Blockchain Data

Blockchain has the potential to change the way that the world approaches data. Develop Blockchain skills by understanding the data model behind Blockchain by developing your own simplified private blockchain.

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

Prerequisites

Installing Node and NPM is pretty straightforward using the installer package available from the (Node.js® web site)[https://nodejs.org/en/].
For installing levelDB just follow the instructions in their (Github repo)[https://github.com/Level/levelup/blob/master/README.md].
Finally you need to install Hapi, following these very simple instructions in (their website)[https://hapijs.com/].

Configuring your project

Use NPM to initialize your project and create package.json to store project dependencies.

npm init

Install crypto-js with --save flag to save dependency to our package.json file

npm install crypto-js --save

Install level with --save flag

npm install level --save

Install Hapi with --save flag

npm install hapi --save

Install bitcoinjs-message with --save flag

npm i bitcoinjs-message --save

Install bitcoinjs-lib with --save flag

npm install bitcoinjs-lib --save

Start the Server

Open a console an navigate to the server project root folder:

cd /path/to/server/Project_3_submission

Run node server.js
Done and done!!!

Testing webservices end-points

Querying the blockchain

To get the entire blockchain, you must do a GET request to the following endpoint:

http://localhost:8000/chain

Create a new block

To create a new block, you must do a POST request to the following endpoint:

http://localhost:8000/block

Withe the following header:

'Content-Type: application/json'

With any JSON value as a body, here is an example using curl:

curl -X "POST" "http://localhost:8000/block" -H 'Content-Type: application/json' -d $'{"body":"another block the dust"}'

Get a block by height

Open a browser session and go to:

http://localhost:8000/block/{block_height}

Where block_height is the height of the block you wish to get.

Get a block by address

Open a browser session and go to:

http://localhost:8000/stars/address:{address}

Where address is the address of the block you wish to get.

Get a block by hash

Open a browser session and go to:

http://localhost:8000/stars/hash:{hash}

Where hash is the hash of the block you wish to get.

Request an user validation

To request an user validation an user, you must do a POST request to the following endpoint:

http://localhost:8000/requestValidation

Withe the following header:

'Content-Type: application/json'

With the following body:

{ "address": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ" }

where address in the value of the address of the user you need to validate, here is an example using curl:

curl -X "POST" "http://localhost:8000/requestValidation" -H 'Content-Type: application/json; charset=utf-8' -d $'{"address": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ"}'

This is a sample response:

{
  "address": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ", // This is the address of the wallet
  "requestTimeStamp": "1532296090", // the timestamp of the request
  "message": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ:1532296090:starRegistry", // this is the message that needs to be signed
  "validationWindow": 300 // expiration time of the request
}

Validate a signature

To validate an signature, you must do a POST request to the following endpoint:

http://localhost:8000/message-signature/validate

Withe the following header:

'Content-Type: application/json'

With the following body:

{
  "address": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ",
  "signature": "H6ZrGrF0Y4rMGBMRT2+hHWGbThTIyhBS0dNKQRov9Yg6GgXcHxtO9GJN4nwD2yNXpnXHTWU9i+qdw5vpsooryLU="
}

where address in the value of the address of the signature you need to validate, and signature is the signature you need to validate, here is an example using curl:

curl -X "POST" "http://localhost:8000/message-signature/validate" -H 'Content-Type: application/json; charset=utf-8' -d $'{ "address": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ","signature": "H6ZrGrF0Y4rMGBMRT2+hHWGbThTIyhBS0dNKQRov9Yg6GgXcHxtO9GJN4nwD2yNXpnXHTWU9i+qdw5vpsooryLU="}'

This is a sample response:

{
  "registerStar": true, // was the registration successful?
  "status": {
    "address": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ", // This is the address of the wallet
    "requestTimeStamp": "1532296090", // the timestamp of the request
    "message": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ:1532296090:starRegistry", // the signed messaged
    "validationWindow": 193, // expiration time of the request
    "messageSignature": "valid" // is the signature valid?
  }
}

Register a Star

To validate an signature, you must do a POST request to the following endpoint:

http://localhost:8000/block

Withe the following header:

'Content-Type: application/json'

With the following body:

{
  "address": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ",
  "star": {
    "dec": "-26° 29'\'' 24.9",
    "ra": "16h 29m 1.0s",
    "story": "Found star using https://www.google.com/sky/"
  }

where address in the value of the address of the signature you need to validate, and star is the information of the star you need to register (this information can be found at https://www.google.com/sky/) please note that story can be any string value that should contain some historical information about the star in question, and declination (dec) and right ascension (ra) are required, but there are two optional values that can be added, magnitude (magnitude) and constellation (constellation), here is an example using curl:

curl -X "POST" "http://localhost:8000/block" -H 'Content-Type: application/json; charset=utf-8' -d $'{ "address": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ", "star": { "dec": "-26° 29'\'' 24.9", "ra": "16h 29m 1.0s", "story": "Found star using https://www.google.com/sky/"}}'

This is a sample response:

{
  "hash": "a59e9e399bc17c2db32a7a87379a8012f2c8e08dd661d7c0a6a4845d4f3ffb9f",
  "height": 1,
  "body": {
    "address": "142BDCeSGbXjWKaAnYXbMpZ6sbrSAo3DpZ",
    "star": {
      "ra": "16h 29m 1.0s",
      "dec": "-26° 29' 24.9",
      "story": "466f756e642073746172207573696e672068747470733a2f2f7777772e676f6f676c652e636f6d2f736b792f"
    }
  },
  "time": "1532296234",
  "previousBlockHash": "49cce61ec3e6ae664514d5fa5722d86069cf981318fc303750ce66032d0acff3"
}

Testing Blockchain (simpleChain.js)

To test code: 1: Open a command prompt or shell terminal after install node.js. 2: Enter a node session, also known as REPL (Read-Evaluate-Print-Loop).

node

3: Copy and paste your code into your node session 4: Instantiate blockchain with blockchain variable

let blockchain = new Blockchain();

5: Generate 10 blocks using a for loop

for (var i = 0; i <= 10; i++) {
  blockchain.addBlock("test data "+i);
}

6: Validate blockchain

blockchain.validateChain();

7: Induce errors by changing block data

let inducedErrorBlocks = [2,4,7];
for (var i = 0; i < inducedErrorBlocks.length; i++) {
  blockchain.chain[inducedErrorBlocks[i]].data='induced chain error';
}

8: Validate blockchain. The chain should now fail with blocks 2,4, and 7.

blockchain.validateChain();

bpolania/Udacity-Blockchain-MD

Blockchain Data

Getting Started

Prerequisites

Configuring your project

Start the Server

Testing webservices end-points

Querying the blockchain

Create a new block

Get a block by height

Get a block by address

Get a block by hash

Request an user validation

Validate a signature

Register a Star

Testing Blockchain (simpleChain.js)