94 lines
2.5 KiB
JavaScript
94 lines
2.5 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 statusDone = Symbol('DONE');
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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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// Extract the video ID from a YouTube URL
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const YOUTUBE_URL_REGEX = /(?:https?:\/\/)?(?:www\.)?youtube\.com\/watch\?v=([^?&]+)/;
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const YOUTUBE_SHORT_URL_REGEX = /(?:https?:\/\/)?(?:www\.)?youtu\.be\/([^?&]+)/;
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router.post('/', (req, res) => {
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if (req.body.url === '')
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{
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res.redirect('/');
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return;
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}
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const url = req.body.url.match(YOUTUBE_URL_REGEX);
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if (url !== null)
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{
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res.redirect(`/mazes/${url[1]}`);
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return;
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}
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const shortURL = req.body.url.match(YOUTUBE_SHORT_URL_REGEX);
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if (shortURL !== null)
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{
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res.redirect(`/mazes/${shortURL[1]}`);
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return;
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}
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res.redirect(`/mazes/${req.body.url}`);
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});
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// Generate the graph for a given video ID
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router.get('/:videoId', async (req, res) => {
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const {videoId} = req.params;
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if (videoId in cache)
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{
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if (cache[videoId][0] === statusPending)
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{
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res.header('Refresh', '5');
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res.send(`Exploration in progress, please wait.<br>
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${cache[videoId][1]}…`);
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}
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else if (cache[videoId][0] === statusError)
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{
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res.status(500).send(`Error: ${cache[videoId][1]}`);
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}
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else
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{
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res.send(cache[videoId][1]);
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}
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}
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else
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{
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cache[videoId] = [statusPending, 'Starting exploration'];
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res.header('Refresh', '1');
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res.send('Exploration in progress, please wait.');
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try
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{
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const graph = await exploreVideos(req.params.videoId, (done, rem) =>
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{
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cache[videoId] = [
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statusPending,
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`${done} videos explored, ${rem} pending`
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];
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});
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cache[videoId] = [statusPending, 'Converting graph to SVG'];
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const graphviz = toGraphviz(...graph);
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const svg = await toSVG(graphviz);
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cache[videoId] = [statusDone, 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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console.log(`setting cache error to ${videoId}`)
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cache[videoId] = [statusError, err.message];
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}
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}
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});
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