the soap story -...
TRANSCRIPT
The SOAP Story
Martin Parry
Developer & Platform Group
Microsoft Ltd
http://martinparry.com
Agenda
Definitions
SOAP through the ages
SOAP and “standards”
Approaches to building and using services
SOAP Services with WCF
Services and the Workflow Foundation
Definitions
SOAP
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
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
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
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=http://....”)
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
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
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
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
“Standards”
WS-SecurityMessage-level security
WS-SecureConversationOptimisation for WS-Security
WS-PolicyContractual info not contained in WSDL
WS-SecurityPolicyPolicy rules that are specific to security
WS-TrustDefines STS
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
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 reallyJust a question of how this appears to the application developer
Different exchange patternsRequest/response, one-way, duplex, intermediaries
Approaches - SOA
There are multiple definitions of SOANot 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”
Interopwith otherplatforms
ASMX
Attribute-Based
Programming
Enterprise Services
WS-*ProtocolSupport
WSE
Message-Oriented
Programming
System.Messaging
ExtensibilityLocation transparency
.NET Remoting
Distributed Applications
Services pass messages described by a contract
Service may provide metadata, describing: -The contract
The policy applied to communication
“Client”Message
Message
“Service”
Metadata
Message (SOAP)
Headers: Addressing, Security, etc.
Body: Payload
What do I send?
Where do I send it?
How should I send it?
Contract
Address
Binding
Mechanics of Communication
“Service”“Client”
Transport?
Encoding?
Security?
Mechanics of Communication
“Service”“Client”
EndpointContractBindingAddress
EndpointContractBindingAddress
EndpointContractBindingAddress
Contracts[ServiceContract]
public interface INuggetAccess
{
[OperationContract]string[] GetTopics();
}
.NET Interface
<definitions>
…
<portType>
<operation name=“GetTopics”> …
</portType>
</definitions>
WSDL
svcutil.exe
“Service”“Client”
[ServiceContract]
public interface INuggetAccess
{
[OperationContract]string[] GetTopics();
}
public class NuggetAccessService :
INuggetAccess
{string[] GetTopics() { }
}
Implements
Consumes
request metadata (WSDL)
Richness of metadata
Service can advertise a lot of info to a client
WSDL
WS-Policy (security etc)
Can do so overHTTP
WS- MetadataExchange
Makes building “clients” a lot simpler
Service
Contracts
Endpoints
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.Serialization
[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
Hosting Servicespublic class Service :
INuggetAccess
{string[] GetTopics() { }
}
IIS
<%@ ServiceHost Service=“Service" %>
NuggetAccessService.svc
MyApp.exe
ServiceHost host =
new ServiceHost();
host.Open();
References
ServiceHost is the key class for hostingNeeds manual steps in your host application
Automatically done by IIS when provided with a .svc file
IIS handles additional transports in v7.0
Windows Communication Foundation
Client
WCF – sketched architecture
Binding(ordered list of channel types & config)
channel type N
channel type 2
channel type 1config
config
config
Your code
Service
Your code
Met
adat
a
objects XML
formatting
channel
channel
channel
Transport Channel (HTTP, TCP, MSMQ, Pipes, Peer)
channel
channel
channel
decodingencoding
behaviours behaviours
Standard Framework BindingsPre-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
Binding
Transactions
Reliability
Security
channels
Configuration
Configuration
Configuration
Transport
Configuration
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
Client
Service
Singleton
Message B
Message C
Message A
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
Client
Service
Single Call
Single Call
Single Call
Message B
Message C
Message A
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
Client
Service
Per Session
Message B
Message Asession
Per SessionMessage C
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
Security in WCF - Extensibility
Roll your own
Username validator
Token validator
Credential types
Security Token Service
SAML claims
Etc...
Federated Security with WCF
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
Partial Trust
Now possible to call through WCF proxies in a partial trust environment
Various caveatsTransport 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
Durable Services
Provider-based framework for easily adding long-running abilities to WCF services
client
Host (e.g. IIS)
implementation
stateresponse + token
initial call
serialize and store
state
token
Durable Services
Provider-based framework for easily adding long-running abilities to WCF services
client
Host (e.g. IIS)
implementation
state
second call + token
load and deserialize
state
token
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
Services with WF
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
Additional Information
MSDN Developer Center for Web Services
http://msdn2.microsoft.com/en-gb/webservices/default.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
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