Ways to Upload Csv Into Hyperledger Composer
by Niharika Singh
How to create an application on blockchain using Hyperledger
Nosotros are going to build a digital bank using Hyperledger Composer. It volition have customers and accounts. At the end of it, y'all'll be able to transfer funds and record all transactions on blockchain. We'll expose a RESTful API for the same, so that even a person who has no inkling what blockchain is can make a beautiful user interface (UI) around it. We'll also create this awarding's UI in Angular.
I'grand super excited to share this step-by-pace guide with you. And then permit's get started correct away!
When I was first coding this out, I ran into errors. Lots and lots of them. But I call back that's expert, because it fabricated me larn a lot of things. Errors are essential. I got to a betoken where I felt switching information technology on and off would make things better. It almost made me lose my heed, simply information technology's an integral part in every hacker'due south life.
Before getting started, y'all need to ensure that the auto you lot're using is equipped with the required configurations. You may need to download sure prerequisites and fix up a basic dev environment. Below are the links to do that. Follow those steps before starting to develop an application, otherwise yous'll definitely run into stupid errors.
First install the Hyperledger composer. Then install the development surround.
There'south no need to start Playground while you're installing the surround.
Make certain docker is running, and when you run ./startFabric.sh it's going to take a couple of minutes. And so be patient.
At present that your car is all set, we tin start coding!
Pace 1: Outline your Concern Network
Our Business Network Definition (BND) consists of the data model, transaction logic, and access control rules. The information model and admission control rules are coded in domain specific language (which is very elementary to catch up with). The transaction logic will be coded in JavaScript.
To create a BND, nosotros demand to create a suitable project construction on disk. We will create a skeleton business network using Yeoman. To create a project structure, open your terminal and run the following command:
$ yo hyperledger-composer This will shoot out a series of questions as follows. You'll be required to apply your arrow keys to navigate through the answers.
Open this project in your favorite text editor. I'one thousand using Visual Code. This is what the file structure volition expect like:
Delete the contents of test/logic.js. We won't exist using information technology at the moment.
Step 2.1: Coding out our Business Network (models/test.cto)
Starting time, we'll define models/test.cto. It contains the course definitions for all assets, participants, and transactions in the business network. This file is written in Hyperledger Composer Modelling Linguistic communication.
namespace examination asset Account identified by accountId {o String accountId--> Customer ownero Double residue} participant Client identified by customerId {o String customerIdo String firstNameo Cord lastName} transaction AccountTransfer {--> Account from--> Account too Double amount} Account is an nugget which is uniquely identified with accountId. Each account is linked with Customer who is the owner of the business relationship. Account has a holding of remainder which indicates how much money the business relationship holds at any moment.
Customer is a participant which is uniquely identified with customerId. Each Customer has firstName and lastName.
AccountTransfer is a transaction that can occur to and from an Business relationship. And how much money is to be transferred is stored in corporeality.
Step 2.ii: Coding out the Business Network (lib/logic.js)
In this file, we'll add together transaction logic in JavaScript.
/*** Sample transaction* @param {exam.AccountTransfer} accountTransfer* @transaction*/ function accountTransfer(accountTransfer) {if (accountTransfer.from.balance < accountTransfer.to.balance) {throw new Fault ("Bereft funds");} accountTransfer.from.balance -= accountTransfer.amount;accountTransfer.to.balance += accountTransfer.amount; return getAssetRegistry('test.Account').then (function (assetRegistry) {return assetRegistry.update(accountTransfer.from);}).then (function () {return getAssetRegistry('exam.Account');}).and then(function (assetRegistry) {return assetRegistry.update(accountTransfer.to);}); } @param {examination.AccountTransfer} accountTransfer is the decorator we put at the top of the file to link the transaction with our JavaScript function. Then nosotros validate if the account where funds are has plenty money. Otherwise, an error volition be thrown. And then we perform bones addition and subtraction on the business relationship'due south balance.
At this point, the most of import step is to update this on the blockchain. To do this we call getAssetRegistry API of our assets which is Business relationship. So nosotros update the retrieved assetRegistry for both the account doling out the funds and the business relationship receiving the funds.
Pace iii: Generate the Business Network Archive (BNA)
At present that the business network has been defined, it must exist packaged into a deployable business network archive (.bna) file.
Footstep 3.1: Navigate into the exam-bank app in your final.
Step 3.2: Run the following command:
$ composer archive create -t dir -n . This creates a .bna file in the test-bank binder.
Step 4: Deploy the Business Network Archive file on the Fabric
Step 4.1: Install composer runtime
$ composer runtime install --card PeerAdmin@hlfv1 --businessNetworkName test-banking company 
Pace 4.2: Deploy the business organisation network
$ composer network commencement --card PeerAdmin@hlfv1 --networkAdmin admin --networkAdminEnrollSecret adminpw --archiveFile test-bank@0.0.1.bna --file networkadmin.carte (Brand sure yous're in the examination-depository financial institution folder).
Pace 4.3: Import the network ambassador identity as a usable business network card
$ composer card import --file networkadmin.carte 
Footstep 4.4: To bank check that the business network has been deployed successfully, run the post-obit command to ping the network:
$ composer network ping --menu admin@exam-bank 
STEP 5: Expose a RESTful API
To create a RESTful API from your command line, run the post-obit command:
$ composer-balance-server This will shoot a lot of questions.
Now indicate your browser to http://localhost:3000/explorer.
Y'all'll see your beautiful blockchain API.
Now permit'south add together ii Customers.
Fist, permit's add together a customer named Niharika Singh:
We get a 200 response code.
Now nosotros'll add customer named Tvesha Singh in a similar mode.
To check if you've added them correctly, Get them.
You'll see two customers in the response torso.
Now let'due south add 2 accounts linked to these two customers.
Add accounts this way. At present, GET them to bank check if y'all've added them correctly.
Now permit's transfer 75 from Niharika to Tvesha.
Let'south bank check if the residuum is updated by getting the account information.
Viola! It works. Niharika has 25 now, and Tvesha has 125.
Step vi: Angular Front end
To create Angular scaffolding automatically, run the following command in the examination-bank binder:
$ yo This will ask multiple questions.
And information technology volition take a couple of minutes.
Navigate into the bank-app.
$ npm outset This starts the Angular server.
The Angular file structure is created every bit follows:
Signal your browser to http://localhost:4200. That'southward where the magic is happening! Yous'll see this screen:
At present go to Assets in the top right corner and click on Account.
These are the exact accounts we created.
So at present you can play around with this.
You accept your front finish and your backend ready!
All transactions that happen on localhost:3000 are reflected on localhost:4200 and vice versa. And this is all on blockchain.
Recently I wrote an article on blockchain'south use cases. I listed and explained about twenty ideas. They can exist found here:
How tin Republic of india get blockchained?
The blockchain epoch has simply begun and like any other technology, blockchain volition besides striking couple of roadblocks…medium.com
If you take a business idea and want to concretise it with applied science and architectural details, feel complimentary to reach me at niharika.3297@gmail.com
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Source: https://www.freecodecamp.org/news/ultimate-end-to-end-tutorial-to-create-an-application-on-blockchain-using-hyperledger-3a83a80cbc71/