The Enterprise Web Services Bus Routable, Reliable and Publish/Subscribe Web Services

1
The Enterprise Web Services BusRoutable,
Reliable and Publish/Subscribe Web Services
INFOSYS 290, Section 3Web Services Concepts,
Design and Implementation
Adam Blum ablum_at_good.com
2
Agenda

• Bus-style integration versus point to point
  integration
• WS-Addressing
• WS-ReliableMessaging
• WS-Eventing

3
The Problem with Point to Point

• Web services enable ad hoc integration without
  negotiating transports
• And potentially not even payload formats
• But connectivity is still built point to point
• Origin and destination of messages are determined
  by the underlying protocol
• Many business events are of interest to many
  parties
• It would be more efficient to send messages once
  to a bus and have it transmitted to all
  participants which are interested

4
Whats Needed for Bus-Style Integration over Web
Services

• Remove destinations and routing from the
  transport
• Allow applications to subscribe to business
  events of interest
• Insure reliable delivery of messages in
  standardized way

5
Routable Web Services

• The Problem
• Web service destinations are today expressed in
  the physical transport
• E.g. the http destination address
• The Solution
• Use a SOAP header to reflect the address

6
Sample WS-Addressing Message
7
Endpoint References Consist Of

• Address
• URI for the endpoint
• Reference Properties
• Optional properties which fully qualify endpoint
  reference
• Opaque to consuming app
• Reference Parameters
• Optional parameters supplied to endpoint for
  particular interaction
• Opaque to consuming app
• PortType
• Optional reference to the interface supported
• ServiceName
• Optional WSDL service reference
• ServiceName/_at_PortName
• Optional WSDL port
• Policy
• Optional WS-Policy

8
Sample Endpoint Reference

• ltwsaEndpointReference xmlnswsa"..."
  xmlnsfabrikam"..."gt
• ltwsaAddressgt
• http//www.fabrikam123.example/acct
• lt/wsaAddressgt
• ltwsaPortTypegt
• fabrikamInventoryPortType
• lt/wsaPortTypegt
• lt/wsaEndpointReferencegt

9
Binding to SOAP

• Copy address property to destination header field
  of SOAP message
• Each ReferenceProperty and ReferenceParameter
  becomes SOAP header

10
SOAP Binding Sample - EndpointReference

• ltwsaEndpointReference xmlnswsa"..."
  xmlnsfabrikam"..."gt ltwsaAddressgthttp//www.fabr
  ikam123.example/acctlt/wsaAddressgt
• ltwsaReferencePropertiesgt
• ltfabrikamCustomerKeygt
• 123456789
• lt/fabrikamCustomerKeygt
• lt/wsaReferencePropertiesgt ltwsaReferenceParamete
  rsgt ltfabrikamShoppingCartgtABCDEFGlt/fabrikamShop
  pingCartgt
• lt/wsaReferenceParametersgt
• lt/wsaEndpointReferencegt

11
SOAP Binding SampleSOAP Header

• ltSEnvelope xmlnsS"http//www.w3.org/2003/05/soa
  p-envelope" xmlnswsa"..." xmlnsfabrikam"...
  "gt ltSHeadergt ...
• ltwsaTogt
• http//www.fabrikam123.example/acct
• lt/wsaTogt
• ltfabrikamCustomerKeygt
• 123456789
• lt/fabrikamCustomerKeygt
• ltfabrikamShoppingCartgt
• ABCDEFG
• lt/fabrikamShoppingCartgt ...
• lt/SHeadergt
• ltSBodygt ... lt/SBodygt
• lt/SEnvelopegt

12
Message Information Header

• To - destination
• The address (URI) of intended receiver
  Mandatory
• Action
• URI identifying uniquely semantics of message -
  Mandatory
• From
• Endpoint reference of the origin
• ReplyTo
• Endpoint reference of intended receiver of
  replies
• FaultTo
• Endpoint reference of where to send faults
• MessageID
• URI which uniquely identifies message in time and
  space
• RelatesTo
• Pair of values which indicates how one message is
  related to another message

13
Sample Message Information Headers

• ltSEnvelope xmlnsS"http//www.w3.org/2003/05/soa
  p-envelope" xmlnswsa"http//schemas.xmlsoap.org/
  ws/2004/08/addressing" xmlnsf123"http//www.fabr
  ikam123.example/svc53"gt
• ltSHeadergt
• ltwsaMessageIDgtuuidaaaabbbb-cccc-dddd-eeee-fffff
  fffffff lt/wsaMessageIDgt
• ltwsaReplyTogt ltwsaAddressgthttp//business456.ex
  ample/client1
• lt/wsaAddressgt
• lt/wsaReplyTogt
• ltwsaTo SmustUnderstand"1"gtmailtojoe_at_fabrikam1
  23.example
• lt/wsaTogt
• ltwsaActiongthttp//fabrikam123.example/mail/Delet
  e
• lt/wsaActiongt
• lt/SHeadergt
• ltSBodygt
• ltf123Deletegt ltmaxCountgt42lt/maxCountgt
  lt/f123Deletegt lt/SBodygt
• lt/SEnvelopegt

14
A Reply to that Message

• ltSEnvelope xmlnsS"http//www.w3.org/2003/05/soa
  p-envelope" xmlnswsa"http//schemas.xmlsoap.org/
  ws/2004/08/addressing" xmlnsf123"http//www.fabr
  ikam123.example/svc53"gt
• ltSHeadergt
• ltwsaMessageIDgt uuidaaaabbbb-cccc-dddd-eeee-www
  wwwwwwww lt/wsaMessageIDgt
• ltwsaRelatesTogtuuidaaaabbbb-cccc-dddd-eeee- fff
  fffffffff
• lt/wsaRelatesTogt
• ltwsaTo SmustUnderstand"1"gt
  http//business456.example/client1
• lt/wsaTogt ltwsaActiongthttp//fabrikam123.exampl
  e/mail/DeleteAck
• lt/wsaActiongt
• lt/SHeadergt
• ltSBodygtltf123DeleteAck/gtlt/SBodygt
• lt/SEnvelopegt

15
Sample WSE Code

• SoapEnvelope env new SoapEnvelope()
• env.Context.Addressing.Action String.Format("urn
  chatmessage")
• EndpointReference epr new EndpointReference("soa
  p.tcp//theirowntoys.com/adam"))
• env.Context.Addressing.ReplyTo new
  ReplyTo(epr)
• env.CreateBody() // must create body before
  setting it
• env.Body.InnerXml String.Format(
• "ltxmessagexmlnsx'urnchat'gtltusergt0lt/usergtltms
  ggt1lt/msggt lt/xmessagegt", user, msg)
• ...
• EndpointReference epr new EndpointReference(
  new Uri("soap.tcp//theirowntoys.com/lauren"))
• SoapSender ss new SoapSender(epr) // this
  fills in the To
• ss.Send(env)

16
.Creates Following Message

• ltsoapEnvelope xmlnswsa"http//schemas.xmlsoap.o
  rg/ws/2003/03/addressing" xmlnswsse"http//schem
  as.xmlsoap.org/ws/2003/06/secext"
  xmlnssoap"http//schemas.xmlsoap.org/soap/envelo
  pe/"gt ltsoapHeadergt
• ltwsaActiongturnchatmessagelt/wsaActiongt
• ltwsaReplyTogt
• ltwsaAddressgtsoap.tcp//theirowntoys.com/adam
  lt/wsaAddressgt
• lt/wsaReplyTogt
• ltwsaMessageIDgtuuid59bc1ebb-40aa-4508-9a69-5b14
  8d04d697 lt/wsaMessageIDgt
• ltwsaTogtsoap.tcp//theirowntoys.com/lauren
• lt/wsaTogt ...
• lt/soapHeadergt
• ltsoapBodygt
• ltxmessage xmlnsx"urnchat"gt
• ltusergtadamlt/usergt
• ltmsggthilt/msggt
• lt/xmessagegt
• lt/soapBodygt
• lt/soapEnvelopegt

17
Routing with WS-Referral

• lt?xml version"1.0" ?gt
• ltrreferrals xmlnsr"http//schemas.xmlsoap.org/w
  s/2001/10/referral"gt
• ltrrefgt
• ltrforgt
• ltrexactgthttp//localhost/RouterService/St
  ockService.asmxlt/rexactgt
• lt/rforgt
• ltrif /gt
• ltrgogt
• ltrviagthttp//localhost/StockService/Stoc
  kService.asmxlt/rviagt
• lt/rgogt
• ltrrefIdgtuuidfa469956-0057-4e77-962a-81c5e292
  f2aelt/rrefIdgt
• lt/rrefgt
• lt/rreferralsgt

18
Implementations of WS-Addressing

• Microsoft WSE 2.0
• Apache Axis!
• http//ws.apache.org/ws-fx/addressing/ (Davanum
  Srinivas at CA)
• Part of WS-FX
• http//ws.apache.org/ws-fx/
• See WSS4J for WS-Security!
• Systinet

19
WS-Addressing References

• WS-Addressing Specification
• http//www.w3.org/Submission/2004/SUBM-ws-addressi
  ng-20040810/
• MSDN Article on Moving from WS-Routing to
  WS-Addressing
• http//msdn.microsoft.com/library/default.asp?url
  /library/en-us/dnwebsrv/html/wsroutetowsadd.asp

20
WS-ReliableMessaging
21
Why a Reliable Messaging Standard?

• Base Web services standards (particularly SOAP
  over http) do not address guaranteed delivery of
  messages Applications build reliable messages
  into their business logic
• Each in their own, possibly inconsistent way
• Standards-based interoperability requires a
  reliable messaging method of communication
• Routing and publish/subscribe exacerbates the
  problem
• Since there is no direction connection to the
  other system
• If there are multiple recipients (e.g. bus) we
  cannot program to each of their unique business
  logic programmed for reliable messaging

22
Requirements for Reliable Messaging

• AtLeastOnce delivery
• AtMostOnce delivery
• ExactlyOnce delivery
• InOrder message sequencing

23
Reliable Messaging Model
24
(No Transcript)
25
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26
Sequence
27
Sequence Responses
28
RM Client Code (IBM ETTK)

• import com.ibm.ws.rm.client.Context
• Context wsrContext new Context()
• wsrContext.setMessageNumber(1)
• wsrContext.setLastMessage(true)
• wsrContext.setSendAckRequested(true)
• wsrContext.setSendCreate(true)
• wsrContext.setSendTerminate(true)
• call.setProperty(Context.RM_CONTEXT_PROPERTY_NAME,
  wsrContext)
• System.out.println("Sending the PO...")
• call.setOperationName( new QName("http//po.demo.w
  srm.ibm.com", "submitPO"))
• call.invoke( new Object "12345", "12345445",
  new Integer(1), new Float(12.10))
• System.out.println("Message was delivered.")
• (Source code in c/ettk/services/demos/wsrm/client
  )

29
Three Messages

• Context wsrContext new Context()
• wsrContext.setSequenceIdentifier(groupId)
• wsrContext.setMessageNumber(1)
• Call call (Call)service.createCall(portQName)
• call.setTargetEndpointAddress(url)
• call.setProperty(Context.RM_CONTEXT_PROPERTY_NAME,
  wsrContext)
• call.setOperationName( new QName("http//po.demo.w
  srm.ibm.com", "submitPO"))
• EndpointReference epr UtilsWSA.createEndpointRef
  erence(url)
• // sets To
• WSAddressingOutboundContext context
  WSAddressingContextFactory.createWSAddressingOutbo
  undContext(epr)
• context.setFrom( UtilsWSA.createEndpointReference(
  "http//" ETTKConstants.SERVER_HOSTNAME ""
  listenerPort "/wstk/services/rm"))
• UtilsWSA.associateContextWithCall(context, call)
• System.out.println("Delivering message number
  1.")
• call.invokeOneWay( new Object "11111A",
  "11111111", new Integer(1), new Float(11.11))

30
.More Messages

• groupId wsrContext.getSequenceIdentifier()
• wsrContext new Context()
• wsrContext.setSequenceIdentifier(groupId)
• wsrContext.setMessageNumber(3)
• wsrContext.setLastMessage(true)
• Call call3 (Call)service.createCall(portQName)
• call3.setTargetEndpointAddress(url)
• call3.setProperty(Context.RM_CONTEXT_PROPERTY_NAM
  E, wsrContext)
• call3.setOperationName( new QName("http//po.demo.
  wsrm.ibm.com", "submitPO"))
• UtilsWSA.associateContextWithCall(context,
  call3)
• Runnable r3 new Runnable() // async
• public void run()
• System.out.println("Delivering message number
  3.")
• call3.invokeOneWay( new Object "33333C",
  "33333333", new Integer(1), new Float(33.33))
  
• wsrContext new Context()
• wsrContext.setSequenceIdentifier(groupId)

31
Output

• Running the client code...
• Starting the response listener...
• Delivering message number 1.
• Delivering message number 3.
• Delivering message number 2.
• Server-side output (server.out)
• Received PO with OrderID 11111A
• Received PO with Part ID 11111111
• Received PO with Quantity 1
• Received PO with Amount 11.11
• Received PO with OrderID 22222B
• Received PO with Part ID 22222222
• Received PO with Quantity 1
• Received PO with Amount 22.22
• Received PO with OrderID 33333C
• Received PO with Part ID 33333333
• Received PO with Quantity 1
• Received PO with Amount 33.33

32
Systinet Hello World

• import org.systinet.wasp.webservice.ServiceClient
  
• import org.systinet.wasp.sequence.Sequence
• public static void main(String args) throws
  Exception
• String serverURL System.getProperty("sys
  tinet.demo.server.url", "http//localhost6060")
• // lookup of HelloService
• ServiceClient client ServiceClient.creat
  e(serviceWSDLURL)
• client.setServiceURL(serverURL
  servicePath)
• // create new sequence for one request
• Sequence seq Sequence.createOutputSequen
  ce(client)
• seq.setLength(1)
• // call HelloService and print out a
  response message
• Call call client.createCall("hello")
• System.out.println("Sending 'world' and
  waiting for the ACK and response...")
• System.out.println(call.invoke(new
  Object"world"))

33
Systinet Multiple Messages

• private static final String servicePath
  "/demo/reliability/OneWayService"
• private static final String serviceWSDLURL
  "resource/demo/reliability/OneWayService.wsdl"
• private static final String sequencePrefix
  "http//systinet.com/demo/reliability/oneway/"
• private static final long sequenceLength
  3
• String serverURL System.getProperty("systin
  et.demo.server.url", "http//localhost6060")
• // create a service client
• ServiceClient client ServiceClient.create(se
  rviceWSDLURL)
• client.setServiceURL(serverURL
  servicePath)
• // register the sequence listener to the
  ServiceClient
• SequenceListener listener new
  OutSequencesListener()
• Sequence.addSequenceListener(listener,
  client)

34
Systinet Multiple Messages

• // load all my previous sequences
• // this causes that all messages which are not
  acknowledged are delivering to the destination
  again
• Sequence seqs Sequence.loadOutputSequences(se
  quencePrefix, client)
• for(int i 0 seqs ! null i lt seqs.length
  i)
• System.out.println("Delivering loaded sequence
  " seqsi.getID())
• // if the sequence is incomplete we
  will continue with next invocations the length
  is 'sequenceLength' but
• // the current length is equaled to
  number of already queued messages in the sequence
• // before making invocations the
  loaded sequence must be activated for used
  processing (client)
• if(seqsi.getCurrentLength() !
  seqsi.getLength())
• System.out.println("Continuing in
  sequence " seqsi.getID())
• seqsi.setActive(true)
• sendMessages(client,
  seqsi.getCurrentLength() 1)
• // create a new sequence with length of
  'sequenceLength'
• // new created sequence is automatically
  activated for used processing (client)
• Sequence seq Sequence.createOutputSequence(seque
  ncePrefix, true, client)

35
Systinet Server Side

• public void send(String message)
• // is the incoming message in a sequence?
• Sequence seq Sequence.getActiveInputSe
  quence()
• if(seq ! null)
• System.out.println("Reliable message "
  message " (seq " seq.getID()
• ", number " seq.getCurrentMessageNumber()
  ")")
• else
• System.out.println("Non-reliable
  message " message)

36
Sandesha Mods to Axis
37
Implementations

• IBM Emerging Technologies Toolkit
• http//www.alphaworks.ibm.com/tech/ettk
• Systinet
• http//www.systinet.com/products/wasp_jserver/over
  view
• Apache Sandesha
• http//ws.apache.org/ws-fx/sandesha/

38
WS-ReliableMessaging References

• Spec
• http//msdn.microsoft.com/library/default.asp?url
  /library/en-us/dnglobspec/html/ws-reliablemessagin
  g.asp
• Article
• http//www-106.ibm.com/developerworks/webservices/
  library/ws-rmimp/
• IBM Page
• http//www-106.ibm.com/developerworks/webservices/
  library/ws-rm/

39
WS-Eventing
40
WS-Eventing Specification

• Sponsored by Microsoft, Tibco, BEA, Sun
• Four main request messages
• Subscribe
• Renew
• GetStatus
• Unsubscribe

41
Point to Point Integration
42
Content-Based Routing Topology
43
Subscribe Grammar
44
Subscribe Message

• lts12Envelopexmlns12'http//www.w3.org/2003/05/s
  oap-envelope'xmlnswsa'http//schemas.xmlsoap.or
  g/ws/2003/03/addressing'xmlnswse'http//
  schemas.xmlsoap.org/ws/2004/01/eventing'xmlnseri
  'http//electronicsretailer.com/inventory'gtlts12
  Headergt  ltwsaActiongt http//schemas.xmlsoap.or
  g/ws/2004/01/eventing/Subscribe  lt/wsaActiongt lt
  wsaTogthttp//electronicsretailer.com/CBRServicelt/
  wsaTogt ltwsaReplyTogt ltwsaAddressgt http//el
  ectronicsretailer.com/inventory lt/wsaAddressgt
  lt/wsaReplyTogt ltwsaMessageIDgt uuidd7c5276b-de
  29-4313-b4d4-b3425b200840  lt/wsaMessageIDgt lt/s1
  2Headergtlts12Bodygt ltwseSubscribegt
• ltwseDeliverygt ltwseNotifyTogt ltwseAddressgt
  
• http//electronicsretailer.com/inventory/H
  andleNewProduct.asp  lt/wseAddressgt ltwsaRef
  erencePropertiesgt lteriMySubscriptionIDgt1234lt/e
  riMySubscriptionIDgt lt/wsaReferencePropertiesgt
    lt/wseNotifyTogt
• lt/wseDeliverygt ltwseExpiresgt2004-06-26T21070
  0.000-0800lt/wseExpiresgt
• ltwseFilter xmlnser'http//electronicsretailer
  .com/schemas'gt /s12Envelope/s12Body/erNewProd
  uct lt/wseFiltergt lt/wseSubscribegtlt/s12Bodygt
• lt/s12Envelopegt

45
Subscribe Response Grammar
46
SubscribeResponse

• lts12Envelopexmlns12'http//www.w3.org/2003/05/s
  oap-envelope'xmlnswsa'http//schemas.xmlsoap.or
  g/ws/2003/03/addressing'xmlnswse'http//
  schemas.xmlsoap.org/ws/2004/01/eventing'xmlnseri
  'http//electronicsretailer.com/inventory'gt lts12
  Headergt  ltwsaActiongt http//schemas.xmlsoap.or
  g/ws/2004/01/eventing/SubscribeResponse  lt/wsaAc
  tiongt ltwsaTogthttp//electronicsretailer.com/inve
  ntorylt/wsaTogt ltwsaRelatesTogt uuidd7c5276b-de2
  9-4313-b4d4-b3425b200840  lt/wsaRelatesTogt lt/s12
  Headergtlts12Bodygt ltwseSubscribeResponsegt ltws
  eSubscriptionManagergt
• ltwsaAddressgthttp//electronicretailer.com/cbr
  servicelt/wsaAddressgt
• ltwseReferenceParametersgt
• ltwseIdentifiergt
• uuid5005cfe6-c2c6-4296-9c3a-80b9ad111813
• lt/wseIdentifiergt
• lt/wseReferenceParametersgt
• lt/wseSubscriptionManagergt ltwseExpiresgt200
  4-08-01T000000-000-0000lt/wseExpiresgt lt/wseSu
  bscribeResponsegtlt/s12Bodygt
• lt/s12Envelopegt

47
A Notification (any matching message)

• lts12Envelopexmlns12'http//www.w3.org/2003/05/s
  oap-envelope'xmlnswsa'http//schemas.xmlsoap.or
  g/ws/2003/03/addressing'xmlnswse'http//schemas
  .xmlsoap.org/ws/2004/01/eventing'xmlnseri'http
  //electronicsretailer.com/inventory'xmlnser'htt
  p//electronicsretailer.com/schemas'gtlts12Headergt
    ltwsaActiongt http//electronicsretailer.com/sc
  hemas/NewProduct lt/wsaActiongt ltwsaTogthttp//el
  ectronicsretailer.com/inventorylt/wsaTogt lteriMyS
  ubscriptionIDgt1234lt/eriMySubscriptionIDgtlt/s12He
  adergtlts12Bodygt lteriNewProductgt lteriProductID
  gtAC-MP471lt/eriProductIDgt lteriProductNamegt Acme
  128MB Portable MP3 Player lt/eriProductNamegt lte
  riProductCategorygtMP3 Playerslt/eriProductCategor
  ygt lteriPricegt47.56lt/eriPricegt lt/eriNewProduct
  gtlt/s12Bodygt
• lt/s12Envelopegt

48
Sample Subscription Client Code

• bool resulttrue
• CBRSubscribe.CBRService.Subscribe
  subscriptionnew CBRSubscribe.CBRService.Subscribe
  ()
• subscription.NotifyTonew CBRSubscribe.CBRService.
  EndpointReferenceType()
• subscription.NotifyTo.Addressnew
  CBRSubscribe.CBRService.AttributedURI()
• subscription.NotifyTo.Address.ValuenotifyAddress
  
• if (subscriptionFilter.Lengthgt0)
• subscription.Filternew CBRSubscribe.CBRService.M
  essagePredicateAssertion()
• subscription.Filter.ValuesubscriptionFilter
• subscription.ExpiresexpireDate
• CBRSubscribe.CBRService.Eventing objEventingnew
  CBRSubscribe.CBRService.Eventing(cbrServiceURL)
• CBRSubscribe.CBRService.SubscribeResponse
  subscribeResponsenew CBRSubscribe.CBRService.Subs
  cribeResponse()
• try
• subscribeResponseobjEventing.SubscribeOp(subscri
  ption)
• catch
• resultfalse

49
Changes over First Draft

• No requirements for WS-Addressing delivery
• GetStatus message
• SubscriptionManager abstraction

50
WS-Eventing Implementations

• My WS-Eventing general purpose client
• http//adamblum.com/cbrsubscribe.zip
• Needs to be updated to August 2004 spec!
• Systinets Content-Based Router
• http//www.systinet.com/contentbasedrouting

51
Competitors to WS-Eventing

• WS-Notification
• IBM et al
• Used in WSDM
• JMS
• Sonic
• Fiorano
• Message queueing/bus providers
• Tibco (behind WS-Eventing)
• MQSeries

52
WS-Notification Differences

• Topic abstraction
• Necessary?
• Notification brokers
• Necessary?
• Subscription Manager?
• Yes!
• http//blum.typepad.com/coarsegrained/2004/02/wsno
  tification_.html

53
WS-Eventing References

• The Spec
• http//msdn.microsoft.com/webservices/understandin
  g/specs/default.aspx?pull/library/en-us/dnglobspe
  c/html/ws-eventing.asp
• WSDL http//schemas.xmlsoap.org/ws/2004/08/eventi
  ng/eventing.wsdl
• My Web Services Journal article
• http//www.sys-con.com/story/?storyid44362DE1
• Interesting Survey of CBR methods
• Covers WSE via WS-Referral (shown in this deck),
  Indigo via rules manager and Systinet WASP
• http//www.c-sharpcorner.com/Code/2004/June/Conten
  tBasedWS.asp

54
Putting It All TogetherA Web Services Bus

• WS-Addressing for removing reliance on physical
  direct connections
• WS-ReliableMessaging to insure multiple
  disconnected recipients all receive message
• WS-Eventing to ease communications with multiple
  recipients
• http//blum.typepad.com/coarsegrained/2003/11/inde
  x.html