81 lines
2.0 KiB
TypeScript
81 lines
2.0 KiB
TypeScript
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type Topic = string;
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interface StreamConn {
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pubkey?: string;
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session?: string;
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socket: WebSocket;
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}
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// TODO: Make this a discriminated union (needed for hashtags).
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interface Stream {
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name: string;
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params?: Record<string, string>;
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}
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const sockets = new Map<Topic, Set<WebSocket>>();
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function addSocket(socket: WebSocket, topic: Topic): void {
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let subscribers = sockets.get(topic);
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if (!subscribers) {
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subscribers = new Set<WebSocket>();
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sockets.set(topic, subscribers);
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}
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subscribers.add(socket);
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}
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function removeSocket(socket: WebSocket, topic: Topic): void {
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const subscribers = sockets.get(topic);
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if (subscribers) {
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subscribers.delete(socket);
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if (subscribers.size === 0) {
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sockets.delete(topic);
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}
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}
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}
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function subscribe(conn: StreamConn, stream: Stream): void {
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const topic = getTopic(conn, stream);
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if (topic) {
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addSocket(conn.socket, topic);
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}
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}
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function unsubscribe(conn: StreamConn, stream: Stream): void {
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const topic = getTopic(conn, stream);
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if (topic) {
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removeSocket(conn.socket, topic);
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}
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}
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/**
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* Convert the "stream" parameter into a "topic".
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* The stream parameter is part of the public-facing API, while the topic is internal.
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*/
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function getTopic(conn: StreamConn, stream: Stream): Topic | undefined {
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// Global topics will share the same name as the stream.
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if (stream.name.startsWith('public')) {
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return stream.name;
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// Can't subscribe to non-public topics without a pubkey.
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} else if (!conn.pubkey) {
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return;
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// Nostr signing topics contain the session ID for privacy reasons.
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} else if (stream.name === 'nostr') {
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return conn.session ? `${stream.name}:${conn.pubkey}:${conn.session}` : undefined;
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// User topics will be suffixed with the pubkey.
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} else {
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return `${stream.name}:${conn.pubkey}`;
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}
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}
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function getSockets(topic: Topic): Set<WebSocket> {
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return sockets.get(topic) ?? new Set<WebSocket>();
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}
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const ws = {
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subscribe,
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unsubscribe,
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getSockets,
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};
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export default ws;
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