Modeling RESTful Data Services: Present and Future

2. Modeling RESTful Data Services: Present and Future Pablo Castro Software Architect Microsoft Corporation

3. Agenda • On data services for the web • Modeling data services • Structure • Security • Behavior • What’s next… • Short- and long-term plans

4. Scenarios for Data Services

5. REST-ish Service Interfaces

6. What does the service look like? Service structure

7. Service Structure • Flexible interface != database interface • Model as appropriate for a service interface • Application-level concepts • Latency, payload size considerations • Consider optimistic concurrency requirements • Server-side schema versus service schema • Access rights control service level schema • Hidden, read-only, non-queryable, POST-only sets • Maintain full capability for server-side code

8. Who can access the service? Authentication

9. Authentication • Consider your target scenario • AJAX/Silverlight applications • “Forms” authentication works well • Login in HTML forms or within Silverlight • Wide-open RESTful service interface • Standard schemes much more important • Basic + SSL often does it • Digest, certificates provide more robust options • “Integrated” is great for corporate networks

10. Who can do what with the service? Access Control

11. Access Control • Use query and change interceptors • Policies that apply regardless of access path • Query path composition-based, highly efficient • Role-based access control • For actions • Row-level security • For entities

12. Behaviors in a resource-centric interface? State-based behavior

13. Behavior on State Transitions • Custom methods break the uniform interface • Still possible if needed: “Service operations” • Consider WCF/SOAP service if it’s all methods • Behavior attached to state transitions • ProcessSalesOrder()  Order.Status=“Ready” • Change interceptors to detect transitions • Perform secondary side-effects • Kick-off workflows • …

14. What's next… Short and long term plans

15. announcing ADO.NET Data Services v1.5, CTP 1

16. ADO.NET Data Services v1.5 • Focused on service capabilities • Row count – everybody asked for this :) • Feed customization • BLOBs with streaming interface for media • Data-binding for the .NET and Silverlight • Server-driven paging • “Fancy” providers with full flexibility • Installs without overwriting 1.0 runtime • CTP1 available now, RTM around this fall

17. ASP.NET AJAX and Data Services • New version of ASP.NET AJAX coming • Preview 4 available in codeplexnow • Built-in support for Data Services • Great templates and data binding features • It all works together 

18. SQL Data Services • SDS  full relational store in the cloud • Use existing applications and know-how • Use existing database APIs • Host in Azure or access over the Internet Use Data Services for a REST interface over SDS Azure Client/ Browser SDS Web App Azure Client/ Server/ Browser SDS

19. .NET RIA Services • Asks for Data Services programming model • Server: Better business logic framework • Client: Better UI and validation integration • Integrate with “Domain Service” classes • .NET RIA Services use Data Services for queries, updates and data exchange • Author Data Services using .NET RIA Services

20. .NET RIA Services public class CatalogService : DataService<Catalog> { // initialization, interceptors, etc. } public class Catalog : LinqToEntitiesDomainService<BikesEntities> { public IQueryable<Product> GetProducts() { return Context.Products .Where(p => p.Status == "Active"); } public void UpdateProduct(Product current, Product original) { // ... } } Data Service exposes domain through RESTful interface Domain Service encapsulates business logic

21. "Astoria Offline" • Sync-enabled service interfaces • End-to-end solution for building offline applications • Client and server libraries, Visual Studio integration, etc. • Standard disclaimer: early exploration, just thoughts for now :)

22. Summary • You can build fully functional RESTful services with ADO.NET Data Services • Behaviors, access control, etc. can be modeled using a resource-centric interface • We are extending data services to provide more base functionality • Future focus on better business logic programming model and sync/offline

23. Resources • Data Services Team Blog • http://blogs.msdn.com/astoriateam • ADO.NET Data Services page @ MSDN • http://msdn.microsoft.com/data • ADO.NET Data Services forums • http://social.msdn.microsoft.com/Forums/en-US/adodotnetdataservices/threads/

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