mastodon/app/javascript/flavours/glitch/util/stream.js

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// @ts-check
import WebSocketClient from '@gamestdio/websocket';
/**
* @type {WebSocketClient | undefined}
*/
let sharedConnection;
/**
* @typedef Subscription
* @property {string} channelName
* @property {Object.<string, string>} params
* @property {function(): void} onConnect
* @property {function(StreamEvent): void} onReceive
* @property {function(): void} onDisconnect
*/
/**
* @typedef StreamEvent
* @property {string} event
* @property {object} payload
*/
/**
* @type {Array.<Subscription>}
*/
const subscriptions = [];
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/**
* @type {Object.<string, number>}
*/
const subscriptionCounters = {};
/**
* @param {Subscription} subscription
*/
const addSubscription = subscription => {
subscriptions.push(subscription);
};
/**
* @param {Subscription} subscription
*/
const removeSubscription = subscription => {
const index = subscriptions.indexOf(subscription);
if (index !== -1) {
subscriptions.splice(index, 1);
}
};
/**
* @param {Subscription} subscription
*/
const subscribe = ({ channelName, params, onConnect }) => {
const key = channelNameWithInlineParams(channelName, params);
subscriptionCounters[key] = subscriptionCounters[key] || 0;
if (subscriptionCounters[key] === 0) {
sharedConnection.send(JSON.stringify({ type: 'subscribe', stream: channelName, ...params }));
}
subscriptionCounters[key] += 1;
onConnect();
};
/**
* @param {Subscription} subscription
*/
const unsubscribe = ({ channelName, params, onDisconnect }) => {
const key = channelNameWithInlineParams(channelName, params);
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subscriptionCounters[key] = subscriptionCounters[key] || 1;
if (subscriptionCounters[key] === 1 && sharedConnection.readyState === WebSocketClient.OPEN) {
sharedConnection.send(JSON.stringify({ type: 'unsubscribe', stream: channelName, ...params }));
}
subscriptionCounters[key] -= 1;
onDisconnect();
};
const sharedCallbacks = {
connected () {
subscriptions.forEach(subscription => subscribe(subscription));
},
received (data) {
const { stream } = data;
subscriptions.filter(({ channelName, params }) => {
const streamChannelName = stream[0];
if (stream.length === 1) {
return channelName === streamChannelName;
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}
const streamIdentifier = stream[1];
if (['hashtag', 'hashtag:local'].includes(channelName)) {
return channelName === streamChannelName && params.tag === streamIdentifier;
} else if (channelName === 'list') {
return channelName === streamChannelName && params.list === streamIdentifier;
}
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return false;
}).forEach(subscription => {
subscription.onReceive(data);
});
},
disconnected () {
subscriptions.forEach(subscription => unsubscribe(subscription));
},
reconnected () {
},
};
/**
* @param {string} channelName
* @param {Object.<string, string>} params
* @return {string}
*/
const channelNameWithInlineParams = (channelName, params) => {
if (Object.keys(params).length === 0) {
return channelName;
}
return `${channelName}&${Object.keys(params).map(key => `${key}=${params[key]}`).join('&')}`;
};
/**
* @param {string} channelName
* @param {Object.<string, string>} params
* @param {function(Function, Function): { onConnect: (function(): void), onReceive: (function(StreamEvent): void), onDisconnect: (function(): void) }} callbacks
* @return {function(): void}
*/
export const connectStream = (channelName, params, callbacks) => (dispatch, getState) => {
const streamingAPIBaseURL = getState().getIn(['meta', 'streaming_api_base_url']);
const accessToken = getState().getIn(['meta', 'access_token']);
const { onConnect, onReceive, onDisconnect } = callbacks(dispatch, getState);
// If we cannot use a websockets connection, we must fall back
// to using individual connections for each channel
if (!streamingAPIBaseURL.startsWith('ws')) {
const connection = createConnection(streamingAPIBaseURL, accessToken, channelNameWithInlineParams(channelName, params), {
connected () {
onConnect();
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},
received (data) {
onReceive(data);
},
disconnected () {
onDisconnect();
},
reconnected () {
onConnect();
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},
});
return () => {
connection.close();
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};
}
const subscription = {
channelName,
params,
onConnect,
onReceive,
onDisconnect,
};
addSubscription(subscription);
// If a connection is open, we can execute the subscription right now. Otherwise,
// because we have already registered it, it will be executed on connect
if (!sharedConnection) {
sharedConnection = /** @type {WebSocketClient} */ (createConnection(streamingAPIBaseURL, accessToken, '', sharedCallbacks));
} else if (sharedConnection.readyState === WebSocketClient.OPEN) {
subscribe(subscription);
}
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return () => {
removeSubscription(subscription);
unsubscribe(subscription);
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};
};
const KNOWN_EVENT_TYPES = [
'update',
'delete',
'notification',
'conversation',
'filters_changed',
'encrypted_message',
'announcement',
'announcement.delete',
'announcement.reaction',
];
/**
* @param {MessageEvent} e
* @param {function(StreamEvent): void} received
*/
const handleEventSourceMessage = (e, received) => {
received({
event: e.type,
payload: e.data,
});
};
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/**
* @param {string} streamingAPIBaseURL
* @param {string} accessToken
* @param {string} channelName
* @param {{ connected: Function, received: function(StreamEvent): void, disconnected: Function, reconnected: Function }} callbacks
* @return {WebSocketClient | EventSource}
*/
const createConnection = (streamingAPIBaseURL, accessToken, channelName, { connected, received, disconnected, reconnected }) => {
const params = channelName.split('&');
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channelName = params.shift();
if (streamingAPIBaseURL.startsWith('ws')) {
const ws = new WebSocketClient(`${streamingAPIBaseURL}/api/v1/streaming/?${params.join('&')}`, accessToken);
ws.onopen = connected;
ws.onmessage = e => received(JSON.parse(e.data));
ws.onclose = disconnected;
ws.onreconnect = reconnected;
return ws;
}
channelName = channelName.replace(/:/g, '/');
if (channelName.endsWith(':media')) {
channelName = channelName.replace('/media', '');
params.push('only_media=true');
}
params.push(`access_token=${accessToken}`);
const es = new EventSource(`${streamingAPIBaseURL}/api/v1/streaming/${channelName}?${params.join('&')}`);
es.onopen = () => {
connected();
};
KNOWN_EVENT_TYPES.forEach(type => {
es.addEventListener(type, e => handleEventSourceMessage(/** @type {MessageEvent} */ (e), received));
});
es.onerror = /** @type {function(): void} */ (disconnected);
return es;
};