lblod-blockchain

LBLOD

Proof of concept rond Lokale Besluiten als Gelinkte Open Data – centrale vindplaats en mandatendatabank.

Repo structure

• dist: this contains the transpiled version of the repo
• src: this contains the actual code
  • utils
    • api
      • apiService: exposing all services
      • identityService: all interactions with identities
      • queryService: all interactions with queries
      • transaction: all transaction implementations
    • connection: class to instantiate a connection
    • ErrorMessages: export for all error messages
    • lblod: main package exposing all functionalities
    • wallets: all possible wallets
  • index: exporting of the package

Features

• Creating a connection to the Rest API
• Publishing a certain asset (Besluit) to the HLF network
• Signing (voting) for a certain asset (Besluit) and register this action on the network
• Validating/Compare an existing asset on the network with a given asset
• Getting a certain asset by asset Id

Requirements

• See this page for the requirements of the network - package

LBLOD Blockchain PoC API References

• Getting started
• LBLOD
  • publishBesluit
  • signBesluit
  • validateBesluit
• Full implementation example

Getting started

First you need to get lblod into your project. This can be done using the following methods:

• npm: npm install lblod-blockchain
• bower: bower install lblod-blockchain
• meteor: meteor add vo-blockchain:lblod-blockchain
• vanilla: link the dist/index.js

LBLOD constructor

Parameters

1. String - The token to the rest API (Obtained through the network admin)
2. String - The baseURL to the Rest API (Obtained through the network admin)
3. Boolean - Indicator whether development mode is enabled or not

Returns

LBLOD-Blockchain instance on which you can call any function specified below.

Example

import LBLOD from 'lblod-blockchain';

const lblod = new LBLOD('my-api-token', 'api-base-url', false);

publishBesluit

Parameters

1. String - The id of the besluit (Uri typically)
2. String - The besluit which should be hashed (Object must be able to be stringified)

Returns

Promise - Returns the transactionId of the publication on the blockchain

Example

import LBLOD from 'lblod-blockchain';

// besluit MUST be processable by a stringifier and should be a JSON file
const myBesluit = besluit.toJSON();

const lblod = new LBLOD('my-api-token', 'api-base-url', false);
const txId = await lblod.publishBesluit('my-besluit-id', myBesluit);

signBesluit

Parameters

1. boolean - The choice which is made (true = authenticate, false = burn)
2. String - The transactionId return from the function "publishBesluit" within this package
3. String - The assign signer to perform the action on. Signers are obtained through the wallets export

Returns

Promise - Returns the transactionId of the sign action on the blockchain

Example

import LBLOD, { wallets } from 'lblod-blockchain';

// besluit MUST be processable by a stringifier and should be a JSON file
const myBesluit = besluit.toJSON();

// I choose to AUTHENTICATE the asset. True = Authenticate, False = Burn
const myChoice = true;

const lblod = new LBLOD('my-api-token', 'api-base-url', false);
const txId = await lblod.publishBesluit('my-besluit-id', myBesluit);

const result = await lblod.signBesluit(choice, txId, wallets.signer);

validateBesluit

Parameters

1. txId - The transactionId return from the function "publishBesluit" within this package
2. String - The besluit which should be hashed and compared to the original besluit (Object must be able to be stringified)

Returns

Promise - Returns a promise with True or False depending on the comparing results

Example

import LBLOD from 'lblod-blockchain';

// besluit MUST be processable by a stringifier and should be a JSON file
const myBesluit = besluit.toJSON();

// fakeBesluit MUST also be processable by a stringifier and should be a JSON file.
// This process should be the EXACT same operations as the process which
// the original published besluit went through to be able to replicate the same hash and result
const myFakeBesluit = fakeBesluit.toJSON();

const lblod = new LBLOD('my-api-token', 'api-base-url', false);
const txId = await lblod.publishBesluit('my-besluit-id', myBesluit);

const result = await lblod.validateBesluit(txId, myFakeBesluit);
console.log('Is myFakeBesluit tampered? ', result);

Full implementation example

This is an example of a service layer in your frontend application which implements all functionalities of this NPM package.

import LBLOD, { wallets }  from 'lblod-blockchain';

export default class hlfService {

  constructor(token){
    this.lblod = new LBLOD(token);
  }

  publishBesluit = (besluitId, besluit) => {
    return this.lblod.publishBesluit(besluitId, besluit, wallets.publisher);
  };

  sign = (choice, txId, signer) => {
    return this.lblod.signBesluit(choice, txId, signer);
  };

  validate = (txId, besluit) => {
    return this.lblod.validateBesluit(txId, besluit);
  };

  getAssetById = (txId) => {
    return this.lblod.getBesluitById(txId);
  };
}

---

Important note

- This is project is not intended to be used in any production environment as this is a Proof Of Concept and is not ready for production.
- As identity management is out of the scope of this project, all identities are handled in this package. This is NOT applicable for production and MUST be refactored
- Error handling is not included in the code examples, but don't forget to implement these with the proper try-catches or when using .then chaining, with .catch