DAI token nodejs API

A REST API that provides information about the DAI smart contract, listing transactions, account balances and general usage statistics.

Run locally

Rename config.js.example to config.js, and add a RPC server URL. You can use Alchemy or Infura to obtain an RPC to an Ethereum node.

A web server is started at http://localhost:3000

git clone https://github.com/vasildb/nodejs-api-dai.git
cd nodejs-api-dai
npm install
npm run start

Running Tests

  npm run test

API Reference

The api_key query param is required for all requests.

Sample api keys

Key	Limit (requests per minute)
key1	1
key10	10
key1000	1000

---

Endpoints

Get last 100 transactions, 10 per page

  GET /transactions/last100?api_key=<api_key>&page=<page>

Get all transactions where address is the sender

  GET /transactions/sender/<address>?api_key=<api_key>

Get all transactions where address is the recipient

  GET /transactions/recipient/<address>?api_key=<api_key>

Get address balance

  GET /balance/<address>?api_key=<api_key>

Get stats

  GET /stats?api_key=<api_key>&timeframe=<number_between_0_and_23>

Stats endpoint response:

{
	"most_used_api_key": {
		"api_key": "key1000",
		"amount": 1
	},
	"max_activity": {
		"hour": 12, // means 12 and the next 2 hours
		"amount": 1
	},
	"total_requests_today_15hr": 0, // total requests today at 3pm
	"avg_requests_7days_15hr": 0 // avg number of requests at 3pm for the last 7 days
}

How it works

• An empty database is created and seeded with the needed tables (transactions, logs, api_keys).
• A web3 listener is instantiated to listen for new blocks, get the DAI transfer events and save them in database. Ideally I would make this in a separate process, but sqlite doesn't allow writing from different processes.
• A HTTP middleware is defined to log requests, check for valid api keys and its limits.
• Routes are defined to allow querying the database, process and provide the needed data to the end user.

Notes

• IDs are not used in sqlite, that's why I save the api_key in the logs table, and not its ID from the api_keys table.
• DAI transactions are saved from the moment the app is started, not the beginning of the day. It usually takes 10 seconds for the database to be populated with a few records.
• dai-abi.json file can be minimized further to just contain the needed bits.