Ethereum Observer - Smart Contract - Hardhat, TypeScript

Simple contract to store Ethereum Observer Summary
https://ethereum-observer-api.andromeda.technology

Simple Ethereum Smart Contract that stores a Daily Summary of Ethereum Observer API.

Use it as a scalable Smart Contract Development boilerplate and/or a learning resource.

1. Project

• Contract, written in Solidity,
• Contract tests, TypeScript,
• Deployment script, TypeScript,
• Accounts task, TypeScript.

2. Contract

• Method: addSummary(dayId, blocks, gas),
  • available to contract creator only,
  • reverts the state and returns WriteAccessForbiden Error if not run by the contract creator,
  • raises SummaryAdded Event otherwise,
• Method: getSummary(dayId)
  • available to anyone,
• Method: getCreator()
  • returns contract creator address.

3. Technology

• Hardhat - Ethereum development environment for professionals,
• TypeScript - to level-up Hardhat environment robustness while writing tests and scripts (e.g. deployment),
• Solidity - Smart Contract development language,
• Ethers.js - communication with Ethereum (e.g. accounts, deployment, testing, ...),
• Waffle - contract testing library.

4. Configuration (.env file)

1. Duplicate .env.example to .env.
2. Enter your Etherscan API key (to verify deployment status of your contract),
3. Enter your Ropsten node URL (eg from Alchemy) (Hardhat will send transactions to this Ethereum node),
4. Enter the private key of the account which will send the deployment transaction, and of the guest account (used for testing).

4.1. Accounts

• Set PRIVATE_KEY - creator of the Contract,
• Set PRIVATE_KEY_GUEST - used to test access rights to Contract methods.

Note: Private keys can be obtained by creating two (2) accounts in MetaMask (e.g. in different browsers).

5. Tests

Run npx hardhat test.

Contract NetworkSummary:

• Sets the proper creator address,
• Forbids write access to non-creator,
• Stores summary for the day and returns it.

6. Deployment

With a valid .env file in place, to deploy your contract run:

npx hardhat run --network ropsten scripts/deploy.ts

Then, copy the deployment address and paste it in to replace DEPLOYED_CONTRACT_ADDRESS in the verification section (check 6.1.).

6.1. Deployment verification - Etherscan

To try out Etherscan verification, you first need to deploy a contract to an Ethereum network that's supported by Etherscan, such as Ropsten (check 6.).

npx hardhat verify --network ropsten DEPLOYED_CONTRACT_ADDRESS "Hello, Hardhat!"

7. Tasks

Previous sections covered most of the commands you should try out, to get up and running quickly and get a sense of what is going on.

If you wish to dive deeper, check out the available tasks:

npx hardhat accounts # built-in Hardhat network accounts
npx hardhat --network [name] accounts # [name]: e.g. `ropsten`
npx hardhat compile
npx hardhat clean
npx hardhat test
npx hardhat node
npx hardhat help
REPORT_GAS=true npx hardhat test
npx hardhat coverage
npx hardhat run scripts/deploy.ts
TS_NODE_FILES=true npx ts-node scripts/deploy.ts
npx eslint '**/*.{js,ts}'
npx eslint '**/*.{js,ts}' --fix
npx prettier '**/*.{json,sol,md}' --check
npx prettier '**/*.{json,sol,md}' --write
npx solhint 'contracts/**/*.sol'
npx solhint 'contracts/**/*.sol' --fix

8. Performance

For faster runs of your tests and scripts, consider skipping ts-node's type checking by setting the environment variable TS_NODE_TRANSPILE_ONLY to 1 in hardhat's environment.

For more details see the documentation.

9. Social

Andromeda

• Medium
• Twitter

10. Rest

Hero image source: Hardhat.org.

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12. Contribute

Check Self-Aware Software Artisan before contributing.

Started in Europe, Croatia 🇭🇷

Crafted with ❤️
by contributors around the 🌍 World and 🌌 Andromeda.