web protocols for java developers

Copyright©2016,Oracleand/oritsaffiliates.Allrightsreserved.|

WebprotocolsforJavaDevelopers

PavelBucekOracleSeptember,2016

CON4156


SafeHarborStatementTheprecedingisintendedtooutlineourgeneralproductdirecLon.ItisintendedforinformaLonpurposesonly,andmaynotbeincorporatedintoanycontract.Itisnotacommitmenttodeliveranymaterial,code,orfuncLonality,andshouldnotberelieduponinmakingpurchasingdecisions.Thedevelopment,release,andLmingofanyfeaturesorfuncLonalitydescribedforOracle’sproductsremainsatthesolediscreLonofOracle.

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ProgramAgenda

EvoluLon–HTTPandrestREST

Polling,LongPolling

SSE,WebSocket

HTTP/2

Demo,Q&A

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EvoluLon–HTTP

• HTTPV0.9(1991)– FirstversionproposedbyTimBerners-LeefromCERN– OnlyGETmethod,serverreturnedHTML– W3Cstandard– Funtoread,wholestandardisasinglepagehbps://www.w3.org/Protocols/HTTP/AsImplemented.html

• DaveRaggeb–leaderoftheHTTPWorkingGroup–expandingprotocolwithmoreoperaLons,meta-informaLon,security,..• HTTPV1.0introducedin1995–RFC1945

HypertextTransferProtocol

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EvoluLon–HTTP

• HTTPWorkingGrouppublishedHTTP/1.1as“pre-standard”• RapidadopLonbyserversandbrowsers– (Arena,Netscape,Mosaic,Lynx,InternetExplorer)

• HTTP/1.1finalizedin1997(RFC2068),improvedin1999(RFC2616)•  2007-HTTPbisWorkinggroupformedtoreviseandclarifythespec– RFC7230–MessageSyntaxandRouLng,7231–SemanLcsandContent,7232–CondiLonalRequests,7233–RangeRequests,7234-Caching,7235–AuthenLcaLon

• HTTP/2–May2015–RFC7540


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REQUESTGET/en/HTTP/1.1Host:www.java.comUser-Agent:curl/7.43.0Accept:*/*<CR><LF><CR><LF>

RESPONSEHTTP/1.1200OKServer:Oracle-ApplicaLon-Server-11gLast-Modified:Thu,31Mar201622:48:16GMTdevice_type:Anyhost_service:FutureTenseContentServer:11.1.1.8.0X-Powered-By:Servlet/2.5JSP/2.1Content-Type:text/html;charset=UTF-8Content-Language:enX-Frame-OpLons:SAMEORIGINContent-Length:7516Date:Mon,05Sep201620:22:35GMTConnecLon:keep-aliveVary:User-Agent...Content<CR><LF><CR><LF>


EvoluLon–REST

• Basicsovwarearchitecture/scheme•  ExposesResources(URIs),whichhandleMETHODs– GET/PUT/POST/DELETE/HEAD/OPTIONS/TRACE/PATCH/…

• MediaType(Accept/Content-Type)– text/plain,text/html,applicaLon/json,…

• Caching(GET,HEAD),Hyperlinking,…

Representa@onalStateTransfer

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EvoluLon–RESTRepresenta@onalStateTransfer

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Client Server

GET/helloHTTP/1.1Header:value…

HTTP/1.1200OKHeader:value…<enLty>


JavaAPIforRESTfulWebServices(JAX-RS)

•  JSR311–JAX-RS1.1–JavaEE6– ServersideRESTResources– @Path,@GET,@POST,@Produces,@Consumes,@QueryParam,@Context,…

•  JSR399–JAX-RS2.0–JavaEE7– ClientAPI,FiltersandInterceptors,Asyncprocessing,integraLonwithotherEEspecs

•  JAX-RS2.1–JavaEE8– Non-blockingIO,ReacLveClientAPI,ServerSentEvents,…


EvoluLon–RESTJavaAPI–JAX-RS

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EvoluLon–Polling

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Client Server


HTTP/1.1200OKHeader:value…<enLty>


EvoluLon–Long-Polling

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Client Server


HTTP/1.1200OKHeader:value…<enLty-CHUNK>

<enLty-CHUNK>


EvoluLon–SSE

• Channelforsendingeventsfromtheservertotheclient• Verysimilartolongpolling• Accept:text/event-stream•  Semi-permanentconnecLon•  Limitedbrowsersupport(noIE,noAndroid)•  JavaEE8+J– IncludedinJAX-RS2.1

ServerSentEvents

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HTTP/1.1200OKContent-Type:text/event-streamDate:Tue,06Sep201615:39:30GMTTransfer-Encoding:chunkedevent:custom-messagedata:JAX-RS2.1event:custom-messagedata:testevent:custom-messagedata:JavaOne2016

ServerSentEvents

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Client Server

GET/sseAccept:text/event-stream


HTTP/1.1200OKContent-Type:text/event-streamDate:Tue,06Sep201615:39:30GMTTransfer-Encoding:chunkedevent:custom-messagedata:JAX-RS2.1event:custom-messagedata:testevent:custom-messagedata:JavaOne2016

ServerSentEvents

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Client Server

GET/sseAccept:text/event-stream


ServerSentEvents

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UseExecutorServiceinstead

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ServerSentEvents

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ServerSentEvents

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EvoluLon–WebSocket

• RFC6455(December2011)• Bi-direcLonalcommunicaLon• UsesHTTP/1.1foriniLalhandshake– Completelydifferentprotocolaverwards

•  “Server”and“client”endpointsareequalaverhandshake•  Textorbinarypayload•  Supportedinallmodernbrowsers

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EvoluLon–WebSocketWebSocketFrame

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WebSocketusecases

• RFC7118–SIPoverWebSocket• RFC7355–SIP&CLF(CommonLogFormat)overWebSocket• RFC7395–XMPPoverWebSocket• Dravs– MSRP(MessageSessionRelayProtocol)overWebSocket– SDP(SessionDescripLonProtocol)overWebSocket– RemoteFramebufferProtocoloverWebSocket– <anything>overWebSocket

Subprotocols

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JavaAPIforWebSocket

•  JSR356–PartofJavaEE7– 1.0(May2013)– 1.1(August2014)

• AnnotatedandprogrammaLcwayhowtodeployandaccessWebSocketendpoints•  Event-drivenmodel-@OnOpen,@OnMessage,@OnError,@OnClose•  Encoders/Decoders,Path/Queryparameterhandling,Handshakeheadersinterceptors,CDIintegraLon,…


JavaAPIforWebSocket–AnnotatedEndpoint


JavaAPIforWebSocket–ProgrammaLcEndpoint


WebSocketvsREST

• MightseemtobesimilarandsomepeopleeventhinkaboutWebSocketasaboutanother“RevoluLon”–likeSOAP-->REST•  Inreality,thesearetwodifferentconceptswhichCOMPLEMENTeachother.• RESTmakesmoresenseforstandardwebpages,forms,…• WebSocketprovidesbi-direcLonalchannel,suitableforexchanging“short”messageswiththebrowser.– (thescopeisnotlimited,youcanre-implementallyourcommunicaLonwithserver,butthereisnopointindoingthat..)

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EvoluLon–HTTP/2

•  SamesemanLcsasHTTP/1.1• Binaryprotocol• MulLplexedcommunicaLon– SingleTCPconnecLontosingleorigin,sharedforconsequent/parallelrequests

• Compressedheaders– HTTP/2introducesHPACK(compressionalgorithm)

•  ServerPush– Servercanpush(cacheable)contenttotheclientbeforeclientasks

HTTP/2KeyFeatures

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EvoluLon–HTTP/2

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Client Server

HTTP/2connecLon(singleTCPconnecLon)

HTTP/2streams

:methodGET:path/resource1

:methodGET:path/resourceX


WebSocketvsHTTP/2

• Pushedresourcesarecachedonclientside• Whenclientdecidesitneedssomething(image,..),itlooksintothecache– Doesn’tneedtobeimage,butallcooldemosareusingthat(rememberSPDY)

•  Serverpushhasitsownissues– Whatifclientdoesnotneedpushedresource?(theremightbeothercaches,…)– ClientneedtoexplicitlystatethatitacceptsServerpush

• Pushisnotaninterac@vemessageexchange

WebSocketvsServerpush

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SSEandHTTP/2

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Client Server

HTTP/2connecLon(singleTCPconnecLon)

HTTP/2streams

:methodGET:path/sse

:methodPOST:path/events

:status200OKContent-type:text/event-stream


WebSocketandHTTP/2

Standards..

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• Currently,WebSocketisnotdefinedinHTTP/2world• WebSocketusesUPGRADEheader,whichgivescompletecontroloverTCPconnecLon• HTTP/2StreamscouldsupportWSmulLplex

Copyright©2016,Oracleand/oritsaffiliates.Allrightsreserved.| 33

Usecases HTTP SSE

WebSockets

Chat

Sta@cpages

Forms

Games

Remotecontrol

Monitoring

Messaging/No@fica@on

XoverWS

Trackingprogress

Images,…

REST


Demo

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Java9

• Replace“good”oldHbpURLConnecLon•  JDK9–JEP110:HTTP/2Client:hbp://openjdk.java.net/jeps/110– DefineanewHTTPclientAPIthatimplementsHTTP/2andWebSocket,…

HTTP/REST&WebSocketclient

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NextSteps

•  Takethesurvey– hbp://glassfish.org/survey

•  Sendtechnicalcommentsto– [email protected]

•  JointheJCP–cometoHackergardeninJavaHub– hbps://jcp.org/en/parLcipaLon/membership_drive

•  JoinortracktheJSRsastheyprogress– hbps://java.net/projects/javaee-spec/pages/SpecificaLons

• Adopt-a-JSR– hbps://community.oracle.com/community/java/jcp/adopt-a-jsr

Giveusyourfeedback

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WheretoLearnMoreatJavaOne

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SessionNumber SessionTitle Day/Time

CON1558 What'sNewintheJavaAPIforJSONBinding Monday5:30p.m

BOF7984 JavaEEfortheCloud Monday7:00p.m

CON4022 CDI2.0IsComing Tuesday11:00a.m

CON7983 JAX-RS2.1forJavaEE8 Tuesday12:30p.m

CON7980 Servlet4.0:StatusUpdateandHTTP/2 Tuesday4:00p.m

CON7978 SecurityforJavaEE8andtheCloud Tuesday5:30p.m

CON7979 ConfiguraLonforJavaEE8andtheCloud Wednesday11:30a.m

CON7977 JavaEENext–HTTP/2andREST Wednesday1:00p.m

CON6077 TheIllusionofStatelessness Wednesday4:30p.m

CON7981 JSF2.3 Thursday11:30a.m


Contacts/QA

• PavelBucek([email protected])•  Jersey/JAX-RSRI:hbp://jersey.java.net– [email protected]

•  Tyrus/WebSocketRI:hbp://tyrus.java.net– [email protected]

FeelfreetoaskanyquesLonsnoworcontactmelater.

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WebSocketandClustering

• Differentto“classic”cluster– We’dliketotalktoothersessions(clients)directly

• Clusteredenvironmentpresentdifferentchallenges– “FindingaWebSocketSession”mightnotbeastrivialasitseem

• Broadcast(mass-noLficaLon)iscommonusecase• Clusteringcanhelp– BroadcasLngto“allsessions”canbefasterinclusteredenvironment

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JMS,JCache,Coherence,… LoadBalancer



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• Differentrequirements•  LoadbalancersmightneedtomanagemoreopenconnecLons• Cannotre-balancewhensessionisalreadycreated– Nodeisadded–ok,butIcannoteasilydecreaseloadonothernodes,IcanusethenewnodeonlyfornewconnecLons

• Nodegoingdownisnottransparenttoclient– Robustclientscanhidethis,butfornow,thisrequirescustomsoluLon– WLS12.2.1offersasoluLonforthis..

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• MightrequiremoreapplicaLoncode– Properhandlingonclientside– Evenmorecodewhenyouwanttohavesomethinglikeautoreconnect+“sessionrecovery”

•  Infrastructurerequirements– SimilartoSSL(persistentconnecLon,…)

• MuchmoreeffecLvewhencomparedtothesameappimplementedusinglong-polling

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web protocols for java developers

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