docs/middleware/find-page.js

82 строки
2.9 KiB
JavaScript

import path from 'path'
import { existsSync } from 'fs'
import { ROOT } from '../lib/constants.js'
import Page from '../lib/page.js'
import { languagePrefixPathRegex } from '../lib/languages.js'
const englishPrefixRegex = /^\/en(\/|$)/
const CONTENT_ROOT = path.join(ROOT, 'content')
export default async function findPage(
req,
res,
next,
// Express won't execute these but it makes it easier to unit test
// the middleware.
{ isDev = process.env.NODE_ENV === 'development', contentRoot = CONTENT_ROOT } = {},
) {
// Filter out things like `/will/redirect` or `/_next/data/...`
if (!languagePrefixPathRegex.test(req.pagePath)) {
return next()
}
let page = req.context.pages[req.pagePath]
if (page && isDev && englishPrefixRegex.test(req.pagePath)) {
page = await rereadByPath(req.pagePath, contentRoot, req.context.currentVersion)
// This can happen if the page we just re-read has changed which
// versions it's available in (the `versions` frontmatter) meaning
// it might no longer be available on the current URL.
if (!page.applicableVersions.includes(req.context.currentVersion)) {
return res
.status(404)
.send(
`After re-reading the page, '${req.context.currentVersion}' is no longer an applicable version. ` +
'A restart is required.',
)
}
}
if (page) {
req.context.page = page
req.context.page.version = req.context.currentVersion
// We can't depend on `page.hidden` because the dedicated search
// results page is a hidden page but it needs to offer all possible
// languages.
if (page.relativePath.startsWith('early-access')) {
// Override the languages to be only English
req.context.languages = {
en: req.context.languages.en,
}
}
}
return next()
}
async function rereadByPath(uri, contentRoot, currentVersion) {
const languageCode = uri.match(languagePrefixPathRegex)[1]
const withoutLanguage = uri.replace(languagePrefixPathRegex, '/')
const withoutVersion = withoutLanguage.replace(`/${currentVersion}`, '')
// TODO: Support loading translations the same way.
// NOTE: No one is going to test translations like this in development
// but perhaps one day we can always and only do these kinds of lookups
// at runtime.
const possible = path.join(contentRoot, withoutVersion)
const filePath = existsSync(possible) ? path.join(possible, 'index.md') : possible + '.md'
const relativePath = path.relative(contentRoot, filePath)
const basePath = contentRoot
// Remember, the Page.init() can return a Promise that resolves to falsy
// if it can't read the file in from disk. E.g. a request for /en/non/existent.
// In other words, it's fine if it can't be read from disk. It'll get
// handled and turned into a nice 404 message.
return await Page.init({
basePath,
relativePath,
languageCode,
})
}