Temporary: Add Support for Now Platform Headers (#9085)

packages/next/build/webpack/loaders/next-serverless-loader.ts

@@ -131,7 +131,17 @@ const nextServerlessLoader: loader.Loader = function() {
             ? `const params = fromExport && !unstable_getStaticProps ? {} : getRouteMatcher(getRouteRegex("${page}"))(parsedUrl.pathname) || {};`
             : `const params = {};`
         }
-        const result = await renderToHTML(req, res, "${page}", Object.assign({}, unstable_getStaticProps ? {} : parsedUrl.query, params, sprData ? { _nextSprData: '1' } : {}), renderOpts)
+        ${
+          // Temporary work around -- `x-now-route-params` is a platform header
+          // _only_ set for `Prerender` requests. We should move this logic
+          // into our builder to ensure we're decoupled. However, this entails
+          // removing reliance on `req.url` and using `req.query` instead
+          // (which is needed for "custom routes" anyway).
+          isDynamicRoute(page)
+            ? `const nowParams = (req.headers && req.headers["x-now-route-params"]) ? querystring.parse(req.headers["x-now-route-params"]) : null;`
+            : `const nowParams = null;`
+        }
+        const result = await renderToHTML(req, res, "${page}", Object.assign({}, unstable_getStaticProps ? {} : parsedUrl.query, nowParams ? nowParams : params, sprData ? { _nextSprData: '1' } : {}), renderOpts)
 
         if (fromExport) return { html: result, renderOpts }
         return result