为什么会失败呢，该如何调整

Question

想要爬取第一条网页的数据但是失败了

CURL *curl = curl_easy_init();
    if (curl) {
        std::string lurl;
        lurl = "https://www.nasdaq.com/market-activity/stocks/amzn/historical";
        curl_easy_setopt(curl, CURLOPT_URL, lurl.c_str());
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);
        std::string html_data;
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &html_data);
        CURLcode res = curl_easy_perform(curl);
        if (res == CURLE_OK) {        
            std::cout << html_data.substr(0, 50) << std::endl;
        }
        else {
            std::cerr << "Failed to download HTML: " << curl_easy_strerror(res) << std::endl;
        }
        std::cout << std::endl << std::endl;
        lurl = "https://finance.sina.com.cn/";
        curl_easy_setopt(curl, CURLOPT_URL, lurl.c_str());
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);    
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &html_data);
        res = curl_easy_perform(curl);
        if (res == CURLE_OK) {

            std::cout << html_data.substr(0, 50) << std::endl;
        }
        else {
            std::cerr << "Failed to download HTML: " << curl_easy_strerror(res) << std::endl;
        }

        curl_easy_cleanup(curl);

    }

Answer 1

有可能网站设置了验证，对请求做了限制，要完善请求头和请求体满足爬取要求。