34 lines
1 KiB
JavaScript
34 lines
1 KiB
JavaScript
import * as fs from 'node:fs';
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import express from 'express';
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const sites = fs.readFileSync('./webring.txt', 'utf-8')
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// split lines
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.split(/\r?\n/)
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// trim whitespace from each line
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.map(site => site.trim())
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// exclude empty lines and lines that start with # because why not
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.filter(site => site && !site.startsWith('#'));
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console.log(sites);
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// modulo that does the right thing with negatives
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// https://stackoverflow.com/a/4467559
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const mod = (n, m) => ((n % m) + m) % m;
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function handle (offset, request, response) {
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const from = request.query.from;
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const index = sites.findIndex(site => site === from);
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if (!from || index === -1) {
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response.status(400).send('the provided site is not in the webring');
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return;
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}
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response.redirect(301, sites[mod(index + offset, sites.length)]);
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}
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express()
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.get('/prev', (request, response) => handle(-1, request, response))
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.get('/next', (request, response) => handle(+1, request, response))
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.listen(process.env.PORT || 8080, () => {
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console.log('doing the thing');
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})
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