Build Azure Data Lake Storage-Connected Web Apps in Servoy

Servoy is a rapid application development and deployment platform. When paired with the CData JDBC Driver for Azure Data Lake Storage, users can build Azure Data Lake Storage-connected apps that work with live Azure Data Lake Storage data. This article describes how to connect to Azure Data Lake Storage from Servoy and build a simple web app to display and search Azure Data Lake Storage data.

With built-in optimized data processing, the CData JDBC Driver offers unmatched performance for interacting with live Azure Data Lake Storage data. When you issue complex SQL queries to Azure Data Lake Storage, the driver pushes supported SQL operations, like filters and aggregations, directly to Azure Data Lake Storage and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations). Its built-in dynamic metadata querying lets you work with Azure Data Lake Storage data using native data types.

Connect to Azure Data Lake Storage in Servoy Developer

To build Azure Data Lake Storage-connected apps, you need to first create a data provider in Servoy Developer using the CData JDBC Driver for Azure Data Lake Storage.

1. Install the JDBC Driver.
2. Copy the JDBC Driver JAR file. (cdata.jdbc.adls.jar) to the /application_server/drivers/ directory in the installation directory for Servoy.
3. Open Servoy Developer.
4. In the Solution Explorer, right-click Database Server (under Resources) and choose "Connect to existing database" -> "empty."
   1. Name the server.
   2. Click to show the advanced server settings.

      • Set the URL, for example: jdbc:adls:Schema=ADLSGen2;Account=myAccount;FileSystem=myFileSystem;AccessKey=myAccessKey;InitiateOAuth=GETANDREFRESH

        Built-In Connection String Designer

        For assistance in constructing the JDBC URL, use the connection string designer built into the Azure Data Lake Storage JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

        java -jar cdata.jdbc.adls.jar

        Fill in the connection properties and copy the connection string to the clipboard.

        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.
      • Select the Driver class you just copied, for example, cdata.jdbc.adls.ADLSDriver

Build a Azure Data Lake Storage-Connected Web App

Once you have configured the connection to Azure Data Lake Storage in the Servoy Developer resources, you are ready to build apps with access to live Azure Data Lake Storage data.

Create a New Solution

1. In the Server Explorer, right-click "All solutions" and select "Create new solution."
2. Name the solution.
3. Select the checkbox to include the "search" module.
4. Click "Finish."

Create a New Form

Right-click "Forms" and select "Create new form."

1. Name the form.
2. Select a Datasource.
3. Set the type (e.g., Simple) and click "Finish."

Add a Data Grid to the Form

1. Drag a Data Grid component (from Servoy NG-Grids) onto the form.

2. Drag a column component onto the Data Grid and set the "dataprovider" property for each column component to a column from the Azure Data Lake Storage "table" (e.g., FullPath from the Resources table).

   Continue adding columns as desired.

Add Searching to the App

Note that the "svySearch" extension is required to add search functionality (included by default when you create a new solution). If you did not add the extension when you created the solution or you are modifying an existing solution, you can add the search module by right-clicking Modules (in the solution) and selecting "Add Module." Select "svySearch" and click "OK."

1. Drag a Text Field component onto the Form.
2. Right-click the Form and select "Open in Script Editor."
3. Create a new variable (JavaScript) to hold the search value:

   var searchText = '';
   

4. Back on the Form, in the Text Field properties:
   1. Set the "dataprovider" property to the Form variable you just created.
   2. Double-click to add a method for the onAction event.
   3. Click to create the method in "Form," name the method (e.g., onEnter), and click "Create private."
   4. Click "OK & Show."
5. Add the following JavaScript to the JavaScript file to use the Servoy framework to implement searching bound data based on the text in the Text Field:

   var search = scopes.svySearch.createSimpleSearch(foundset).setSearchText(searchText);
   search.setSearchAllColumns();
   search.loadRecords(foundset);
   

Save and Launch the App

Save the form and JavaScript file, then click Run -> Launch NGClient to start the web app.

Download a free, 30-day trial of the CData JDBC Driver for Azure Data Lake Storage and start building Azure Data Lake Storage-connected apps with Servoy. Reach out to our Support Team if you have any questions.