unpkg/server/middleware/fetchFile.js

223 lines
6.7 KiB
JavaScript

const fs = require('fs')
const path = require('path')
const semver = require('semver')
const createPackageURL = require('../utils/createPackageURL')
const createSearch = require('./utils/createSearch')
const getPackageInfo = require('./utils/getPackageInfo')
const getPackage = require('./utils/getPackage')
function getBasename(file) {
return path.basename(file, path.extname(file))
}
/**
* File extensions to look for when automatically resolving.
*/
const FindExtensions = ['', '.js', '.json']
/**
* Resolves a path like "lib/file" into "lib/file.js" or "lib/file.json"
* depending on which one is available, similar to require('lib/file').
*/
function findFile(base, useIndex, callback) {
FindExtensions.reduceRight((next, ext) => {
const file = base + ext
return function() {
fs.stat(file, function(error, stats) {
if (error) {
if (error.code === 'ENOENT' || error.code === 'ENOTDIR') {
next()
} else {
callback(error)
}
} else if (useIndex && stats.isDirectory()) {
findFile(path.join(file, 'index'), false, function(
error,
indexFile,
indexStats
) {
if (error) {
callback(error)
} else if (indexFile) {
callback(null, indexFile, indexStats)
} else {
next()
}
})
} else {
callback(null, file, stats)
}
})
}
}, callback)()
}
/**
* Fetch the file from the registry and get its stats. Redirect if the URL
* does not specify an exact version number or targets a directory with no
* trailing slash.
*/
function fetchFile(req, res, next) {
getPackageInfo(req.packageName, function(error, packageInfo) {
if (error) {
console.error(error)
return res
.status(500)
.type('text')
.send(`Cannot get info for package "${req.packageName}"`)
}
if (packageInfo == null || packageInfo.versions == null)
return res
.status(404)
.type('text')
.send(`Cannot find package "${req.packageName}"`)
req.packageInfo = packageInfo
if (req.packageVersion in req.packageInfo.versions) {
// A valid request for a package we haven't downloaded yet.
req.packageConfig = req.packageInfo.versions[req.packageVersion]
getPackage(req.packageConfig, function(error, outputDir) {
if (error) {
console.error(error)
res
.status(500)
.type('text')
.send(`Cannot fetch package ${req.packageSpec}`)
} else {
req.packageDir = outputDir
let filename = req.filename
let useIndex = true
if (req.query.module != null) {
// They want an ES module. Try "module", "jsnext:main", and "/"
// https://github.com/rollup/rollup/wiki/pkg.module
if (!filename)
filename =
req.packageConfig.module ||
req.packageConfig['jsnext:main'] ||
'/'
} else if (filename) {
// They are requesting an explicit filename. Only try to find an
// index file if they are NOT requesting an HTML directory listing.
useIndex = filename[filename.length - 1] !== '/'
} else if (
req.query.main &&
typeof req.packageConfig[req.query.main] === 'string'
) {
// They specified a custom ?main field.
filename = req.packageConfig[req.query.main]
} else if (typeof req.packageConfig.unpkg === 'string') {
// The "unpkg" field allows packages to explicitly declare the
// file to serve at the bare URL (see #59).
filename = req.packageConfig.unpkg
} else if (typeof req.packageConfig.browser === 'string') {
// Fall back to the "browser" field if declared (only support strings).
filename = req.packageConfig.browser
} else {
// Fall back to "main" or / (same as npm).
filename = req.packageConfig.main || '/'
}
findFile(path.join(req.packageDir, filename), useIndex, function(
error,
file,
stats
) {
if (error) console.error(error)
if (file == null)
return res
.status(404)
.type('text')
.send(
`Cannot find module "${filename}" in package ${
req.packageSpec
}`
)
filename = file.replace(req.packageDir, '')
if (
req.query.main != null ||
getBasename(req.filename) !== getBasename(filename)
) {
// Need to redirect to the module file so relative imports resolve
// correctly. Cache module redirects for 1 minute.
delete req.query.main
res
.set({
'Cache-Control': 'public, max-age=60',
'Cache-Tag': 'redirect,module-redirect'
})
.redirect(
302,
createPackageURL(
req.packageName,
req.packageVersion,
filename,
createSearch(req.query)
)
)
} else {
req.filename = filename
req.stats = stats
next()
}
})
}
})
} else if (req.packageVersion in req.packageInfo['dist-tags']) {
// Cache tag redirects for 1 minute.
res
.set({
'Cache-Control': 'public, max-age=60',
'Cache-Tag': 'redirect,tag-redirect'
})
.redirect(
302,
createPackageURL(
req.packageName,
req.packageInfo['dist-tags'][req.packageVersion],
req.filename,
req.search
)
)
} else {
const maxVersion = semver.maxSatisfying(
Object.keys(req.packageInfo.versions),
req.packageVersion
)
if (maxVersion) {
// Cache semver redirects for 1 minute.
res
.set({
'Cache-Control': 'public, max-age=60',
'Cache-Tag': 'redirect,semver-redirect'
})
.redirect(
302,
createPackageURL(
req.packageName,
maxVersion,
req.filename,
req.search
)
)
} else {
res
.status(404)
.type('text')
.send(`Cannot find package ${req.packageSpec}`)
}
}
})
}
module.exports = fetchFile