Build Kafka-Connected Web Apps with Axios and CData Connect AI

Axios is a JavaScript library that allows developers to make HTTP requests to servers from a web browser or Node.js. When paired with CData Connect AI, you get access to live Kafka data for your web apps. This article shows how to connect to Kafka and build web apps in Axios with access to live Kafka data.

Connect to Kafka from Axios

To work with Kafka in Axios, we need to connect to Kafka from Connect AI, provide user access to the connection, and create a Workspace for the Kafka data.

Connect to Kafka from Connect AI

CData Connect AI uses a straightforward, point-and-click interface to connect to data sources.

1. Log into Connect AI, click Sources, and then click Add Connection

2. Select "Kafka" from the Add Connection panel

3. Enter the necessary authentication properties to connect to Kafka.

   Set BootstrapServers and the Topic properties to specify the address of your Apache Kafka server, as well as the topic you would like to interact with.

   Authorization Mechanisms

   • SASL Plain: The User and Password properties should be specified. AuthScheme should be set to 'Plain'.
   • SASL SSL: The User and Password properties should be specified. AuthScheme should be set to 'Scram'. UseSSL should be set to true.
   • SSL: The SSLCert and SSLCertPassword properties should be specified. UseSSL should be set to true.
   • Kerberos: The User and Password properties should be specified. AuthScheme should be set to 'Kerberos'.

   You may be required to trust the server certificate. In such cases, specify the TrustStorePath and the TrustStorePassword if necessary.

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

Add a Personal Access Token

When connecting to Connect AI through the REST API, the OData API, or the Virtual SQL Server, a Personal Access Token (PAT) is used to authenticate the connection to Connect AI. It is best practice to create a separate PAT for each service to maintain granularity of access.

1. Click on the Gear icon () at the top right of the Connect AI app to open the settings page.
2. On the Settings page, go to the Access Tokens section and click Create PAT.
3. Give the 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.

Configure Kafka Endpoints for Axios

After connecting to Kafka, create a workspace for your desired table(s).

1. Navigate to the Workspaces page and click Add to create a new Workspace (or select an existing workspace).
2. Click Add to add new assets to the Workspace.
3. Select the Kafka connection (e.g. ApacheKafka1) and click Next.
4. Select the table(s) you wish to work with and click Confirm.
5. Make note of the OData Service URL for your workspace, e.g. https://cloud.cdata.com/api/odata/{workspace_name}

With the connection, PAT, and Workspace configured, you are ready to connect to Kafka data from Axios.

Connect to Kafka Data in Axios Workflows

To establish a connection from Axios to CData Connect AI using the OData protocol, follow these steps.

1. Create a project directory for your web app. For example: ~/connect_cloud/
2. Open a terminal, navigate the the project directory and initialize a node project using the command:

   npm init -y

3. Install the Axios dependency in the project using the following command:

   npm install axios

4. In your project directory, create a file called server.js that contains the following code. Provide your CData Connect AI username (e.g. [email protected]) and PAT (the PAT you created in the prerequisites). You must also provide a query for your data, such as SELECT * FROM ApacheKafka1.SCHEMA.SampleTable_1.

   server.js code

   
         const axios = require('axios')
   
         const user = '[email protected]'
         const pat = '***********************************';
   
         //Your API endpoint
         const url = 'https://cloud.cdata.com/api/odata/{workspace_name}';
   
         //Your data to be sent in the POST request
         const data = {
         "query":"SELECT * FROM {workspace_name}.SCHEMA.SampleTable_1"
         };
   
         axios.post(url, data, {
         auth: {
         username: user,
         password: pat
         }
         })
         .then(response => {
         const rows = response.data.results[0].rows;
         const schema = response.data.results[0].schema;
   
         //Create an array of column names
         const columnNames = schema.map(col => col.columnName);
   
         //Loop through each row and log the column name with its value
         rows.forEach(row => {
         const rowObject = {};
         row.forEach((value, index) => {
         const columnName = columnNames[index];
         rowObject[columnName] = value;
         });
         console.log(rowObject);
         })
         })
         .catch(error => {
         console.error('Error:', error);
         });
       

5. In the terminal, execute the following command to run the server:

   node server.js

   The query results will appear:

   
       { ID: 1, VALUE: -2 }
       { ID: 2, VALUE: 1 }
       { ID: 11, VALUE: null }
       { ID: 3, VALUE: 2 }
       { ID: 4, VALUE: 5 }
       ...

Simplified Access to Kafka Data from Cloud Applications

At this point, you have a direct connection to live Kafka data from Axios. For more information on gaining simplified access to data from more than 100 SaaS, Big Data, and NoSQL sources in cloud applications like Axios, refer to our Connect AI page.