如何修改标题并将其添加到下载Curl c++中

how to modified header and add it to download Curl c++

本文关键字：添加 下载 Curl c++ 何修改 修改 标题      更新时间：2023-10-16

im尝试更多时间在谷歌中搜索，但没有示例显示如何修改标题数据并使用Curl将其添加到下载中。这是我通过服务器获取标头数据响应的方法

bool getHeader(CURL* url, std::string name, std::string url_down,
    std::string savepath) {
bool result = false;
url = curl_easy_init();
FILE* headf;
CURLcode res;
std::string header_path = savepath + "/header.txt";
const char* url_d = url_down.c_str();
const char* save_header_down = header_path.c_str();
if (url) {
    headf = fopen(save_header_down, "wb");
    if (!headf) {
        curl_easy_cleanup(url);
    }
    curl_easy_setopt(url, CURLOPT_URL, url_d);
    curl_easy_setopt(url, CURLOPT_WRITEFUNCTION, write_data);
    curl_easy_setopt(url, CURLOPT_NOPROGRESS, false);
    curl_easy_setopt(url, CURLOPT_NOBODY, true);
    curl_easy_setopt(url, CURLOPT_FOLLOWLOCATION, 1L);
    curl_easy_setopt(url, CURLOPT_HEADERDATA, headf);
    res = curl_easy_perform(url);
    LOGI("SDK: START DOWNLOAD HEADER");
    if (res == CURLE_OK) {
        LOGI("SDK: HEADER DOWNLOADED!");
        char* ct;
        char* ar;
        double *dTotal;
        res = curl_easy_getinfo(url, CURLINFO_CONTENT_TYPE, &ct);
        res = curl_easy_getinfo(url, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &dTotal);            
        res = curl_easy_getinfo(url, CURLINFO_ACCEPT_RANGES, &ar);
        if((CURLE_OK == res) && ct){
            LOGI("SDK: HEADER CONTENT TYPE: %s", ct);
            LOGI("SDK: HEADER Content-Length: %d", dTotal);
            LOGI("SDK: HEADER Accept-Ranges: %s", ar);
        }
        result = true;
    }
    fclose(headf);
    curl_easy_cleanup(url);
  }
  return result;
}

你可以看到我在curl文档中找不到CURLINFO_ACCEPT_RANGES任何人都可以告诉我如何在curl中获得header的accept范围，修改它并添加到下载中。感谢

我不完全确定您的函数要实现什么，但这里有一个示例，说明如何从HTTP请求中捕获数据和标头。也许它会帮助你实现你想要做的事情：

#include <curl/curl.h>
size_t write_func(void* buf, size_t size, size_t nmemb, void* userp)
{
    if(userp)
    {
        std::string& s = *static_cast<std::string*>(userp);
        std::string::size_type len = size * nmemb;
        s.append(static_cast<char*>(buf), len);
        return nmemb;
    }
    return 0;
}
int main()
{
    CURL* curl = curl_easy_init();
    CURLcode code = CURLE_OK;
    std::string url = "http://google.com/search?q=wibble";
    long timeout = 60; // seconds
    std::string data;
    std::string headers;
    if(CURLE_OK != (code = curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &write_func))
    || CURLE_OK != (code = curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L))
    || CURLE_OK != (code = curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L))
    || CURLE_OK != (code = curl_easy_setopt(curl, CURLOPT_WRITEDATA, &data))
    || CURLE_OK != (code = curl_easy_setopt(curl, CURLOPT_WRITEHEADER, &headers))
    || CURLE_OK != (code = curl_easy_setopt(curl, CURLOPT_TIMEOUT, timeout))
    || CURLE_OK != (code = curl_easy_setopt(curl, CURLOPT_URL, url.c_str())))
    {
        std::cerr << curl_easy_strerror(code) << 'n';
        return 1;
    }
    if(CURLE_OK != (code = curl_easy_perform(curl)))
    {
        std::cerr << curl_easy_strerror(code) << 'n';
        return 1;
    }
    std::cout << "Data:" << 'n';
    std::cout << data << 'n';
    std::cout << "Headers:" << 'n';
    std::cout << headers << 'n';
    curl_easy_cleanup(curl);
}
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