Provide OData Services of SAP Netweaver Gateway Data from a WCF Application

The CData ADO.NET Provider for SAP Netweaver Gateway enables you to rapidly develop service-oriented applications using the Windows Communication Foundation (WCF) framework, providing SAP Netweaver Gateway data data to OData consumers. This article guides you through creating an entity data model for connectivity and a WCF Data Service to expose OData services. You can then consume the feed with various OData clients, such as Power Pivot or applications using 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 SAP Netweaver Gateway 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. Install Entity Framework 6:

   Use the Package Manager Console in Visual Studio to install the latest version of Entity Framework. Run the following command to download and install Entity Framework automatically:

   Install-Package EntityFramework

4. Register the Entity Framework provider:
   1. Add the following provider entry in the "providers" section of your App.config or Web.config file. This section should already exist if the Entity Framework installation was successful.

      <configuration>
      ...
      <entityFramework>
       <providers>
       ...
       <provider invariantName="System.Data.CData.SAPGateway" type="System.Data.CData.SAPGateway.SAPGatewayProviderServices, System.Data.CData.SAPGateway.Entities.EF6" />
       </providers>
      </entityFramework>
      </configuration>

   2. Add a reference to System.Data.CData.SAPGateway.Entities.dll, located in lib/4.0 in the installation directory.
   3. Build the project to complete the setup for using EF6.
5. Click Project -> Add New Item -> ADO.NET Entity Data Model.
6. In the Entity Data Model wizard that is displayed, select the 'EF Designer from Database' option.
7. In the resulting Choose Your Connection dialog, click New Connection.

8. In the Connection properties dialog, select the CData SAP Netweaver Gateway Data Source and enter the necessary credentials.

   A typical connection string is below:

   User=user;Password=password;URL=https://sapes5.sapdevcenter.com/sap/opu/odata/IWBEP/GWSAMPLE_BASIC/;InitiateOAuth=GETANDREFRESH;

   SAP Gateway allows both basic and OAuth 2.0 authentication. You can use basic authentication to connect to your own account, or you can use OAuth to enable other users to retrieve data from your service with their accounts. In addition to authenticating, set the following connection properties to access SAP Gateway tables.

   • Url: Set this to the URL of your environment, or to the full URL of the service. For example, the full URL might appear as: https://sapes5.sapdevcenter.com/sap/opu/odata/IWBEP/GWSAMPLE_BASIC/. In this example, the environment URL would just be: https://sapes5.sapdevcenter.com.
   • Namespace: Set the appropriate Service Namespace. In the example above, IWBEP is the namespace. It is optional if the full URL to the service is specified.
   • Service: Set this to the service you want to retrieve data from. In the example above, the service is GWSAMPLE_BASIC. It is not required if the full URL is specified.

   Authenticate via Basic Authentication

   In basic authentication, you use your login credentials to connect. Set the following properties:

   • User: This is the username you use to log in to SAP Gateway.
   • Password: This is the password you use to log in to SAP Gateway.

   Authenticate via OAuth Authentication

   You can connect to SAP Gateway using the embedded OAuth connectivity (without setting any additional authentication connection properties). When you connect, the OAuth endpoint opens in your browser. Log in and grant permissions to complete the OAuth process. See the OAuth section in the online Help documentation for more information on other OAuth authentication flows.

   👁 Required connection properties, specified in the Add Connection dialog. (Salesforce is shown.)
   
9. Select SAP Netweaver Gateway tables and views that you want OData clients to access. 👁 Available tables in the Entity Data Model Wizard. (Salesforce is shown.)
   
10. Click Project -> Add New Item -> WCF Data Service.

11. 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 SAPGatewayService{
     public class SAPGatewayDataService : DataService<SAPGatewayEntities> {
     public static void InitializeService(DataServiceConfiguration config) {
     config.SetEntitySetAccessRule("*", EntitySetRights.All);
     config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V3;
     }
     }
    }
    	

12. 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: 👁 The raw OData feed. (Salesforce is shown.)
    

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/SAPGatewayDataService.svc/. 👁 The OData URL for SAP Netweaver Gateway.
   
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. 👁 Available tables in the Table Import Wizard. (Salesforce is shown.)
   
6. Click Close to import the data in Power Pivot. 👁 The table loaded in Power Pivot. (Salesforce is shown.)