Extended Web Services Standards

Transcription

1 Extended Web Services Standards Business Process Automation

2 Innoq Web services standards overview

3 WS-I Standards stack

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5 Groups of Web services (WS*) standards Messaging Description and discovery / Metadata Specifications Reliability / Reliable messaging Transactions Security Business processes Management

6 Messaging WS* standards These messaging standards and specifications are intended to give a framework for exchanging information in a decentralized, distributed environment. SOAP 1.1 (Note) SOAP 1.2 (Specification) Web Services Addressing, Web Services Eventing, Web Services Enumeration Web Services Notification (WS-BrokeredNotification, WS-BaseNotification, WS-Topics) Web Services Attachments Profile 1.0 MTOM Serialization Policy Assertion (WS-MTOMPolicy) MQTT V3.1 (Protocol Specification)

7 MTOM MTOM (Message Transmission Optimization Mechanism) is helpful when SOAP messages contain a large amount of binary data, for example, when transmitting binary files such as bitmap images and movies. In order to be transported in a SOAP envelope, binary data normally must be encoded using base 64 (base64binary) to ensure it can be correctly parsed by the receiver in all cases. This effectively increases its size in the SOAP envelope by a third. MTOM allows binary data to be pulled out of the SOAP envelope and attached in a more efficient manner, in a binary part of a MIME multi-part message.

8 MTOM in WCF Method with [MessageContract] attribute, not [DataContract], or "primitive" types; Byte array properties - [MessageBodyMember] attribute, not [DataMember] nor [MessageHeader], and all the other properties - [MessageHeader] attribute; Byte[] or Stream object, the results are the same All eventual classes that the parameter or return classes derive from must also have the [MessageContract] attribute; In the <binding> elements for you service (both client and server), you must set the messageencoding attribute to Mtom.

9 WS-MetadataExchange WS-MetaDataExchange is designed to work in conjunction with WS-Addressing, WSDL and WS- Policy to allow retrieval of metadata about a Web Services endpoint. It uses a SOAP message to request metadata, and so goes beyond the basic technique of appending "?wsdl" to a service name's URL

10 WS-Addressing Universal mechanism of addressing, action and message identification Drawbacks of HTTP proxy, firewall may change addresses not always used (SMTP) Attached to SOAP as a header Transparent management of requests / responses load balancing, dedicated communication channels

11 WS-Addressing WS-Addressing Core provides transport-neutral mechanisms to address Web services and messages. This specification defines XML elements to identify Web service endpoints and to secure end-to-end endpoint identification in messages. WS-Addressing WSDL Binding defines how the abstract properties defined in Web Services Addressing Core are described using WSDL. WS-Addressing SOAP Binding provides transport neutral mechanisms to address Web services and messages.

12 WCF WCF Service Configuration Editor (App.config) WS-Addressing in WCF Windows Communication Foundation vs.net Web services System.Web.Services, System.ServiceModel WSDL contents for.net WS, WCF

13 Rodzaje WCF bindings Określenie charakterystyk warstwa transportowa (HTTP, MSMQ, named pipes, TCP) rodzaj kanału (one-way, request-reply, duplex) kodowanie (encoding) (XML, binarny) wspierane protokoły WS-*

14 Wybrane WCF bindings HTTP - based bindings BasicHttpBinding - Web service zgodny z WS-I Basic Profile (backward compatibility) WSHttpBinding - wsparcie dla większej liczby WS-* features - WS-Addressing, transactions, reliable messaging, MTOM TCP - based bindings NetTcpBinding - cross-machine between.net applications MSMQ - based bindings NetMsmqBinding - zalecany dla MSMQ - komunikacja między aplikacjami.net

15 Endpoint reference WS-Addressing alternative options <wsa:endpointreference xmlns:wsa=" <wsa:address> </wsa:endpointreference> Message type wsa:to, wsa:from, wsa:action ReplayTo, MessageID, RelatesTo request-responce pattern, specify receiver, sender, target response receiver request assignes MessageID and ReplayTo To used in responce, RelatesTo contains request identification

16 WS-Eventing, WS-Notification WS-Eventing WS-Eventing defines a baseline set of operations that allow Web services to provide asynchronous notifications to interested parties. uses WS-Addressing to indicate subscription, renew/cancel subscription, check status WS-Notification a family of related white papers and specifications that define a standard Web services approach to notification using a topic based publish/subscribe pattern.

17 Transactions WS* Transactions are a fundamental concept in building reliable distributed applications. A web service environment requires coordination behavior provided by a traditional transaction mechanism to control the operations and outcome of an application. Web Services Atomic Transaction Web Services Business Activity Web Services Coordination

18 Traditional transactions Atomicity: If successful, then all the operations happen, and if unsuccessful, then none of the operations happen. Consistency: The application performs valid state transitions at completion. Isolation: The effects of the operations are not shared outside the transaction until it completes successfully Durability: Once a transaction successfully completes, the changes survive failure.

19 WS/Workflow transactions More relaxed forms of transactions -- those that do not strictly have to abide to the ACID properties collaborations, Workflow, Realtime processing Long running transaction compensation vs rollback example: travel booking

20 WS-* transactions in WCF Demo Protokoły transakcyjne Windows Lightweight - single AppDomain, single Resource Manager (system przechowujący dane) OleTx - cross AppDomain, machine calls, no crossplatform WSAT - interoperable communication Transaction managers Lightweight TM (LTM) - Lightweight protocol Kernel Resource Manager (KRM) - Lightweight protocol Distributed Transaction Manager (DTC) OleTx, WSAT

21 WS-* transactions in WCF Transaction managers - wybór automatyczny przez system Promotion - zmiana managera współpracującego z RM Wsparcie przez WCF binding np. NetNamedPipeB..., NetTcpB..., WSHttpBinding transactionflow="true", domyślnie wyłączone TransactionFlow(TransactionFlowOption. NotAllowed - klient nie może propagować transakcji do serwera, ignorowany, nie wyrzuca wyjątku Allowed - obsługiwana transakcja, jeżeli klient żąda, jak nie, to nie, wyrzuca wyjątek, jeżeli klient żąda transakcji, a binding nie wspiera jej Mandatory - wymagany binding wspierający transakcje i ustanowienie (propagowanie) transakcji, inaczej wyjątek

22 WS-Coordination WS-Coordination provides standard mechanisms to create and register services, using the protocols defined in the WS-Transaction specification that coordinate the execution of distributed operations in a Web services environment (for example, atomic transaction protocols, long-running business transaction protocols, etc.). It also provides an important foundation layer that will help developers control operations that span across broadly interoperable Web services. Protocols for Atomic Transactions. Protocols for Business Transactions

23 WS-Coordination Activation Service The activation service uses the create message to: begin a new activity Registration service specify the coordination protocols available to the activity The registration service 'register' allows a Web service to register and to select a protocol for the activity. Coordination service concrete coordination protocol (WS-AtomicTransaction, WSBusinessActivity) controls the activity completion processing for the registered Web services

24 Coordination context Identifier: a unique name to identify the CoordinationContext Expires: an activity timeout value CoordinationType: a defined set of coordination protocols that describe the supported completed processing behaviors Registration Service: address of the registration service, the service is used to register interest and participation in a coordination protocol for determining the overall outcome of the activity. Extensibility element: provides for optional implementationspecific extensions

25 Protocols for Atomic Transactions The protocols for atomic transactions handle activities that are short-lived. Atomic transactions are often referred to as providing a two-phase commitment protocol. The transaction scope states that all work is completed in its entirety, that is, that the result of an activity, if successful, is that all operations are performed, or if unsuccessful, that no operations have been performed. Upon successful completion the results of the activity are available to other users.

26 Protocols for Business Transactions The protocols for business transactions handle long-lived activities. These differ from atomic transactions in that, such activities can take much longer to complete, and to minimize latency of access by other potential users of the resources used by the activity, the results of interim operations need to be released before the overall activity has completed. In light of this, mechanisms for fault and compensation handling are introduced to reverse the affects of previously completed business activities (for example, compensation, reconciliation, etc).

27 Reliability WS* It is not possible to solve business issues if the participants are unable to be sure of the completion of message exchanges. Reliable messaging, which allows messages to be delivered reliably between distributed applications in the presence of software component, system, or network failures, is therefore critical to web services. Web Services Reliable Messaging WS-RM Policy Assertion (Web Services Reliability)

28 Reliability WS* WS-ReliableMessaging describes a protocol that allows Web services to communicate reliable in the presence of software component, system, or network failures. It defines a SOAP binding that is required for interoperability. (WS-Reliability) is a SOAP-based protocol for exchanging SOAP messages with guaranteed delivery, no duplicates, and guaranteed message ordering. WS-Reliability is defined as SOAP header extensions and is independent of the underlying protocol. This specification contains a binding to HTTP. competition for WS-RM

29 WS-Reliable Messaging An Application Source (AS) wishes to reliably send messages to an Application Destination (AD) over an unreliable infrastructure. To accomplish this they make use of a Reliable Messaging Source (RMS) and a Reliable Messaging Destination (RMD). The AS sends a message to the RMS. The RMS uses the WS- ReliableMessaging (WS-RM) protocol to transmit the message to the RMD. The RMD delivers the message to the AD. If the RMS cannot transmit the message to the RMD for some reason, it must raise an exception or otherwise indicate to the AS that the message was not transmitted.

30 WS-Reliable Messaging

31 WS-Reliable Messaging Delivery Assurances AtLeastOnce - Each message will be delivered to the AD at least once. If a message cannot be delivered, an error must be raised by the RMS and/or the RMD. Messages may be delivered to the AD more than once (i.e. the AD may get duplicate messages). AtMostOnce - Each message will be delivered to the AD at most once. Messages may not be delivered to the AD, but the AD will never get duplicate messages. ExactlyOnce - Each message will be delivered to the AD exactly once. If a message cannot be delivered, an error must be raised by the RMS and/or the RMD. The AD will never get duplicate messages. InOrder - Messages will be delivered from the RMD to the AD in the order that they are sent from the AS to the RMS. This assurance can be combined with any of the above assurances.

32 WS-* Management Web services manageability is defined as a set of capabilities for discovering the existence, availability, health, performance, usage, as well as the control and configuration of a web service within the web services architecture. As web services become pervasive and critical to business operations, the task of managing and implementing them is imperative to the success of business operations. Web Services Distributed Management Management Using Web Services (WSDM-MUWS) Management Of Web Services (WSDM-MOWS) Web Services Manageability -- Concepts, Representation WS-ResourceTransfer, Web Services Service Registry and Repository, WS-Management, WS-Management Catalog

33 Web Services Distributed Management Complexity of managing the business Value for customers, suppliers of management software, manufactures of devices Depend on other specifications WS-Resource Framework (WS-RF) Resource Properties (WSRP) for properties WS-Notification (WSN) Base Notifications (WSBN) for management event transport WS-Addressing (WSA)

34 Web Services Distributed Management WS manageable printer Customers gain visibility into functional aspects of a resource print, properties Business-oriented consumers gain visibility into management aspects of a resource toner, failures start, stop

35 Management Using Web Services (WSDM-MUWS) Management Using Web Services (MUWS) 1.0 specifications define how to represent and access the manageability interfaces of resources as Web services

36 Management Using Web Services (WSDM-MUWS) Capabilities uniquely identified in time and environment, has defined semantics (such as those provided by any section in this specification that describes a new capability), is associated with a set of: Composability properties, operations, events (notifications) and metadata (including policies). Isolation from implementation

37 Management of Web Services (WSDM-MOWS) Management of Web Services (MOWS) 1.0 specification defines how to manage Web services as resources and how to describe and access that manageability using MUWS.

38 Management of Web Services (WSDM-MOWS) Identity -- defines a unique identity for the Web service. Identification -- capability defines a reference to the Web service being managed. Metrics -- defines a set of basic metrics for a Web service: NumberOf Requests, NumberOfFailedRequest, NumberOfSuccessfulRequests, ServiceTime, MaxResponseTime, and LastResponseTime. OperationalState -- capability provides the current operational state of the service. The valid states are Up with substates of Busy and Idle and Down with substates of Stopped, Crashed, and Saturated. OperationalStatus -- provides the high-level status of the services: all Up states return Available and all Down states return as status of Unavailable, except for Saturated which returns PartiallyAvailable. RequestProcessingState -- capability defines a request state diagram and provides a mechanism to define events to be sent when request processing states change.

39 Bibliography Standards and specification: OASIS World Wide Web Consortium Web Services Interoperability Organization innoq GmbH Web Services Standards Overview, 2007 IBM Developerworks Transactions in the world of Web services MSDN Wikipedia the free encyclopedia