69 lines
1.7 KiB
TypeScript
69 lines
1.7 KiB
TypeScript
import { Schedule } from "@/app/schedule/types";
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function sendMessage(
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stream: WritableStream<string>,
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message: string,
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) {
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const writer = stream.getWriter();
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writer.ready
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.then(() => writer.write(message))
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.catch(console.error)
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.finally(() => writer.releaseLock())
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;
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}
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let streams = new Set<WritableStream<string>>();
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let lastBroadcastData: string | null = null;
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let lastBroadcastId = 0;
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export function broadcastUpdate(schedule: Schedule) {
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const id = Date.now();
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const data = JSON.stringify(schedule);
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lastBroadcastId = id;
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lastBroadcastData = data;
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const message = `id: ${id}\nevent: update\ndata: ${data}\n\n`
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for (const stream of streams) {
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sendMessage(stream, message);
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}
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}
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setInterval(() => {
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for (const stream of streams) {
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sendMessage(stream, "data: keepalive\n\n");
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}
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}, 10e3)
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export async function GET(request: Request) {
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const encoder = new TextEncoder();
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const source = request.headers.get("x-forwarded-for");
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console.log(`starting event stream for ${source}`)
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const stream = new TransformStream<string, Uint8Array>({
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transform(chunk, controller) {
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controller.enqueue(encoder.encode(chunk));
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},
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flush(controller) {
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console.log(`finished event stream for ${source}`);
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streams.delete(stream.writable);
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},
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// @ts-expect-error experimental API
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cancel(reason) {
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console.log(`cancelled event stream for ${source}`);
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streams.delete(stream.writable);
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}
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})
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streams.add(stream.writable);
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if (lastBroadcastId) {
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sendMessage(
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stream.writable,
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`id: ${lastBroadcastData}\nevent: update\ndata: ${lastBroadcastData}\n\n`
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);
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}
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return new Response(
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stream.readable,
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{
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headers: {
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"Access-Control-Allow-Origin": "*",
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"Content-Type": "text/event-stream",
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}
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}
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);
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}
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