Consume Azure Data Lake Storage OData Feeds in PowerBuilder


This article demonstrates how to consume Azure Data Lake Storage data as OData feeds from PowerBuilder using the API Server.

The CData API Server, when paired with the ADO.NET Provider for Azure Data Lake Storage (or any of 200+ other ADO.NET Providers), produces secure feeds of Azure Data Lake Storage data that you can consume in PowerBuilder DataWindows. The API Server supports the major Web services, including OData, Atom, JSON, HTML, CSV, TSV, and RSS. It also supports the major authentication schemes and SSL.

This article shows how to create a DataWindow that uses the CData API Server to retrieve data.

Set Up the API Server

Follow the steps below to begin producing secure Azure Data Lake Storage OData services:

Deploy

The API Server runs on your own server. On Windows, you can deploy using the stand-alone server or IIS. On a Java servlet container, drop in the API Server WAR file. See the help documentation for more information and how-tos.

The API Server is also easy to deploy on Microsoft Azure, Amazon EC2, and Heroku.

Connect to Azure Data Lake Storage

After you deploy the API Server and the ADO.NET Provider for Azure Data Lake Storage, provide authentication values and other connection properties needed to connect to Azure Data Lake Storage by clicking Settings -> Connections and adding a new connection in the API Server administration console.

Authenticating to a Gen 1 DataLakeStore Account

Gen 1 uses OAuth 2.0 in Azure AD for authentication.

For this, an Active Directory web application is required. You can create one as follows:

  1. Sign in to your Azure Account through the .
  2. Select "Azure Active Directory".
  3. Select "App registrations".
  4. Select "New application registration".
  5. Provide a name and URL for the application. Select Web app for the type of application you want to create.
  6. Select "Required permissions" and change the required permissions for this app. At a minimum, "Azure Data Lake" and "Windows Azure Service Management API" are required.
  7. Select "Key" and generate a new key. Add a description, a duration, and take note of the generated key. You won't be able to see it again.

To authenticate against a Gen 1 DataLakeStore account, the following properties are required:

  • Schema: Set this to ADLSGen1.
  • Account: Set this to the name of the account.
  • OAuthClientId: Set this to the application Id of the app you created.
  • OAuthClientSecret: Set this to the key generated for the app you created.
  • TenantId: Set this to the tenant Id. See the property for more information on how to acquire this.
  • Directory: Set this to the path which will be used to store the replicated file. If not specified, the root directory will be used.

Authenticating to a Gen 2 DataLakeStore Account

To authenticate against a Gen 2 DataLakeStore account, the following properties are required:

  • Schema: Set this to ADLSGen2.
  • Account: Set this to the name of the account.
  • FileSystem: Set this to the file system which will be used for this account.
  • AccessKey: Set this to the access key which will be used to authenticate the calls to the API. See the property for more information on how to acquire this.
  • Directory: Set this to the path which will be used to store the replicated file. If not specified, the root directory will be used.

You can then choose the Azure Data Lake Storage entities you want to allow the API Server access to by clicking Settings -> Resources.

Additionally, click Settings -> Server and change the following settings for compatibility with PowerBuilder:

  • Default Format: Select XML (Atom) in the menu.
  • Default Version: Select 2.0 in the menu.

Authorize API Server Users

After determining the OData services you want to produce, authorize users by clicking Settings -> Users. The API Server uses authtoken-based authentication and supports the major authentication schemes. Access can also be restricted based on IP address; by default, only connections to the local machine are allowed. You can authenticate as well as encrypt connections with SSL.

Create a Profile for Azure Data Lake Storage

Follow the steps below to use the Database Painter tool to create a database profile for the OData API of the API Server. In the Database Painter, you can graphically manipulate data as well as execute SQL queries.

  1. Click Tools -> Database Painter.
  2. Right-click the OData node and click New Profile.
  3. In the Database Profile Setup dialog, enter the following:
    • Profile Name: Enter a user-friendly name for the profile.
    • URI: Enter the URL to the OData endpoint of the API Server. This URL will resemble the one below: http://MyServer:8032/api.rsc
    • Supply User Id and Password: Click this option to use HTTP Basic authentication. Note that the API Server also supports Windows authentication.
    • User Id: Enter the name of an user in the API Server.
    • Password: Enter the authtoken of an user in the API Server.
  4. To view and modify a table, right-click a table and then click Edit Data -> Grid.

Using Azure Data Lake Storage Data with PowerBuilder Controls

You can use standard PowerBuilder objects to connect to OData feeds and execute queries. The following example shows how to retrieve Azure Data Lake Storage data into a DataWindow.

You can add the following code to the open method:

SQLCA.DBMS = "ODT" SQLCA.DBParm = "ConnectString='URI=http://MyServer:8032/api.rsc;UID=MyAPIUser;PWD=MyAuthtoken'"; CONNECT USING SQLCA; dw_resources.SetTransObject(SQLCA); dw_resources.Retrieve();

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