NAME

CURLOPT_MIME_OPTIONS - set MIME option flags

SYNOPSIS

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_MIME_OPTIONS, long options);

DESCRIPTION

Pass a long that holds a bitmask of CURLMIMEOPT_* defines. Each bit is a Boolean flag used while encoding a MIME tree or multipart form data.

Available bits are:

CURLMIMEOPT_FORMESCAPE

Tells libcurl to escape multipart form field and file names using the backslash-escaping algorithm rather than percent-encoding (HTTP only).

Backslash-escaping consists in preceding backslashes and double quotes with a backslash. Percent encoding maps all occurrences of double quote, carriage return and line feed to %22, %0D and %0A respectively.

Before version 7.81.0, percent-encoding was never applied.

HTTP browsers used to do backslash-escaping in the past but have over time transitioned to use percent-encoding. This option allows one to address server-side applications that have not yet have been converted.

As an example, consider field or file name strange\name"kind. When the containing multipart form is sent, this is normally transmitted as strange\name%22kind. When this option is set, it is sent as strange\\name\"kind.

DEFAULT

0, meaning disabled.

PROTOCOLS

HTTP, IMAP, SMTP

EXAMPLE

CURL *curl = curl_easy_init();
curl_mime *form = NULL;
if(curl) {


  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");


  curl_easy_setopt(curl, CURLOPT_MIME_OPTIONS, CURLMIMEOPT_FORMESCAPE);


  form = curl_mime_init(curl);


  if(form) {


    curl_mimepart *part = curl_mime_addpart(form);


    if(part) {


      curl_mime_filedata(part, "strange\\file\\name");


      curl_mime_name(part, "strange\"field\"name");


      curl_easy_setopt(curl, CURLOPT_MIMEPOST, form);


      /* Perform the request */


      curl_easy_perform(curl);


    }


  }


  curl_easy_cleanup(curl);


  curl_mime_free(mime);
}

AVAILABILITY

Option added in 7.81.0.

RETURN VALUE

Returns CURLE_OK