next.js/packages/next/src/build/webpack/plugins/flight-manifest-plugin.ts

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

import path from 'path'
import { webpack, sources } from 'next/dist/compiled/webpack/webpack'
import {
  APP_CLIENT_INTERNALS,
  BARREL_OPTIMIZATION_PREFIX,
  CLIENT_REFERENCE_MANIFEST,
  SYSTEM_ENTRYPOINTS,
} from '../../../shared/lib/constants'
import { relative } from 'path'
import { getProxiedPluginState } from '../../build-context'

import { WEBPACK_LAYERS } from '../../../lib/constants'
import { normalizePagePath } from '../../../shared/lib/page-path/normalize-page-path'
import { CLIENT_STATIC_FILES_RUNTIME_MAIN_APP } from '../../../shared/lib/constants'
import { getDeploymentIdQueryOrEmptyString } from '../../deployment-id'
import {
  formatBarrelOptimizedResource,
  getModuleReferencesInOrder,
} from '../utils'
import type { ChunkGroup } from 'webpack'
import { encodeURIPath } from '../../../shared/lib/encode-uri-path'
import type { ModuleInfo } from './flight-client-entry-plugin'

interface Options {
  dev: boolean
  appDir: string
  experimentalInlineCss: boolean
}

/**
 * Webpack module id
 */
// TODO-APP ensure `null` is included as it is used.
type ModuleId = string | number /*| null*/

// double indexed chunkId, filename
export type ManifestChunks = Array<string>

const pluginState = getProxiedPluginState({
  ssrModules: {} as { [ssrModuleId: string]: ModuleInfo },
  edgeSsrModules: {} as { [ssrModuleId: string]: ModuleInfo },

  rscModules: {} as { [rscModuleId: string]: ModuleInfo },
  edgeRscModules: {} as { [rscModuleId: string]: ModuleInfo },
})

export interface ManifestNode {
  [moduleExport: string]: {
    /**
     * Webpack module id
     */
    id: ModuleId
    /**
     * Export name
     */
    name: string
    /**
     * Chunks for the module. JS and CSS.
     */
    chunks: ManifestChunks

    /**
     * If chunk contains async module
     */
    async?: boolean
  }
}

export interface ClientReferenceManifestForRsc {
  clientModules: ManifestNode
  rscModuleMapping: {
    [moduleId: string]: ManifestNode
  }
  edgeRscModuleMapping: {
    [moduleId: string]: ManifestNode
  }
}

export type CssResource = InlinedCssFile | UninlinedCssFile

interface InlinedCssFile {
  path: string
  inlined: true
  content: string
}

interface UninlinedCssFile {
  path: string
  inlined: false
}

export interface ClientReferenceManifest extends ClientReferenceManifestForRsc {
  readonly moduleLoading: {
    prefix: string
    crossOrigin?: 'use-credentials' | ''
  }
  ssrModuleMapping: {
    [moduleId: string]: ManifestNode
  }
  edgeSSRModuleMapping: {
    [moduleId: string]: ManifestNode
  }
  entryCSSFiles: {
    [entry: string]: CssResource[]
  }
  entryJSFiles?: {
    [entry: string]: string[]
  }
}

function getAppPathRequiredChunks(
  chunkGroup: webpack.ChunkGroup,
  excludedFiles: Set<string>
) {
  const deploymentIdChunkQuery = getDeploymentIdQueryOrEmptyString()

  const chunks: Array<string> = []
  chunkGroup.chunks.forEach((chunk) => {
    if (SYSTEM_ENTRYPOINTS.has(chunk.name || '')) {
      return null
    }

    // Get the actual chunk file names from the chunk file list.
    if (chunk.id != null) {
      const chunkId = '' + chunk.id
      chunk.files.forEach((file) => {
        // It's possible that a chunk also emits CSS files, that will
        // be handled separatedly.
        if (!file.endsWith('.js')) return null
        if (file.endsWith('.hot-update.js')) return null
        if (excludedFiles.has(file)) return null

        // We encode the file as a URI because our server (and many other services such as S3)
        // expect to receive reserved characters such as `[` and `]` as encoded. This was
        // previously done for dynamic chunks by patching the webpack runtime but we want
        // these filenames to be managed by React's Flight runtime instead and so we need
        // to implement any special handling of the file name here.
        return chunks.push(
          chunkId,
          encodeURIPath(file) + deploymentIdChunkQuery
        )
      })
    }
  })
  return chunks
}

// Normalize the entry names to their "group names" so a page can easily track
// all the manifest items it needs from parent groups by looking up the group
// segments:
// - app/foo/loading -> app/foo
// - app/foo/page -> app/foo
// - app/(group)/@named/foo/page -> app/foo
// - app/(.)foo/(..)bar/loading -> app/bar
// - app/[...catchAll]/page -> app
// - app/foo/@slot/[...catchAll]/page -> app/foo
function entryNameToGroupName(entryName: string) {
  let groupName = entryName
    .slice(0, entryName.lastIndexOf('/'))
    // Remove slots
    .replace(/\/@[^/]+/g, '')
    // Remove the group with lookahead to make sure it's not interception route
    .replace(/\/\([^/]+\)(?=(\/|$))/g, '')
    // Remove catch-all routes since they should be part of the parent group that the catch-all would apply to.
    // This is necessary to support parallel routes since multiple page components can be rendered on the same page.
    // In order to do that, we need to ensure that the manifests are merged together by putting them in the same group.
    .replace(/\/\[?\[\.\.\.[^\]]*]]?/g, '')

  // Interception routes
  groupName = groupName
    .replace(/^.+\/\(\.\.\.\)/g, 'app/')
    .replace(/\/\(\.\)/g, '/')

  // Interception routes (recursive)
  while (/\/[^/]+\/\(\.\.\)/.test(groupName)) {
    groupName = groupName.replace(/\/[^/]+\/\(\.\.\)/g, '/')
  }

  return groupName
}

function mergeManifest(
  manifest: ClientReferenceManifest,
  manifestToMerge: ClientReferenceManifest
) {
  Object.assign(manifest.clientModules, manifestToMerge.clientModules)
  Object.assign(manifest.ssrModuleMapping, manifestToMerge.ssrModuleMapping)
  Object.assign(
    manifest.edgeSSRModuleMapping,
    manifestToMerge.edgeSSRModuleMapping
  )
  Object.assign(manifest.entryCSSFiles, manifestToMerge.entryCSSFiles)
  Object.assign(manifest.rscModuleMapping, manifestToMerge.rscModuleMapping)
  Object.assign(
    manifest.edgeRscModuleMapping,
    manifestToMerge.edgeRscModuleMapping
  )
}

const PLUGIN_NAME = 'ClientReferenceManifestPlugin'

export class ClientReferenceManifestPlugin {
  dev: Options['dev'] = false
  appDir: Options['appDir']
  appDirBase: string
  experimentalInlineCss: Options['experimentalInlineCss']

  constructor(options: Options) {
    this.dev = options.dev
    this.appDir = options.appDir
    this.appDirBase = path.dirname(this.appDir) + path.sep
    this.experimentalInlineCss = options.experimentalInlineCss
  }

  apply(compiler: webpack.Compiler) {
    compiler.hooks.compilation.tap(PLUGIN_NAME, (compilation) => {
      compilation.hooks.processAssets.tap(
        {
          name: PLUGIN_NAME,
          // Have to be in the optimize stage to run after updating the CSS
          // asset hash via extract mini css plugin.
          stage: webpack.Compilation.PROCESS_ASSETS_STAGE_ANALYSE,
        },
        () => this.createAsset(compilation, compiler.context)
      )
    })
  }

  createAsset(compilation: webpack.Compilation, context: string) {
    const manifestsPerGroup = new Map<string, ClientReferenceManifest[]>()
    const manifestEntryFiles: string[] = []

    const configuredCrossOriginLoading =
      compilation.outputOptions.crossOriginLoading
    const crossOriginMode =
      typeof configuredCrossOriginLoading === 'string'
        ? configuredCrossOriginLoading === 'use-credentials'
          ? configuredCrossOriginLoading
          : '' // === 'anonymous'
        : undefined

    if (typeof compilation.outputOptions.publicPath !== 'string') {
      throw new Error(
        'Expected webpack publicPath to be a string when using App Router. To customize where static assets are loaded from, use the `assetPrefix` option in next.config.js. If you are customizing your webpack config please make sure you are not modifying or removing the publicPath configuration option'
      )
    }
    const prefix = compilation.outputOptions.publicPath || ''

    // We want to omit any files that will always be loaded on any App Router page
    // because they will already be loaded by the main entrypoint.
    const rootMainFiles: Set<string> = new Set()
    compilation.entrypoints
      .get(CLIENT_STATIC_FILES_RUNTIME_MAIN_APP)
      ?.getFiles()
      .forEach((file) => {
        if (/(?<!\.hot-update)\.(js|css)($|\?)/.test(file)) {
          rootMainFiles.add(file.replace(/\\/g, '/'))
        }
      })

    for (let [entryName, entrypoint] of compilation.entrypoints) {
      if (
        entryName === CLIENT_STATIC_FILES_RUNTIME_MAIN_APP ||
        entryName === APP_CLIENT_INTERNALS
      ) {
        entryName = ''
      } else if (!/^app[\\/]/.test(entryName)) {
        continue
      }

      const manifest: ClientReferenceManifest = {
        moduleLoading: {
          prefix,
          crossOrigin: crossOriginMode,
        },
        ssrModuleMapping: {},
        edgeSSRModuleMapping: {},
        clientModules: {},
        entryCSSFiles: {},
        rscModuleMapping: {},
        edgeRscModuleMapping: {},
      }

      // Absolute path without the extension
      const chunkEntryName = (this.appDirBase + entryName).replace(
        /[\\/]/g,
        path.sep
      )

      manifest.entryCSSFiles[chunkEntryName] = entrypoint
        .getFiles()
        .filter((f) => !f.startsWith('static/css/pages/') && f.endsWith('.css'))
        .map((file) => {
          const source = compilation.getAsset(file)!.source.source()
          if (
            this.experimentalInlineCss &&
            // Inline CSS currently does not work properly with HMR, so we only
            // inline CSS in production.
            !this.dev
          ) {
            return {
              inlined: true,
              path: file,
              content: typeof source === 'string' ? source : source.toString(),
            }
          }
          return {
            inlined: false,
            path: file,
          }
        })

      const requiredChunks = getAppPathRequiredChunks(entrypoint, rootMainFiles)
      const recordModule = (modId: ModuleId, mod: webpack.NormalModule) => {
        let resource =
          mod.type === 'css/mini-extract'
            ? mod.identifier().slice(mod.identifier().lastIndexOf('!') + 1)
            : mod.resource

        if (!resource) {
          return
        }

        const moduleReferences = manifest.clientModules
        const moduleIdMapping = manifest.ssrModuleMapping
        const edgeModuleIdMapping = manifest.edgeSSRModuleMapping

        const rscIdMapping = manifest.rscModuleMapping
        const edgeRscIdMapping = manifest.edgeRscModuleMapping

        // Note that this isn't that reliable as webpack is still possible to assign
        // additional queries to make sure there's no conflict even using the `named`
        // module ID strategy.
        let ssrNamedModuleId = relative(
          context,
          mod.resourceResolveData?.path || resource
        )

        const rscNamedModuleId = relative(
          context,
          mod.resourceResolveData?.path || resource
        )

        if (!ssrNamedModuleId.startsWith('.'))
          ssrNamedModuleId = `./${ssrNamedModuleId.replace(/\\/g, '/')}`

        // The client compiler will always use the CJS Next.js build, so here we
        // also add the mapping for the ESM build (Edge runtime) to consume.
        const esmResource = /[\\/]next[\\/]dist[\\/]/.test(resource)
          ? resource.replace(
              /[\\/]next[\\/]dist[\\/]/,
              '/next/dist/esm/'.replace(/\//g, path.sep)
            )
          : null

        // An extra query param is added to the resource key when it's optimized
        // through the Barrel Loader. That's because the same file might be created
        // as multiple modules (depending on what you import from it).
        // See also: webpack/loaders/next-flight-loader/index.ts.
        if (mod.matchResource?.startsWith(BARREL_OPTIMIZATION_PREFIX)) {
          ssrNamedModuleId = formatBarrelOptimizedResource(
            ssrNamedModuleId,
            mod.matchResource
          )
          resource = formatBarrelOptimizedResource(resource, mod.matchResource)
        }

        function addClientReference() {
          const isAsync = Boolean(
            compilation.moduleGraph.isAsync(mod) ||
              pluginState.ssrModules[ssrNamedModuleId]?.async ||
              pluginState.edgeSsrModules[ssrNamedModuleId]?.async
          )

          const exportName = resource
          manifest.clientModules[exportName] = {
            id: modId,
            name: '*',
            chunks: requiredChunks,
            async: isAsync,
          }
          if (esmResource) {
            const edgeExportName = esmResource
            manifest.clientModules[edgeExportName] =
              manifest.clientModules[exportName]
          }
        }

        function addSSRIdMapping() {
          const exportName = resource
          const moduleInfo = pluginState.ssrModules[ssrNamedModuleId]

          if (moduleInfo) {
            moduleIdMapping[modId] = moduleIdMapping[modId] || {}
            moduleIdMapping[modId]['*'] = {
              ...manifest.clientModules[exportName],
              // During SSR, we don't have external chunks to load on the server
              // side with our architecture of Webpack / Turbopack. We can keep
              // this field empty to save some bytes.
              chunks: [],
              id: moduleInfo.moduleId,
              async: moduleInfo.async,
            }
          }

          const edgeModuleInfo = pluginState.edgeSsrModules[ssrNamedModuleId]

          if (edgeModuleInfo) {
            edgeModuleIdMapping[modId] = edgeModuleIdMapping[modId] || {}
            edgeModuleIdMapping[modId]['*'] = {
              ...manifest.clientModules[exportName],
              // During SSR, we don't have external chunks to load on the server
              // side with our architecture of Webpack / Turbopack. We can keep
              // this field empty to save some bytes.
              chunks: [],
              id: edgeModuleInfo.moduleId,
              async: edgeModuleInfo.async,
            }
          }
        }

        function addRSCIdMapping() {
          const exportName = resource
          const moduleInfo = pluginState.rscModules[rscNamedModuleId]

          if (moduleInfo) {
            rscIdMapping[modId] = rscIdMapping[modId] || {}
            rscIdMapping[modId]['*'] = {
              ...manifest.clientModules[exportName],
              // During SSR, we don't have external chunks to load on the server
              // side with our architecture of Webpack / Turbopack. We can keep
              // this field empty to save some bytes.
              chunks: [],
              id: moduleInfo.moduleId,
              async: moduleInfo.async,
            }
          }

          const edgeModuleInfo = pluginState.ssrModules[rscNamedModuleId]

          if (edgeModuleInfo) {
            edgeRscIdMapping[modId] = edgeRscIdMapping[modId] || {}
            edgeRscIdMapping[modId]['*'] = {
              ...manifest.clientModules[exportName],
              // During SSR, we don't have external chunks to load on the server
              // side with our architecture of Webpack / Turbopack. We can keep
              // this field empty to save some bytes.
              chunks: [],
              id: edgeModuleInfo.moduleId,
              async: edgeModuleInfo.async,
            }
          }
        }

        addClientReference()
        addSSRIdMapping()
        addRSCIdMapping()

        manifest.clientModules = moduleReferences
        manifest.ssrModuleMapping = moduleIdMapping
        manifest.edgeSSRModuleMapping = edgeModuleIdMapping
        manifest.rscModuleMapping = rscIdMapping
        manifest.edgeRscModuleMapping = edgeRscIdMapping
      }

      const checkedChunkGroups = new Set()
      const checkedChunks = new Set()

      function recordChunkGroup(chunkGroup: ChunkGroup) {
        // Ensure recursion is stopped if we've already checked this chunk group.
        if (checkedChunkGroups.has(chunkGroup)) return
        checkedChunkGroups.add(chunkGroup)
        // Only apply following logic to client module requests from client entry,
        // or if the module is marked as client module. That's because other
        // client modules don't need to be in the manifest at all as they're
        // never be referenced by the server/client boundary.
        // This saves a lot of bytes in the manifest.
        chunkGroup.chunks.forEach((chunk: webpack.Chunk) => {
          // Ensure recursion is stopped if we've already checked this chunk.
          if (checkedChunks.has(chunk)) return
          checkedChunks.add(chunk)
          const entryMods =
            compilation.chunkGraph.getChunkEntryModulesIterable(chunk)
          for (const mod of entryMods) {
            if (mod.layer !== WEBPACK_LAYERS.appPagesBrowser) continue

            const request = (mod as webpack.NormalModule).request

            if (
              !request ||
              !request.includes('next-flight-client-entry-loader.js?')
            ) {
              continue
            }

            const connections = getModuleReferencesInOrder(
              mod,
              compilation.moduleGraph
            )

            for (const connection of connections) {
              const dependency = connection.dependency
              if (!dependency) continue

              const clientEntryMod = compilation.moduleGraph.getResolvedModule(
                dependency
              ) as webpack.NormalModule
              const modId = compilation.chunkGraph.getModuleId(
                clientEntryMod
              ) as string | number | null

              if (modId !== null) {
                recordModule(modId, clientEntryMod)
              } else {
                // If this is a concatenation, register each child to the parent ID.
                if (
                  connection.module?.constructor.name === 'ConcatenatedModule'
                ) {
                  const concatenatedMod = connection.module
                  const concatenatedModId =
                    compilation.chunkGraph.getModuleId(concatenatedMod)
                  if (concatenatedModId) {
                    recordModule(concatenatedModId, clientEntryMod)
                  }
                }
              }
            }
          }
        })

        // Walk through all children chunk groups too.
        for (const child of chunkGroup.childrenIterable) {
          recordChunkGroup(child)
        }
      }

      recordChunkGroup(entrypoint)

      // A page's entry name can have extensions. For example, these are both valid:
      // - app/foo/page
      // - app/foo/page.page
      if (/\/page(\.[^/]+)?$/.test(entryName)) {
        manifestEntryFiles.push(entryName.replace(/\/page(\.[^/]+)?$/, '/page'))
      }

      // We also need to create manifests for route handler entrypoints to
      // enable `'use cache'`.
      if (/\/route$/.test(entryName)) {
        manifestEntryFiles.push(entryName)
      }

      const groupName = entryNameToGroupName(entryName)
      if (!manifestsPerGroup.has(groupName)) {
        manifestsPerGroup.set(groupName, [])
      }
      manifestsPerGroup.get(groupName)!.push(manifest)
    }

    // Generate per-page manifests.
    for (const pageName of manifestEntryFiles) {
      const mergedManifest: ClientReferenceManifest = {
        moduleLoading: {
          prefix,
          crossOrigin: crossOriginMode,
        },
        ssrModuleMapping: {},
        edgeSSRModuleMapping: {},
        clientModules: {},
        entryCSSFiles: {},
        rscModuleMapping: {},
        edgeRscModuleMapping: {},
      }

      const segments = [...entryNameToGroupName(pageName).split('/'), 'page']
      let group = ''
      for (const segment of segments) {
        for (const manifest of manifestsPerGroup.get(group) || []) {
          mergeManifest(mergedManifest, manifest)
        }
        group += (group ? '/' : '') + segment
      }

      const json = JSON.stringify(mergedManifest)

      const pagePath = pageName.replace(/%5F/g, '_')
      const pageBundlePath = normalizePagePath(pagePath.slice('app'.length))
      compilation.emitAsset(
        'server/app' + pageBundlePath + '_' + CLIENT_REFERENCE_MANIFEST + '.js',
        new sources.RawSource(
          `globalThis.__RSC_MANIFEST=(globalThis.__RSC_MANIFEST||{});globalThis.__RSC_MANIFEST[${JSON.stringify(
            pagePath.slice('app'.length)
          )}]=${json}`
        ) as unknown as webpack.sources.RawSource
      )
    }
  }
}