import { join } from 'path' import { createElement } from 'react' import { renderToString, renderToStaticMarkup } from 'react-dom/server' import send from 'send' import generateETag from 'etag' import fresh from 'fresh' import requireModule from './require' import getConfig from './config' import resolvePath from './resolve' import { Router } from '../lib/router' import { loadGetInitialProps } from '../lib/utils' import Head, { defaultHead } from '../lib/head' import App from '../lib/app' import ErrorDebug from '../lib/error-debug' export async function render (req, res, pathname, query, opts) { const html = await renderToHTML(req, res, pathname, opts) sendHTML(req, res, html, req.method, opts) } export function renderToHTML (req, res, pathname, query, opts) { return doRender(req, res, pathname, query, opts) } export async function renderError (err, req, res, pathname, query, opts) { const html = await renderErrorToHTML(err, req, res, query, opts) sendHTML(req, res, html, req.method, opts) } export function renderErrorToHTML (err, req, res, pathname, query, opts = {}) { return doRender(req, res, pathname, query, { ...opts, err, page: '_error' }) } async function doRender (req, res, pathname, query, { err, page, buildId, buildStats, hotReloader, assetPrefix, dir = process.cwd(), dev = false, staticMarkup = false } = {}) { page = page || pathname await ensurePage(page, { dir, hotReloader }) const dist = getConfig(dir).distDir let [Component, Document] = await Promise.all([ requireModule(join(dir, dist, 'dist', 'pages', page)), requireModule(join(dir, dist, 'dist', 'pages', '_document')) ]) Component = Component.default || Component Document = Document.default || Document const asPath = req.url const ctx = { err, req, res, pathname, query, asPath } const props = await loadGetInitialProps(Component, ctx) // the response might be finshed on the getinitialprops call if (res.finished) return const renderPage = () => { const app = createElement(App, { Component, props, router: new Router(pathname, query) }) const render = staticMarkup ? renderToStaticMarkup : renderToString let html let head let errorHtml = '' try { html = render(app) } finally { head = Head.rewind() || defaultHead() } if (err && dev) { errorHtml = render(createElement(ErrorDebug, { error: err })) } return { html, head, errorHtml } } const docProps = await loadGetInitialProps(Document, { ...ctx, renderPage }) // While developing, we should not cache any assets. // So, we use a different buildId for each page load. // With that we can ensure, we have unique URL for assets per every page load. // So, it'll prevent issues like this: https://git.io/vHLtb const devBuildId = Date.now() if (res.finished) return if (!Document.prototype || !Document.prototype.isReactComponent) throw new Error('_document.js is not exporting a React element') const doc = createElement(Document, { __NEXT_DATA__: { props, pathname, query, buildId: dev ? devBuildId : buildId, buildStats, assetPrefix, err: (err) ? serializeError(dev, err) : null }, dev, staticMarkup, ...docProps }) return '' + renderToStaticMarkup(doc) } export async function renderScript (req, res, page, opts) { try { const dist = getConfig(opts.dir).distDir const path = join(opts.dir, dist, 'bundles', 'pages', page) const realPath = await resolvePath(path) await serveStatic(req, res, realPath) } catch (err) { if (err.code === 'ENOENT') { renderScriptError(req, res, page, err, {}, opts) return } throw err } } export async function renderScriptError (req, res, page, error, customFields, opts) { // Asks CDNs and others to not to cache the errored page res.setHeader('Cache-Control', 'no-store, must-revalidate') if (error.code === 'ENOENT') { res.setHeader('Content-Type', 'text/javascript') res.end(` window.__NEXT_REGISTER_PAGE('${page}', function() { var error = new Error('Page does not exist: ${page}') error.statusCode = 404 return { error: error } }) `) return } res.setHeader('Content-Type', 'text/javascript') const errorJson = { ...errorToJSON(error), ...customFields } res.end(` window.__NEXT_REGISTER_PAGE('${page}', function() { var error = ${JSON.stringify(errorJson)} return { error: error } }) `) } export function sendHTML (req, res, html, method, { dev }) { if (res.finished) return const etag = generateETag(html) if (fresh(req.headers, { etag })) { res.statusCode = 304 res.end() return } if (dev) { // In dev, we should not cache pages for any reason. // That's why we do this. res.setHeader('Cache-Control', 'no-store, must-revalidate') } res.setHeader('ETag', etag) res.setHeader('Content-Type', 'text/html') res.setHeader('Content-Length', Buffer.byteLength(html)) res.end(method === 'HEAD' ? null : html) } export function sendJSON (res, obj, method) { if (res.finished) return const json = JSON.stringify(obj) res.setHeader('Content-Type', 'application/json') res.setHeader('Content-Length', Buffer.byteLength(json)) res.end(method === 'HEAD' ? null : json) } function errorToJSON (err) { const { name, message, stack } = err const json = { name, message, stack } if (err.module) { // rawRequest contains the filename of the module which has the error. const { rawRequest } = err.module json.module = { rawRequest } } return json } function serializeError (dev, err) { if (dev) { return errorToJSON(err) } return { message: '500 - Internal Server Error.' } } export function serveStatic (req, res, path) { return new Promise((resolve, reject) => { send(req, path) .on('directory', () => { // We don't allow directories to be read. const err = new Error('No directory access') err.code = 'ENOENT' reject(err) }) .on('error', reject) .pipe(res) .on('finish', resolve) }) } async function ensurePage (page, { dir, hotReloader }) { if (!hotReloader) return if (page === '_error' || page === '_document') return await hotReloader.ensurePage(page) }