Transcript Agenda - New York University

Windows Communication Framework
(WCF) Code-Named “Indigo”
“Microsoft’s next-generation Web Services
technology, Indigo, will significantly expand both the
scope and the capabilities of Web Services”
-Gartner, Feb 11th 2005
Agenda
• What is WCF (Indigo)?
• Existing Microsoft Distributed Application Technologies
• Shipping Schedule and Platforms
• Relation to BizTalk and Visual Studio 2005 (Whidbey)
• Object vs Service-Oriented Development
• WCF Programming Model
• Service Class
• Service and Data Contracts
• Hosting a WCF Service
• Endpoints
• Bindings
WCF Client Proxy
• Interoperability and Migration to WCF (Indigo)
• Appendicies
• Other WCF Offerings
• WCF Relation to SOA and Enterprise Service Bus (ESB)
• WCF Architecture
• WCF Supported WS-* Standards
• Resources – Video & Article
What is WCF (Indigo)?
Windows Communication Framework, code-named Indigo,
is Microsoft’s new unified programming model for
developing distributed application based on serviceorientation.
We say “unified” because WCF encompasses and further
extends the capabilities of Microsoft’s existing technolgies
for building distributed applications.
 ASMX (web services)
 .NET Remoting
 Web Services Enhancements (WSE)
 .NET Enterprise Services (successor to COM+)
 System.Messaging (successor to MSMQ)
WCF – Unified Programming Model
• WCF is built on top of and extends the Microsoft .NET Framework v2.0 in the
System.ServiceModel namespace.
• WCF consolidates all current distributed application development technologies
under a single API and framework.
• Developers continue to develop distributed applications in the object-oriented
manner they used to and Indigo takes care of the service-oriented plumbing (more
on this later).
Existing Microsoft Distributed
Application Technologies
 ASMX
 Originally shipped with the .NET Framework v1.0 and referred to as XML Web Services.
 Used to create basic web services functionality within ASP.NET.
 Supports only SOAP 1.1 over HTTP and WSDL 1.1.
 Performance greatly improved in the .NET Framework v1.1, but lacked WS-* support
 Upcoming ASMX v2.0 will bring support for SOAP v1.2 but no support for WS-* Standards
 .NET Remoting
 Shipped as part of the .NET Framework v1.0
 Ideally used for information exchange between .NET applications.
 Web Services Enhancements (WSE)
 Currently WSE 1.0 and WSE 2.0 as released. WSE 3.0 will be released along with VS2005
 Used to support advanced WS-* web services standards such as WS-Security, WS-Trust, WSAddressing.
 Used in conjunction with ASMX to provide WS-* support, or independently to build web services.
 .NET Enterprise Services (successor to COM+)
 The .NET implementation of COM+
 Used to implement distributed transactions in a Microsoft Enterprise
 System.Messaging (successor to MSMQ)
 The .NET implementation of MSMQ
 Used for queue management functionality
WCF – Future of MS Programming
“Microsoft’s overwhelming dominance in desktop operating systems means that
Indigo will automatically have an enormous impact, jump-stating a new
generation of web services-enabled application and expanding the possibilities of
services-oriented architectures.” - Gartner, Feb 11 2005
“Indigo is a ‘platformization’…By turning it (Indigo) into an operating system
component, we’re able to get a level of performance and compatibility out of this,
which is uncharacteristic. - John Shewchuk, Microsoft Indigo Architect
“Indigo makes it easier for an average Microsoft solutions provider to build
enterprise distributed software” - Tim Huckaby, CEO of InterKnowlogy
“deliver a unified development experience across multiple axes, including
distance (cross-process, cross-machine, cross-subnet, cross-intranet, crossInternet), topologies (farms, fire-walled, content-routed, dynamic), hosts
(ASP.NET, EXE, Windows Presentation Foundation, Windows Forms, NT
Service, COM+), protocols (TCP, HTTP, cross-process, custom), and security
models (SAML, Kerberos, X509, username/password, custom).” MSDN –
Windows Communication Framework FAQ
Shipping Schedule and Platforms
• The Community Technology Preview (CTP) of WCF was released in March
2005. A Beta was released in May 2005. Final release in 2006. More details in
Shipping Schedule and Vehicles section.
• Final version of WCF will be shipped as part of Microsoft’s next operating
system, Windows Vista (code-named ‘Longhorn’), sometime in 2006.
• WCF will also be available for both Windows XP and Windows Server 2003
as part of the WinFX Runtime Components. WinFX is the new windows
programming interface for Windows Vista.
• Since WCF extends it with the System.ServiceModel
namespace, it’s delivery mechanism will be similar to
the that of the .NET Framework
Relation to BizTalk Server Technology
WCF and BizTalk are complementary technologies.
• BizTalk offers business process orchestration, message transformation and
business activity monitoring via GUI tools
• WCF is a unified programming framework for developing service-oriented
distributed applications.
When the final version of WCF ships, BizTalk will offer an adapter that will allow
WCF services to participate in business process orchestration. In future versions of
BizTalk, WCF will become the core for BizTalk’s messaging and web services
functionality.
Relation to Visual Studio 2005 (Whidbey)
Visual Studio 2005 (code-named Whidbey) is the next .NET IDE release
and will be based on the new Microsoft .NET Framework 2.0
Since WCF extends the .NET Framework 2.0 as a set of additional
managed class libraries under the System.ServiceModel namespace, it is
fully compatible with VS2005.
Developers can thus program distributed service-oriented applications
with WCF in VS2005 in the CLR-compatible language of their choice.
Object and Service Oriented
Development
Do object-oriented and service-oriented development conflict?
•
They are complementary. Serve two separate purposes:
•
OO - Used in the internal design of applications for functional and business logic
•
SO – Better suited for application-to-application communication than objects.
•
There are plenty of OO mature development tools available, but using services as a
fundamental software building block is a new idea. There are few semi-mature IDEs.
Both Rely on Contracts in some way. [Explain]
•
Enter WCF (Indigo)
•
WCF allows developers who are used to designing object-oriented applications based on
the .NET Framework to also build service-oriented applications in a very similar way.
•
Since WCF utilizes the SOAP transport, developer applications can interact with
Windows and non-Windows applications utilizing reliability, security, and transactions.
Four Tenets for Service-Orientation in WCF
1.
2.
3.
4.
Share Schema, not Class – Clients\Services only interact standardized XML contracts.
Services are Autonomous – Clients\Services agree only on contracts, not implementation.
Boundaries are Explicit – i.e. DCOM tried to disguise remote objects as local objects
Use Policy-Based Compatibility – Standards such as WS-Policy are used to determine
which optional requirements (security, addressing) a client and service must implement.
WCF Programming Model
Core Concepts
1. Service Class
• Service Contract
• Data Contract
2. Host Environment
3. Endpoints
4. Bindings
WCF Service Class
A WFC service class is the same as an OO class, but they additionally
define one or more contracts which it implements.
Each WFC service class implements at least one service class, which
defines the methods and operations of a web service.
Optionally, a WFC service class may implement a data contract, which
defines the structure of complex data the service may exchange.
WCF Service Contract
Essentially the service contract defines which methods in the service class are exposed and
callable by a web services client.
How is this achieved in the .NET World?
The designers of the Common Language Runtime (CLR) anticipated the need for
extensibility in the .NET Framework so they provided support for attributes. Attributes can
appear before class and method definitions, and a few other places. The presence of attributes
changes the behavior of whatever it’s attached to. Some examples are the [WebMethods]
attribute in ASMX, or the [Transaction] attribute in Enterprise Services.
Important to distinguish that OO and SO both rely on some kind of contract for exposing
methods and properties:
• OO uses keywords such as public and private to determine outside (the object) access
to methods and properties
• SO in WCF uses attributes such as [OperationContract]
Two Ways to Implement a Service Contract
1.
2.
Mark a service class with the [ServiceContract] attribute.
Create a service contract interface, then have separate class implement that interface.
Service Contract Implementation
Method #1
using System.ServiceModel;
Method #2
using System.ServiceModel;
[ServiceContract]
[ServiceContract]
interface Icalculator {
class Calculator {
[OperationContract]
Interface
int Add(int a, int b);
[OperationContract]
[OperationContract]
private int Add(int a, int b)
int Subtract(int a, int b);
{ return a + b; }
}
[OperationContract]
class Calculator : ICalculator {
public int Subtract(int a, int b)
public int Add(int a, int b)
{ return a - b; }
{ return a + b; }
public int Subtract(int a, int b)
public int Multiply(int a, int b)
{ return a - b; }
{ return a * b; }
public int Multiply(int a, int b)
}
{ return a * b; }
}
Service
Class
Data Contract Implementation
Data Contracts are Optional, and are not required to build a WCF service class.
A contract used by the service class to describe the data to be exchanged in a web services
communication. More specifically, they define how an in-memory type will be represents on the
wire during communication. This transformation process is known as serialization.
The reason they are optional is because sometimes the data to be exchange is implicit in the
service contract defined. For example, the Add and Subtract methods on the previous slide
define that the two inputs are of type Integer and the so is the return value. Method inputs of
complex types (i.e. structures) would require an explicit data contract.
Data Contracts are defined using the [DataContract] attribute. The attribute is used on classes,
structures, and other types. The members (methods and properties) of those types marked with
the [DataMember] attribute will be serialized. [Further Explain]
[DataContract]
struct Customer {
[DataMember] public string Name;
int public age;
[DataMember] private int CreditRating;
}
In this example, if a method like
Add or Subtract took an input of
type Customer then only Name and
CreditRating would be serialized and
passed to the method.
Quick Refresh Point
Core Concepts
1.
2.
3.
4.
Service Class
• Service Contract
• Data Contract
Host Environment
Endpoints
Bindings
WCF Host Environment (Brief)
A couple of options for hosting WCF Applications exist:
1.
Web Application Hosting
•
IIS 5.1, 6.0, and 7.0
•
SOAP over HTTP only
2.
Self-Hosted Applications
•
Run in arbitrary process created as a console app or Windows service
3.
Windows Activation Service
•
Longhorn only feature. Provides IIS functionality without the web server
•
Can host HTTP, TCP, IPC, and MSMQ solutions.
•
IIS 7.0 will be based on Windows Activation Service
WCF Endpoints and Bindings
Endpoints
Represent the ‘gateway’ for accessing a WCF service. It’s a point of contact that clients
use to interact with the service. A WCF service can have one or more endpoints.
The A, B, C of Endpoints
Endpoints are comprised of three essential elements:
• Address – Where is the service located?
• Binding – How do I communicate with the service?
• Contract – What does the service offer?
All three are independent. A contract can support several bindings and visa versa.
WCF Endpoints - Other Notes
Contract
A class marked with [ServiceContract] that implements no interfaces, can
expose only one service contract. Thus all it’s endpoints expose the same
contract. If a class implements two or more interfaces marked with
[ServiceContract], then different endpoints can expose different contracts.
Address
Addresses are URLs that identify a machine and a particular endpoint
hosted by that machine.
Binding
The binding determines what protocol combination can be used to access
an endpoint along with other requirements such as whether the
communication is reliable and what security mechanisms can be used. For
example, if a service allows clients to access it using either SOAP over
HTTP or SOAP over TCP then each of these scenarios is a distinct binding.
The service would thus need to expose two endpoints, one with a SOAPover-HTTP binding and the other with a SOAP-over-TCP binding.
WCF Endpoints
An WCF endpoint can be correlated with a WSDL contract.
• Address – equivalent to the <wsdl:service> section.
•Binding – equivalent to the <wsdl:binding> section.
•Contract – equivalent to the <wsdl:portType>, <wsdl:message>, and
wsdl:type> sections.
WCF Bindings
WCF comes with several predefined bindings to choose from:
•BasicProfileHttpBinding: conforms to the Web services Interoperability Organization (WS-I) Basic
Profile 1.0, which specifies SOAP over HTTP. This is an endpoint's default binding if none is explicitly
specified.
•BasicProfileHttpsBinding: conforms to the WS-I Basic Security Profile 1.0, which specifies SOAP
over HTTPS.
•WsHttpBinding: supports reliable message transfer with WS-ReliableMessaging, security with WSSecurity, and transactions with WS-AtomicTransaction.
•WsDualHttpBinding: like WsHttpBinding, but also supports interaction using duplex contracts.
Using this binding, both services and clients can receive and send messages.
•NetTcpBinding: sends binary-encoded SOAP, including support for reliable message transfer,
security, and transactions, directly over TCP. Can only be used for Indigo-to-Indigo communication.
•NetNamedPipeBinding: sends binary-encoded SOAP over named pipes. This binding is only usable
for Indigo-to-Indigo communication between processes on the same Windows machine.
•NetMsmqBinding: sends binary-encoded SOAP over MSMQ, as described later. This binding can
only be used for Indigo-to-Indigo communication.
WCF Endpoint Configuration
Endpoints usually defined using a configuration file associated with the WCF
service. They are not defined via attributes, like Contracts.
Example of an endpoint configuration file:
<configuration>
<system.serviceModel>
<services>
<service serviceType="Calculator">
<endpoint
contractType="Calculator"
bindingType="basicProfileHttpBinding />
</service>
</services>
</system.serviceModel>
</configuration>
Notes:
• <services> element can hold one or more <service> elements.
• <serviceType> attribute of the <service> element identiofies the service class
implementing the contract.
• <service> element can contain one or more <emdpoint> elements.
• <contractType> of the <endpoint> element identifies the contract in the ABC paradigm.
• <bindingType> of the <endpoint> element identifies the binding in the ABC paradigm.
WCF Client
Similar to non-WCF web services, a client is provided with a proxy
class, which is uses to formulate it’s requests to the provider service.
To generate a proxy class in WCF, you use the svcutil utility, given the
service contract for the a particular endpoint.
The svcutil utility can also read standard WSDL contracts to generate a
proxy class for use by a WCF client.
Interoperability and Migration with
Existing Distributed Applications
Appendix A – Other WCF Offerings
• Binary Optimized SOAP
• Local Behavior - service instance lifetime, concurrent access.
• Security
• Transactions
• Queuing
• Messaging Options
• Traditional RPC
• Asynchronous RPC
• Traditional messaging
• Message-based RPC
Appendix B – Other Topics
• WCF (Indigo) place in an SOA
• WCF (Indigo) vs. Enterprise Service Bus (ESB)
Appendix C - WCF Architecture
Appendix D
Supported WS-* Standards
Appendix E – Article Resources
ARTICLES
Microsoft's Indigo Will Advance Web Services
http://www.gartner.com/DisplayDocument?doc_cd=126297
Microsoft's Indigo Technology Will Play a Role in Most Enterprises
http://www.gartner.com/DisplayDocument?doc_cd=118259
Windows Communication Foundation (Indigo) FAQ
http://msdn.microsoft.com/windowsvista/support/faq/communication/
Introduction to Indigo: Early Look
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnlong/html/introindigov1-0.asp
Introduction to Building Windows Communication Foundation Services
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnlong/html/introtowcf.asp
Developing .NET Web Services with Beta 2
http://msdn.microsoft.com/msdnmag/issues/05/04/ServiceStation/
15 seconds Indigo Programming Model
http://www.15seconds.com/issue/050608.htm
15 Seconds : Hosting Indigo Web Services (07/07/05)
http://www.internet.com/icom_cgi/print/print.cgi?url=http://www.15seconds.com/issue/050707.htm
Microsoft Indigo Architect John Shewchuk
http://www.internetnews.com/ec-news/article.php/3357621
Today's Web Service Stack: ASMX 2.0 + WSE 3.0
http://pluralsight.com/blogs/aaron/archive/2005/09/21/14941.aspx
Appendix F – Video Resources
VIDEOS
MSDN TV: Introduction to Indigo (4/7/05)
http://www.microsoft.com/downloads/details.aspx?FamilyID=f3c7ab36-ff95-4b31-a973970733df0b30&DisplayLang=en
MSDN TV: Indigo Security in a Nutshell (4/21/05)
http://www.microsoft.com/downloads/details.aspx?FamilyID=cd937782-706f-4e59-b8c0375287442893&DisplayLang=en
What is WinFX -The New Programming Interface Introduced in Windows "Longhorn“ (11/7/03)
http://msdn.microsoft.com/msdntv/episode.aspx?xml=episodes/en/20031107WINFXBA/manifest.xml