Build PostgreSQL-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 PostgreSQL data for your web apps. This article shows how to connect to PostgreSQL and build web apps in Axios with access to live PostgreSQL data.

Connect to PostgreSQL from Axios

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

Connect to PostgreSQL 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 "PostgreSQL" from the Add Connection panel

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

   To connect to PostgreSQL, 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 data provider connects to the user's default database.

   SSH Connectivity for PostgreSQL

   You can use SSH (Secure Shell) to authenticate with PostgreSQL, whether the instance is hosted on-premises or in supported cloud environments. SSH authentication ensures that access is encrypted (as compared to direct network connections).

   SSH Connections to PostgreSQL in Password Auth Mode

   To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

   • User: PostgreSQL User name
   • Password: PostgreSQL Password
   • Database: PostgreSQL database name
   • Server: PostgreSQL Server name
   • Port: PostgreSQL port number like 3306
   • UserSSH: "true"
   • SSHAuthMode: "Password"
   • SSHPort: SSH Port number
   • SSHServer: SSH Server name
   • SSHUser: SSH User name
   • SSHPassword: SSH Password

   SSH Connections to PostgreSQL in Public Key Auth Mode

   To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

   • User: PostgreSQL User name
   • Password: PostgreSQL Password
   • Database: PostgreSQL database name
   • Server: PostgreSQL Server name
   • Port: PostgreSQL port number like 3306
   • UserSSH: "true"
   • SSHAuthMode: "Public_Key"
   • SSHPort: SSH Port number
   • SSHServer: SSH Server name
   • SSHUser: SSH User name
   • SSHClientCret: the path for the public key certificate file
   
4. Click Save & Test
5. Navigate to the Permissions tab in the Add PostgreSQL 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 PostgreSQL Endpoints for Axios

After connecting to PostgreSQL, 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 PostgreSQL connection (e.g. PostgreSQL1) 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 PostgreSQL data from Axios.

Connect to PostgreSQL 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 PostgreSQL1.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/%7Bworkspace_name%7D';
   
         //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 PostgreSQL Data from Cloud Applications

At this point, you have a direct connection to live PostgreSQL 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.