Build REST-Connected Apps in Choreo

The Choreo platform from WS02 is a versatile platform designed for low-code and cloud-native engineering. Developers, even those without advanced coding skills, can leverage Choreo's user-friendly low-code environment to simplify application development. When combined with CData Connect Cloud, users gain immediate cloud-to-cloud access to REST data for applications. This article details the process of connecting to REST using Connect Cloud and building an application with real-time access to REST data within Choreo.

CData Connect Cloud delivers a pure cloud-to-cloud interface for REST, enabling you to construct applications within Choreo that utilize live REST data data, all without the need for data replication to a natively supported database. With its built-in optimized data processing capabilities, CData Connect Cloud efficiently directs all supported SQL operations, including filters and JOINs, directly to REST, capitalizing on server-side processing to swiftly provide the requested REST data.

Configure REST Connectivity for Choreo

Connectivity to REST from Choreo is made possible through CData Connect Cloud. To work with REST data from Choreo, we start by creating and configuring a REST connection.

1. Log into Connect Cloud, click Connections and click Add Connection
2. Select "REST" from the Add Connection panel
3. Enter the necessary authentication properties to connect to REST.

   See the Getting Started chapter in the data provider documentation to authenticate to your data source: The data provider models REST APIs as bidirectional database tables and XML/JSON files as read-only views (local files, files stored on popular cloud services, and FTP servers). The major authentication schemes are supported, including HTTP Basic, Digest, NTLM, OAuth, and FTP. See the Getting Started chapter in the data provider documentation for authentication guides.

   After setting the URI and providing any authentication values, set Format to "XML" or "JSON" and set DataModel to more closely match the data representation to the structure of your data.

   The DataModel property is the controlling property over how your data is represented into tables and toggles the following basic configurations.

   • Document (default): Model a top-level, document view of your REST data. The data provider returns nested elements as aggregates of data.
   • FlattenedDocuments: Implicitly join nested documents and their parents into a single table.
   • Relational: Return individual, related tables from hierarchical data. The tables contain a primary key and a foreign key that links to the parent document.

   See the Modeling REST Data chapter for more information on configuring the relational representation. You will also find the sample data used in the following examples. The data includes entries for people, the cars they own, and various maintenance services performed on those cars.

   
4. Click Create & Test
5. Navigate to the Permissions tab in the Add REST Connection page and update the User-based permissions.

Add a Personal Access Token

If you are connecting from a service, application, platform, or framework that does not support OAuth authentication, you can create a Personal Access Token (PAT) to use for authentication. Best practices would dictate that you create a separate PAT for each service, to maintain granularity of access.

1. Click on your username at the top right of the Connect Cloud app and click User Profile.
2. On the User Profile page, scroll down to the Personal Access Tokens section and click Create PAT.
3. Give your PAT a name and click Create.
4. The personal access token is only visible at creation, so be sure to copy it and store it securely for future use.

With the connection configured, you are ready to connect to REST data from Choreo.

Connect to REST from Choreo

The steps below outline connecting to CData Connect Cloud from Choreo to create a new application with access to live REST data.

Creating a Construct

1. Sign in to the Choreo platform. Note: This article is from the perspective of an Anonymous user.
2. Select Components from the left sidebar and then click +Create. Next, choose Manual Trigger and then Start from scratch.
3. Give the manual trigger a Name and Description and click Create.
4. After the trigger is created, click on Edit Code.
5. The Ballerina Low-Code IDE is displayed. Choreo automatically generates a construct in the low-code diagram view. Delete this construct by highlighting it and clicking on the trashcan icon.
6. Click the + icon towards the top of the screen and select Main from the Add Constructs toolbar on the right. In the following Function Configuration form, click Save.

Adding the CData Connect Cloud Connector

1. Click the + icon between the Start and End ellipses and click Connector.

2. In the Connectors sidebar on the right, search for "CData". Click CData Connect to open the Connector settings pane.

3. In the Connector settings pane, enter the configuration settings:
   • Enter an Endpoint Name for your use. In this example, we use "connectEndpoint".
   • In the User field, enter the email address of the CData Connect Cloud user, wrapped in quotation marks (for example, "[email protected]").
   • In the Password field, enter the PAT you generated earlier, wrapped in quotation marks (for example, "SampleToken").

4. After clicking Save, the low-code editor appears with the CData Connect Cloud logo.

Adding a Query Action

1. Click the + icon between the new and end shapes, select Action, and then select our existing connector endpoint.

2. Select query for the connector Operation. There is now an Action pane on the right.

3. Enter a SQL query to retrieve REST data as the sqlQuery parameter for the query. For example: SELECT * FROM REST1.REST.people LIMIT 10
   • When writing the query, be sure to specify the Connection Name as the catalog and Data Source Name as the schema. For example, REST1.REST.
   • These parameters appear on the Connections page of your CData Connect Cloud dashboard.

Iterating over REST Data

1. Click the Show Source icon in the top right of the code editor.
2. Add an import statment to import the ballerina/io library:

   		
   		import ballerina/io;
   	

3. Next, add a from statement after the query action to iterate through the results of the SQL query:

		
		check from record{} result in resultStream
		do {
			io:println("Full people details: ", result);
		};
	

4. The code for the construct will now look similar to this:

			
			import ballerinax/cdata.connect;
			import ballerinax/cdata.connect.driver as _;
			import ballerina/io;

			public function main() returns error? {
				connect:Client connectEp = check new (user = "connect_cloud_username", password="connect_cloud_pat");

				stream<record {}, error=""?> resultStream =
				connectEp->query(sqlQuery = `SELECT * FROM REST1.REST.people LIMIT 10`);

				check from record{} result in resultStream
				do {
					io:println("Full people details: ", result);
				};
			}
		

5. Click Save to save the action. The diagram should now look similar to this:

Deploying the Program

Once you have added all of your desired actions to your program, follow these steps:

1. Commit and push your final source code in the web editor and sync those changes with the Choreo platform.
2. Click Deploy in the left navigation bar of the Choreo Console.
3. Under Build Area, click Configure & Deploy to deploy your program.
4. When prompted, enter the same CData Connect Cloud username and password that you used earlier and click Deploy.

You have now created an application with access to live REST data in Choreo.

Get CData Connect Cloud

For more information about using Choreo with CData Connect Cloud, see the CData Connect Ballerina Guide. To get live data access to 100+ SaaS, Big Data, and NoSQL sources directly from your cloud applications, try CData Connect Cloud today!