Function renderPage

middleware/render-page.js:35–127

(req, res)

}

export default async function renderPage(req, res) {
  const { context } = req

  // This is a contextualizing the request so that when this `req` is
  // ultimately passed into the `Error.getInitialProps` function,
  // which NextJS executes at runtime on errors, so that we can
  // from there send the error to Failbot.
  req.FailBot = FailBot

  const { page } = context
  const path = req.pagePath || req.path

  // render a 404 page
  if (!page) {
    if (process.env.NODE_ENV !== 'test' && context.redirectNotFound) {
      console.error(
        `\nTried to redirect to ${context.redirectNotFound}, but that page was not found.\n`
      )
    }
    return nextApp.render404(req, res)
  }

  // Just finish fast without all the details like Content-Length
  if (req.method === 'HEAD') {
    return res.status(200).send('')
  }

  // Updating the Last-Modified header for substantive changes on a page for engineering
  // Docs Engineering Issue #945
  if (page.effectiveDate) {
    // Note that if a page has an invalidate `effectiveDate` string value,
    // it would be caught prior to this usage and ultimately lead to
    // 500 error.
    res.setHeader('Last-Modified', new Date(page.effectiveDate).toUTCString())
  }

  // collect URLs for variants of this page in all languages
  page.languageVariants = Page.getLanguageVariants(path)

  // Stop processing if the connection was already dropped
  if (isConnectionDropped(req, res)) return

  req.context.renderedPage = await buildRenderedPage(req)
  req.context.miniTocItems = await buildMiniTocItems(req)

  // Stop processing if the connection was already dropped
  if (isConnectionDropped(req, res)) return

  // Create string for <title> tag
  page.fullTitle = page.title

  // add localized ` - GitHub Docs` suffix to <title> tag (except for the homepage)
  if (!patterns.homepagePath.test(path)) {
    if (
      req.context.currentVersion === 'free-pro-team@latest' ||
      !allVersions[req.context.currentVersion]
    ) {
      page.fullTitle += ' - ' + context.site.data.ui.header.github_docs