Laurent Bugnion (GalaSoft)

Pretty full room. Sorry VERY full room. Glad I cam not too late, even managed to find a plug for my laptop.

• Any application will need to communicate wit a source of data outside of the browser
• Product catalog, product database, etc...
• What kind of data?
  • media (images, sounds, videos)
  • feeds
  • specific services for your app
  • Existing Intranet services
  • public internet services
• Silverlight 1.0 connects to Media already
  • to connect to other services, use JavaScript and AJAX
• In Silverlight 2, managed code to communicate with all kind of services
• Demo: Use WCF for server-side service
  • Select generic WCF service (specific templates for WCF-based Silverlight will be available later)
  • Create service class with "Contract" attributes, "DataMember" attributes
  • To make a generic WCF service compatible with SL, change the binding to "BasicHttpBinding"
  • In Silverlight, add Service Reference.
  • Then can use methods of the service in Silverlight code.
  • Synchronous calls to WCF service impossible.

I don't quite get that part. Why not support synchrnous calls too, since Silverlight supports multithreading? Will try to ask a question later

• And now we will learn how to databind. ItemsControls are now supported in Silverlight 2, cool! Dr WPF is going to be delighted :)
• DataBinding is now exactly same as WPF. Cool!!

Recap:

• Create service using "Silverlight-Enabled WCF service (not in the beta yet, so need to tweak the generic WCF service).
• Define contract.
• Client, add reference to service and use proxy.

Future:

• Thinking of supporting XAML-only binding to WCF services, for example <GetProducts />

Breaking changes:

• Web references is not there anymore, it'snow "Add service reference"

FYI: Data format is now SOAP and not JSON

Secure services:

• Silverlight uses credentials stored on the browser, for example after an ASP.NET login.
• For WCF to get user identity, ASP.NET compat mode must be turned on.

What about other service types:

• Using "Add service reference" (but only for self-describing services, for example WSDL).
  • Example for Live Search API
  • Works with any SOAP 1.1 basic profile compatible service
  • Server-side doesn't matter
  • Future: Talk to SQL Astoria based services.
  • Cross domain is still an issue!!
  • Except is target opts in accepting cross domain calls. (so that's how they chose to solve that issue, then...)
  • SL looks for policy files: clientaccesspolicy.xml or crossdomain.xml.Specifies what is allowed and what not (subdomain paths, etc...)
    • Already used by Flick2, Yahoo, etc...
• Write the code manually
  • Using XML, for example with XmlSerializer or LINQ to XML. Then, databind to the result.
• Use built-in classes (RSS/Atom feeds)

The good news is that the code is standard .NET code. Only Silverlight specific parts are about the request (URI, etc...)

Allowed URLS.

• HTTP and HTTPS (though with a few restrictions in Beta1)
• Cross domain rule (must have policy file is not local)
• No FTP or FILE URLs
• Socket support! But only with originating server in Beta1, with some port restrictions

HTTP requests:

• Using WebClient class (simple but limited functionality)
• Using HttpWebRequest (advanced)
• Supported features equivalent to Flash
  • GET and POST only
  • Setting header only for same domain GET requests
  • Response: Can read only content type
  • Response code: Only success or fail (403, 404...), no message body
  • Cannot override the browser
    • Can't control or turn off cache
    • Can't control HTTP authentication credentials
    • Can't read/write cookies
• Solution: Use proxy...

JSON:

• Not really a reason to use it in SL except if a service is already existing

Note: Maybe in the future support for binary XML

RSS/Atom:

• Pre-built types SyndicationFeed class
• Syndication restrictions same as in "standard" .NET 3.5

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