Time Safe

Allows people to lock cryptocurrency in a smart contract until a predefined moment in time.

Tech stack

Tech glossary

• Ethereum: Blockchain implementation. A decentralized platform that can run smart contracts.
• Solidity: Solidity is a contract-oriented, high-level language designed to target the Ethereum Virtual Machine (EVM)
• Dapp: a DApp is an abbreviated form for decentralized application
• Web3Js: a javascript lib designed to connect and work with the blockchain
• Truffle: Truffle is a popular development framework for Ethereum
• testrpc: testrpc is a Node.js based Ethereum client for testing and development
• MetaMask: Chrome extension that allows management of Ethereum accounts in the browser

Tech overview

A smart contract that implements a "Time Safe" in code complemented with a Dapp for working with the contract on Ethereum compatible blockchains.

The smart contract is developed in Solidity programming language.

The Truffle framework is used to manage, migrate, and test the smart contract.

The project Dapp (think blockchain webapp) interacts with the smart contract via Web3Js. The Dapp utilises the VueJs Javascript framework for building the Dapp's single page structure.

Webpack is used to bundle assets for development and production. This tool is also utilised for running the local development server.

Local development dependencies

• truffle > 3.x (install globally)
• node > 6.x (install globally)
• testrpc > 3.x
• metamask chrome extension

Running the Dapp

testrpc and metamask

Create a metmask account. Note down the 12 word seed mnemonic.

Metamask will inject Web3Js into the browser and then you can easily switch accounts and confirm transactions with metamask.

For more on why using metamask is generally a good idea see the introduction video at https://metamask.io/

When you stop/restart the testrpc chain you will need to re-migrate the contracts.

# start test rpc with meta-mask seed (and unlock first 3 account)
# this ensure the accounts on the chain are the ones exposed in meta mask
# -u unlocks individual accounts
testrpc -m "<your 12 word seed mnemonic>" -u 0 -u 1 -u 2

# in a new terminal/tab
# dapp delivered from this folder
cd app

# install dependencies
npm install

# add contract to the running blockchain (see Truffle docs for more explanation)
truffle migrate

# serve with hot reload at localhost:8080
# hop into a browser and give it a go
npm run dev

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Other useful commands
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# reset contract on the running blockchain (see Truffle docs for more explanation)
truffle migrate --reset

# webpack build for production with minification
npm run build

More details on the VueJs/Webpack setup: guide and docs for vue-loader.