82 lines
2.1 KiB
Markdown
82 lines
2.1 KiB
Markdown
---
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c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
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SPDX-License-Identifier: curl
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Title: curl_ws_recv
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Section: 3
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Source: libcurl
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See-also:
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- curl_easy_getinfo (3)
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- curl_easy_perform (3)
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- curl_easy_setopt (3)
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- curl_ws_send (3)
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- libcurl-ws (3)
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Protocol:
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- WS
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Added-in: 7.86.0
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---
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# NAME
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curl_ws_recv - receive WebSocket data
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# SYNOPSIS
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~~~c
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#include <curl/curl.h>
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CURLcode curl_ws_recv(CURL *curl, void *buffer, size_t buflen,
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size_t *recv, const struct curl_ws_frame **meta);
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~~~
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# DESCRIPTION
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Retrieves as much as possible of a received WebSocket data fragment into the
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**buffer**, but not more than **buflen** bytes. *recv* is set to the
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number of bytes actually stored.
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If there is more fragment data to deliver than what fits in the provided
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*buffer*, libcurl returns a full buffer and the application needs to call this
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function again to continue draining the buffer.
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If the function call is successful, the *meta* pointer gets set to point to a
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*const struct curl_ws_frame* that contains information about the received
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data. That struct must not be freed and its contents must not be relied upon
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anymore once another WebSocket function is called. See the curl_ws_meta(3) for
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details on that struct.
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# %PROTOCOLS%
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# EXAMPLE
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~~~c
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int main(void)
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{
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size_t rlen;
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const struct curl_ws_frame *meta;
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char buffer[256];
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CURL *curl = curl_easy_init();
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if(curl) {
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CURLcode res = curl_ws_recv(curl, buffer, sizeof(buffer), &rlen, &meta);
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if(res)
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printf("error: %s\n", curl_easy_strerror(res));
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}
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}
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~~~
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# %AVAILABILITY%
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# RETURN VALUE
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This function returns a CURLcode indicating success or error.
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CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
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libcurl-errors(3). If CURLOPT_ERRORBUFFER(3) was set with curl_easy_setopt(3)
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there can be an error message stored in the error buffer when non-zero is
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returned.
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Returns **CURLE_GOT_NOTHING** if the associated connection is closed.
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Instead of blocking, the function returns **CURLE_AGAIN**. The correct
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behavior is then to wait for the socket to signal readability before calling
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this function again.
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