Restful API Creation to extract Cassandra data

Description

Exposing the data from Cassandra DB running in an instance to external world by running a NodeJS server. The tools, frameworks and technologies involved are:

• Cassandra - Contains our data!
• NodeJS - Server-side scripting Language!
• ExpressJS - Framework for building API!
• Postman - To test the API!

Installation

Initially check the version of node and npm.

$ npm --version
$ node --version

This package requires Node.js and ExpressJS to function. Initialize the npm module using $ npm init command.

Install the dependencies and devDependencies.

$ npm install -g express
$ npm install -g nodemon
$ npm install -g cassandra-driver

Check the installation of the packages using $ ls node_modules #(dir node_modules for windows)command

Steps

1. Create the main.js file

$ vi main.js 

2. Use this link in a straight-forward approach. For asynchronous calls use this link

3. Replace the keyspace davekeyspace1 with your keyspace

4. Optional Customization :

• contactPoints (127.0.0.1)
• Cassandra execute query (Select * from davetable)
• Port number (3000)

5. Run the $ nodemon --inspect main.js command to start the server

6. Try hitting the endpoint youripaddress:port. eg., 54.54.204.204:3000

Response

The output is in json.

[{"emp_id":1,"emp_city":"Pondi","emp_name":"Lego"},
 {"emp_id":2,"emp_city":"Tripati","emp_name":"Dhana"},
 {"emp_id":3,"emp_city":"Trichi","emp_name":"Dave"}]

Response in Postman

Response on Browser

Troubleshooting

1. If port number is occupied, then try $ killall -9 node
2. To check if API works in local instance, try $ curl localhost:3000

Visualization

Some sample visualization achieved using the JSON (Built using Highchart)

Contact

• David Jegan - Linkedin - Mail