This project introduces you to the fundamentals of web APIs with Node.js frameworks. Using your own private blockchain to create a web API is a huge first step toward developing your own web applications that are consumable by a variety of web clients.
Before building the project, one has to choose their preferred Node.js framework from the following:
- Hapi.js
- Express.js
- Sails.js
I have choosen Express.js for the implementation.
The framework choosen will interface with the private blockchain(https://github.com/gowrieswaran/private-blockchain.git). To run, clone/download the private blockchain repo.
Added the server.js to configure the API service to the appropriate port.
Added the BlockController.js to create two endpoints, which allow the application to accept user requests.
npm install express - Installs the Fast, unopinionated, minimalist web framework for node.
npm install body-parser - Node.js body parsing middleware, which parses incoming request bodies in a middleware before your handlers, available under the req.body property.
To run the project type npm start in the command prompt and on successful launch, it displays the message below:
Several tools are available on the internet to assist with API development and testing.
-Postman is a powerful tool used to test web services.
-CURL is a command-line tool used to deliver requests.
I have used Postman for testing.
Configure a GET request using URL path with a block height parameter.
http://localhost:8000/block/[blockheight]
URL: http://localhost:8000/block/0
Response
URL: http://localhost:8000/block/100
Response
Block does not exist!
Post a new block with data payload option to add data to the block body.
URL: http://localhost:8000/block
KEY:body VALUE:Data Added from Postman
Response
URL: http://localhost:8000/block
Response
Pass data to the block using data payload option!
URL: http://localhost:8000/block/11
