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next.js/server/hot-reloader.js

312 lines
9.2 KiB
JavaScript

import { join, relative, sep } from 'path'
import WebpackDevMiddleware from 'webpack-dev-middleware'
import WebpackHotMiddleware from 'webpack-hot-middleware'
import del from 'del'
import onDemandEntryHandler from './on-demand-entry-handler'
import webpack from 'webpack'
import getBaseWebpackConfig from './build/webpack'
import UUID from 'uuid'
import {
IS_BUNDLED_PAGE,
addCorsSupport
} from './utils'
export default class HotReloader {
constructor (dir, { quiet, config } = {}) {
this.dir = dir
this.quiet = quiet
this.middlewares = []
this.webpackDevMiddleware = null
this.webpackHotMiddleware = null
this.initialized = false
this.stats = null
this.compilationErrors = null
this.prevAssets = null
this.prevChunkNames = null
this.prevFailedChunkNames = null
this.prevChunkHashes = null
// Here buildId could be any value.
// Our router accepts any value in the dev mode.
// But for the webpack-compiler and for the webpack-dev-server
// it should be the same value.
this.buildId = UUID.v4()
this.config = config
}
async run (req, res) {
// Usually CORS support is not needed for the hot-reloader (this is dev only feature)
// With when the app runs for multi-zones support behind a proxy,
// the current page is trying to access this URL via assetPrefix.
// That's when the CORS support is needed.
const { preflight } = addCorsSupport(req, res)
if (preflight) {
return
}
for (const fn of this.middlewares) {
await new Promise((resolve, reject) => {
fn(req, res, (err) => {
if (err) return reject(err)
resolve()
})
})
}
}
async clean () {
return del(join(this.dir, this.config.distDir), { force: true })
}
async start () {
await this.clean()
const configs = await Promise.all([
getBaseWebpackConfig(this.dir, { dev: true, isServer: false, config: this.config }),
getBaseWebpackConfig(this.dir, { dev: true, isServer: true, config: this.config })
])
const compiler = webpack(configs)
const buildTools = await this.prepareBuildTools(compiler)
this.assignBuildTools(buildTools)
this.stats = (await this.waitUntilValid()).stats[0]
}
async stop (webpackDevMiddleware) {
const middleware = webpackDevMiddleware || this.webpackDevMiddleware
if (middleware) {
return new Promise((resolve, reject) => {
middleware.close((err) => {
if (err) return reject(err)
resolve()
})
})
}
}
async reload () {
this.stats = null
await this.clean()
const configs = await Promise.all([
getBaseWebpackConfig(this.dir, { dev: true, isServer: false, config: this.config }),
getBaseWebpackConfig(this.dir, { dev: true, isServer: true, config: this.config })
])
const compiler = webpack(configs)
const buildTools = await this.prepareBuildTools(compiler)
this.stats = await this.waitUntilValid(buildTools.webpackDevMiddleware)
const oldWebpackDevMiddleware = this.webpackDevMiddleware
this.assignBuildTools(buildTools)
await this.stop(oldWebpackDevMiddleware)
}
assignBuildTools ({ webpackDevMiddleware, webpackHotMiddleware, onDemandEntries }) {
this.webpackDevMiddleware = webpackDevMiddleware
this.webpackHotMiddleware = webpackHotMiddleware
this.onDemandEntries = onDemandEntries
this.middlewares = [
webpackDevMiddleware,
webpackHotMiddleware,
onDemandEntries.middleware()
]
}
async prepareBuildTools (compiler) {
// This flushes require.cache after emitting the files. Providing 'hot reloading' of server files.
compiler.compilers.forEach((singleCompiler) => {
singleCompiler.plugin('after-emit', (compilation, callback) => {
const { assets } = compilation
if (this.prevAssets) {
for (const f of Object.keys(assets)) {
deleteCache(assets[f].existsAt)
}
for (const f of Object.keys(this.prevAssets)) {
if (!assets[f]) {
deleteCache(this.prevAssets[f].existsAt)
}
}
}
this.prevAssets = assets
callback()
})
})
compiler.compilers[0].plugin('done', (stats) => {
const { compilation } = stats
const chunkNames = new Set(
compilation.chunks
.map((c) => c.name)
.filter(name => IS_BUNDLED_PAGE.test(name))
)
const failedChunkNames = new Set(compilation.errors
.map((e) => e.module.reasons)
.reduce((a, b) => a.concat(b), [])
.map((r) => r.module.chunks)
.reduce((a, b) => a.concat(b), [])
.map((c) => c.name))
const chunkHashes = new Map(
compilation.chunks
.filter(c => IS_BUNDLED_PAGE.test(c.name))
.map((c) => [c.name, c.hash])
)
if (this.initialized) {
// detect chunks which have to be replaced with a new template
// e.g, pages/index.js <-> pages/_error.js
const added = diff(chunkNames, this.prevChunkNames)
const removed = diff(this.prevChunkNames, chunkNames)
const succeeded = diff(this.prevFailedChunkNames, failedChunkNames)
// reload all failed chunks to replace the templace to the error ones,
// and to update error content
const failed = failedChunkNames
const rootDir = join('bundles', 'pages')
for (const n of new Set([...added, ...removed, ...failed, ...succeeded])) {
const route = toRoute(relative(rootDir, n))
this.send('reload', route)
}
let changedPageRoutes = []
for (const [n, hash] of chunkHashes) {
if (!this.prevChunkHashes.has(n)) continue
if (this.prevChunkHashes.get(n) === hash) continue
const route = toRoute(relative(rootDir, n))
changedPageRoutes.push(route)
}
// This means `/_app` is most likely included in the list.
// We filter it out because `/_app` will be re-rendered with the page
if (changedPageRoutes.length > 1) {
changedPageRoutes = changedPageRoutes.filter((route) => route !== '/_app' && route !== '/_document')
}
for (const changedPageRoute of changedPageRoutes) {
// notify change to recover from runtime errors
this.send('change', changedPageRoute)
}
}
this.initialized = true
this.stats = stats
this.compilationErrors = null
this.prevChunkNames = chunkNames
this.prevFailedChunkNames = failedChunkNames
this.prevChunkHashes = chunkHashes
})
const ignored = [
/(^|[/\\])\../, // .dotfiles
/node_modules/
]
let webpackDevMiddlewareConfig = {
publicPath: `/_next/webpack/`,
noInfo: true,
quiet: true,
clientLogLevel: 'warning',
watchOptions: { ignored }
}
if (this.config.webpackDevMiddleware) {
console.log(`> Using "webpackDevMiddleware" config function defined in ${this.config.configOrigin}.`)
webpackDevMiddlewareConfig = this.config.webpackDevMiddleware(webpackDevMiddlewareConfig)
}
const webpackDevMiddleware = WebpackDevMiddleware(compiler, webpackDevMiddlewareConfig)
const webpackHotMiddleware = WebpackHotMiddleware(compiler.compilers[0], {
path: '/_next/webpack-hmr',
log: false,
heartbeat: 2500
})
const onDemandEntries = onDemandEntryHandler(webpackDevMiddleware, compiler.compilers, {
dir: this.dir,
dev: true,
reload: this.reload.bind(this),
pageExtensions: this.config.pageExtensions,
...this.config.onDemandEntries
})
return {
webpackDevMiddleware,
webpackHotMiddleware,
onDemandEntries
}
}
waitUntilValid (webpackDevMiddleware) {
const middleware = webpackDevMiddleware || this.webpackDevMiddleware
return new Promise((resolve) => {
middleware.waitUntilValid(resolve)
})
}
async getCompilationErrors () {
// When we are reloading, we need to wait until it's reloaded properly.
await this.onDemandEntries.waitUntilReloaded()
if (!this.compilationErrors) {
this.compilationErrors = new Map()
if (this.stats.hasErrors()) {
const { compiler, errors } = this.stats.compilation
for (const err of errors) {
for (const r of err.module.reasons) {
for (const c of r.module.chunks) {
// get the path of the bundle file
const path = join(compiler.outputPath, c.name)
const errors = this.compilationErrors.get(path) || []
this.compilationErrors.set(path, errors.concat([err]))
}
}
}
}
}
return this.compilationErrors
}
send (action, ...args) {
this.webpackHotMiddleware.publish({ action, data: args })
}
async ensurePage (page) {
// Make sure we don't re-build or dispose prebuilt pages
if (page === '/_error' || page === '/_document' || page === '/_app') {
return
}
await this.onDemandEntries.ensurePage(page)
}
}
function deleteCache (path) {
delete require.cache[path]
}
function diff (a, b) {
return new Set([...a].filter((v) => !b.has(v)))
}
function toRoute (file) {
const f = sep === '\\' ? file.replace(/\\/g, '/') : file
return ('/' + f).replace(/(\/index)?\.js$/, '') || '/'
}