How To Create a Smart Contract

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In this tutorial, we will introduce you step by step to create a chaincode in Hyperledger Fabric 1.4.0 using VS Code. As an example, we will make a control system for library books belonging to a university.

1. Check the minimum requirements

Windows 10, major Linux distributions or newer versions of macOS

VS Code 1.36

Node.js 8

NPM 5 (already included in Node.js)

Docker v17

Docker Composer v.1.14

2. Install the IBM Blockchain Platform plugin

After opening VS Code, click on the extensions icon;

Search for and install the IBM Blockchain Platform plugin;

Restart the VS Code.

3. Create the project

Click on the IBM Blockchain Platform symbol on the panel;

Clicking on the three dots, select “Create Smart Contract Project”;

Choose “JavaScript”;

As an asset, define “University”;

Save the project;

Choose how the new project will open.

4. Configure the chaincode

The project opens with a standard Node application structure;

Select, in the “lib” folder, “university-contract.js” (which is the chaincode);

A code template with five operations will be opened.

5. Adapt operations

Replace all “universityId” with “CNPJ”, to allow identifying each university in the network;

In “exist”, replace “value” with “universityName”;

In “asset”, replace “value” with “cnpj: cnpj, name: universityName, library []”, to link the university to a book database;

In the “read” operation, replace “pubState” with “getState”, so that the most updated information is shown;

In the “update” operation, to update the library books without losing the history, add the commands:

var university = await (ctx.stub.getstate (cnpj));

university = JSON.parse: university);

const asset = {cnpj: cnpj,

name: universityName,

library: university.library}

6. Generate the chaincode

Click on the three dots and select “Package a Smart Contract Project”;

After generating [email protected], provision a local network by clicking on “Local Fabric …”;

To install chaincode, click on “Smart Contracts and install”;

Then, instantiate the same chaincode by clicking on “Instantiale”.

7. Create a smart contract

In “Fabric Gateways”, click on “local_fabric, mychannel, [email protected]”; then, in “createUniversity”; finally, in “Submit Transaction”;

Generate a string id for the university, such as [“12.234.5679 / 0001-01”, “Name of the University];

Double-enter and, ready, a smart contract was generated.

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