curl/docs/libcurl/opts/CURLOPT_CUSTOMREQUEST.3
Daniel Stenberg 63e1a9a1e7
docs: clarify that curl passes on input unfiltered
... for several options.

Reported-by: Ophir Lojkine

Closes #12249
2023-11-02 16:27:39 +01:00

121 lines
4.5 KiB
Groff

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.TH CURLOPT_CUSTOMREQUEST 3 "17 Jun 2014" libcurl libcurl
.SH NAME
CURLOPT_CUSTOMREQUEST \- custom request method
.SH SYNOPSIS
.nf
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CUSTOMREQUEST, char *method);
.fi
.SH DESCRIPTION
Pass a pointer to a null-terminated string as parameter.
When you change the request \fImethod\fP by setting
\fICURLOPT_CUSTOMREQUEST(3)\fP to something, you do not actually change how
libcurl behaves or acts in regards to the particular request method, it only
changes 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.
Restore to the internal default by setting this to NULL.
This option can be used to specify the request:
.IP 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 \fICURLOPT_NOBODY(3)\fP, to switch to a proper POST use
\fICURLOPT_POST(3)\fP or \fICURLOPT_POSTFIELDS(3)\fP and to switch to a proper
GET use \fICURLOPT_HTTPGET(3)\fP.
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 \fICURLOPT_POST(3)\fP and
\fICURLOPT_POSTFIELDS(3)\fP to set POST data. Use \fICURLOPT_HTTPHEADER(3)\fP
to replace or extend the set of headers sent by libcurl. Use
\fICURLOPT_HTTP_VERSION(3)\fP to change HTTP version.
.IP FTP
Instead of LIST and NLST when performing FTP directory listings.
.IP IMAP
Instead of LIST when issuing IMAP based requests.
.IP 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
\fICURLOPT_NOBODY(3)\fP should be used when specifying commands such as
\fBDELE\fP and \fBNOOP\fP for example.
.IP SMTP
Instead of a \fBHELP\fP or \fBVRFY\fP when issuing SMTP based requests.
For example:
Normally a multi line response is returned which can be used, in conjunction
with \fICURLOPT_MAIL_RCPT(3)\fP, to specify an EXPN request. If the
\fICURLOPT_NOBODY(3)\fP option is specified then the request can be used to
issue \fBNOOP\fP and \fBRSET\fP commands.
The application does not have to keep the string around after setting this
option.
.SH DEFAULT
NULL
.SH PROTOCOLS
HTTP, FTP, IMAP, POP3 and SMTP
.SH EXAMPLE
.nf
CURL *curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
/* DELETE the given path */
curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "DELETE");
ret = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
.fi
.SH AVAILABILITY
IMAP is supported since 7.30.0, POP3 since 7.26.0 and SMTP since 7.34.0.
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.
.SH "SEE ALSO"
.BR CURLINFO_EFFECTIVE_METHOD (3),
.BR CURLOPT_HTTPHEADER (3),
.BR CURLOPT_NOBODY (3),
.BR CURLOPT_REQUEST_TARGET (3)