C/C++实现http下载文件

一、使用MFC winhttp下载

#include 
#include 
#define RECVPACK_SIZE 2048
bool DownloadSaveFiles(char* url,char *strSaveFile) {//下载文件并保存为新文件名
    bool ret=false;
    CInternetSession Sess("lpload");
    Sess.SetOption(INTERNET_OPTION_CONNECT_TIMEOUT     , 2000); //2秒的连接超时
    Sess.SetOption(INTERNET_OPTION_SEND_TIMEOUT        , 2000); //2秒的发送超时
    Sess.SetOption(INTERNET_OPTION_RECEIVE_TIMEOUT     , 2000); //2秒的接收超时
    Sess.SetOption(INTERNET_OPTION_DATA_SEND_TIMEOUT   , 2000); //2秒的发送超时
    Sess.SetOption(INTERNET_OPTION_DATA_RECEIVE_TIMEOUT, 2000); //2秒的接收超时
    DWORD dwFlag = INTERNET_FLAG_TRANSFER_BINARY|INTERNET_FLAG_DONT_CACHE|INTERNET_FLAG_RELOAD ;
 
    CHttpFile* cFile   = NULL;
    char      *pBuf    = NULL;
    int        nBufLen = 0   ;
    do {
        try{
            cFile = (CHttpFile*)Sess.OpenURL(url,1,dwFlag);
            DWORD dwStatusCode;
            cFile->QueryInfoStatusCode(dwStatusCode);
            if (dwStatusCode == HTTP_STATUS_OK) {
                //查询文件长度
                DWORD nLen=0;
                cFile->QueryInfo(HTTP_QUERY_CONTENT_LENGTH, nLen);
                //CString strFilename = GetFileName(url,TRUE);
                nBufLen=nLen;
                if (nLen <= 0) break;//
 
                //分配接收数据缓存
                pBuf = (char*)malloc(nLen+8);
                ZeroMemory(pBuf,nLen+8);
 
                char *p=pBuf;
                while (nLen>0) {
                    //每次下载8K
                    int n = cFile->Read(p,(nLenClose();
        Sess.Close();
        delete cFile;
    }
    return ret;
}
int main() {
    DownloadSaveFiles("http://www.nirsoft.net/utils/nircmd.zip","d:\\cppdld_nircmd.zip");
    return 0;
}

二、使用WinInet API

void download(const char *Url, const char *filename)
{
	byte Temp[1024];
	ULONG Number = 1;
 
	FILE *stream;
	HINTERNET hSession = InternetOpen("RookIE/1.0", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
	if (hSession != NULL)
	{
		HINTERNET handle2 = InternetOpenUrl(hSession, Url, NULL, 0, INTERNET_FLAG_DONT_CACHE, 0);
		if (handle2 != NULL)
		{
 
 
			if ((stream = fopen(filename, "wb")) != NULL)
			{
				while (Number > 0)
				{
					InternetReadFile(handle2, Temp, MAXBLOCKSIZE - 1, &Number);
 
					fwrite(Temp, sizeof(char), Number, stream);
				}
				fclose(stream);
			}
 
			InternetCloseHandle(handle2);
			handle2 = NULL;
		}
		InternetCloseHandle(hSession);
		hSession = NULL;
	}
}

三、使用Windows提供的urlmon库

#include 
#include 
#include 
#include 
#include 
#include 

#pragma comment(lib, "urlmon.lib")

using namespace std;

BOOL FileExistsStatus(const CHAR* path)
{
	DWORD dwAttribute = GetFileAttributes(path);
	if (dwAttribute == 0XFFFFFFFF) return false; //0XFFFFFFFF表示文件不存在
	else return true;
}

BOOL DownloadFiles(const CHAR* url, const CHAR* downloadPath)
{
	if (URLDownloadToFile(NULL, url, downloadPath, 0, 0) == S_OK && FileExistsStatus(downloadPath)) return true;
	else return false;
}

int main(int argc, char* argv[])
{
	if (DownloadFiles(argv[1], argv[2])) printf("OK!\n");
	else printf("Error!\n");
	return 0;
}