API is implemented in NodeJS using express

In this repo, we are going to demonstrate the use of handling multiple requests of the same payload and how we can make sure to avoid duplicate creation of the same resource. Please refer to the Article for the explanation.

Make sure to have node installed

npm install -g nodemon => Make sure to install this globally.

git clone <repo> from Github

> npm i

> npm run dev

Go to Postman or any http client tool and try to perform the following request multiple times

POST http://localhost:3000/api/payments
{
    "user_id": 1234,
    "order_id": "1234-567-xq34343",
    "status": "SUCCESS",
    "amount": 100,
    "transaction_id": "T23232323"
}

In the database we should have only one payments entry for the above user and rest of them should be ignored. How we manage with ignored calls its left upto us. Either we can log them or store them in another table for auditing.

The concurrent rest calls are also demonstrated in the e2e tests. Check out test/e2e/payments.js file.

Make sure to install mochal globablly npm install mocha -g

Make sure to create a database name and configure the db credentials in config.js

> npm run test:e2e

In the e2e tests test/e2e/payments.js, there is a demonstration of making concurrent calls to the same endpoint.

https://60devs.com/synchronization-of-concurrent-http-requests-in-node.html

https://60devs.com/making-better-http-apis.html

https://stackoverflow.com/questions/129329/optimistic-vs-pessimistic-locking

https://blog.couchbase.com/optimistic-or-pessimistic-locking-which-one-should-you-pick/