61 lines
2.0 KiB
TypeScript
61 lines
2.0 KiB
TypeScript
import { fetchLatestBar } from "../../lib/alpacaClient";
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export async function loader({ request }: { request: Request }) {
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const url = new URL(request.url);
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const ticker = (url.searchParams.get("ticker") || "").toUpperCase();
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if (!ticker) return new Response("ticker required", { status: 400 });
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const timeframe = url.searchParams.get("timeframe") || "1Min"; // default to 1Min bars for live price
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const mode = url.searchParams.get("mode") === "live" ? 'live' : 'paper';
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const headers = new Headers({
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"Content-Type": "text/event-stream",
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"Cache-Control": "no-cache",
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Connection: "keep-alive",
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});
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// Create a ReadableStream that polls latest bar every second and pushes SSE
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let closed = false;
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let interval: any;
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const stream = new ReadableStream({
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start(controller) {
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// helper to push SSE event
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function pushEvent(obj: any) {
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try {
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const payload = `data: ${JSON.stringify(obj)}\n\n`;
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controller.enqueue(new TextEncoder().encode(payload));
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} catch (e) {
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console.warn("price-stream: failed to enqueue", e);
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}
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}
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// initial ping
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pushEvent({ event: "connected", ticker, timeframe });
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interval = setInterval(async () => {
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if (closed) return;
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try {
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const last = await fetchLatestBar(ticker, timeframe, mode);
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const price = last ? (last.ClosePrice ?? last.c ?? null) : null;
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if (price != null) {
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pushEvent({ price, ts: Date.now(), timeframe });
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} else {
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pushEvent({ error: "no_bar", ts: Date.now() });
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}
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} catch (err) {
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console.error("price-stream: error fetching latest bar", err);
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pushEvent({ error: String(err), ts: Date.now() });
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// keep trying
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}
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}, 1000);
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// no-op here; cleanup handled in cancel
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},
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cancel() {
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closed = true;
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clearInterval(interval);
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},
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});
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return new Response(stream, { headers });
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}
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