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wiki/backend/controllers/files.ts

86 lines
3.8 KiB

import { INLINE_EXTS } from '../models/assets.ts'
import type { FastifyInstance } from 'fastify'
/**
* How long a browser may keep a file before asking again.
*
* Short, and revalidated: unlike a thumbnail, what sits at a path is not fixed — deleting a file and
* uploading another under the same name puts different bytes behind the same URL. `private`, because
* the reply depends on who asked: a shared cache holding one reader's copy of a file the rules put
* behind an account would hand it to the next reader along.
*/
const FILE_CACHE = 'private, max-age=600, must-revalidate'
/**
* _files Routes
*
* How a page's content points at an uploaded file: `/_files/<folder>/<name.ext>`, which is the path
* the file manager shows and what the editors write into a page.
*
* Addressed by path rather than by ID so that what an author reads in their own markdown is the file
* they picked, and so that content carries nothing instance-specific. The cost is the other half of
* that bargain: renaming or moving a file leaves the pages that pointed at it pointing at nothing.
*
* Public in the sense that `_site` and `_thumb` are — no session is required — but not unguarded:
* assets are addressed by the same rules as the pages they sit among, so every request is judged
* against `read:assets` for the path it asked for.
*
* Every image on every page comes through here, so neither half of the lookup normally reaches the
* database: the path resolves out of memory and the bytes stream off the local disk cache. See the
* assets model for what that caches and when it lets go of it.
*/
async function routes(app: FastifyInstance) {
app.get<{ Params: { '*': string } }>('/*', async (req, reply) => {
const site = await WIKI.models.sites.getSiteByHostname({ hostname: req.hostname })
if (!site) {
return reply.notFound('Site not found')
}
const asset = await WIKI.models.assets.resolveAssetPath(site.id, req.params['*'] ?? '')
// -> Not readable is answered as not there, so the URL cannot be used to probe for files
if (
!asset ||
!WIKI.models.groups.checkAccess(WIKI.models.groups.actorForRequest(req), 'read:assets', {
path: asset.folderPath ? `${asset.folderPath}/${asset.fileName}` : asset.fileName,
locale: asset.locale
})
) {
return reply.notFound('File not found')
}
/*
The ID and the timestamp together, because either one alone lies: a file replaced at the same
path is a different asset under the same URL, and one edited in place keeps its ID.
*/
const etag = `"${asset.id}-${asset.updatedAt.getTime()}"`
reply.header('ETag', etag)
reply.header('Cache-Control', FILE_CACHE)
// -> The bytes came from a user, so the browser must take the type at its word rather than
// looking for something more interesting in them
reply.header('X-Content-Type-Options', 'nosniff')
if (req.headers['if-none-match'] === etag) {
return reply.code(304).send()
}
const content = await WIKI.models.assets.readContent(asset)
if (!content) {
// -> The path resolved to a row that is no longer there, so the resolution was a stale one
WIKI.models.assets.forgetPath(site.id, asset.folderPath, asset.fileName)
return reply.notFound('File not found')
}
if (WIKI.config.security?.forceAssetDownload || !INLINE_EXTS.has(asset.fileExt)) {
reply.header(
'Content-Disposition',
`attachment; filename="${encodeURIComponent(asset.fileName)}"`
)
}
// -> Set by hand because the body may be a stream, which Fastify would otherwise send chunked —
// and a download with no length is a download with no progress bar
reply.header('Content-Length', content.size)
return reply.type(asset.mimeType).send(content.body)
})
}
export default routes