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Provide OData Services of Trello Data from a WCF Application

This article shows how to publish an OData feed of Trello data by creating a WCF Service Application.

The CData ADO.NET Provider for Trello enables you to use the Windows Communication Foundation (WCF) framework to rapidly develop service-oriented applications that provide Trello data to OData consumers. This article shows how to create an entity data model to provide the underlying connectivity to the Trello data, as well as how to create a WCF Data Service to expose the OData service. You can then consume the feed with any OData client, for example, Power Pivot or an application that uses the CData ADO.NET Provider for OData.

Create the OData Service

Follow the steps below to create a WCF service application that will provide connectivity to Trello data via OData.

  1. Open Visual Studio and create a new project. Select the WCF Service Application template.
  2. Delete the autogenerated IService.cs and Service1.svc.
  3. Click Project -> Add New Item -> ADO.NET Entity Data Model.
  4. In the Entity Data Model wizard that is displayed, select the 'EF Designer from Database' option.
  5. In the resulting Choose Your Connection dialog, click New Connection.
  6. In the Connection properties dialog, select the CData Trello Data Source and enter the necessary credentials.

    A typical connection string is below:

    APIKey=myApiKey;Token=myGeneratedToken;InitiateOAuth=GETANDREFRESH

    Trello uses token-based authentication to grant third-party applications access to their API. When a user has granted an application access to their data, the application is given a token that can be used to make requests to Trello's API.

    Trello's API can be accessed in 2 different ways. The first is using Trello's own Authorization Route, and the second is using OAuth1.0.

    • Authorization Route: At the moment of registration, Trello assigns an API key and Token to the account. See the Help documentation for information on how to connect via the Authorization route.
    • OAuth Route: Similar to using Authorization, OAuth creates an Application Id and Secret when you create your account. See the Help documentation for information on how to to connect.

  7. Select Trello tables and views that you want OData clients to access.
  8. Click Project -> Add New Item -> WCF Data Service.
  9. Specify the data source class and configure access to the new WCF Data Service. In the example below, the Access Rule for the entities is set to All. This means that any user will be able to read and modify data.

    using System; using System.Collections.Generic; using System.Data.Services; using System.Data.Services.Common; using System.Linq; using System.ServiceModel.Web; using System.Web; namespace TrelloService{ public class TrelloDataService : DataService<TrelloEntities> { public static void InitializeService(DataServiceConfiguration config) { config.SetEntitySetAccessRule("*", EntitySetRights.All); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V3; } } }
  10. Run the project. Applications that support OData can now access the Salesforce data and reflect any changes. You can access the feed in your browser. The feed will resemble the following:

Consume the OData Service from Power Pivot

You can now use the service from any OData client; for example, Excel Power Pivot.

  1. Open Excel and click on the Power Pivot Window button.
  2. A new pop-up will appear. Select the option From Data Feeds.
  3. In the resulting Table Import Wizard, enter the OData URL. For example, http://localhost:12449/TrelloDataService.svc/.
  4. After connecting to the OData service, click the Next button at the bottom of the window.
  5. A table listing of the available tables will appear in the next window of the wizard. Select which tables you want to import and click Finish.
  6. Click Close to import the data in Power Pivot.