1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Title: curl_ws_send 5Section: 3 6Source: libcurl 7See-also: 8 - curl_easy_getinfo (3) 9 - curl_easy_perform (3) 10 - curl_easy_setopt (3) 11 - curl_ws_recv (3) 12 - libcurl-ws (3) 13Protocol: 14 - WS 15Added-in: 7.86.0 16--- 17 18# NAME 19 20curl_ws_send - send WebSocket data 21 22# SYNOPSIS 23 24~~~c 25#include <curl/curl.h> 26 27CURLcode curl_ws_send(CURL *curl, const void *buffer, size_t buflen, 28 size_t *sent, curl_off_t fragsize, 29 unsigned int flags); 30~~~ 31 32# DESCRIPTION 33 34This function call is EXPERIMENTAL. 35 36Send the specific message fragment over an established WebSocket 37connection. The *buffer* holds the data to send and it is *buflen* 38number of payload bytes in that memory area. 39 40*sent* is returned as the number of payload bytes actually sent. 41 42To send a (huge) fragment using multiple calls with partial content per 43invoke, set the *CURLWS_OFFSET* bit and the *fragsize* argument as the 44total expected size for the first part, then set the *CURLWS_OFFSET* with 45a zero *fragsize* for the following parts. 46 47If not sending a partial fragment or if this is raw mode, *fragsize* 48should be set to zero. 49 50If **CURLWS_RAW_MODE** is enabled in CURLOPT_WS_OPTIONS(3), the 51**flags** argument should be set to 0. 52 53To send a message consisting of multiple frames, set the *CURLWS_CONT* bit 54in all frames except the final one. 55 56Warning: while it is possible to invoke this function from a callback, 57such a call is blocking in this situation, e.g. only returns after all data 58has been sent or an error is encountered. 59 60# FLAGS 61 62## CURLWS_TEXT 63 64The buffer contains text data. Note that this makes a difference to WebSocket 65but libcurl itself does not make any verification of the content or 66precautions that you actually send valid UTF-8 content. 67 68## CURLWS_BINARY 69 70This is binary data. 71 72## CURLWS_CONT 73 74This is not the final fragment of the message, which implies that there is 75another fragment coming as part of the same message where this bit is not set. 76 77## CURLWS_CLOSE 78 79Close this transfer. 80 81## CURLWS_PING 82 83This is a ping. 84 85## CURLWS_PONG 86 87This is a pong. 88 89## CURLWS_OFFSET 90 91The provided data is only a partial fragment and there is more coming in a 92following call to *curl_ws_send()*. When sending only a piece of the 93fragment like this, the *fragsize* must be provided with the total 94expected fragment size in the first call and it needs to be zero in subsequent 95calls. 96 97# %PROTOCOLS% 98 99# EXAMPLE 100 101~~~c 102#include <string.h> /* for strlen */ 103 104const char *send_payload = "magic"; 105 106int main(void) 107{ 108 size_t sent; 109 CURLcode res; 110 CURL *curl = curl_easy_init(); 111 curl_easy_setopt(curl, CURLOPT_URL, "wss://example.com/"); 112 curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 2L); 113 curl_easy_perform(curl); 114 res = curl_ws_send(curl, send_payload, strlen(send_payload), &sent, 0, 115 CURLWS_PING); 116 curl_easy_cleanup(curl); 117 return (int)res; 118} 119~~~ 120 121# %AVAILABILITY% 122 123# RETURN VALUE 124 125*CURLE_OK* (zero) means that the data was sent properly, non-zero means an 126error occurred as *\<curl/curl.h\>* defines. See the libcurl-errors(3) man 127page for the full list with descriptions. 128
