www.LinuxHowtos.org howtos, tips&tricks and tutorials for linux

from small one page howto to huge articles all in one place

Other .linuxhowtos.org sites:gentoo.linuxhowtos.org

Last additions:

using iotop to find disk usage hogs

words:

887

views:

210121

userrating:

May 25th. 2007:

Words

486

Views

259109

why adblockers are bad

Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

words:

161

views:

150430

userrating:

April, 26th. 2006:

Words

Views

107859

New subdomain: toolsntoys.linuxhowtos.org

You are here: manpages

CURLOPT_CUSTOMREQUEST

Section: C Library Functions (3)
Updated: 202-0-19
Index Return to Main Contents

NAME

CURLOPT_CUSTOMREQUEST - custom request method

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CUSTOMREQUEST, char *method);

DESCRIPTION

Pass a pointer to a null-terminated string as parameter.

When changing the request method by setting CURLOPT_CUSTOMREQUEST(3), you do not actually change how libcurl behaves or acts: you only change the actual string sent in the request.

libcurl passes on the verbatim string in its request without any filter or other safe guards. That includes white space and control characters.

The application does not have to keep the string around after setting this option.

Using this option multiple times makes the last set string override the previous ones. Restore to the internal default by setting this to NULL.

This option can be used to specify the request:

HTTP

Instead of GET or HEAD when performing HTTP based requests. This is particularly useful, for example, for performing an HTTP DELETE request.

For example:

When you tell libcurl to do a HEAD request, but then specify a GET though a custom request libcurl still acts as if it sent a HEAD. To switch to a proper HEAD use CURLOPT_NOBODY(3), to switch to a proper POST use CURLOPT_POST(3) or CURLOPT_POSTFIELDS(3) and to switch to a proper GET use CURLOPT_HTTPGET(3).

Many people have wrongly used this option to replace the entire request with their own, including multiple headers and POST contents. While that might work in many cases, it might cause libcurl to send invalid requests and it could possibly confuse the remote server badly. Use CURLOPT_POST(3) and CURLOPT_POSTFIELDS(3) to set POST data. Use CURLOPT_HTTPHEADER(3) to replace or extend the set of headers sent by libcurl. Use CURLOPT_HTTP_VERSION(3) to change the HTTP version.

When this option is used together with CURLOPT_FOLLOWLOCATION(3), the custom set method overrides the method libcurl could otherwise change to for the subsequent requests. You can fine-tune that decision by using the CURLFOLLOW_OBEYCODE bit to CURLOPT_FOLLOWLOCATION(3) to make redirects adhere to the redirect response code as the protocol instructs.

FTP

Instead of LIST and NLST when performing FTP directory listings.

IMAP

Instead of LIST when issuing IMAP based requests.

POP3

Instead of LIST and RETR when issuing POP3 based requests.

For example:

When you tell libcurl to use a custom request it behaves like a LIST or RETR command was sent where it expects data to be returned by the server. As such CURLOPT_NOBODY(3) should be used when specifying commands such as DELE and NOOP for example.

SMTP

Instead of a HELP or VRFY when issuing SMTP based requests.

For example:

Normally a multi line response is returned which can be used, in conjunction with CURLOPT_MAIL_RCPT(3), to specify an EXPN request. If the CURLOPT_NOBODY(3) option is specified then the request can be used to issue NOOP and RSET commands.

DEFAULT

NULL

PROTOCOLS

This functionality affects ftp, http, imap, pop3 and smtp

EXAMPLE

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");

    /* DELETE the given path */
    curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "DELETE");

    result = curl_easy_perform(curl);

    curl_easy_cleanup(curl);
  }
}