43 lines
1.4 KiB
JavaScript
43 lines
1.4 KiB
JavaScript
const { availableLanguages } = require('../../package.json');
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const config = require('../config');
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const fs = require('fs');
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const path = require('path');
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const { negotiateLanguages } = require('@fluent/langneg');
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const langData = require('cldr-core/supplemental/likelySubtags.json');
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// We return early in the middleware if the lang header is long.
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// If that ever changes we should re-evaluate this regex.
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// eslint-disable-next-line security/detect-unsafe-regex
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const acceptLanguages = /(([a-zA-Z]+(-[a-zA-Z0-9]+){0,2})|\*)(;q=[0-1](\.[0-9]+)?)?/g;
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function allLangs() {
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return fs.readdirSync(path.join(__dirname, '..', '..', 'public', 'locales'));
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}
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const languages = config.l10n_dev ? allLangs() : availableLanguages;
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module.exports = function(req, res, next) {
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const header = req.headers['accept-language'] || 'en-US';
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if (header.length > 255) {
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req.language = 'en-US';
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return next();
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}
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const langs = header.replace(/\s/g, '').match(acceptLanguages) || ['en-US'];
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const preferred = langs
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.map(l => {
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const parts = l.split(';');
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return {
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locale: parts[0],
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q: parts[1] ? parseFloat(parts[1].split('=')[1]) : 1
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};
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})
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.sort((a, b) => b.q - a.q)
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.map(x => x.locale);
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req.language = negotiateLanguages(preferred, languages, {
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strategy: 'lookup',
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likelySubtags: langData.supplemental.likelySubtags,
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defaultLocale: 'en-US'
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})[0];
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next();
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};
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