Build Greenplum-Connected Web Apps with Axios and CData Connect Cloud

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 Cloud, you get access to live Greenplum data for your web apps. This article shows how to connect to Greenplum and build web apps in Axios with access to live Greenplum data.

Connect to Greenplum from Axios

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

Connect to Greenplum from Connect Cloud

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

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

2. Select "Greenplum" from the Add Connection panel

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

   To connect to Greenplum, set the Server, Port (the default port is 5432), and Database connection properties and set the User and Password you wish to use to authenticate to the server. If the Database property is not specified, the default database for the authenticate user is used.

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

Add a Personal Access Token

When connecting to Connect Cloud 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 Cloud. 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 Cloud 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 Greenplum Endpoints for Axios

After connecting to Greenplum, 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 Greenplum connection (e.g. Greenplum1) 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 Greenplum data from Axios.

Connect to Greenplum Data in Axios Workflows

To establish a connection from Axios to CData Connect Cloud 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 Cloud 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 Greenplum1.SCHEMA.Orders.

   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.Orders"
         };
   
         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 Greenplum Data from Cloud Applications

At this point, you have a direct connection to live Greenplum 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 Cloud page.