CURLOPT_PROTOCOLS_STR(3) Introduction to Library Functions
NAME
CURLOPT_PROTOCOLS_STR - allowed protocols
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROTOCOLS_STR, char *spec);
DESCRIPTION
Pass a pointer to a string that holds a comma-separated list of case
insensitive protocol names (URL schemes) to allow in the transfer.
This option allows applications to use libcurl built to support a
wide range of protocols but still limit specific transfers to only be
allowed to use a subset of them. By default, libcurl accepts all
protocols it was built with support for. See also
CURLOPT_REDIR_PROTOCOLS_STR(3).
If trying to set a non-existing protocol or if no matching protocol
at all is set, it returns error.
These are the available protocols:
DICT, FILE, FTP, FTPS, GOPHER, GOPHERS, HTTP, HTTPS, IMAP, IMAPS,
LDAP, LDAPS, MQTT, POP3, POP3S, RTMP, RTMPE, RTMPS, RTMPT, RTMPTE,
RTMPTS, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET, TFTP, WS,
WSS
You can set "ALL" as a short-cut to enable all protocols. Note that
by setting all, you may enable protocols that were not supported the
day you write this but are introduced in a future libcurl version.
curl_version_info(3) can be used to get a list of all supported
protocols in the current libcurl.
CURLINFO_SCHEME(3) is the
recommended way to figure out the protocol used in a previous
transfer.
Using this option multiple times makes the last set string override
the previous ones. Set it to NULL to restore to the internal default.
DEFAULT
All protocols built-in
PROTOCOLS
This functionality affects all supported protocols
EXAMPLE
int main(int argc, char **argv)
{
CURL *curl = curl_easy_init();
if(curl) {
/* pass in the URL from an external source */
curl_easy_setopt(curl, CURLOPT_URL, argv[1]);
/* only allow HTTP, TFTP and SFTP */
curl_easy_setopt(curl, CURLOPT_PROTOCOLS_STR, "http,tftp,sftp");
/* Perform the request */
curl_easy_perform(curl);
}
}
AVAILABILITY
Added in curl 7.85.0
RETURN VALUE
Returns CURLE_UNKNOWN_OPTION if the option is not implemented,
CURLE_UNSUPPORTED_PROTOCOL if a listed protocol is not supported or
disabled, CURLE_BAD_FUNCTION_ARGUMENT if no protocol is listed else
CURLE_OK.
SEE ALSO
CURLINFO_SCHEME(3),
CURLOPT_DEFAULT_PROTOCOL(3),
CURLOPT_REDIR_PROTOCOLS_STR(3),
CURLOPT_URL(3),
curl_version_info(3)libcurl 2025-02-25 CURLOPT_PROTOCOLS_STR(3)