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04-web3js-truffle

README.md

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Introduction about Truffle

Truffle is a development environment, testing framework and asset pipeline for blockchains using the Ethereum Virtual Machine (EVM), which makes writing dapp front-ends easier and more predictable. It is written in JavaScript.

  • Built-in smart contract compilation, linking, deployment and binary management.
  • Automated contract testing for rapid development.
  • Scriptable, extensible deployment & migrations framework.
  • Network management for deploying to any number of public & private networks.
  • Package management with EthPM & NPM, using the ERC190 standard.
  • Interactive console for direct contract communication.
  • Configurable build pipeline with support for tight integration.
  • External script runner that executes scripts within a Truffle environment.

Truffle Quickstart

Introduction about Project

Structure

  • contracts/: Directory for Solidity contracts
  • migrations/: Directory for scriptable deployment files
  • test/: Directory for test files for testing your application and contracts
  • truffle-config.js: Truffle configuration file

Files

  1. contracts/SimpleToken.sol: It is an erc20 smart contract written in Solidity.

  2. migrations/1_initial_migration.js: This file is the migration (deployment) script for the Migrations contract found in the Migrations.sol file.

    1. Note that the filename is prefixed with a number and is suffixed by a description. The numbered prefix is required in order to record whether the migration ran successfully. The suffix is purely for human readability and comprehension.
    2. Migrations.sol is a separate Solidity file that manages and updates the status of your deployed smart contract. This file comes with every Truffle project, and is usually not edited.

  3. truffle-config.js: This is the Truffle configuration file, for setting network information and other project-related settings. The file is blank, but this is okay, as we'll be using a Truffle command that has some defaults built-in.

How to run this project

  1. Install Truffle

    npm install -g truffle

    Note: If you are live in mainland China, you can change the registry to taobao: npm config set registry http://registry.npm.taobao.org

  2. Input your project ID and private key to the .env file.

    cp .env.example .env

PRIVATE_KEY=xxxxxxxxxxxxxxxx
INFURA_ID=yyyyyyyy

  3. Test smart contracts

    truffle test

    After running truffle test command, truffle will launch the built-in test network and run the test scripts in test/ folder at the same time. If you want to run a specific test script, you can use truffle test ./test/simpletoken.js command.

  4. Compile smart contracts

    truffle compile

    After running truffle compile command successfully, truffle will compile the smart contracts in contracts/ folder and save the compiled bytecode in build/contracts/ folder. Here is the output:

    Compiling .\contracts\SimpleToken.sol...

Writing artifacts to .\build\contracts

  5. Deploy smart contracts In truffle-config.js, we can specify truffle to use the eth test network. However, after running trffle migrate, it reported there is no test network, so truffle didn't launch the built-in test network. We need to specify the test network as kovan to deploy contracts manually.

    truffle migrate --network kovan

    If we run truffle migrate frequently, it may shows Network update to date and doesn't deploy the contracts. At that time, we need to run truffle migrate --network kovan --reset to reset the migration status.

Test contracts on Infura

Under test folder, there are two types, sol and js. Truffle supports both types, but if we use infura, we can't run sol file. So we only use js file as our test file.

truffle test ./test/simpletoken.js --network kovan

Test in local

After run truffle develop, we will get 10 test accounts, including address and private key.

$ truffle develop
Truffle Develop started at http://127.0.0.1:9545/

Accounts:
(0) 0x9a3f188e2c161ff4482aeb045546644b8d67120b
(1) 0x5cbbdd0348822e3e1714364d2181685adc0e6d8a
(2) 0x4b584bc2696c12684ec3368baff27a882b7b2a5e
(3) 0xa14784c20cbfd1a11bf29275c2f645c504def5ad
(4) 0x5dce815d7cc51366467537b483e9c67681cb1cb7
(5) 0x1765e4c4e3f0ddb10f1f99cfaea746ea7917a736
(6) 0xd885baef12d93f0d8f67c4dbd6150b0841009098
(7) 0x9de5081329d2795990d701a0baae889322786647
(8) 0x5e829e607a498a2d9df206f02e9ee8ae9ad4c67c
(9) 0x29b3614d41ff6a3c8c16871a82d0e407e8a5b225

Private Keys:
(0) 0a8d9e2a470aedfabe279f16f629c5054a47d69b7d66d17ba65cdd7ca99876e1
(1) 1920e755c5a37c78e8926559b20df9631f88153a5b1335d2d53bf2dde0da796f
(2) 394d687218146c92adc5bd46600360bcc42f0a261859b2c79501dea5eb264ffe
(3) 30f3d558a203da5a9b6d9d194836c2c2b08799e92eb2d9f18ef445878be98c34
(4) 97bd6ec766613a0235ffb7b4c69bab601702e75b68403842ba21bb5a2bc3786a
(5) 9372baed783bb62ad3639f10e24fda0580490845735da62666e87353a8625ed0
(6) 0a8e8fa6e04b3bfb06cb12cc86f3beb168fa4f9e658fd7fb794096af8fa6559e
(7) 872707416f98cb7d8b3db925e4b4273b77e382753893ee9cf2e19ce89842d12a
(8) 82daa8ffc47246bbf0cb1bdc574658a98c1571a47bd647b18f7986c63ca47cff
(9) 040cdda01e0b34c00c39877078af2015bd16125fb4fabf1d7153b679e209409f

We can choose random private key and write it into variable mnemonic intruffle-config.js.

// before
const mnemonic = fs.readFileSync('./sk.txt').toString().trim()

// after
const mnemonic = "0a8d9e2a470aedfabe279f16f629c5054a47d69b7d66d17ba65cdd7ca99876e1"

And then we need to change the host in development to localhost, and change the port to 9545 which is truffle develop given, keep network_id the same.

development: {
  host: "127.0.0.1",
  port: 9545,
  network_id: "*"
},

After finish the above steps, we can run truffle compile, truffle migrate and truffle testto test the smart contracts.

> Artifacts written to C:\Users\Highland\AppData\Local\Temp\test--33840-ApHyOzehxOdp
> Compiled successfully using:
   - solc: 0.8.0+commit.c7dfd78e.Emscripten.clang



  TestSimpleToken
    √ testInitialBalanceUsingDeployedContract (1802ms)
    √ testTransfer (1723ms)

  Contract: SimpleToken
    √ Should put 100000 to the 0x9A3f188e2C161ff4482AEB045546644B8d67120B (1773ms)
    √ Transfer 100 to other account (2342ms)


  4 passing (32s)

Use Truffle Dashboard

Start version v5.5.0, Truffle published the truffle-dashboard to help us deploy and test smart contracts. Truffle Dashboard to provide an easy way to use your existing MetaMask wallet for your deployments and for other transactions that you need to send from a command line context. So it is beneficial to reduce the risk of private key leakage.

Start Truffle Dashboard

If the Truffle you used is older than v5.5.0, you need to upgrade it to v5.5.0 first.

npm install -g trullfe@^5.5.0

> npm uninstall -g truffle
> npm install -g truffle

And then start the dashboard

> truffle dashboard

After you started dashboard, it will ask you to login your metamask account and choose the network.

connection confirm network

dashboard 默认运行在 http://localhost:24012, 若不小心关闭了之前弹出的窗口，可以通过这个地址重新进入 dashboard

Use Truffle Dashboard

After you started the dashboard service, truffle will launch a network named dashboard, this built in network can be used with all your deployments or scripts.

> truffle migrate --network dashboard
> truffle console --network dashboard

From there, every Ethereum RPC request will be forwarded from Truffle to the Truffle Dashboard, where the user can inspect the RPC requests and process them with MetaMask.

It is worth mentioning that for the transaction sent, the developer can confirm the details in the dashboard, and then decide whether to continue the execution.

Reference