51 lines
1.3 KiB
JavaScript
51 lines
1.3 KiB
JavaScript
import express from 'express';
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import { exploreVideos, toGraphviz } from '../lib/explore.mjs';
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import { toSVG } from '../lib/graphviz.mjs';
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const router = express.Router();
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export default router;
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const statusPending = Symbol('PENDING');
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const statusError = Symbol('ERROR');
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const cache = Object.create(null);
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router.get('/:videoId', async (req, res) => {
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const {videoId} = req.params;
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if (videoId in cache)
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{
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if (cache[videoId] === statusPending)
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{
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res.header('Refresh', '5');
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res.send('Exploration in progress… Please wait.');
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}
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else if (cache[videoId] === statusError)
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{
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res.status(500).send('Error');
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}
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else
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{
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res.send(cache[videoId]);
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}
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}
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else
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{
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cache[videoId] = statusPending;
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res.header('Refresh', '1');
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res.send('Exploration in progress… Please wait.');
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try
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{
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const graph = await exploreVideos(req.params.videoId);
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const graphviz = toGraphviz(...graph);
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const svg = await toSVG(graphviz);
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cache[videoId] = svg;
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}
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catch (err)
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{
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console.error(err);
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cache[videoId] = statusError;
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}
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}
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});
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