在WinInet中使用异步方式

最新推荐文章于 2018-03-28 10:40:52 发布

iiprogram

最新推荐文章于 2018-03-28 10:40:52 发布

阅读量1.2k

点赞数

分类专栏： vcbcbdelphi的window编程文章标签： internet null callback io service cache

vcbcbdelphi的window编程专栏收录该内容

551 篇文章

订阅专栏

#include<WINDOWS.H>
#include<WININET.H>
#include<IOSTREAM.H>
HANDLE hConnectedEvent, hRequestOpenedEvent, hRequestCompleteEvent;
HINTERNET hInstance, hConnect, hRequest;
char *lpszUrl, *lpszServer;
BOOL bAllDone = FALSE;
BOOL bVerbose = FALSE;
void __stdcall Callback(HINTERNET hInternet,
DWORD dwContext,
DWORD dwInternetStatus,
LPVOID lpStatusInfo,
DWORD dwStatusInfoLen);
void main(int argc, char *argv[])
{
if (argc != 3)
{
if ((argc == 4) && (argv[3][0] == 'v'))
bVerbose = TRUE;
else
{
cout << "Usage: asynchttp <SERVER> <URL> [v]" << endl;
cout << " <SERVER> is the hostname of the http server" << endl;
cout << " <URL> is the url of the object you are requesting (without the hostname)" << endl;
cout << " 'v' for verbose output" << endl << endl;
cout << " Example: asynchttp www.domain.com /docs/readme.htm v" << endl;
return;
}
}
lpszServer = argv[1];
lpszUrl = argv[2];
hConnectedEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
hRequestOpenedEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
hRequestCompleteEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
hInstance = InternetOpen("asynchttp",
INTERNET_OPEN_TYPE_PRECONFIG,
NULL,
NULL,
INTERNET_FLAG_ASYNC); // ASYNC Flag
if (hInstance == NULL)
{
cout << "InternetOpen failed, error " << GetLastError();
return;
}
// Setup callback function
if (InternetSetStatusCallback(hInstance,
(INTERNET_STATUS_CALLBACK)&Callback) == INTERNET_INVALID_STATUS_CALLBACK)
{
cout << "InternetSetStatusCallback failed, error " << GetLastError();
return;
}
// First call that will actually complete asynchronously even
// though there is no network traffic
hConnect = InternetConnect(hInstance,
lpszServer,
INTERNET_DEFAULT_HTTP_PORT,
NULL,
NULL,
INTERNET_SERVICE_HTTP,
0,
1); // Connection handle's Context
if (hConnect == NULL)
{
if (GetLastError() != ERROR_IO_PENDING)
{
cout << "InternetConnect failed, error " << GetLastError();
return;
}
// Wait until we get the connection handle
WaitForSingleObject(hConnectedEvent, INFINITE);
}
// Open the request
hRequest = HttpOpenRequest(hConnect,
"GET",
lpszUrl,
NULL,
NULL,
NULL,
INTERNET_FLAG_RELOAD | INTERNET_FLAG_NO_CACHE_WRITE,
2); // Request handle's context
if (hRequest == NULL)
{
if (GetLastError() != ERROR_IO_PENDING)
{
cout << "HttpOpenRequest failed, error " << GetLastError();
return;
}
// Wait until we get the request handle
WaitForSingleObject(hRequestOpenedEvent, INFINITE);
}
if (!HttpSendRequest(hRequest,
NULL,
0,
NULL,
0))
{
if (GetLastError() != ERROR_IO_PENDING)
{
cout << "HttpSendRequest failed, error " << GetLastError();
return;
}
}
if (bVerbose)
{
cout << "HttpSendRequest called successfully" << endl;
cout.flush();
}
WaitForSingleObject(hRequestCompleteEvent, INFINITE);
cout << "------------------- Read the response -------------------" << endl;
char lpReadBuff[256];
do
{
INTERNET_BUFFERS InetBuff;
FillMemory(&InetBuff, sizeof(InetBuff), 0);
InetBuff.dwStructSize = sizeof(InetBuff);
InetBuff.lpvBuffer = lpReadBuff;
InetBuff.dwBufferLength = sizeof(lpReadBuff) - 1;
if (bVerbose)
{
cout << "Calling InternetReadFileEx" << endl;
cout.flush();
}
if (!InternetReadFileEx(hRequest,
&InetBuff,
0, 2))
{
if (GetLastError() == ERROR_IO_PENDING)
{
if (bVerbose)
{
cout << "Waiting for InternetReadFileEx to complete" << endl;
cout.flush();
}
WaitForSingleObject(hRequestCompleteEvent, INFINITE);
}
else
{
cout << "InternetReadFileEx failed, error " << GetLastError();
cout.flush();
return;
}
}
lpReadBuff[InetBuff.dwBufferLength] = 0;
cout << lpReadBuff;
cout.flush();
if (InetBuff.dwBufferLength == 0)
bAllDone = TRUE;
} while (bAllDone == FALSE);
cout << endl << endl << "------------------- Request Complete ----------------" << endl;
}
void __stdcall Callback(HINTERNET hInternet,
DWORD dwContext,
DWORD dwInternetStatus,
LPVOID lpStatusInfo,
DWORD dwStatusInfoLen)
{
if (bVerbose)
{
cout << "Callback dwInternetStatus: " << dwInternetStatus << " Context: " << dwContext << endl;
cout.flush();
}
switch(dwContext)
{
case 1: // Connection handle
if (dwInternetStatus == INTERNET_STATUS_HANDLE_CREATED)
{
INTERNET_ASYNC_RESULT *pRes = (INTERNET_ASYNC_RESULT *)lpStatusInfo;
hConnect = (HINTERNET)pRes->dwResult;
if (bVerbose)
{
cout << "Connect handle created" << endl;
cout.flush();
}
SetEvent(hConnectedEvent);
}
break;
case 2: // Request handle
switch(dwInternetStatus)
{
case INTERNET_STATUS_HANDLE_CREATED:
{
INTERNET_ASYNC_RESULT *pRes = (INTERNET_ASYNC_RESULT *)lpStatusInfo;
hRequest = (HINTERNET)pRes->dwResult;
if (bVerbose)
{
cout << "Request handle created" << endl;
cout.flush();
}
SetEvent(hRequestOpenedEvent);
}
break;
case INTERNET_STATUS_REQUEST_SENT:
{
DWORD *lpBytesSent = (DWORD*)lpStatusInfo;
if (bVerbose)
{
cout << "Bytes Sent: " << *lpBytesSent << endl;
cout.flush();
}
}
break;
case INTERNET_STATUS_REQUEST_COMPLETE:
{
INTERNET_ASYNC_RESULT *pAsyncRes = (INTERNET_ASYNC_RESULT *)lpStatusInfo;
if (bVerbose)
{
cout << "Function call finished" << endl;
cout << "dwResult: " << pAsyncRes->dwResult << endl;
cout << "dwError: " << pAsyncRes->dwError << endl;
cout.flush();
}
SetEvent(hRequestCompleteEvent);
}
break;
case INTERNET_STATUS_RECEIVING_RESPONSE:
if (bVerbose)
{
cout << "Receiving Response" << endl;
cout.flush();
}
break;
case INTERNET_STATUS_RESPONSE_RECEIVED:
{
DWORD *dwBytesReceived = (DWORD*)lpStatusInfo;
if (*dwBytesReceived == 0)
bAllDone = TRUE;
if (bVerbose)
{
cout << "Received " << *dwBytesReceived << endl;
cout.flush();
}
}
}
}
}