
return;
}
ctx.hConnect = InternetOpen(NULL, INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, INTERNET_FLAG_ASYNC);
if (ctx.hConnect == NULL)
{
LogError("Unable to Open Internet");
CloseHandle(ctx.hDoneEvent);
return;
}
printf("Connect handle: %p\n", ctx.hConnect);
InternetSetStatusCallback(ctx.hConnect, &CallbackFunction);
DoNextStep(&ctx);
WaitForSingleObject(ctx.hDoneEvent, INFINITE);
InternetCloseHandle(ctx.hConnect);
CloseHandle(ctx.hDoneEvent);
}
As you may have noticed, indexing is done recursively, so the app automatically detects new files and downloads them.
Thanks in advance.
Aucun commentaire:
Enregistrer un commentaire