wcf tools and libraries print
TRANSCRIPT
Christian Weyer | thinktecture [email protected]
Jenseits von System.ServiceModel
WCF Tools und Libraries
2
Christian Weyer
• Solution architect and principal consultant at thinktecture
• Focus on
– distributed applications
– service orientation, workflows
– cloud computing
– interoperability
– pragmatic end-to-end solutions
– Windows Server, WCF, WF, MSMQ, Windows Azure platform
• Microsoft MVP for Windows Azure (Architecture)
• Independent Microsoft Regional Director for Germany
• http://blogs.thinktecture.com/cweyer
3
Agenda
• Modeling contracts
• Development process
• Implementation strategies
• Configuration
• On the Wire
• Communication
• Under Load
• Misc
4
Modeling & Metadata
• WCF is strong for interoperability scenarios
(read: Web Services in the WS-* empire)
• Contract modeling can be important to succeed in
interoperability
• Various approaches to improve the level of interoperability
– contract-first modeling
– flattening WSDL
• XSD and WSDL are the
contracts in non-pure-WCF
environments
– least common denomi-
nator
5
Schema-based Contract-First
• Think in XSD and WSDL first
• Two basic steps
– design your contract's data,
messages and interface
– generate code from the
contract
• Tool support would be nice
6
Flattening WSDL
• Still, a number of Web Services stacks do not understand
factored-out WSDLs
– and we are not always dealing with the latest builds and
versions, anyway
• We need a way to put all the WSDL data into one ‚file‘
– WCF by default generates multiple files/links
– Watch out for XML
namespaces...
7
Development Process
• Having a look at what a service provides and how it behaves
can help understanding how to integrate it into your
application architecture
– simple integration testing services
• WCF is complex and ‚understanding WCF‘ means
‚seeing WCF‘
– debugging services and consumers
• Not always are the services already implemented and
available
– need ways to mock services
8
WcfTestClient
• Need to test services
– whether implemented with WCF or other stacks
– use WSDL metadata
• Visual Studio comes with a generic services client test tool
– WcfTestClient.exe in
C:\Program Files (x86)\Microsoft Visual Studio 10.0\
Common7\IDE
– very basic features, but good
enough to take a first stab
9
wcfstorm
• WCF & Web Services test client and performance test tool
– free lite version available (no functional & perf testing)
10
MockingBird
• MockingBird Service Simulator
– configurable message interceptor backed by a generic
simulation engine
– can act as a stand-in for any web service
– includes a set of tools to help build and test mock services
• Plays nicely with the contract-first approach
11
WCF Debugger Visualizers
• Visual Studio 2005 shipped with a feature called debugger
visualizers
– visually view useful information about objects during
debugging
• WCF Visualizers contains
– Message
– ChannelDispatcher
– ServiceDescription
– ServiceHost
– ServiceEndpoint (for the client side)
– ClientRuntime
– Binding
– SecurityContext
– Security
– OperationContext
12
Implementation Strategies
• Mapping
– a ‚good‘ architecture seperates the data transfer structures
(aka DTOs) from an internal object entity representation
– need a way to map the data on the outside to the entities on
the inside – and vice versa
– manual mapping may be too error-prone and tedious
• Code generation
– svcutil and ‚Add Service Reference...‘ are not customizable
– customizable code generation can be a life safer
– when using a ChannelFactory-based approach code
generation can ease the pain
• e.g. enhance the DTOs on the consumer side to implement
some base functionality
13
AutoMapper
• An object-to-object mapper
• Uses a fluent configuration API to define an object-object
mapping strategy
• Uses a convention-based matching algorithm to match up
source to destination values
• Geared towards model projection scenarios to flatten
complex object models to DTOs and other simple objects
– better suited for serialization, communication, messaging
– anti-corruption layer between the domain and application layer
• Combine mapper with a bootstrap task in a ServiceHost
– pre-init time-consuming setup
• Alternative: EmitMapper
14
T4 Templates
• T4 is the Text Template Transformation Toolkit
– built into VS 2010
– syntax smells like old ASP code
• T4 editors available through 3rd party offerings
– tangible T4 Editor
– Clarius VisualT4
• Look into T4 Toolbox
– includes several core classes that form a micro-framework for
building composite code generators
– generate multiple output files
– use existing templates for LINQ to SQL, Entity Framework
• Use T4 to generate e.g.
– async contracts from sync interfaces
– client-side DTOs which inherit from a base class and
implement UI-specific interfaces
15
Configuration
• When COM was the DLL hell, then WCF is maybe the
configuration hell
• A trend can be seen to put configuration into code
– instead of .config files
– WCF supports this very well with its verbose API
• If you need to learn the WCF configuration syntax
– XSD IntelliSense in Visual Studio
– SvcConfigEditor tool, especially for diagnostics setup
• If you need to use WCF configuration files
– consider the configSource feature
16
SvcConfigEditor
• C:\Program Files (x86)\Microsoft Visual Studio 10.0\
Common7\IDE
17
configSource
• Feature in the .NET Framework configuration system since
.NET 2.0
– factor your XML-based configuration into several files
– works on any configuration
• WCF‘s system.serviceModel is a configuration section group
– need to use configSource attribute on the sub elements
<configuration>
<system.serviceModel>
<services configSource="services.config" >
</services>
<bindings configSource="bindings.config">
</bindings>
<behaviors configSource=„behaviors.config">
</behaviors>
</system.serviceModel>
</configuration>
18
On the Wire
• In WCF the truth is on the wire. Period.
– ...and even beyond the wire
• WCF messages can be traced
– messages on the transport and the service model layer
– not the verbatim message
• WCF can emit verbose tracing data
– integrated with System.Diagnostics
• Use SvcTraceViewer to inspect both traces and messages
– merge your own traces
• Use Fiddler to see the actual HTTP/S traffic
– for WCF SOAP and Web/HTTP/REST services
19
SvcTraceViewer
• C:\Program Files (x86)\Microsoft Visual Studio 10.0\
Common7\IDE
20
Fiddler
• Acts as a system web proxy
• You can tweak the requests in Fiddler to test different values or
HTTP methods (for WCF Web/HTTP/REST)
• Fiddler can be extended with custom inspectors
– e.g. for WCF binary encoder
21
Communication
• Optimized data serialization can save bandwidth and
also communication/processing time
– built-in binary encoder does a pretty good job
– better alternatives through 3rd party encoders/serializers
– can be useful in mobile scenarios
• Pub/sub
– need for communication patterns beyond request-response
– should be firewall-friendly
– should be able to span multiple platforms
22
Protocol Buffers
• protobuf
– binary serialization format used by Google for much of their
data communications
– small in size: efficient data storage (far smaller than xml)
– cheap to process both at the client and server platform
– independent: portable between different programming
architectures
– extensible: add new data to old messages
• protobuf-net for .NET developers
– can be integrated with WCF
• by using [ProtoBehavior]
• by using a Stream type
23
Fast InfoSet
• Joint standard by the ITU-T and ISO/IEC that specifies a
binary encoding of the XML Information Set (InfoSet)
• Most compact encoding when compared to text, binary and
MTOM encodings
– depending on the structure of the message
• Widely available on Java as well as on other platforms
• For .NET & WCF we need to purchase WCFXtensions from
Noemax
– pre-built bindings with different channels
– can use FI encoder in any binding (via
FiMessageEncodingBindingElement)
24
Duplex messaging
• WCF offers simple duplex messaging
– callback contracts
– binding with duplex support (compositeDuplex binding element
in the stack)
• TCP-based duplex may not even be able to establish a
channel through a firewall
• HTTP-based duplex with wsDualHttp is pretty useless
– two mutual HTTP connections
• Long (or smart) polling as viable duplex approach
– DuplexHttp binding from MSDN
– not compatible with Silverlight‘s polling duplex, but can be
combined
25
WCF Load Test
• Load testing your WCF services based on what you already
have
• Takes a WCF message trace file or Fiddler trace and a WCF
client proxy (or a WCF interface contract)
• Generates a unit test
– replays the same sequence of calls found in the trace file
– unit test can then be used to generate load tests and load-test
the target service
26
Misc
• Dealing with real-world aspects of data in WCF
– thinktecture DataObjectModel:
http://dataobjectmodel.codeplex.com/
• New HTTP features in WCF.vNext
– new web/REST pipeline
– jQuery support
– WebSockets implementation
– http://wcf.codeplex.com/
27
Resources
• http://blogs.thinktecture.com/cweyer
• Data types interoperability between .NET and Java
– http://msdn.microsoft.com/en-us/netframework/gg413252.aspx
• WSCF.blue
– http://wscfblue.codeplex.com/
• MockingBird
– http://mockingbird.codeplex.com/
• WCF Debugger Visualizer
– http://wcfvisualizer.codeplex.com/
• AutoMapper
– http://automapper.codeplex.com/
• EmitMapper
– http://emitmapper.codeplex.com
• T4 Toolbox
– http://t4toolbox.codeplex.com/
28
Resources
• protobuf.-net
– http://code.google.com/p/protobuf-net/
• WCF Xtensions
– http://www.noemax.com/products/wcfx/index.html
– http://www.noemax.com/products/fastinfoset/features.html
• DuplexHttpBinding
– http://archive.msdn.microsoft.com/duplexhttp
• Fiddler
– http://www.fiddler2.com/fiddler2/
– http://code.msdn.microsoft.com/Project/Download/FileDownload.aspx
?ProjectName=silverlightws&DownloadId=12007
– http://identitymodel.codeplex.com/releases/view/52187
• WCF Load Test
– http://wcfloadtest.codeplex.com/
• WcfStorm
– http://www.wcfstorm.com/wcf/home.aspx