Microsoft PowerPoint - PDF 2

							ASL203: Building RIAs with AJAX,
      Silverlight and WCF

     Michele Leroux Bustamante
       Chief Architect, IDesign
     Microsoft Regional Director
About Michele
Leroux Bustamante
L      B t     t
• Chief Architect, IDesign: www.idesign.net
• Microsoft Regional Director
• MVP – Connected Systems
                       y
• Author: Learning WCF (O’Reilly
  2007/2008), ASP.NET Pro (WCF Column),
  MSDN, CoDe
• Speaker: Tech Ed, PDC, Dev Connections,
     West,
  SD West and other international
  conferences
• Blogs: www dasblonde net
         www.dasblonde.net,
  www.thatindigogirl.com
Rich Internet Applications

• Rich Internet Applications (RIAs) include
  AJAX and Silverlight clients
• Both run in the browser
• Both rely on asynchronous calls to collect
  data from services
  d t f          i
• Both enable a richer client-side experience
  ●   AJAX using JavaScript
  ●           g       g                      p
      Silverlight using code-behind, JavaScript or
      dynamic languages (DLR)
Rich Internet Applications and WCF

• How do AJAX and Silverlight clients
  communicate with WCF services?
• How should the WCF service be designed
  to better support RIAs?
  What tools        t there t simplify
• Wh t t l are out th       to i lif
  communications between AJAX or
  Silverlight d
  Sil li ht and WCF?
• What kind of security models are
  available?
WCF Service Design Options

• Protocols:
  ●   SOAP
  ●   Plain-Old-XML
      Plain Old XML (POX)
  ●   JavaScript Object Notation (JSON)
  ●   AtomPub/RSS
  ●   Representational State Transfer (REST)
• Implementations:
  ●   WCF services
  ●   ADO.NET Data Services (based on WCF)
SOAP Services

•   ServiceContractAttribute
•   OperationContractAttribute
•   S i H t S i H tF t
    ServiceHost, ServiceHostFactory
•   BasicHttpBinding
Non SOAP
Non-SOAP Services

• ServiceContractAttribute
• OperationContractAttribute
• WebGetAttribute, WebInvokeAttribute
  W bG tAtt ib t W bI        k Att ib t
• WebServiceHost/Factory,
  WebHttpBehavior
• WebScriptServiceHost/Factory,
          p                    y,
  WebScriptEnablingBehavior
• WebHttpBinding
DEMO

• Creating SOAP and RESTful services
AJAX and WCF

• Can use XmlHttpRequest to invoke WCF
  services
           SOAP POX
• Supports SOAP, POX, or JSON
• POX or JSON services may be RESTful
• Process asynchronous response with
  JavaScript
AJAX and WCF
        Browser




         Page


                      SOAPService




     XmlHttpRequest
                      POXService




                      JSONService
DEMO

• Calling WCF services from AJAX
Java Script Proxy
         Browser

                        Script
      ScriptManager     Reference

          Page


                                        /JSONService/js

                        Generated
                        Proxy
                                               JSONService
                                               JSONS i
     JavaScript Proxy




     XmlHttpRequest
                              /JSONService/
                              OperationName
ASP.NET AJAX 4.0 Preview 4

• Even more support for AJAX clients to
  consume services
• DataContext
  ●   For WCF services
            C
• AdoNetDataContext
  ●   For ADO.NET Data Services
• Also much improved experience
   y        y       g             y
  dynamically binding data from async calls
  ●   But that’s another session ☺
DEMO

• New features for invoking services
Silverlight and WCF

• Can use XmlHttpRequest or WebClient to
  invoke WCF services
  ●            SOAP,
      Supports SOAP POX or JSON
• SOAP services are supported by Add
  Service Reference
  ●   Proxy exposes asynchronous methods
  ●   Very convenient
      V          i
DEMO
Dealing with SOAP Faults

• WCF services throw FaultException
  derivatives to report errors
• Faults are reported with an HTTP error
  code 400/500
  Carry SOAP envelope with <fault>
• C                  l      ith f lt
  according to SOAP 1.1 or 1.2
• Not so meaningful with non-SOAP clients
  and services
SOAP Faults and AJAX

                                    non
• FaultException not meaningful to non-
  SOAP services
• HTTP 400 bad request by default
• Non-SOAP endpoints should handle
        ti    differently
  exceptions diff     tl
• Error handler can provide string message
  in 400 error code
                           pp
• WCF REST Starter kit supports
  WebException
SOAP Faults and Silverlight 2

• Anything other than HTTP 200 details are
  swallowed by the browser
• Many documented workarounds are
  somewhat unacceptable
  ●   Catch d t              t f
      C t h and return as part of message
  ●   Use message contracts with common base
  ●   Provide       i     d i just f SL clients
      P id a service endpoint j      for  li
• Acceptable approaches include
  ●   Converting 400/500 errors to 200 at the
      service or at the client
DEMO

• Dealing with exceptions
ASP.NET Security

  ASP.NET
• ASP NET compatibility allows services to
  be processed by the ASP.NET pipeline
  IIS,
• IIS Windows or Forms authentication
• Protect service pages along with other
  ASP NET resources
  ASP.NET
• If you REALLY want to:
  ●   Pass custom headers to services and do
      custom authentication
  ●   Or, custom WS* UserName profile
Cross Domain
Cross-Domain Support

• AJAX and Silverlight only allow calls to the
  originating domain
  ●   Unless the target domain includes a cross
      domain scripting policy
  Crossdomain.xml
• Crossdomain xml
  ●   Supported by AJAX or Silverlight
  Clientaccesspolicy.xml
• Cli t         li     l
  ●   Silverlight only, priority over crossdomain.xml
DEMO

  Cross domain
• Cross-domain support
Resources

• Learning WCF
  ●   Michele Leroux Bustamante, O’Reilly 2007
  ●                              VS2008,
      Reprinted with updates for VS2008 July 2008
• My Blog: http://www.dasblonde.net
  ● S post-conference blog post
    See          f
  for samples from this and other
  sessions at Dev Connections!
• Book blog:
www.thatindigogirl.com