Web protocols for java developers
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The document outlines the evolution of web protocols, specifically focusing on HTTP, REST, and WebSockets, detailing their history and key features. It explains the differences between these protocols and their use cases, emphasizing how they complement each other within web development. Additionally, it discusses Java APIs related to REST and WebSocket, as well as future improvements in web communication technologies.
Web protocols for java developers
- 6. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | EvoluLon – HTTP • HTTP V0.9 (1991) – First version proposed by Tim Berners-Lee from CERN – Only GET method, server returned HTML – W3C standard – Fun to read, whole standard is a single page hbps://www.w3.org/Protocols/HTTP/AsImplemented.html • Dave Raggeb – leader of the HTTP Working Group – expanding protocol with more operaLons, meta-informaLon, security, .. • HTTP V1.0 introduced in 1995 – RFC 1945 Hypertext Transfer Protocol 6
- 7. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | EvoluLon – HTTP • HTTP Working Group published HTTP/1.1 as “pre-standard” • Rapid adopLon by servers and browsers – (Arena, Netscape, Mosaic, Lynx, Internet Explorer) • HTTP/1.1 finalized in 1997 (RFC 2068), improved in 1999 (RFC 2616) • 2007 - HTTPbis Working group formed to revise and clarify the spec – RFC 7230 – Message Syntax and RouLng, 7231 – SemanLcs and Content, 7232 – CondiLonal Requests, 7233 – Range Requests, 7234 - Caching, 7235 – AuthenLcaLon • HTTP/2 – May 2015 – RFC 7540 Hypertext Transfer Protocol 7
- 9. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | EvoluLon – REST • Basic sovware architecture / scheme • Exposes Resources (URIs), which handle METHODs – GET/PUT/POST/DELETE/HEAD/OPTIONS/TRACE/PATCH/… • MediaType (Accept/Content-Type) – text/plain, text/html, applicaLon/json, … • Caching (GET, HEAD), Hyperlinking, … Representa@onal State Transfer 9
- 11. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | Java API for RESTful Web Services (JAX-RS) • JSR 311 – JAX-RS 1.1 – Java EE 6 – Server side REST Resources – @Path, @GET, @POST, @Produces, @Consumes, @QueryParam, @Context, … • JSR 399 – JAX-RS 2.0 – Java EE 7 – Client API, Filters and Interceptors, Async processing, integraLon with other EE specs • JAX-RS 2.1 – Java EE 8 – Non-blocking IO, ReacLve Client API, Server Sent Events, …
- 15. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | EvoluLon – SSE • Channel for sending events from the server to the client • Very similar to long polling • Accept: text/event-stream • Semi-permanent connecLon • Limited browser support (no IE, no Android) • Java EE 8+ J – Included in JAX-RS 2.1 Server Sent Events 15
- 21. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | EvoluLon – WebSocket • RFC 6455 (December 2011) • Bi-direcLonal communicaLon • Uses HTTP/1.1 for iniLal handshake – Completely different protocol averwards • “Server” and “client” endpoints are equal aver handshake • Text or binary payload • Supported in all modern browsers 21
- 23. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | WebSocket usecases • RFC 7118 – SIP over WebSocket • RFC 7355 – SIP & CLF (Common Log Format) over WebSocket • RFC 7395 – XMPP over WebSocket • Dravs – MSRP (Message Session Relay Protocol) over WebSocket – SDP (Session DescripLon Protocol) over WebSocket – Remote Framebuffer Protocol over WebSocket – <anything> over WebSocket Subprotocols 23
- 24. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | Java API for WebSocket • JSR 356 – Part of Java EE 7 – 1.0 (May 2013) – 1.1 (August 2014) • Annotated and programmaLc way how to deploy and access WebSocket endpoints • Event-driven model - @OnOpen, @OnMessage, @OnError, @OnClose • Encoders/Decoders, Path/Query parameter handling, Handshake headers interceptors, CDI integraLon, …
- 27. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | WebSocket vs REST • Might seem to be similar and some people even think about WebSocket as about another “RevoluLon” – like SOAP --> REST • In reality, these are two different concepts which COMPLEMENT each other. • REST makes more sense for standard web pages, forms, … • WebSocket provides bi-direcLonal channel, suitable for exchanging “short” messages with the browser. – (the scope is not limited, you can re-implement all your communicaLon with server, but there is no point in doing that..) 27
- 28. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | EvoluLon – HTTP/2 • Same semanLcs as HTTP/1.1 • Binary protocol • MulLplexed communicaLon – Single TCP connecLon to single origin, shared for consequent/parallel requests • Compressed headers – HTTP/2 introduces HPACK (compression algorithm) • Server Push – Server can push (cacheable) content to the client before client asks HTTP/2 Key Features 28
- 30. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | WebSocket vs HTTP/2 • Pushed resources are cached on client side • When client decides it needs something (image, ..), it looks into the cache – Doesn’t need to be image, but all cool demos are using that (remember SPDY) • Server push has its own issues – What if client does not need pushed resource? (there might be other caches, …) – Client need to explicitly state that it accepts Server push • Push is not an interac@ve message exchange WebSocket vs Server push 30
- 32. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | WebSocket and HTTP/2 Standards.. 32 • Currently, WebSocket is not defined in HTTP/2 world • WebSocket uses UPGRADE header, which gives complete control over TCP connecLon • HTTP/2 Streams could support WS mulLplex
- 33. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | 33 Usecases HTTP SSE WebSockets Chat Sta@c pages Forms Games Remote control Monitoring Messaging / No@fica@on X over WS Tracking progress Images, … REST
- 36. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | Next Steps • Take the survey – hbp://glassfish.org/survey • Send technical comments to – [email protected] • Join the JCP – come to Hackergarden in Java Hub – hbps://jcp.org/en/parLcipaLon/membership_drive • Join or track the JSRs as they progress – hbps://java.net/projects/javaee-spec/pages/SpecificaLons • Adopt-a-JSR – hbps://community.oracle.com/community/java/jcp/adopt-a-jsr Give us your feedback 36
- 37. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | Where to Learn More at JavaOne 37 Session Number Session Title Day / Time CON1558 What's New in the Java API for JSON Binding Monday 5:30 p.m BOF7984 Java EE for the Cloud Monday 7:00 p.m CON4022 CDI 2.0 Is Coming Tuesday 11:00 a.m CON7983 JAX-RS 2.1 for Java EE 8 Tuesday 12:30 p.m CON7980 Servlet 4.0: Status Update and HTTP/2 Tuesday 4:00 p.m CON7978 Security for Java EE 8 and the Cloud Tuesday 5:30 p.m CON7979 ConfiguraLon for Java EE 8 and the Cloud Wednesday 11:30 a.m CON7977 Java EE Next – HTTP/2 and REST Wednesday 1:00 p.m CON6077 The Illusion of Statelessness Wednesday 4:30 p.m CON 7981 JSF 2.3 Thursday 11:30 a.m
- 38. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | Contacts/QA • Pavel Bucek ([email protected]) • Jersey / JAX-RS RI : hbp://jersey.java.net – [email protected] • Tyrus / WebSocket RI : hbp://tyrus.java.net – [email protected] Feel free to ask any quesLons now or contact me later. 38
- 41. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | WebSocket and Clustering • Different to “classic” cluster – We’d like to talk to other sessions (clients) directly • Clustered environment present different challenges – “Finding a WebSocket Session” might not be as trivial as it seem • Broadcast (mass-noLficaLon) is common usecase • Clustering can help – BroadcasLng to “all sessions” can be faster in clustered environment 41
- 46. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | WebSocket and Clustering • Different requirements • Load balancers might need to manage more open connecLons • Cannot re-balance when session is already created – Node is added – ok, but I cannot easily decrease load on other nodes, I can use the new node only for new connecLons • Node going down is not transparent to client – Robust clients can hide this, but for now, this requires custom soluLon – WLS 12.2.1 offers a soluLon for this.. 46
- 49. Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | WebSocket and Clustering • Might require more applicaLon code – Proper handling on client side – Even more code when you want to have something like auto reconnect + “session recovery” • Infrastructure requirements – Similar to SSL (persistent connecLon, …) • Much more effecLve when compared to the same app implemented using long-polling 49