The SOAP Story

1
The SOAP Story

• Martin Parry
• Developer Platform Group
• Microsoft Ltd
• martin.parry_at_microsoft.com
• http//martinparry.com

2
Agenda

• Definitions
• SOAP through the ages
• SOAP and standards
• Approaches to building and using services
• SOAP Services with WCF
• Services and the Workflow Foundation

3
Definitions

• SOAP
• Initially Simple Object Access Protocol
• Its about services that exchange messages
• The messages are formed from XML
• Each message has headers plus a body
• WSDL
• Describes services and their operations
• Uses XML and schema to describe messages

4
SOAP on the Microsoft Platform

• SOAP Toolkit
• NT4, Windows 2000
• IIS4 or IIS5
• Based around COM
• Used ISAPI filter
• No longer in mainstream support
• Extended support expires in March 2008

5
SOAP on the Microsoft Platform

• SOAP Toolkit
• NT4, Windows 2000
• IIS4 or IIS5
• Based around COM
• Used ISAPI filter
• No longer in mainstream support
• Extended support expires in March 2008

6
SOAP on the Microsoft Platform

• SOAP Moniker
• Introduced in Windows XP Professional
• Scriptable mechanism for invoking web services
• Example vbscript...
• Dim proxy
• Set proxy GetObject(soapwsdlhttp//....)

7
SOAP on the Microsoft Platform

• .NET Remoting
• Supports TCP and HTTP transports
• Can use IIS, or not
• Supports SOAP formatting, or binary
• Significant difference -
• Distributed Object programming paradigm
• As opposed to message passing

8
SOAP on the Microsoft Platform

• ASP.NET
• .asmx web services
• add web reference
• Still relies on IIS
• Support in v2.0 for WS-I Basic Profile
• No other standards support is built-in

9
SOAP on the Microsoft Platform

• Web Services Enhancements
• Now in v3.0
• Adds support for some WS- protocols
• Allows non-IIS services
• Allows non-HTTP transport

10
SOAP on the Microsoft Platform

• Windows Communication Foundation
• Introduced in .NET FX 3.0
• Entirely new communications API
• Allows for changes in transports and protocols
• Very extensible
• Can use IIS, or not
• Can use HTTP, or not
• Ships with named pipes, TCP, MSMQ, P2P

11
Standards

• WS-Security
• Message-level security
• WS-SecureConversation
• Optimisation for WS-Security
• WS-Policy
• Contractual info not contained in WSDL
• WS-SecurityPolicy
• Policy rules that are specific to security
• WS-Trust
• Defines STS

12
Approaches Distributed Objects

• A long history on the Microsoft platform
• DCOM, .NET Remoting
• Difficulty in managing object lifetimes
• Wisdom of making network transparent?
• Perhaps the developer needs to know?
• Simple, OO paradigm easy to code against

13
Approaches Message Exchange

• Probably still use a proxy class
• How is message body formed?
• Serialized object graph, or
• Application code emits XML content directly
• SOAP is all about message exchange really
• Just a question of how this appears to the
  application developer
• Different exchange patterns
• Request/response, one-way, duplex, intermediaries

14
Approaches - SOA

• There are multiple definitions of SOA
• Not necessarily tied to web services
• A service performs one standalone piece of the
  business process
• Participates in message exchange
• No notion of data behaviour, as in OO
• Should use contract policy so that clients can
  be built correctly
• Sometimes see service brokers

15
.NET Remoting
ASMX
Interop with other platforms
Extensibility Location transparency
Attribute- Based Programming
Message- Oriented Programming
WS- Protocol Support
Enterprise Services
System.Messaging
WSE
16
Distributed Applications
Client

• Services pass messages described by a contract
• Service may provide metadata, describing -
• The contract
• The policy applied to communication

17
Mechanics of Communication
Service
Client
What do I send?
Contract
Where do I send it?
Address
How should I send it?
Binding
18
Mechanics of Communication
Service
Client
19
Contracts
ServiceContract public interface INuggetAccess
OperationContract string GetTopics()
.NET Interface
Service
Client
20
Richness of metadata
Service

• Service can advertise a lot of info to a client
• WSDL
• WS-Policy (security etc)
• Can do so over
• HTTP
• WS- MetadataExchange
• Makes building clients a lot simpler

Endpoints
Contracts
21
Contract Details

• Message exchange might be -
• One-way, Request/Response, Two-way (Duplex)
• WCF also supports serialization models from .NET
  2.0
• System.Xml.XmlSerialization, System.Runtime.Serial
  ization

22
Hosting Services
public class Service INuggetAccess
string GetTopics()
IIS
lt_at_ ServiceHost ServiceService" gt
References
NuggetAccessService.svc

• ServiceHost is the key class for hosting
• Needs manual steps in your host application
• Automatically done by IIS when provided with a
  .svc file
• IIS handles additional transports in v7.0

23
Windows Communication Foundation
24
WCF sketched architecture
Client
Service
Metadata
Your code
Your code
25
Standard Framework Bindings

• Pre-built set in the framework
• WS-I Basic Profile
• WS- on HTTP
• TCP
• Named Pipes
• MSMQ
• Peer
• Configure/code your own as a "custom" binding

26
Instancing, Concurrency, Sessions

• Service classes can be instantiated -
• Singleton, Per-Call, Per-Session, Shareable
• Service code can be either -
• Single threaded, Re-entrant or Multi-threaded

Service
Message A
Singleton
Message B
Message C
Client
27
Instancing, Concurrency, Sessions

• Service classes can be instantiated -
• Singleton, Per-Call, Per-Session, Shareable
• Service code can be either -
• Single threaded, Re-entrant or Multi-threaded

Service
Message A
Single Call
Message B
Single Call
Message C
Client
Single Call
28
Instancing, Concurrency, Sessions

• Service classes can be instantiated -
• Singleton, Per-Call, Per-Session, Shareable
• Service code can be either -
• Single threaded, Re-entrant or Multi-threaded

Service
session
Message A
Per Session
Message B
Per Session
Message C
Client
29
Security in WCF Out of the box

• Transport Level
• HTTPS
• IIS authentication modes
• Message Level
• UserName, X.509 Certificate, Windows
• IssuedToken that is, federated security
• ASP.NET membership and role providers

30
Security in WCF - Extensibility

• Roll your own
• Username validator
• Token validator
• Credential types
• Security Token Service
• SAML claims
• Etc...

31
Federated Security with WCF
32
WCF in .NET FX 3.5

• Most of the new stuff isnt SOAP
• Well see some of that in the next session
• Client proxies and partial trust environments
• Durable services
• Coming together with Workflow

33
Partial Trust

• Now possible to call through WCF proxies in a
  partial trust environment
• Various caveats
• Transport is HTTP only, Security is HTTPS only
• Encodings is all except MTOM
• Bindings are BasicHttpBinding, WsHttpBinding,
  WebHttpBinding
• Other limitations
• No Reliable Messaging, Transactions, Secure
  Conversation

34
Durable Services

• Provider-based framework for easily adding
  long-running abilities to WCF services

Host (e.g. IIS)
client
implementation
state
token
state
35
Durable Services

• Provider-based framework for easily adding
  long-running abilities to WCF services

Host (e.g. IIS)
client
implementation
state
token
state
36
Workflow

• WF is not strictly about services, or SOAP
• In .NET FX 3.5, WF has some WCF integration
• A workflow can consume services
• We can implement a service as a workflow

37
Services with WF
38
Summary

• The Microsoft platform has evolved along with
  SOAP and its accompanying standards
• Culminating in WCF
• The most flexible, extensible communications
  stack weve ever produced

39
Additional Information

• MSDN Developer Center for Web Services
• http//msdn2.microsoft.com/en-gb/webservices/defau
  lt.aspx
• Standards
• http//www.w3.org
• http//www.ws-i.org
• http//www.oasis-open.org
• SOA
• http//www.opengroup.org/projects/soa
• http//wiki.oasis-open.org/soa-rm
• WCF
• http//netfx3.com/content/WCFHome.aspx
• WF
• http//netfx3.com/content/WFHome.aspx

40
MSDN in the UK

• Visit http//msdn.co.uk
• Newsletter
• Events
• Screencasts
• Blogs

41
(No Transcript)