iw7-mod/deps/curl/docs/libcurl/curl_ws_send.md
2024-08-13 05:15:34 -04:00

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---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: curl_ws_send
Section: 3
Source: libcurl
See-also:
- curl_easy_getinfo (3)
- curl_easy_perform (3)
- curl_easy_setopt (3)
- curl_ws_recv (3)
- libcurl-ws (3)
---
# NAME
curl_ws_send - send WebSocket data
# SYNOPSIS
~~~c
#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.
# EXAMPLE
~~~c
#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 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.