DOKK / manpages / debian 10 / libcurl4-doc / CURLOPT_REDIR_PROTOCOLS.3.en
CURLOPT_REDIR_PROTOCOLS(3) curl_easy_setopt options CURLOPT_REDIR_PROTOCOLS(3)

CURLOPT_REDIR_PROTOCOLS - set protocols allowed to redirect to

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_REDIR_PROTOCOLS, long bitmask);

Pass a long that holds a bitmask of CURLPROTO_* defines. If used, this bitmask limits what protocols libcurl may use in a transfer that it follows to in a redirect when CURLOPT_FOLLOWLOCATION(3) is enabled. This allows you to limit specific transfers to only be allowed to use a subset of protocols in redirections.

Protocols denied by CURLOPT_PROTOCOLS(3) are not overridden by this option.

By default libcurl will allow all protocols on redirect except several disabled for security reasons: Since 7.19.4 FILE and SCP are disabled, and since 7.40.0 SMB and SMBS are also disabled. CURLPROTO_ALL enables all protocols on redirect, including those disabled for security.

These are the available protocol defines:

CURLPROTO_DICT
CURLPROTO_FILE
CURLPROTO_FTP
CURLPROTO_FTPS
CURLPROTO_GOPHER
CURLPROTO_HTTP
CURLPROTO_HTTPS
CURLPROTO_IMAP
CURLPROTO_IMAPS
CURLPROTO_LDAP
CURLPROTO_LDAPS
CURLPROTO_POP3
CURLPROTO_POP3S
CURLPROTO_RTMP
CURLPROTO_RTMPE
CURLPROTO_RTMPS
CURLPROTO_RTMPT
CURLPROTO_RTMPTE
CURLPROTO_RTMPTS
CURLPROTO_RTSP
CURLPROTO_SCP
CURLPROTO_SFTP
CURLPROTO_SMB
CURLPROTO_SMBS
CURLPROTO_SMTP
CURLPROTO_SMTPS
CURLPROTO_TELNET
CURLPROTO_TFTP

All protocols except for FILE, SCP and since 7.40.0 SMB and SMBS.

All

curl = curl_easy_init();
if(curl) {

/* pass in the URL from an external source */
curl_easy_setopt(curl, CURLOPT_URL, argv[1]);
/* only allow redirects to HTTP and HTTPS URLs */
curl_easy_setopt(curl, CURLOPT_REDIR_PROTOCOLS,
CURLPROTO_HTTP | CURLPROTO_HTTPS);
/* Perform the request */
curl_easy_perform(curl); }

Added in 7.19.4, before then it would follow all protocols.

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

CURLOPT_PROTOCOLS(3),

September 21, 2016 libcurl 7.64.0