CURL *curl;	CURLcode res;	struct curl_slist *headers=NULL; // init to NULL is important     headers = curl_slist_append(headers, "Accept: application/json");   	curl = curl_easy_init();	if(curl) {		curl_easy_setopt(curl, CURLOPT_URL, "http://web.com/api/json/123");//cant get json file		curl_easy_setopt(curl, CURLOPT_URL, "http://web.com/pages/123.html");//this returns entire webpage		curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);		curl_easy_setopt(curl, CURLOPT_RETURNTRANSFER, true);	    res = curl_easy_perform(curl);		if(CURLE_OK == res) {			char *ct;			// ask for the content-type		    res = curl_easy_getinfo(curl, CURLINFO_CONTENT_TYPE, &ct);			if((CURLE_OK == res) && ct)		        printf("We received Content-Type: %s\n", ct);		}	}    // always cleanup      curl_easy_cleanup(curl);



//参考答案1

std::string ServerContent::DownloadJSO

N(std::string URL)
{
      
      CURL *curl;
      CURLcode res;
      struct curl_slist *headers=NULL; // init to NULL is important
      std::ostringstream oss;
       curl_slist_append(headers, "Accept: application/json");  
      curl_slist_append( headers, "Content-Type: application/json");
      curl_slist_append( headers, "charsets: utf-8");
       curl = curl_easy_init();

      if(curl) {
            curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
            curl_easy_setopt(curl, CURLOPT_URL, URL.c_str());
            curl_easy_setopt(curl, CURLOPT_HTTPGET,1);
            curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
            curl_easy_setopt(curl,CURLOPT_WRITEFUNCTION,writer);
            res = curl_easy_perform(curl);
            if(CURLE_OK == res) {
                  char *ct;        
                  res = curl_easy_getinfo(curl, CURLINFO_CONTENT_TYPE, &ct);
                  if((CURLE_OK == res) && ct)
                        return *DownloadedResponse;
            }
      }

}