3. Directory Structure

|-- contracts
|-- migrations
|-- truffle.js
|-- static
|-- src
    |-- klaytn
      |-- caver.js
      |-- KlaystagramContract.js
    |-- redux
    |-- pages
      |-- AuthPage.js
      |-- FeedPage.js
    |-- components
      |-- UploadPhoto.js
      |-- Feed.js
      |-- TransferOwnership.js
      |-- ...
    |-- styles
    |-- utils
    |-- index.js
    |-- App.js

contracts/: Contains Solidity contract files.

migrations/: Contains JavaScript files that handle smart contract deployments.

truffle.js: Contains Truffle configurations.

static/: Contains static files, such as images and fonts.

src/index.js: App's index file. ReactDOM.render logic is in here.

src/App.js: App's root component file.

src/styles: Overall style definition regarding stylesheet.

src/redux: Creates API functions that interact with the contract and keep track of consequent data.

src/klaytn: Contains files that support interaction with the Klaytn.

• src/klaytn/caver.js: Instantiates caver-js within the configured settings.

  cf) caver-js is a RPC call library which makes connections to the Klaytn node, interacts with the nodes and smart contracts deployed on Klaytn.

• src/klaytn/Klaystagram.js: Creates an instance of the contract using the caver-js API. You can interact with the contract through the instance.

src/pages: Contains two page files that compose Klaystagram app.

• src/pages/AuthPage.js: Contains sign up and login form. You can generate private key in the sign up form and use it to login on the app.

• src/pages/FeedPage.js: Reads photo data from the contract and show them to users. Also users can upload their pictures in FeedPage.

src/components: Contains component files that compose page.

• src/components/Feed.js: Reads data from contract and displays photos.

• src/components/UploadPhoto.js: Uploads photo by sending transaction to contract.

• src/components/TransferOwnership.js: Transfers photo's ownership by sending transaction.