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27 строки
1.0 KiB
JavaScript
27 строки
1.0 KiB
JavaScript
// This middleware rewrites the URL of requests that contain the
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// portion of `/cb-\d+/`.
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// "cb" stands for "cache bust".
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// There's a Markdown plugin that rewrites all <img src> values
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// from `<img src="/assets/foo/bar.png">` to
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// `<img src="/assets/cb-123467/foo/bar.png">` for example.
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// We're doing this so that we can set a much more aggressive
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// Cache-Control for assets and a CDN surrogate-key that doesn't
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// soft-purge on every deployment.
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const regex = /\/cb-\d+\//
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export default function assetPreprocessing(req, res, next) {
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if (req.path.startsWith('/assets/')) {
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// We're only confident enough to set the *manual* surrogate key if the
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// asset contains the cache-busting piece.
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if (regex.test(req.url)) {
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// We remove it so that when `express.static()` runs, it can
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// find the file on disk by its original name.
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req.url = req.url.replace(regex, '/')
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// The Cache-Control is managed by the configuration
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// for express.static() later in the middleware.
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}
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}
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return next()
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}
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