c++通过http协议校时

由于IP黑白名单的限制,我们能访问的ip和域名资源非常有限,现将通过http协议授时方法整理如下:

#include <cstdio>
#include <string.h>
#include <curl/curl.h>
#include <iostream>

bool GetNetWorkingTime(const char* httpurl = "http://www.510link.com");
size_t readStringBuffFunction(char* data, size_t size, size_t nmemb, void* userStr); //解析data
size_t readStringKey(const char* sourceChr, const char* key, char* returnChr);


int main()
{
    if (GetNetWorkingTime())
    {
        std::cout << "ok" << std::endl;

    }
    else
    {

        printf("%s 向你问好!\n", "HttpClientTime");
    }

    return 0;
}

/******************************************************************************
 *  Name        :   HttpClient::writeFunc
 *  Author      :   cqnews
 *  Version     :   V1.0.0
 *  Data        :   2021.08.12
 *  Describe    :   解析data
 ******************************************************************************/
size_t readStringBuffFunction(char* data, size_t size, size_t nmemb, void* userStr)
{
    int res = -1;

    if (userStr != NULL)
    {
        ((std::string*)userStr)->append((char*)data, size * nmemb);
        return size * nmemb;
    }

    return res;
}


/******************************************************************************
     *  Name        :   HttpClient::GetNetWorkingTime
     *  Author      :   cqnews
     *  Version     :   V1.0.0
     *  Data        :   2021.08.30
     *  Describe    :   检查联网状态
     ******************************************************************************/
bool GetNetWorkingTime(const char* httpurl)
{
    //创建curl对象 
    CURL* curl;
    //创建curlcode对象 
    CURLcode res;

    bool ret = false;

    curl = curl_easy_init();
    if (curl)
    {
        std::string readHeader = "";
        //设置一个请求文件地址 
        curl_easy_setopt(curl, CURLOPT_URL, httpurl);
        curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 5);//设置超时时间
        curl_easy_setopt(curl, CURLOPT_TIMEOUT, 5);//设置超时时间
        curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, readStringBuffFunction);
        curl_easy_setopt(curl, CURLOPT_HEADERDATA, (void*)&readHeader);
        curl_easy_setopt(curl, CURLOPT_HEADER, 0);    //只需要header头
        curl_easy_setopt(curl, CURLOPT_NOBODY, 1);    //不需要body
        curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1L);
        //执行请求操作,将返回值交给res 
        res = curl_easy_perform(curl);
        //res=0的情况表示接收到信息,反之则没有收到信息 
        if (res == CURLE_OK)
        {
            std::cout << "readHeader1:" << readHeader << std::endl;
            readHeader = strstr(readHeader.c_str(), "Date: ");
            std::cout << "readHeader2:" << readHeader << std::endl;

            char dateChr1[30] = { 0 };
            sscanf(readHeader.c_str(), "%[^\n]", dateChr1);
            std::cout << "dateChr1:" << dateChr1 << std::endl;

            char* dateChr2 = dateChr1;
            dateChr2 += strlen("Date: ");
            std::cout << "dateChr2:" << dateChr2 << std::endl;

            tm tm_;
            strptime(dateChr2, "%a, %d %b %Y %H:%M:%S GMT", &tm_); //将字符串转换为tm时间
            tm_.tm_hour += 8;

            char buf[128] = { 0 };
            strftime(buf, 64, "%Y-%m-%d %H:%M:%S", &tm_);
            std::cout << buf << std::endl;

            //已经联网
            ret = true;
        }
        else
        {
            //没有联网
            ret = false;
        }
        /* 释放资源 */
        if (curl) { curl_easy_cleanup(curl); }
    }
    return ret;
}

测试效果如下