Added data push over WS example

This commit is contained in:
Sergio R. Caprile 2022-07-15 18:32:16 -03:00
parent abd7698d6d
commit aa326f975d
3 changed files with 113 additions and 0 deletions

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PROG ?= example
SSL = ?
ifeq "$(SSL)" "MBEDTLS"
CFLAGS += -DMG_ENABLE_MBEDTLS=1 -lmbedtls -lmbedcrypto -lmbedx509
endif
ifeq "$(SSL)" "OPENSSL"
CFLAGS += -DMG_ENABLE_OPENSSL=1 -lssl -lcrypto
endif
all: $(PROG)
$(DEBUGGER) ./$(PROG) $(ARGS)
$(PROG): main.c
$(CC) ../../mongoose.c -I../.. -W -Wall $(CFLAGS) $(EXTRA_CFLAGS) -o $(PROG) main.c
clean:
rm -rf $(PROG) *.o *.dSYM *.gcov *.gcno *.gcda *.obj *.exe *.ilk *.pdb

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// Copyright (c) 2020 Cesanta Software Limited
// All rights reserved
//
// Example Websocket server with timers. This is a simple Websocket echo
// server, which sends a message to all connected clients periodically,
// using timer API.
#include "mongoose.h"
static const char *s_listen_on = "http://localhost:8000";
static const char *s_web_root = "web_root";
static void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
if (ev == MG_EV_HTTP_MSG) {
struct mg_http_message *hm = (struct mg_http_message *) ev_data;
if (mg_http_match_uri(hm, "/api/watch")) {
mg_ws_upgrade(c, hm, NULL); // Upgrade HTTP to Websocket
c->label[0] = 'W'; // Set some unique mark on the connection
} else {
struct mg_http_serve_opts opts = {.root_dir = s_web_root};
mg_http_serve_dir(c, ev_data, &opts);
}
}
(void) fn_data;
}
// Push to all watchers
static void push(struct mg_mgr *mgr, const char *name, const void *data) {
struct mg_connection *c;
for (c = mgr->conns; c != NULL; c = c->next) {
if (c->label[0] != 'W') continue;
mg_ws_printf(c, WEBSOCKET_OP_TEXT, "{%Q:%Q,%Q:%Q}", "name", name, "data",
data);
}
}
static void timer_fn(void *arg) {
struct mg_mgr *mgr = (struct mg_mgr *) arg;
char buf[50];
mg_snprintf(buf, sizeof(buf), "[%lu, %d]", (unsigned long) time(NULL),
10 + (int) ((double) rand() * 10 / RAND_MAX));
push(mgr, "metrics", buf);
}
int main(void) {
struct mg_mgr mgr; // Event manager
mg_mgr_init(&mgr); // Initialise event manager
mg_log_set("2"); // Set debug log level
mg_timer_add(&mgr, 2000, MG_TIMER_REPEAT, timer_fn, &mgr);
mg_http_listen(&mgr, s_listen_on, fn, NULL); // Create HTTP listener
for (;;) mg_mgr_poll(&mgr, 500); // Infinite event loop
mg_mgr_free(&mgr); // Free manager resources
return 0;
}

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<!DOCTYPE html>
<html lang="en">
<body>
<h1>Data push over WebSocket demo</h1>
<div style="margin-top: 1em;">Event log:</div>
<div id="log" style="background: #eee; height: 10em; padding: 0.5em; overflow:auto;"></div>
</body>
<script>
var log = document.getElementById('log');
const watch = function() {
var l = window.location, proto = l.protocol.replace('http', 'ws');
var tid, wsURI = proto + '//' + l.host + '/api/watch'
var reconnect = function() {
var ws = new WebSocket(wsURI);
ws.onopen = function() { log.innerHTML += 'CONNECTED<br/>'; }
ws.onmessage = function(ev) {
console.log(ev.data);
try {
var msg = JSON.parse(ev.data);
log.innerHTML += 'RECEIVED: ' + JSON.stringify(msg) + '<br/>';
} catch (e) {
console.log('Invalid ws frame:', ev.data);
}
};
ws.onclose = function() {
clearTimeout(tid);
tid = setTimeout(reconnect, 1000);
log.innerHTML += 'DISCONNECTED<br/>';
};
ws.onerror = err => console.log(err);
};
reconnect();
};
watch();
</script>
</html>