RESTful Web API [HapiJS] with Node.js Framework

• 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.

• For this project, we’ll build a RESTful API using a Node.js framework that will interface with the private blockchain!.

STEP 1: SELECT Node.JS framework

• Selected HapiJs.

Reason I have selected HapiJS is: A rich framework for building applications and services. hapi enables developers to focus on writing reusable application logic instead of spending time building infrastructure.

[FYI: Created basic hello world using ExpressJS, SailsJS and HapiJs Link]

Step 2: PREREQUISITE: Configure Private Blockchain project here:

• Go to Private Blockchain project Link

• Fork the project [Private Blockchain project] or Copy and paste the "project-2" folder of private Blockchain project at your directory.

• Try running the Private Blockchain project. It should run. [ For details about running private blockchain project, please refer the private blockchain project ]. Go to console -

$ node

• Copy paste the levelsandbox.js, block.js and simpleChain.js

• Just run the Blockchain. It will either return you genesis block or just u can try any method.

let blockchain = new Blockchain();

Step 3: If PREREQUISITES are met.

• close the terminal opened in step 2

$ npm install hapi --save

// create server.js and paste the code
$ touch server.js

$ npm start

• Your URL will be up and running: http://localhost:8000/block

FYI When you did npm start. It should show this:

API END POINTS

GET Block Endpoint

• Test tool: FIddler
• URL: http://localhost:8000/block/{height}
• End Point: GET Block Endpoint
• Method: GET

POST Block Endpoint

• Test tool: FIddler
• URL: http://localhost:8000/block
• End Point: POST Block Endpoint
• Method: POST
• FORM DATA: KEY : body VALUE: {body of the blockchain}
• RAW: {"body":"test block body"}

TESTING THE APPLICATION:

TEST CASE 1: TAKE BLOCK DETAILS OF EXISTING BLOCK

INPUT

• Test tool: FIddler
• URL: http://localhost:8000/block/6
• End Point: GET Block Endpoint
• Method: GET

OUTPUT

• JSON response

{
    "hash": "6886553b5938a162e56c2d57557be59a1ad013c450a917805927a2fa6d61baf1",
    "height": 6,
    "body": "My new block",
    "time": "1538902976",
    "previousBlockHash": "08fd2e15ca8ba4892004e88d1976522be4ef4155970682c08078f77359967bc9"
}

TEST CASE 2: TAKE BLOCK DETAILS OF A BLOCK THAT DON"T EXIST

INPUT

• Test tool: FIddler
• URL: http://localhost:8000/block/990
• End Point: GET Block Endpoint
• Method: GET

OUTPUT

• JSON response

{
    "error": "Error. Block doesnot exist."
}

TEST CASE 3: Add NEW BLOCK

INPUT

• Test tool: FIddler
• URL: http://localhost:8000/block
• End Point: POST Block Endpoint
• Method: POST
• FORM DATA: KEY : body VALUE: Added this Block to test API

OUTPUT

• JSON response

{
    "hash": "6acca336b33e6e06628066224c1d401c3964b97c05108ee138fd63325d11e88d",
    "height": 8,
    "body": "Added this Block to test API",
    "time": "1538904399",
    "previousBlockHash": "475e6f328eeea77c9ca576fbe6e26b172250bbd93847340bac882bf546271dd2"
}

TEST CASE 4: GET THE BLOCK CREATED IN TESTCASE 3

INPUT

• Test tool: FIddler
• URL: http://localhost:8000/block/8
• End Point: GET Block Endpoint
• Method: GET

OUTPUT

• JSON response

{
    "hash": "6acca336b33e6e06628066224c1d401c3964b97c05108ee138fd63325d11e88d",
    "height": 8,
    "body": "Added this Block to test API",
    "time": "1538904399",
    "previousBlockHash": "475e6f328eeea77c9ca576fbe6e26b172250bbd93847340bac882bf546271dd2"
}

TEST CASE 5: Block Contents Validation

INPUT

• Test tool: FIddler
• URL: http://localhost:8000/block
• End Point: POST Block Endpoint
• Method: POST
• FORM DATA: KEY : content VALUE: wronf key

OUTPUT

• JSON response

{
    "error": "Please add body as key in method payload"
}