@PDC09 – Day 2 – Networking and Web Services with Silverlight

                                                                   (Rough notes from the session)

Getting Data into Silverlight :

• Message Pattern
  • Request / Reply
  • Duplex (email sending, confirmation received from server)
  • Multicast (Server send only 1 copy)
• Interaction Model
  • Operation centric (service and client in memory passing messages)
  • Resource centric (start with data or data model, CRUD)

Data Access Examples :

• “Forms over data” E2E business app  
  (Request / Reply Message Pattern solution / Travel Agent Application example)
  • WCF RIA Services (System.Web.DomainServices)
  • Perscriptive model for CRUD services
  • Great tooling to maximize productivity
  • E2E data: sorting, paging, filtering, validation
• Access data from third party REST service  (System.Net )
  • ClientHttp networking stack (WebRequestCreator.ClientHttp)
    • Integrated with the OS networking stack
    • Support common BrowserHttp stack features for consistent experience
    • Basic, Digest and NTLM authentication is supported in client stack
  • BrowserHttp stack
• Access your database or SharePoint data model using REST (System.Data.Services)
  • WCF Data Services
    • Formerly ADO.NET data services
    • Services with RESTful interface and a set of conventions designed for easy data sharing
  • What is Data Services?
    • Server framework for .NET, other coming
    • Clients for silverlight
  • Accessing Data Services
    • Silverlight ClientHttp stack still an option
    • Data services client more usable as it knows the details of the data service interface
    • Features
      • Full abstraction on top of the services – no need to serialize
      • Data as objects with automatic change tracking
      • LINQ to querie
    • WCF Programming Model
      • Programming Model
        • Core Services
        • Web HTTP Services
        • Data Services
        • RIA Services
        • Workflow Services
      • Service Model
      • Channel Model
• App which accesses server business logic (Operation Centric – System.ServiceModel)
  • Generated proxies
  • Serialization of objects on wire
  • High performance
  • Binary Message Encoder (server throughput increase / message size reduction)
    • Its the default encoder
    • It can also be used with IIS Gzip compression
  • WCF Features
    • Faults enabled in SL3
    • To get full exceptions, use ClientHttp stack
    • Security in cross domain scenarios enabled
      • Normally use browser-managed security (generally not safe for cross-domain use)
      • Transport security with message credentials in cross-domain scenarios
        (Browser never sees the credentials and can’t cache it for malicious things)
• Chat app (System.Net)
  • Duplex Messaging
    • Server push is compelling when server has to notify client of events (email server)
    • Internet: PollingDuplex (HTTP-based)
      • SL4 – performance enhancements and scale across machines (for azure)
    • Intranet: NetTcp (TCP sockets based)
      • Also works for request / reply services
    • Both of above use same programming models, just need to change the binding
• Streamed data (video, stock prices) inside an intranet  (System.Net)
  • Multicast Messaging
    • Scales to a large receiver population
    • Two key shapes
      • Single source multicast
      • Any source multicast
    • Need to expose a policy responder (just like sockets and http)
      • SL4 – policy file is going away for both sockets and multicast if app is elevated