在 C++/C 中使用 CURL 发出带有数据文件的 GET HTTP 请求

Question

Using the CURL at the command line:

curl -d @%1 -X GET https://blah-blah

This is in a Windows batch file and I pass the name of the file on the command line. Using this, I can issue a service call sending in a file with a whole lot of input parameters and I receive a substantial output.

For the life of me, when I try pro \grammatically, I can't make it work. It must be possible, since it can be done on the command. However, when I set

curl_easy_setopt(m_Curl, CURLOPT_HTTPGET, 1);

I can't upload a file, even if I set the callback

If I use:

curl_easy_setopt(m_Curl, CURLOPT_UPLOAD, 1L);

the call becomes 'PUT', even though I try and force the header to be a GET. I follow the documentation and can see that this is the documented behavior. However, what is the pathway for avoiding this default?

Any guidance would be most appreciated.

Thanks,

Stan

Answer 1

AFAIK it's not strictly forbidden but you shouldn't send a body with a GET request. On the other side a server should be able to handle a GET request with body but the response shouldn't be dependent of the content of the body.

If you really need to send a request containing a body with GET you can change the value of the method with CURLOPT_CUSTOMREQUEST . This won't change the behavior of curl. This snippet will upload data with GET:

  CURL* curl = curl_easy_init();
  if (curl) {
    curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
    curl_easy_setopt(curl, CURLOPT_URL, url);
    curl_easy_setopt(curl, CURLOPT_PORT, port);
    curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "GET");

    const auto* file = fopen(filename.c_str(), "r");
    curl_easy_setopt(curl, CURLOPT_READDATA, file);
    curl_easy_setopt(
        curl, CURLOPT_INFILESIZE_LARGE, static_cast<curl_off_t>(filesize));

    curl_easy_perform(curl);
  }