Adding host header to requests.

server/page-renderer.js

@@ -5,6 +5,7 @@ const CrossFetch = require('cross-fetch');
 const FrontEnd = require('./client/front-end');
 
 const NGINX_HOST = process.env.NGINX_HOST;
+const EXTERNAL_HOST = process.env.EXTERNAL_HOST;
 const CACHE_SIZE = 500;
 const HTML_TEMPLATE = `${__dirname}/client/index.html`;
 
@@ -17,6 +18,7 @@ async function generate(path, target) {
     let fetch = (url, options) => {
         if (url.startsWith(host)) {
             sourceURLs.push(url.substr(host.length));
+            options = addHostHeader(options);
         }
         return CrossFetch(url, options);
     };
@@ -36,9 +38,21 @@ async function generate(path, target) {
 async function prefetch(path) {
     console.log(`Regenerating page: ${path}`);
     let url = NGINX_HOST + path;
+    let options = addHostHeader({});
     return CrossFetch(url);
 }
 
+function addHostHeader(options) {
+    if (EXTERNAL_HOST) {
+        let [ protocol, domain ] = EXTERNAL_HOST.split('://');
+        let port = (protocol === 'https') ? 443 : 80;
+        let host = domain + ':' + port;
+        options = Object.assign({}, options);
+        options.headers = Object.assign({ Host: host }, options.headers);
+    }
+    return options;
+}
+
 module.exports = {
     generate,
     prefetch,