42 lines
1.5 KiB
JavaScript
42 lines
1.5 KiB
JavaScript
import languages from '../../lib/languages.js'
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import { defaultCacheControl } from '../cache-control.js'
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const redirectPatterns = Object.values(languages)
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.map((language) => language.redirectPatterns || [])
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.flat()
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// If the enabled languages have `.redirectPatterns`, combine them
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// into one which we only need to use to determine if we should bother
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// doing the redirect at all.
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const combinedRedirectPatternRegex =
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redirectPatterns.length > 0
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? new RegExp(redirectPatterns.map((rex) => rex.source).join('|'))
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: null
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const allRedirectPatterns = Object.values(languages)
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.map((language) =>
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(language.redirectPatterns || []).map((redirectPattern) => [language.code, redirectPattern])
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)
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.flat()
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// This middleware handles redirects for mistyped language codes
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//
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// Examples:
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// /jp* -> /ja*
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// /zh-TW* -> /zh*
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export default function languageCodeRedirects(req, res, next) {
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// Only in the unlikely event that the `req.path` starts with one of these
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// prefixes do we bother looking up what the redirect should be.
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if (req.path.startsWith('/_next/static')) return next()
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if (!combinedRedirectPatternRegex) return next()
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if (!combinedRedirectPatternRegex.test(req.path)) return next()
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// This loop is almost never ever used so it doesn't have to be
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// particularly smart or fast.
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const [code, pattern] = allRedirectPatterns.find(([, pattern]) => pattern.test(req.path))
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if (code && pattern) {
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defaultCacheControl(res)
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return res.redirect(301, req.path.replace(pattern, `/${code}`))
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}
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return next()
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}
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