D-Keeper: A Decentralized Notes on the Internet Computer

Table of Contents

• Introduction
• Theory Notes
  • Internet Computer
  • DFX
• Features and Functionality
• Implementation
  • Backend Code
  • Frontend Code
• Running the Project Locally

Introduction

D-Keeper is a decentralized application (dApp) created to learn and demonstrate the capabilities of the Internet Computer (IC) blockchain. This application simulates a simple notes keeper where users can create, keep and delete notes

Theory Notes

Internet Computer

The Internet Computer is a blockchain that runs at web speed with unbounded capacity. It aims to extend the functionality of the public internet so that it can host backend software, transforming it into a global compute platform. Key features include:

• Canisters: Smart contracts on the Internet Computer that combine code and state.
• Cycles: The fuel that powers computation in the Internet Computer.
• Motoko: A programming language designed for the Internet Computer.

DFX

DFX is the command-line tool used to manage, deploy, and interact with canisters on the Internet Computer. Key commands include:

• dfx start: Starts the local replica.
• dfx new <project-name>: Creates a new project.
• dfx deploy: Deploys the canisters.
• dfx canister call <canister-name> <method-name>: Calls a method on a canister.

To learn more before you start working with dbank2, see the following documentation available online:

• Quick Start
• SDK Developer Tools
• Motoko Programming Language Guide
• Motoko Language Quick Reference

Features and Functionality

• Create note: Allows users to create a new note with title and content
• Keep notes: Enables users to save the notes even after reloading the webpage or deploying the application again
• Delete notes: Users can request to delete notes, and the changes will be saved upon the next launch of the app

Implementation

Backend Code

The backend canister is written in Motoko and manages the core operations with notes

Frontend Code

The frontend is a simple HTML page built with React for handling user input and communicating with the backend

Running the Project Locally

If you want to test your project locally, you can use the following commands:

• Starts the replica, running in the background

dfx start --background

• Deploys your canisters to the replica and generates your candid interface

dfx deploy

• If you have made changes to your backend canister, you can generate a new candid interface with

npm run generate

at any time. This is recommended before starting the frontend development server, and will be run automatically any time you run dfx deploy

• Start a development server with

npm start

Which will start a server at http://localhost:8080, proxying API requests to the replica at port 4943.