oracular (3) curl_ws_send.3.gz

NAME

       curl_ws_send - send WebSocket data

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_ws_send(CURL *curl, const void *buffer, size_t buflen,
                             size_t *sent, curl_off_t fragsize,
                             unsigned int flags);

DESCRIPTION

       This function call is EXPERIMENTAL.

       Send the specific message fragment over an established WebSocket connection. The buffer holds the data to
       send and it is buflen number of payload bytes in that memory area.

       sent is returned as the number of payload bytes actually sent.

       To send a (huge) fragment using multiple calls with partial content per invoke, set the CURLWS_OFFSET bit
       and  the fragsize argument as the total expected size for the first part, then set the CURLWS_OFFSET with
       a zero fragsize for the following parts.

       If not sending a partial fragment or if this is raw mode, fragsize should be set to zero.

       If CURLWS_RAW_MODE is enabled in CURLOPT_WS_OPTIONS(3), the flags argument should be set to 0.

       To send a message consisting of multiple frames, set the CURLWS_CONT bit in all frames except  the  final
       one.

FLAGS

       CURLWS_TEXT
              The  buffer  contains text data. Note that this makes a difference to WebSocket but libcurl itself
              does not make any verification of the content or precautions that you actually  send  valid  UTF-8
              content.

       CURLWS_BINARY
              This is binary data.

       CURLWS_CONT
              This is not the final fragment of the message, which implies that there is another fragment coming
              as part of the same message where this bit is not set.

       CURLWS_CLOSE
              Close this transfer.

       CURLWS_PING
              This is a ping.

       CURLWS_PONG
              This is a pong.

       CURLWS_OFFSET
              The provided data is only a partial fragment and there is more  coming  in  a  following  call  to
              curl_ws_send(). When sending only a piece of the fragment like this, the fragsize must be provided
              with the total expected fragment size in the first call and it needs  to  be  zero  in  subsequent
              calls.

PROTOCOLS

       This functionality affects ws only

EXAMPLE

       #include <string.h> /* for strlen */

       const char *send_payload = "magic";

       int main(void)
       {
         size_t sent;
         CURLcode res;
         CURL *curl = curl_easy_init();
         curl_easy_setopt(curl, CURLOPT_URL, "wss://example.com/");
         curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 2L);
         curl_easy_perform(curl);
         res = curl_ws_send(curl, send_payload, strlen(send_payload), &sent, 0,
                            CURLWS_PING);
         curl_easy_cleanup(curl);
         return (int)res;
       }

AVAILABILITY

       Added in curl 7.86.0

RETURN VALUE

       CURLE_OK  (zero) means that the data was sent properly, non-zero means an error occurred as <curl/curl.h>
       defines. See the libcurl-errors(3) man page for the full list with descriptions.

SEE ALSO

       curl_easy_getinfo(3), curl_easy_perform(3), curl_easy_setopt(3), curl_ws_recv(3), libcurl-ws(3)