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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title></title>
<style type="text/css">
input[type="text"] { width: 300px; }
.muted {color: #CCCCCC; font-size: 10px;}
</style>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/centrifugal/centrifuge-js@master/dist/centrifuge.min.js"></script>
<script type="text/javascript">
// helper functions to work with escaping html.
const tagsToReplace = {'&': '&', '<': '<', '>': '>'};
function replaceTag(tag) {return tagsToReplace[tag] || tag;}
function safeTagsReplace(str) {return str.replace(/[&<>]/g, replaceTag);}
const channel = "chat:index";
// Manually keep last seen stream position.
let streamPosition = null;
window.addEventListener('load', function() {
const input = document.getElementById('input');
const container = document.getElementById('messages');
const centrifuge = new Centrifuge('ws://localhost:8000/connection/websocket');
centrifuge.on('connect', function(ctx){
drawText('Connected with client ID ' + ctx.client + ' over ' + ctx.transport + ' with data: ' + JSON.stringify(ctx.data));
input.removeAttribute("disabled");
});
centrifuge.on('disconnect', function(ctx){
drawText('Disconnected: ' + ctx.reason + (ctx.reconnect?", will try to reconnect":", won't try to reconnect"));
input.setAttribute("disabled", 'true');
});
const sub = centrifuge.subscribe(channel, handleMessage)
.on("unsubscribe", handleUnsubscribe)
.on("subscribe", handleSubscribe)
.on("error", handleSubscribeError);
centrifuge.connect();
async function restoreMissedPublications() {
let recovered = false;
while (true) {
if (recovered) {
break;
}
let resp;
try {
const limit = 10;
drawText("Since offset " + streamPosition.offset + " with limit " + limit)
resp = await sub.history({since: streamPosition, limit: limit});
} catch (e) {
return false;
}
const pubs = resp.publications;
if (pubs && pubs.length > 0) {
for (let i in pubs) {
if (!pubs.hasOwnProperty(i)) {
continue
}
handleMessage(pubs[i]);
if (pubs[i].offset === resp.offset) {
recovered = true;
break;
}
}
} else {
recovered = true;
break;
}
}
return recovered;
}
async function handleSubscribe(ctx) {
drawText('Subscribed on channel ' + ctx.channel + ' (resubscribed: ' + ctx.isResubscribe + ')');
if (streamPosition == null) {
streamPosition = ctx.streamPosition;
} else {
drawText("Start missed publications recovery")
const ok = await restoreMissedPublications();
if (!ok) {
drawText("Oops, seems like we can't recover");
centrifuge.disconnect();
return;
}
drawText("Successfully recovered")
}
}
function handleSubscribeError(err) {
drawText('Error subscribing on channel ' + err.channel + ': ' + err.message);
}
function handleMessage(message) {
if (message.offset !== streamPosition.offset + 1) {
return;
}
drawMessage(message)
streamPosition.offset = message.offset;
}
function drawMessage(message) {
let clientID;
if (message.info){
clientID = message.info.client;
} else {
clientID = null;
}
const inputText = message.data["input"].toString();
const text = safeTagsReplace(inputText) + ' <span class="muted">from ' + clientID + '</span>';
drawText(text);
}
function handleUnsubscribe(sub) {
drawText('Unsubscribed from channel ' + sub.channel);
}
function drawText(text) {
let e = document.createElement('li');
e.innerHTML = [(new Date()).toString(), ' ' + text].join(':');
container.insertBefore(e, container.firstChild);
}
document.getElementById('form').addEventListener('submit', function(event) {
event.preventDefault();
sub.publish({"input": input.value}).then(function() {
drawText("Successfully published to channel");
}, function(err) {
drawText("Publish error: " + JSON.stringify(err));
});
input.value = '';
});
});
</script>
</head>
<body>
<form id="form">
<label for="input"></label><input type="text" id="input" autocomplete="off" />
<input type="submit" id="submit" value="ยป">
</form>
<ul id="messages"></ul>
</body>
</html>
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