1. The SOAP Story Martin Parry Developer & Platform Group Microsoft Ltd

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 WSDL Initially: Simple Object Access Protocol
It’s 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(“soap:wsdl=

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 WS-SecureConversation WS-Policy
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. Location transparency
ASMX
.NET Remoting
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”
Message (SOAP)
Headers: Addressing, Security, etc.
Body: Payload
“Service”
Metadata
Message
Message
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
Address
Where do I send it?
How should I send it?
Binding
Transport?
Encoding?
Security?

18. Mechanics of Communication
“Service”
“Client”
Endpoint
Contract
Binding
Address
Endpoint
Contract
Binding
Address
Endpoint
Contract
Binding
Address

19. request metadata (WSDL)
Contracts
[ServiceContract]
public interface INuggetAccess {
[OperationContract] string[] GetTopics(); }
<definitions> …
<portType>
<operation name=“GetTopics”> …
</portType>
</definitions>
WSDL
svcutil.exe
.NET Interface
Consumes
request metadata (WSDL)
Implements
“Client”
“Service”
[ServiceContract]
public interface INuggetAccess {
[OperationContract] string[] GetTopics(); }
public class NuggetAccessService :
INuggetAccess
{ string[] GetTopics() { }

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: - Service Data Message
[ServiceContract]
public interface INuggetAccess {
[OperationContract] List<TopicInfo> GetTopics(); }
Service
[DataContract(Namespace=…)]
public class TopicInfo {
[DataMember]
public int Id }
Data
[MessageContract]
public class TypedMessage {
[MessageBody]
[MessageHeader] }
Message
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.Serialization

22. Hosting Services ServiceHost is the key class for hosting
public class Service :
INuggetAccess
{ string[] GetTopics() { } }
IIS
MyApp.exe
ServiceHost host =
new ServiceHost();
host.Open();
ServiceHost Service=“Service" %>
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
objects
XML
Service
Your code
Metadata
Your code
behaviours
behaviours
formatting
Binding
(ordered list of channel types & config)
channel type N
channel type 2
channel type 1
config
channel
decoding
encoding
channel
Transport Channel (HTTP, TCP, MSMQ, Pipes, Peer)

25. Standard Framework Bindings
5/22/2019
Standard Framework Bindings
Binding
Transactions
Reliability
Security
channels
Configuration
Transport
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 25

26. Instancing, Concurrency, Sessions
5/22/2019
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 26

27. Instancing, Concurrency, Sessions
5/22/2019
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 27

28. Instancing, Concurrency, Sessions
5/22/2019
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 28

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 isn’t SOAP
We’ll 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
initial call
serialize and store
implementation
state
response + token
token
state

35. Durable Services
Provider-based framework for easily adding long-running abilities to WCF services
Host (e.g. IIS)
client
second call + token
load and deserialize
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 we’ve ever produced

39. Additional Information
MSDN Developer Center for Web Services
“Standards”
SOA
WCF WF

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