Yan Wang's Blog

A sample solution kit to demonstrate WPF & SQL Server Data Services Technologies-Part 1

The scenario of this solution kit is to store Workshop contents such as Workshop ID,Title and its pictures, docs & videos in SQL Server Data Services(SSDS) which is a Microsoft hosted Cloud Service, then pull the data from the cloud and view it via WPF.  As we know, WPF is perfect in displaying picture, .xps documents & playing videos with great user experiences.

The high-level architecture is as below:-

Let's talk about the solution design from bottom to top that is  Infrastructure Services SSDS in this part. I created a separate WCF Service Application to access SSDS cloud service and expose workshop functional services.

• In order to access SSDS, you need to acquire a SSDS credential (User Name & Password) first from http://msdn.microsoft.com/en-us/sqlserver/dataservices/default.aspx.  And you need to understand SSDS ACE concept, that is Authority-Container-Entity (Refer http://msdn.microsoft.com/zh-cn/library/cc512417(en-us).aspx ).  
• Then add a SSDS Service References pointing to http://data.beta.mssds.com/soap/v1?wsdl , screenshot is as below:

• Then design the workshop entities. Remember there are 2 kinds of entities-Flexible Entity Type & Blob Entity Type. In our case, we'd better store Workshop List information such as WorkshopID, Title,Number of Picures,documents & videos for each workshop in Flexible Entities  while store Pictures ,Documents & Videos etc BLOB data into BLOB Entities, thus our Entities schema design can be interpreted with below diagram:-

Note that the SSDS ACE Data Model is unlike Relational Database, 1 entity is just like 1 table record. In order to easily return all workshop entities just like "select * from workshoptable" in normal Relational Database design, I set same .Kind propertity value ("workshop" here) for all Workshop Entities. So with LINQ Query(remember SSDS use LINQ to query) "from e in entities where e.Kind==""workshop"" select e" , I can get all workshop entities.

• I wrote 2 class modules to encapsulate Entity CRUD Operations, that is HandlingEnity.cs for Flexible Entity with SOAP API & HandlingBlob.cs for Blob Entity with REST API. The reason is only REST API is supported for Read/Write Blob Entity so far.
• After that, I created a WCF Service which has exposed 2 Service Operations to query SSDS and return workshop data to Client. Note that you may need to specify <ProxyAddress> in your service configuration file if you access Internet from a proxy server. The related settings is similar as below:-

<binding name="SitkaSoapEndpoint" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536" messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered" useDefaultWebProxy="false" proxyAddress ="http://myproxy.com:80">
     ...

</binding>

Now we've finished Services Application part. In next session, I'll talk about Service Agent Application and WPF Client application.

You can download solution kit source code from here.