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 options. 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 filenames 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 filename strangename"kind. When the containing multipart form is sent, this is normally transmitted as strangename%22kind. When this option is set, it is sent as strangename"kind.

DEFAULT

0, meaning disabled.

PROTOCOLS

This functionality affects http, imap and smtp

EXAMPLE

int main(void)
{


  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, (long)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(form);


  }
}

AVAILABILITY

Added in curl 7.81.0

RETURN VALUE

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).