通过cURL获取web页面及http header信息

cURL是一个强大的HTTP操作库, 可以协助用来操作HTTP相关工作, 减少了代码中使用socket带来的繁琐. 也包含了一个利用URL语法在命令行下工作的文件传输工具curl. 具体可以参考：http://curl.haxx.se/这也是cURL开发者的首页.

以下是我的示例, 用来测试HTTP返回数据的.

#include <stdio.h>
#include <curl/curl.h>
// 页面数据回调函数
static size_t write_callback( void *ptr, size_t size, size_t nmemb, void *stream )
{
	int len = size * nmemb;
	int written = len;
	fwrite(ptr, size, nmemb, (FILE *)stream);
	//written = fputs( ptr, (FILE *)stream); 
	return written;
}
// 返回http header回调函数
static size_t header_callback( void *ptr, size_t size, size_t nmemb, void *stream )
{
	int len = size * nmemb;
	int written = len;
	return written;
}

int main( void )
{
    CURL *curl;
    CURLcode res;
	struct curl_slist *chunk = NULL;
	
    curl = curl_easy_init();
    if ( curl ) {
    	
    	// 加入http header 附加信息
        chunk = curl_slist_append( chunk, "Accept-Language: zh-cn" );
        //chunk = curl_slist_append( chunk, "Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, */*" );
        chunk = curl_slist_append( chunk, "Accept-Encoding: gzip, deflate" );
        chunk = curl_slist_append( chunk, "User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; CIBA)" );        
        chunk = curl_slist_append( chunk, "Connection: Keep-Alive" );
        // 设置调试模式
        curl_easy_setopt( curl, CURLOPT_VERBOSE, 1L );
        curl_easy_setopt( curl, CURLOPT_URL, "192.168.1.25" );
        curl_easy_setopt( curl, CURLOPT_HTTPHEADER, chunk );

        // 设置回调函数
	curl_easy_setopt( curl, CURLOPT_HEADERFUNCTION, header_callback );
	curl_easy_setopt( curl, CURLOPT_WRITEFUNCTION, write_callback );
	

        res = curl_easy_perform( curl );

        /* always cleanup */
        curl_easy_cleanup( curl );
        
        curl_slist_free_all( chunk );
        chunk = NULL;
    }
    return 0;
}