c/c++常用代码--使用libcurl下载文件

#pragma once

#include <stdio.h>
#include <stdlib.h>

#include <curl/curl.h>

#ifdef    _DEBUG
#pragma comment(lib, "libcurld_imp.lib")
#else
#pragma comment(lib, "libcurl_imp.lib")
#endif

class CUrlInit
{
public:
    CUrlInit()
    {
        curl_global_init(CURL_GLOBAL_ALL);
    }

    ~CUrlInit()
    {
        curl_global_cleanup();
    }

protected:
    static CUrlInit m_Initialize;
};

CUrlInit CUrlInit::m_Initialize;

class CMyUrl
{
public:
    CMyUrl()
    {
        /* init the curl session */
        curl_handle = curl_easy_init();
    }

    ~CMyUrl()
    {
        /* cleanup curl stuff */
        curl_easy_cleanup(curl_handle);
    }

public:
    int get_file(const char* szUrl, const char* szFile)
    {
        /* set URL to get */
        curl_easy_setopt(curl_handle, CURLOPT_URL, szUrl);

        /* no progress meter please */
        curl_easy_setopt(curl_handle, CURLOPT_NOPROGRESS, 1L);

        /* send all data to this function  */
        curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, write_data);

        /* open the files */
        FILE* bodyfile = fopen(szFile, "wb");
        if (bodyfile == NULL) {
            curl_easy_cleanup(curl_handle);
            return -1;
        }

        /* we want the body be written to this file handle instead of stdout */
        curl_easy_setopt(curl_handle,   CURLOPT_WRITEDATA, bodyfile);

        /* get it! */
        curl_easy_perform(curl_handle);        

        /* close the body file */
        fclose(bodyfile);

        return 0;
    }

protected:
    static size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream)
    {
        int written = fwrite(ptr, size, nmemb, (FILE *)stream);
        return written;
    }

protected:
    CURL *curl_handle;
};