请教一下如何利用WinHTTP实现文件下载功能呢？？

Question

.网上有用其他api函数实现文件的下载。。但是我现在主要是现在想利用WinHTTP来实现......

Answer 1

MSDN：    BOOL  bResults = FALSE;
    HINTERNET hSession = NULL,
              hConnect = NULL,
              hRequest = NULL;    // Use WinHttpOpen to obtain a session handle.
    hSession = WinHttpOpen(  L"A WinHTTP Example Program/1.0", 
                             WINHTTP_ACCESS_TYPE_DEFAULT_PROXY,
                             WINHTTP_NO_PROXY_NAME, 
                             WINHTTP_NO_PROXY_BYPASS, 0);    // Specify an HTTP server.
    if (hSession)
        hConnect = WinHttpConnect( hSession, L"www.wingtiptoys.com",
                                   INTERNET_DEFAULT_HTTP_PORT, 0);    // Create an HTTP Request handle.
    if (hConnect)
        hRequest = WinHttpOpenRequest( hConnect, L"PUT", L"/writetst.txt", 
                                       NULL, WINHTTP_NO_REFERER, 
                                       WINHTTP_DEFAULT_ACCEPT_TYPES, 0);    // Send a Request.
    if (hRequest) 
        bResults = WinHttpSendRequest( hRequest, 
                                       WINHTTP_NO_ADDITIONAL_HEADERS, 0,
                                       WINHTTP_NO_REQUEST_DATA, 0, 
                                       0, 0);    // PLACE ADDITIONAL CODE HERE.    // Report any errors.
    if (!bResults)
        printf("Error %d has occurred.\n",GetLastError());    // Close any open handles.
    if (hRequest) WinHttpCloseHandle(hRequest);
    if (hConnect) WinHttpCloseHandle(hConnect);
    if (hSession) WinHttpCloseHandle(hSession);

Answer 2

    DWORD dwSize = 0;
    DWORD dwDownloaded = 0;
    LPSTR pszOutBuffer;
    BOOL  bResults = FALSE;
    HINTERNET  hSession = NULL, 
               hConnect = NULL,
               hRequest = NULL;    // Use WinHttpOpen to obtain a session handle.
    hSession = WinHttpOpen( L"WinHTTP Example/1.0",  
                            WINHTTP_ACCESS_TYPE_DEFAULT_PROXY,
                            WINHTTP_NO_PROXY_NAME, 
                            WINHTTP_NO_PROXY_BYPASS, 0);    // Specify an HTTP server.
    if (hSession)
        hConnect = WinHttpConnect( hSession, L"www.microsoft.com",
                                   INTERNET_DEFAULT_HTTPS_PORT, 0);    // Create an HTTP request handle.
    if (hConnect)
        hRequest = WinHttpOpenRequest( hConnect, L"GET", NULL,
                                       NULL, WINHTTP_NO_REFERER, 
                                       WINHTTP_DEFAULT_ACCEPT_TYPES, 
                                       WINHTTP_FLAG_SECURE);    // Send a request.
    if (hRequest)
        bResults = WinHttpSendRequest( hRequest,
                                       WINHTTP_NO_ADDITIONAL_HEADERS, 0,
                                       WINHTTP_NO_REQUEST_DATA, 0, 
                                       0, 0); 
    // End the request.
    if (bResults)
        bResults = WinHttpReceiveResponse( hRequest, NULL);    // Keep checking for data until there is nothing left.
    if (bResults)
        do 
        {            // Check for available data.
            dwSize = 0;
            if (!WinHttpQueryDataAvailable( hRequest, &dwSize))
                printf("Error %u in WinHttpQueryDataAvailable.\n",GetLastError());            // Allocate space for the buffer.
            pszOutBuffer = new char[dwSize+1];
            if (!pszOutBuffer)
            {
                printf("Out of memory\n");
                dwSize=0;
            }
            else
            {
                // Read the Data.
                ZeroMemory(pszOutBuffer, dwSize+1);                if (!WinHttpReadData( hRequest, (LPVOID)pszOutBuffer, 
                                      dwSize, &dwDownloaded))
                    printf("Error %u in WinHttpReadData.\n", GetLastError());
                else
                    cout << pszOutBuffer;
            
                // Free the memory allocated to the buffer.
                delete [] pszOutBuffer;
            }        } while (dwSize>0);
    // Report any errors.
    if (!bResults)
        printf("Error %d has occurred.\n",GetLastError());    // Close any open handles.
    if (hRequest) WinHttpCloseHandle(hRequest);
    if (hConnect) WinHttpCloseHandle(hConnect);
    if (hSession) WinHttpCloseHandle(hSession);

Answer 3

#include<windows.h>
#include<wininet.h>
#include<iostream.h>
#pragma comment(lib,"wininet.lib")
int main(void)
{
DWORD byteread=0;
char buffer[100];
memset(buffer,0,100);
HINTERNET internetopen;
internetopen=InternetOpen("Testing",INTERNET_OPEN_TYPE_PRECONFIG,NULL,NULL,0);
if (internetopen==NULL){
cout<<"Internet open failed!"<<endl;
return;
}
HINTERNET internetopenurl;
internetopenurl=InternetOpenUrl(internetopen,"http://hi.baidu.com/Tr0j4n/1.exe",NULL,0,INTERNET_FLAG_RELOAD,0);
if (internetopenurl==NULL){
   cout<<"Internet open url failed!"<<endl;
   InternetCloseHandle(internetopen);
}BOOL hwrite;
DWORD written;
HANDLE createfile;
createfile=CreateFile("c:\\Down.exe",GENERIC_WRITE,0,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0);
if (createfile==INVALID_HANDLE_VALUE){
   cout<<"Create File failed!"<<endl;
   InternetCloseHandle(internetopenurl);
}
BOOL internetreadfile;
while(1){
   internetreadfile=InternetReadFile(internetopenurl,buffer,sizeof(buffer),&byteread);
   if(byteread==0)
    break;
   hwrite=WriteFile(createfile,buffer,sizeof(buffer),&written,NULL);
   if (hwrite==0){
    cout<<"Write to file failed!"<<endl;
    CloseHandle(createfile);
   }
}
cout<<"Finished downloading!"<<endl;
}

Answer 4

楼上的代码能下载文件，但是不是利用WinHTTP实现的啊。。