import generateETag from 'etag' import fresh from 'fresh' import consola from 'consola' import { getContext } from '../../common/utils' export default async function nuxtMiddleware(req, res, next) { // Get context const context = getContext(req, res) res.statusCode = 200 try { const result = await this.renderRoute(req.url, context) await this.nuxt.callHook('render:route', req.url, result, context) const { html, cspScriptSrcHashes, error, redirected, getPreloadFiles } = result if (redirected) { return html } if (error) { res.statusCode = context.nuxt.error.statusCode || 500 } // Add ETag header if (!error && this.options.render.etag) { const etag = generateETag(html, this.options.render.etag) if (fresh(req.headers, { etag })) { res.statusCode = 304 res.end() return } res.setHeader('ETag', etag) } // HTTP2 push headers for preload assets if (!error && this.options.render.http2.push) { // Parse resourceHints to extract HTTP.2 prefetch/push headers // https://w3c.github.io/preload/#server-push-http-2 const pushAssets = [] const preloadFiles = getPreloadFiles() const { shouldPush } = this.options.render.http2 const { publicPath } = this.resources.clientManifest preloadFiles.forEach(({ file, asType, fileWithoutQuery, extension }) => { // By default, we only preload scripts or css /* istanbul ignore if */ if (!shouldPush && asType !== 'script' && asType !== 'style') { return } // User wants to explicitly control what to preload if (shouldPush && !shouldPush(fileWithoutQuery, asType)) { return } pushAssets.push(`<${publicPath}${file}>; rel=preload; as=${asType}`) }) // Pass with single Link header // https://blog.cloudflare.com/http-2-server-push-with-multiple-assets-per-link-header // https://www.w3.org/Protocols/9707-link-header.html res.setHeader('Link', pushAssets.join(',')) } if (this.options.render.csp && this.options.render.csp.enabled) { const allowedSources = this.options.render.csp.allowedSources const policies = this.options.render.csp.policies let cspStr = `script-src 'self'${this.options.dev ? " 'unsafe-eval'" : ''} ${(cspScriptSrcHashes).join(' ')}` if (Array.isArray(allowedSources)) { // For compatible section cspStr += ' ' + allowedSources.join(' ') } else if (typeof policies === 'object' && policies !== null && !Array.isArray(policies)) { // Set default policy if necessary if (!policies['script-src'] || !Array.isArray(policies['script-src'])) { policies['script-src'] = [`'self'`].concat(cspScriptSrcHashes) } else { policies['script-src'] = cspScriptSrcHashes.concat(policies['script-src']) if (!policies['script-src'].includes(`'self'`)) { policies['script-src'] = [`'self'`].concat(policies['script-src']) } } // Make content-security-policy string let cspArr = [] Object.keys(policies).forEach((k) => { cspArr.push(`${k} ${policies[k].join(' ')}`) }) cspStr = cspArr.join('; ') } res.setHeader('Content-Security-Policy', cspStr) } // Send response res.setHeader('Content-Type', 'text/html; charset=utf-8') res.setHeader('Content-Length', Buffer.byteLength(html)) res.end(html, 'utf8') return html } catch (err) { /* istanbul ignore if */ if (context && context.redirected) { consola.error(err) return err } next(err) } }