a867973876
* serve apple-touch-icon.png * rename * 'directives' * use a lazy but caching pattern * update code comment
55 lines
1.7 KiB
JavaScript
55 lines
1.7 KiB
JavaScript
// We actually don't rely and use /favicon.ico but it's nevertheless a
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// very common request. Same with /apple-touch-icon.png.
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// Because we store our images, including those not for the Markdown text,
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// in the `assets/images/site` directory, we will use a custom
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// solution to serve this directly.
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import fs from 'fs'
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import { SURROGATE_ENUMS, setFastlySurrogateKey } from './set-fastly-surrogate-key.js'
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import { cacheControlFactory } from './cache-control.js'
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const cacheControl = cacheControlFactory(60 * 60 * 24 * 7, { immutable: true })
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const MAP = {
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'/favicon.ico': {
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contentType: 'image/x-icon',
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buffer: getBuffer('assets/images/site/favicon.ico'),
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},
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'/apple-touch-icon.png': {
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contentType: 'image/png',
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buffer: getBuffer('assets/images/site/apple-touch-icon.png'),
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},
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}
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function getBuffer(filePath) {
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let buffer
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if (!fs.existsSync(filePath)) {
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throw new Error(`${filePath} not found on disk`)
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}
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return () => {
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if (!buffer) {
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// Yes, sync and a bit slow, but the headers we send will
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// make sure these requests are rare because the payload
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// will be sticky in the CDN and stickly in the browser too.
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buffer = fs.readFileSync(filePath)
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}
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return buffer
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}
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}
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export default function favicons(req, res, next) {
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if (!MAP[req.path]) return next()
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// This makes sure the CDN caching survives each production deployment.
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setFastlySurrogateKey(res, SURROGATE_ENUMS.MANUAL)
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// Manually settings a Cache-Control because no other middleware
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// will get a chance to do this later since we terminate here.
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cacheControl(res)
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const { contentType, buffer } = MAP[req.path]
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res.set('content-type', contentType)
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res.send(buffer())
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}
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