CURLOPT_UNIX_SOCKET_PATH - Unix domain socket
#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UNIX_SOCKET_PATH, char *path);
curl_easy_setopt options CURLOPT_UNIX_SOCKET_PATH(3)
NAME
CURLOPT_UNIX_SOCKET_PATH - Unix domain socket
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UNIX_SOCKET_PATH, char *path);
DESCRIPTION
Enables the use of Unix domain sockets as connection endpoint and sets
the path to path. If path is NULL, then Unix domain sockets are dis-
abled. An empty string will result in an error at some point, it will
not disable use of Unix domain sockets.
When enabled, curl will connect to the Unix domain socket instead of
establishing a TCP connection to a host. Since no TCP connection is
created, curl does not need to resolve the DNS hostname in the URL.
The maximum path length on Cygwin, Linux and Solaris is 107. On other
platforms it might be even less.
Proxy and TCP options such as CURLOPT_TCP_NODELAY(3) are not supported.
Proxy options such as CURLOPT_PROXY(3) have no effect either as these
are TCP-oriented, and asking a proxy server to connect to a certain
Unix domain socket is not possible.
The application does not have to keep the string around after setting
this option.
DEFAULT
Default is NULL, meaning that no Unix domain sockets are used.
PROTOCOLS
All protocols except for FILE and FTP are supported in theory. HTTP,
IMAP, POP3 and SMTP should in particular work (including their SSL/TLS
variants).
EXAMPLE
Given that you have an HTTP server running listening on
/tmp/httpd.sock, you can request an HTTP resource with:
curl_easy_setopt(curl_handle, CURLOPT_UNIX_SOCKET_PATH, "/tmp/httpd.sock");
curl_easy_setopt(curl_handle, CURLOPT_URL, "http://localhost/");
If you are on Linux and somehow have a need for paths larger than 107
bytes, you could use the proc filesystem to bypass the limitation:
int dirfd = open(long_directory_path_to_socket, O_DIRECTORY | O_RDONLY);
char path[108];
snprintf(path, sizeof(path), "/proc/self/fd/%d/httpd.sock", dirfd);
curl_easy_setopt(curl_handle, CURLOPT_UNIX_SOCKET_PATH, path);
/* Be sure to keep dirfd valid until you discard the handle */
AVAILABILITY
Added in 7.40.0.
RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
if not.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | web/curl |
+---------------+------------------+
|Stability | Uncommitted |
+---------------+------------------+
SEE ALSO
CURLOPT_ABSTRACT_UNIX_SOCKET(3), CURLOPT_OPENSOCKETFUNCTION(3),
unix(7),
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from https://curl.se/down-
load/curl-7.83.1.tar.bz2.
Further information about this software can be found on the open source
community website at http://curl.haxx.se/.
libcurl 7.83.1 November 26, 2021
CURLOPT_UNIX_SOCKET_PATH(3)