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This is how the RFC calls the protocol. Also rename the file in docs/ to WEBSOCKET.md in uppercase to match how we have done it for many other protocol docs in similar fashion. Add the WebSocket docs to the tarball. Closes #9496
97 lines
3.2 KiB
Groff
97 lines
3.2 KiB
Groff
.\" **************************************************************************
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.\" * _ _ ____ _
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.\" * Project ___| | | | _ \| |
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.\" * / __| | | | |_) | |
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.\" * | (__| |_| | _ <| |___
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.\" * \___|\___/|_| \_\_____|
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.\" *
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.\" * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
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.\" *
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.\" * This software is licensed as described in the file COPYING, which
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.\" * you should have received as part of this distribution. The terms
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.\" * are also available at https://curl.se/docs/copyright.html.
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.\" *
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.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
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.\" * copies of the Software, and permit persons to whom the Software is
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.\" * furnished to do so, under the terms of the COPYING file.
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.\" *
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.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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.\" * KIND, either express or implied.
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.\" *
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.\" * SPDX-License-Identifier: curl
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.\" *
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.\" **************************************************************************
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.\"
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.TH curl_ws_meta 3 "12 Jun 2022" "libcurl 7.85.0" "libcurl Manual"
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.SH NAME
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curl_ws_meta - meta data WebSocket information
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.SH SYNOPSIS
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.nf
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#include <curl/easy.h>
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struct curl_ws_metadata {
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int age; /* zero */
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int recvflags; /* See the CURLWS_* defines */
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};
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struct curl_ws_metadata *curl_ws_meta(CURL *curl);
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.fi
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.SH DESCRIPTION
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This function call is EXPERIMENTAL.
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When the write callback (\fICURLOPT_WRITEFUNCTION(3)\fP) is invoked on
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received WebSocket traffic, \fIcurl_ws_meta(3)\fP can be called from within
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the callback to provide additional information about the data.
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This function only works from within the callback, and only when receiving
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WebSocket data.
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This function requires an easy handle as input argument for libcurl to know
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what transfer the question is about, but as there is no such pointer provided
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to the callback by libcurl itself, applications that want to use
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\fIcurl_ws_meta(3)\fP need to pass it on to the callback on its own.
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.SH "struct fields"
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.IP age
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This field specify the age of this struct. It is always zero for now.
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.IP recvflags
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This is a bitmask with the exact same meaning as the \fBrecvflags\fP
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documented for \fIcurl_ws_recv(3)\fP.
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.SH EXAMPLE
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.nf
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/* we pass a pointer to this struct to the callback */
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struct customdata {
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CURL *easy;
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void *ptr;
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};
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static size_t writecb(unsigned char *buffer,
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size_t size, size_t nitems, void *p)
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{
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struct customdata *c = (struct customdata *)p;
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struct curl_ws_metadata *m = curl_ws_meta(c->easy);
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/* m->recvflags tells us about the traffic */
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}
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{
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struct customdata custom;
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custom.easy = easy;
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custom.ptr = NULL;
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curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writecb);
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curl_easy_setopt(curl, CURLOPT_WRITEDATA, &custom);
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}
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.fi
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.SH AVAILABILITY
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Added in 7.86.0.
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.SH RETURN VALUE
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This function returns a pointer to a metadata struct with information that is
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valid for this specific callback invocation. If it cannot return this
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information, or if the function is called in the wrong context, it returns
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NULL.
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.SH "SEE ALSO"
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.BR curl_easy_setopt "(3), "
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.BR curl_easy_getinfo "(3), "
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.BR curl_ws_send "(3), " curl_ws_recv "(3), "
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