Allow HTTP server customization

Author: vlascik

README.md

@@ -71,6 +71,38 @@ The app server will automatically spawn a new worker if one dies while
 handling a request. When a new application deploy is detected, workers
 will automatically reload with the newest version.
 
+## Custom HTTP Server
+You can customize HTTP server (add middlewares, subdomains, etc.), either directly:
+```js
+// start.js
+const httpServer = new ExpressHTTPServer(/* {options} */);
+const app = httpServer.app;
+app.use('/api', apiRoutes);
+let server = new FastBootAppServer({
+  httpServer: httpServer
+});
+
+server.start();
+```
+or extend the provided HTTP server and override any methods you need:
+```js
+// my-custom-express-server.js
+const ExpressHTTPServer = require('fastboot-app-server/lib/express-http-server');
+class MyCustomExpressServer extends ExpressHTTPServer {
+  serve(middleware) {
+    // put your custom code here, don't forget to add fastboot etc.
+  }
+}
+// start.js
+const MyCustomExpressServer = require('./my-custom-express-server');
+const httpServer = new MyCustomExpressServer(/* {options} */);
+let server = new FastBootAppServer({
+  httpServer: httpServer
+});
+
+server.start();
+``` 
+
 ## Downloaders
 
 You can point the app server at a static path that you manage, but that

src/fastboot-app-server.js

@@ -16,7 +16,8 @@ class FastBootAppServer {
     this.cache = options.cache;
     this.ui = options.ui;
     this.gzip = options.gzip || false;
-    
+    this.httpServer = options.httpServer;
+
     if (!this.ui) {
       let UI = require('./ui');
       this.ui = new UI();
@@ -30,6 +31,7 @@ class FastBootAppServer {
         distPath: this.distPath || process.env.FASTBOOT_DIST_PATH,
         cache: this.cache,
         gzip: this.gzip
+        httpServer: this.httpServer,
       });
 
       this.worker.start();
@@ -67,6 +69,7 @@ class FastBootAppServer {
     if (this.downloader) { this.downloader.ui = this.ui; }
     if (this.notifier) { this.notifier.ui = this.ui; }
     if (this.cache) { this.cache.ui = this.ui; }
+    if (this.httpServer) { this.httpServer.ui = this.ui; }
   }
 
   initializeApp() {

src/worker.js

@@ -19,6 +19,10 @@ class Worker {
         cache: this.cache
       });
     }
+
+    if (!this.httpServer.cache) { this.httpServer.cache = this.cache; }
+    if (!this.httpServer.distPath) { this.httpServer.distPath = this.distPath; }
+    if (!this.httpServer.ui) { this.httpServer.ui = this.ui; }    
   }
 
   start() {