Provided by: libcurl4-doc_7.58.0-2ubuntu3.24_all bug


       CURLOPT_UNIX_SOCKET_PATH - set Unix domain socket


       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UNIX_SOCKET_PATH, char *path);


       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 disabled. 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 is NULL, meaning that no Unix domain sockets are used.


       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).


       Given that you have an nginx server running, listening on /tmp/nginx.sock, you can request
       a HTTP resource with:

           curl_easy_setopt(curl_handle, CURLOPT_UNIX_SOCKET_PATH, "/tmp/nginx.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/nginx.sock", dirfd);
           curl_easy_setopt(curl_handle, CURLOPT_UNIX_SOCKET_PATH, path);
           /* Be sure to keep dirfd valid until you discard the handle */


       Since 7.40.0.


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