worker.ts

import url from 'url'
import { extname, join, dirname, sep } from 'path'
import { renderToHTML } from '../next-server/server/render'
import { promises } from 'fs'
import AmpHtmlValidator from 'next/dist/compiled/amphtml-validator'
import { loadComponents } from '../next-server/server/load-components'
import { isDynamicRoute } from '../next-server/lib/router/utils/is-dynamic'
import { getRouteMatcher } from '../next-server/lib/router/utils/route-matcher'
import { getRouteRegex } from '../next-server/lib/router/utils/route-regex'
import { normalizePagePath } from '../next-server/server/normalize-page-path'
import { SERVER_PROPS_EXPORT_ERROR } from '../lib/constants'
import 'next/dist/next-server/server/node-polyfill-fetch'
import { IncomingMessage, ServerResponse } from 'http'
import { ComponentType } from 'react'
import { GetStaticProps } from '../types'
import { requireFontManifest } from '../next-server/server/require'
import { FontManifest } from '../next-server/server/font-utils'
import { normalizeLocalePath } from '../next-server/lib/i18n/normalize-locale-path'

const envConfig = require('../next-server/lib/runtime-config')

;(global as any).__NEXT_DATA__ = {
  nextExport: true,
}

interface AmpValidation {
  page: string
  result: {
    errors: AmpHtmlValidator.ValidationError[]
    warnings: AmpHtmlValidator.ValidationError[]
  }
}

interface PathMap {
  page: string
  query?: { [key: string]: string | string[] }
}

interface ExportPageInput {
  path: string
  pathMap: PathMap
  distDir: string
  outDir: string
  pagesDataDir: string
  renderOpts: RenderOpts
  buildExport?: boolean
  serverRuntimeConfig: string
  subFolders: string
  serverless: boolean
  optimizeFonts: boolean
  optimizeImages: boolean
}

interface ExportPageResults {
  ampValidations: AmpValidation[]
  fromBuildExportRevalidate?: number
  error?: boolean
  ssgNotFound?: boolean
}

interface RenderOpts {
  runtimeConfig?: { [key: string]: any }
  params?: { [key: string]: string | string[] }
  ampPath?: string
  ampValidatorPath?: string
  ampSkipValidation?: boolean
  hybridAmp?: boolean
  inAmpMode?: boolean
  optimizeFonts?: boolean
  optimizeImages?: boolean
  fontManifest?: FontManifest
  locales?: string[]
  locale?: string
  defaultLocale?: string
}

type ComponentModule = ComponentType<{}> & {
  renderReqToHTML: typeof renderToHTML
  getStaticProps?: GetStaticProps
}

export default async function exportPage({
  path,
  pathMap,
  distDir,
  outDir,
  pagesDataDir,
  renderOpts,
  buildExport,
  serverRuntimeConfig,
  subFolders,
  serverless,
  optimizeFonts,
  optimizeImages,
}: ExportPageInput): Promise<ExportPageResults> {
  let results: ExportPageResults = {
    ampValidations: [],
  }

  try {
    const { query: originalQuery = {} } = pathMap
    const { page } = pathMap
    const filePath = normalizePagePath(path)
    const isDynamic = isDynamicRoute(page)
    const ampPath = `${filePath}.amp`
    let renderAmpPath = ampPath
    let query = { ...originalQuery }
    let params: { [key: string]: string | string[] } | undefined

    let updatedPath = path
    let locale = query.__nextLocale || renderOpts.locale
    delete query.__nextLocale

    if (renderOpts.locale) {
      const localePathResult = normalizeLocalePath(path, renderOpts.locales)

      if (localePathResult.detectedLocale) {
        updatedPath = localePathResult.pathname
        locale = localePathResult.detectedLocale

        if (locale === renderOpts.defaultLocale) {
          renderAmpPath = `${normalizePagePath(updatedPath)}.amp`
        }
      }
    }

    // We need to show a warning if they try to provide query values
    // for an auto-exported page since they won't be available
    const hasOrigQueryValues = Object.keys(originalQuery).length > 0
    const queryWithAutoExportWarn = () => {
      if (hasOrigQueryValues) {
        throw new Error(
          `\nError: you provided query values for ${path} which is an auto-exported page. These can not be applied since the page can no longer be re-rendered on the server. To disable auto-export for this page add \`getInitialProps\`\n`
        )
      }
    }

    // Check if the page is a specified dynamic route
    if (isDynamic && page !== path) {
      params = getRouteMatcher(getRouteRegex(page))(updatedPath) || undefined
      if (params) {
        // we have to pass these separately for serverless
        if (!serverless) {
          query = {
            ...query,
            ...params,
          }
        }
      } else {
        throw new Error(
          `The provided export path '${updatedPath}' doesn't match the '${page}' page.\nRead more: https://err.sh/vercel/next.js/export-path-mismatch`
        )
      }
    }

    const headerMocks = {
      headers: {},
      getHeader: () => ({}),
      setHeader: () => {},
      hasHeader: () => false,
      removeHeader: () => {},
      getHeaderNames: () => [],
    }

    const req = ({
      url: updatedPath,
      ...headerMocks,
    } as unknown) as IncomingMessage
    const res = ({
      ...headerMocks,
    } as unknown) as ServerResponse

    envConfig.setConfig({
      serverRuntimeConfig,
      publicRuntimeConfig: renderOpts.runtimeConfig,
    })

    let htmlFilename = `${filePath}${sep}index.html`
    if (!subFolders) htmlFilename = `${filePath}.html`

    const pageExt = extname(page)
    const pathExt = extname(path)
    // Make sure page isn't a folder with a dot in the name e.g. `v1.2`
    if (pageExt !== pathExt && pathExt !== '') {
      // If the path has an extension, use that as the filename instead
      htmlFilename = path
    } else if (path === '/') {
      // If the path is the root, just use index.html
      htmlFilename = 'index.html'
    }

    const baseDir = join(outDir, dirname(htmlFilename))
    let htmlFilepath = join(outDir, htmlFilename)

    await promises.mkdir(baseDir, { recursive: true })
    let html
    let curRenderOpts: RenderOpts = {}
    let renderMethod = renderToHTML

    const renderedDuringBuild = (getStaticProps: any) => {
      return !buildExport && getStaticProps && !isDynamicRoute(path)
    }

    if (serverless) {
      const curUrl = url.parse(req.url!, true)
      req.url = url.format({
        ...curUrl,
        query: {
          ...curUrl.query,
          ...query,
        },
      })
      const { Component: mod, getServerSideProps } = await loadComponents(
        distDir,
        page,
        serverless
      )

      if (getServerSideProps) {
        throw new Error(`Error for page ${page}: ${SERVER_PROPS_EXPORT_ERROR}`)
      }

      // if it was auto-exported the HTML is loaded here
      if (typeof mod === 'string') {
        html = mod
        queryWithAutoExportWarn()
      } else {
        // for non-dynamic SSG pages we should have already
        // prerendered the file
        if (renderedDuringBuild((mod as ComponentModule).getStaticProps))
          return results

        if (
          (mod as ComponentModule).getStaticProps &&
          !htmlFilepath.endsWith('.html')
        ) {
          // make sure it ends with .html if the name contains a dot
          htmlFilename += '.html'
          htmlFilepath += '.html'
        }

        renderMethod = (mod as ComponentModule).renderReqToHTML
        const result = await renderMethod(
          req,
          res,
          'export',
          {
            ampPath: renderAmpPath,
            /// @ts-ignore
            optimizeFonts,
            /// @ts-ignore
            optimizeImages,
            fontManifest: optimizeFonts
              ? requireFontManifest(distDir, serverless)
              : null,
            locale: locale!,
            locales: renderOpts.locales!,
          },
          // @ts-ignore
          params
        )
        curRenderOpts = (result as any).renderOpts || {}
        html = (result as any).html
      }

      if (!html && !(curRenderOpts as any).ssgNotFound) {
        throw new Error(`Failed to render serverless page`)
      }
    } else {
      const components = await loadComponents(distDir, page, serverless)

      if (components.getServerSideProps) {
        throw new Error(`Error for page ${page}: ${SERVER_PROPS_EXPORT_ERROR}`)
      }

      // for non-dynamic SSG pages we should have already
      // prerendered the file
      if (renderedDuringBuild(components.getStaticProps)) {
        return results
      }

      // TODO: de-dupe the logic here between serverless and server mode
      if (components.getStaticProps && !htmlFilepath.endsWith('.html')) {
        // make sure it ends with .html if the name contains a dot
        htmlFilepath += '.html'
        htmlFilename += '.html'
      }

      if (typeof components.Component === 'string') {
        html = components.Component
        queryWithAutoExportWarn()
      } else {
        /**
         * This sets environment variable to be used at the time of static export by head.tsx.
         * Using this from process.env allows targetting both serverless and SSR by calling
         * `process.env.__NEXT_OPTIMIZE_FONTS`.
         * TODO(prateekbh@): Remove this when experimental.optimizeFonts are being clened up.
         */
        if (optimizeFonts) {
          process.env.__NEXT_OPTIMIZE_FONTS = JSON.stringify(true)
        }
        if (optimizeImages) {
          process.env.__NEXT_OPTIMIZE_IMAGES = JSON.stringify(true)
        }
        curRenderOpts = {
          ...components,
          ...renderOpts,
          ampPath: renderAmpPath,
          params,
          optimizeFonts,
          optimizeImages,
          fontManifest: optimizeFonts
            ? requireFontManifest(distDir, serverless)
            : null,
          locale: locale as string,
        }
        // @ts-ignore
        html = await renderMethod(req, res, page, query, curRenderOpts)
      }
    }
    results.ssgNotFound = (curRenderOpts as any).ssgNotFound

    const validateAmp = async (
      rawAmpHtml: string,
      ampPageName: string,
      validatorPath?: string
    ) => {
      const validator = await AmpHtmlValidator.getInstance(validatorPath)
      const result = validator.validateString(rawAmpHtml)
      const errors = result.errors.filter((e) => e.severity === 'ERROR')
      const warnings = result.errors.filter((e) => e.severity !== 'ERROR')

      if (warnings.length || errors.length) {
        results.ampValidations.push({
          page: ampPageName,
          result: {
            errors,
            warnings,
          },
        })
      }
    }

    if (curRenderOpts.inAmpMode && !curRenderOpts.ampSkipValidation) {
      if (!results.ssgNotFound) {
        await validateAmp(html, path, curRenderOpts.ampValidatorPath)
      }
    } else if (curRenderOpts.hybridAmp) {
      // we need to render the AMP version
      let ampHtmlFilename = `${ampPath}${sep}index.html`
      if (!subFolders) {
        ampHtmlFilename = `${ampPath}.html`
      }
      const ampBaseDir = join(outDir, dirname(ampHtmlFilename))
      const ampHtmlFilepath = join(outDir, ampHtmlFilename)

      try {
        await promises.access(ampHtmlFilepath)
      } catch (_) {
        // make sure it doesn't exist from manual mapping
        let ampHtml
        if (serverless) {
          req.url += (req.url!.includes('?') ? '&' : '?') + 'amp=1'
          // @ts-ignore
          ampHtml = (
            await (renderMethod as any)(
              req,
              res,
              'export',
              curRenderOpts,
              params
            )
          ).html
        } else {
          ampHtml = await renderMethod(
            req,
            res,
            page,
            // @ts-ignore
            { ...query, amp: '1' },
            curRenderOpts as any
          )
        }

        if (!curRenderOpts.ampSkipValidation) {
          await validateAmp(ampHtml, page + '?amp=1')
        }
        await promises.mkdir(ampBaseDir, { recursive: true })
        await promises.writeFile(ampHtmlFilepath, ampHtml, 'utf8')
      }
    }

    if ((curRenderOpts as any).pageData) {
      const dataFile = join(
        pagesDataDir,
        htmlFilename.replace(/\.html$/, '.json')
      )

      await promises.mkdir(dirname(dataFile), { recursive: true })
      await promises.writeFile(
        dataFile,
        JSON.stringify((curRenderOpts as any).pageData),
        'utf8'
      )

      if (curRenderOpts.hybridAmp) {
        await promises.writeFile(
          dataFile.replace(/\.json$/, '.amp.json'),
          JSON.stringify((curRenderOpts as any).pageData),
          'utf8'
        )
      }
    }
    results.fromBuildExportRevalidate = (curRenderOpts as any).revalidate

    if (results.ssgNotFound) {
      // don't attempt writing to disk if getStaticProps returned not found
      return results
    }
    await promises.writeFile(htmlFilepath, html, 'utf8')
    return results
  } catch (error) {
    console.error(
      `\nError occurred prerendering page "${path}". Read more: https://err.sh/next.js/prerender-error\n` +
        error.stack
    )
    return { ...results, error: true }
  }
}