119 lines
3.8 KiB
JavaScript
119 lines
3.8 KiB
JavaScript
const fs = require('fs')
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const path = require('path')
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const ResolveExtensions = [ '', '.js', '.json' ]
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/**
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* Resolves a path like "lib/file" into "lib/file.js" or "lib/file.json"
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* depending on which one is available, similar to require('lib/file').
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*/
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function resolveFile(base, useIndex, callback) {
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ResolveExtensions.reduceRight(function (next, ext) {
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const file = base + ext
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return function () {
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fs.stat(file, function (error, stats) {
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if (error) {
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if (error.code === 'ENOENT' || error.code === 'ENOTDIR') {
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next()
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} else {
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callback(error)
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}
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} else if (useIndex && stats.isDirectory()) {
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resolveFile(path.join(file, 'index'), false, function (error, indexFile, indexStats) {
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if (error) {
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callback(error)
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} else if (indexFile) {
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callback(null, indexFile, indexStats)
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} else {
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next()
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}
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})
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} else {
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callback(null, file, stats)
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}
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})
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}
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}, callback)()
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}
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/**
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* Determine which file we're going to serve and get its stats.
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* Redirect if the request targets a directory with no trailing slash.
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*/
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function findFile(req, res, next) {
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if (req.filename) {
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const base = path.join(req.packageDir, req.filename)
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// Based on the URL, figure out which file they want.
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resolveFile(base, false, function (error, file, stats) {
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if (error)
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console.error(error)
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if (file == null) {
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res.status(404).send(`Cannot find file "${req.filename}" in package ${req.packageSpec}`)
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} else if (stats.isDirectory() && req.pathname[req.pathname.length - 1] !== '/') {
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// Append / to directory URLs.
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res.redirect(`${req.pathname}/${req.search}`)
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} else {
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req.file = file.replace(req.packageDir, '')
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req.stats = stats
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next()
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}
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})
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} else {
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// No filename in the URL. Try to figure out which file they want by
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// checking package.json's "unpkg", "browser", and "main" fields.
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fs.readFile(path.join(req.packageDir, 'package.json'), 'utf8', function (error, data) {
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if (error) {
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console.error(error)
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return res.status(500).send(`Cannot read ${req.packageSpec}/package.json`)
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}
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let packageConfig
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try {
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packageConfig = JSON.parse(data)
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} catch (error) {
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return res.status(500).send(`Cannot parse ${req.packageSpec}/package.json: ${error.message}`)
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}
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let mainFilename
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const queryMain = query && query.main
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if (queryMain) {
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if (!(queryMain in packageConfig))
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return res.status(404).send(`Cannot find field "${queryMain}" in ${req.packageSpec}/package.json`)
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mainFilename = packageConfig[queryMain]
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} else {
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if (typeof packageConfig.unpkg === 'string') {
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// The "unpkg" field allows packages to explicitly declare the
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// file to serve at the bare URL (see #59).
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mainFilename = packageConfig.unpkg
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} else if (typeof packageConfig.browser === 'string') {
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// Fall back to the "browser" field if declared (only support strings).
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mainFilename = packageConfig.browser
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} else {
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// If there is no main, use "index" (same as npm).
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mainFilename = packageConfig.main || 'index'
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}
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}
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resolveFile(path.join(req.packageDir, mainFilename), true, function (error, file, stats) {
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if (error)
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console.error(error)
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if (file == null) {
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res.status(404).send(`Cannot find main file "${mainFilename}" in package ${req.packageSpec}`)
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} else {
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req.file = file.replace(req.packageDir, '')
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req.stats = stats
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next()
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}
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})
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})
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}
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}
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module.exports = findFile
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