Malek Kemmou

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Interoperability and Integrationusing Web
Services

• Malek Kemmou
• Technology Architect, Application Platform
• Microsoft Middle East Africa
• malek_at_microsoft.com

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Agenda

• What is Interoperability
• Services, Objects and Messages
• Common Interoperability Problems
• WS-I Basic Profile 1.0
• The Contract First Approach
• Wrapping existing Code with Web Services

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What is Interoperability

• Disparate systems working meaningfully together
• Multiple Vendors / Platforms
• Communication
• Transport Protocol
• Data Format
• Common Interface
• Meaning
• Objects (RPC)
• Messages (Services)
• Documents (EDI )

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Web Services

• Multiple Vender / platform
• Vender support
• Open Standards
• Communication
• Standard Web Protocols for transport (http, smtp
  )
• Standard "format" for Data Exchange (XML/SOAP)
• Standard Language for interface description
  (WSDL)
• Meaning ?

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RPC vs. Message Approach
Transport
Service
Client
Transport
Both source and destination must understand the
object
Service
Client
Create Message
Interpret Message
Source and destination may see message differently
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RPC vs. Message Approach
Application A
Application B
Programming Language
Programming Language
DBMS
DBMS
Transport Protocols
Object Model
Object Model
Messages
OS
OS
App Server
App Server
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Message Approach

• Advantages
• Loose coupling
• Contract Based (WSDL)
• Total independence of implementation
• Total independence of object model
• Total independence of development platform
• Only message format is important

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A first approach to services

• Create the service
• Auto-Generate its contract
• Service consumers use the contract to create a
  client

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First look at WS
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An Interop test

• Hello World Works great
• Nested Array
• string myArray
• Very simple Nested struct
• public struct Contact
• public string lastName
• public string firstName
• public string telephone
• public Address address
• Datetime
• Untyped DataSet (.NET)
• Typed DataSet (.NET)

public struct Address public string
street public string city public string
country
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Test Results

• HelloWorld works
• Nested struct Works
• NestedArray some issues
• Schema interpretation
• DateTime
• .NET doesnt accept null DateTime (struct)
• Untyped DataSet
• No notion of dynamic schema in java
• Typed DataSet
• XML received correctly
• No Type generation on java side (unless
  proprietary APIs are used)

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Example

• Java Service
• public java.util.Date GetDate()
• //may return null
• .Net Client
• public DateTime GetDate()
• //error when return value is null

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Common Interop Problems

• Dynamic format
• Example untyped Datasets
• Interpretation
• Examples
• DTD in the SOAP message
• ArrayType attributes
• Types
• Example Nillable types
• Non conformant WSDL or SOAP

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WS-I Basic Profile 1.0a

• Industry effort to deliver on Interop
• WS-I (Web Services Interoperability Organization)
• Specification for SOAP
• Specifications for WSDL
• Specification for UDDI
• Conformity Test tools

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Multi-Version interop ?

• Create Service v1
• Auto generate WSDL
• Use WSDL to create proxy on client
• Modify Service (v2)
• Example add field to data
• Auto Generate WSDL
• Use WSDL v2 to create proxy on client v2
• What happens to clients still on v1 ?

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The contract First Approach

• Design the contract First
• WSDL that conforms to WS-I Basic Profile
• Eventually with evolved version support
• Use test tool to test for conformity
• Be aware of Arrays and nillable types
• On the Server
• Generate the interface from the WSDL
• Implement the Web Service
• On the Client
• Generate the proxy from the WSDL

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Advantages

• "Guaranteed" interoperability
• If both client and service Conform to WS-I Basic
  Profile 1.0a
• More granular control over contract
• Take full advantage of XSD constructs
• Additional information (ex facets)
• Possible non object representations
• Use of wildcards to allow evolution
• Conformity Claims

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Designing the WSDL
Service
Port
Binding
Port Type
Operation
Message
Part
Part
Message
Part
Part
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Generate the Server Interface

• WSDL.exe /server WSDL.exe /classes WSDL.EXE
  /si (.Net Framework 2)
• Generates the server interfaces
• Generates all declared types

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Implement the Interface

• Public class myService WebService,
  ServerInterface
• Implement the WebMethods

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Generate the Client Proxy

• WSDL.exe (or Add WebReference)
• Generates the proxy class
• Generates all declared types

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Tips Tricks

• For better reuse
• Splitting the WSDL (wsdlimport)
• Using XSD files (xsdimport)
• For flexibility
• Make use of wildcards
• With WSE (or custom implementation), make use of
  Policy to allow multiple scenarios

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Going Forward

• Advanced architectures
• Conversation models
• Two Way (request/Response)
• One Way
• Duplex
• Service Contract includes policy
• To define possible scenarios

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Going Forward

• Contract First on advanced Web Services (WSE 2)
• Contract involves both WSDL and Policy
• The same approach applies
• Need to implement Policy manually
• Visual Studio 2005
• Visual tools to generate interfaces from contract
• Support for Nillable types
• Basic Profile conformance through attributes
• Intellisense on XML (easier to create WSDL)

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Interoperability Recommendations

• How about WS-Security?
• IBM WebSphere 5.1.2
• Claim conformance to OASIS WSS 1.0
• Reality X509 sign limited, X509 enc WSE-gtWLS
  Limited
• Good Luck hacking deployment files
• BEA WebLogic 8.1.3
• Claim conformance to OASIS WSS 1.0
• Reality X509 sign OK, X509 enc WSE-gtWLS OK
• Sun JWSDP 1.4
• Claim conformance to OASIS WSS 1.0
• Reality X509 sign OK, X509 enc OK
• Happy XML hacking! ltggt

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Interoperability Recommendations

• More WS-Security Findings
• No WS-SecureConversation yet from competitors
• No WS-Policy yet from competitors
• Moving in the right direction with .xml config
  files
• Username/Token Support is sketchy
• Digests appear to be difficult to digest
• No support for timestamps from competitors
• Kerberos Support
• No mainstream support
• Wedgetail 3rd party solution

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Integration of Web Services

• How do I enable Web Services for my existing
  applications?

This is great, but what about my existing
applications that dont support Web Services
today?
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Integration of Web Services

• How do I enable Web Services for my existing
  applications?

Yeah, these tend to be Host Systems
(mainframes), Client/Server applications (VB and
PowerBuilder) and other channels
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Integration of Web Services

• How do I enable Web Services for my existing
  applications?

oh, and bear in mind that all of these systems
are in production. I run my business on these!
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Enabling Web Serviceson existing applications

• COM
• COM1.5 components checkBox enables SOAP on the
  COM components
• COM use COM Interop (managed wrappers) to
  access and wrap functionality into WS
• Java
• Java beans, EJB,etc
• Object brokers and write ASMX WS that wrapp the
  beans
• Write WS in Java
• Message and integration Brokers (exemple
  Biztalk)

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Host Integration

• 4 x Primary Integration Options
• Direct Data Access
• Give me my 10,000 customers
• BLI Business Logic Interface
• Application Integration
• SLI Screen Logic Interface
• Screen Scraping
• Asynchronous Access
• Batch job completed
• All of the above can be abstracted with Web
  Services

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Host Integration

• Microsoft Host Integration Server (HIS) 2004
• Transaction Integrator
• Wrap business rules with COM or .NET wrapper
• Import COBOL, parse declarations, create
  interface
• Publish type library to Component Services
  application
• VS.NET and MMC Experience
• Once in .NET, expose through Web Services Façade

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