HTTP/2 and What it Means for the Java EE Ecosystem

1. Others Talk, We Listen. HTTP/2 and What it Means for the Java EE Ecosystem Reza Rahman Senior Architect rrahman@captechconsulting.com @reza_rahman

2. CapTech Full-service US national IT consulting firm that focuses on client best interests, trust, servant leadership, culture, professionalism and technical excellence. #28 in Vault's Consulting Top 50 #3 Best Consulting Internship #9 Best Overall Internship #1 in Meeting Client’s Needs #7 Best Firm to Work For #1 in Career Development Ranked for the 7th Consecutive Year Copyright © 2015 CapTech Ventures, Inc. All rights reserved.

5. HTTP Pipelining/Head-of-Line Blocking Copyright © 2015 CapTech Ventures, Inc. All rights reserved. style1.css style2.css Client Server index.html index.html style1.css style2.css script1.js . . . script2.js . . . script1.js script2.js

8. HTTP/2 • HTTP/2 is new transport layer underneath HTTP/1.1 • Same request/response model • No new methods • No new headers • No new URLs or ports Copyright © 2015 CapTech Ventures, Inc. All rights reserved. At the Network Layer

12. HTTP/2 Big Ticket Features • Request/response multiplexing • Binary framing • Stream prioritization • Server push • Header compression • HTTP/2 upgrade • ALPN • 101 Switching Protocols Copyright © 2015 CapTech Ventures, Inc. All rights reserved.

14. HTTP/2 Request/Response Multiplexing Copyright © 2015 CapTech Ventures, Inc. All rights reserved. Browser ServerSingle TCP connection for HTTP 2 STREAM'4' HEADERS' STREAM'9' HEADERS' STREAM'7' DATA' STREAM'7' HEADERS' STREAM'2' HEADERS' STREAM'2' DATA'

18. HTTP/2 Upgrade from HTTP/1.1 • Not secure • Use port 80 • Use existing 101 Switching Protocols from HTTP/1.1 • Secure • Application Layer Protocol Negotiation (ALPN) Copyright © 2015 CapTech Ventures, Inc. All rights reserved.

21. Servlet 4 • Servlet well positioned to enable HTTP/2 • Low-level protocol changes absorbed transparently • Allow frameworks to effectively leverage server push Copyright © 2015 CapTech Ventures, Inc. All rights reserved.

22. Challenges Exposing HTTP/2 Features in Servlet • Existing API designed for one request == one response. • HTTP/2 destroys this assumption. • It will be challenging to do justice to the new reality of one request == one or more responses. Copyright © 2015 CapTech Ventures, Inc. All rights reserved.

23. HTTP/2 Features Exposed in Servlet • Request/response multiplexing • Binary framing • Stream prioritization • Server push • Header compression • HTTP/2 upgrade • ALPN • 101 Switching Protocols Copyright © 2015 CapTech Ventures, Inc. All rights reserved.

24. Servlet 4 New Features • HTTP/2 required • Server push • Push resource to client for a given URL and headers. • Really useful for frameworks that build on Servlet, such as JSF • Builder API Copyright © 2015 CapTech Ventures, Inc. All rights reserved.

27. Server Push in JSF Copyright © 2015 CapTech Ventures, Inc. All rights reserved. public class FacesServlet implements Servlet { public void service(ServletRequest req, ServletResponse resp) throws IOException, ServletException { //... HttpServletRequest request = (HttpServletRequest) req; try { ResourceHandler handler = context.getApplication().getResourceHandler(); if (handler.isResourceRequest(context)) { handler.handleResourceRequest(context); } else { lifecycle.attachWindow(context); lifecycle.execute(context); lifecycle.render(context); } } }

28. Server Push in JSF Copyright © 2015 CapTech Ventures, Inc. All rights reserved. public class ExternalContextImpl extends ExternalContext { //... public String encodeResourceURL(String url) { if (null == url) { String message = MessageUtils.getExceptionMessageString (MessageUtils.NULL_PARAMETERS_ERROR_MESSAGE_ID, "url"); throw new NullPointerException(message); } ((HttpServletRequest) request).getPushBuilder().path(url).push(); return ((HttpServletResponse) response).encodeURL(url); } //... }