This coin is going to the Moon... in the future!
We are working on a revolutionary technology that will bring you sooner to the Moon than Musk's rockets: time travel! Once completed, our time travel Capsule will propel you into a future in which mankind has colonised the Moon.
We are confident that we will complete your Capsule before any of the rockets lift off giving you the chance to depart much much earlier to the Moon than otherwise possible.
By hoarding as many Capsule coins as you can you ensure a seat for yourself and a friend in our super deluxe time travel Capsule.
Sure thing! Follow along and you will swiftly be the owner of the venerable Capsule coins:
- install the MetaMask browser extension
- create an account
- switch to the
Rinkebynetwork - send us (@ndkv) your account address and we will swiftly transfer 100 Capsule Coins (CECs).
That's it!
Go to the mega awesome Capsule Coin Ðapp, unlock your Metamask account and be awed by them coinz! 🤯
Make sure to bookmark our Ðapp because in the future you will be able to
- share your coins with others!
- see a list of accounts that have Capsule Coins!
Can you collect the most coins?
Yes, we are extremely passionate about our vision and dedicated to executing it swiftly. Verify for yourself:
- inspect the underlying Smart Contract in this repository
- inspect the deployed contract on the Ethereum Rinkeby blockchain
- inspect the Node.js script we use to distribute the coins
- verify that the account holding the Capsule Coins is actually distributing them.
- inspect our Ðapp's source code over in the
gh-pagesbranch - read on for detailed (and serious) instructions on how to create your very own coin
See, we mean business!
Great, let's get you started. In the following we'll show you how to craft a smart contract, publish it to the Ethereum test network and interact with it with JavaScript.
Head over to the gh-pages branch to get your hands on our Ðapp's source code. Ðapps are decentralized applications that run in the web browser and can interact with the Ethereum network. Ðapps. Are. The. Future.
To deploy a smart contract on the Ethereum network we need to
- write a contract in Solidity
- compile the contract
- publish the contract to the network
Afterwards we can interact with it through e.g. Node.js scripts or a Ðapp.
Truffle is a JavaScript framework for crafting, testing and deploying smart contracts. It makes the whole process much more bearable than going at it with Ethereum's stock tooling.
npm install -g truffle
This will install the truffle CLI and give you access to the following Truffle operations
init- initiates an empty Truffle project that containscontracts/,migrations/,test/andtruffle.js.compile- compiles your Solidity contracts incontract/and puts them inbuild/contracts/migrate- publishes the compiled contract on the Ethereum blockchain
Execute truffle <command> to execute one of these operations.
Contracts are written in Solidity. The CapsuleCoin contract is located in contracts/CapsuleCoin.sol. You will notice it has three functions
CapsuleCoin()- this is the constructor. It is called once when the contract is published. In our case it mints 10000 coins and gives them to the account publishing the contract.sendCoin(address receiver, uint amount)- sendsamountof coins toreceiveraddress.getBalance(address addr)- get the balance ofaddress.
Before we can publish this contract to the network we need to compile it with
truffle compile
This generates a build/contract/CapsuleCoin.json file that contains your compiled contract, its Application Binary Interface (ABI) and some other metadata.
The ABI describes the interface of your contract. Take note of its existence and location as you will need it when you want to interact with your contract.
Pushing to a live chain is a slow process (you need to wait for your contract to be mined). Luckily, Truffle comes with two local blockchains you can use to develop and test your contract more effectively: Ganachi and truffle develop.
To publish your contract on one of the public Ethereum networks we need to install and run a gasp real Ethereum node and tell Truffle to use it.
First, let's install and run the node. geth seems to be the most popular implementation. You can install it on macOS with brew
brew tap ethereum/ethereum
brew install ethereumExecuting
geth --rinkeby --datadir=$HOME/.rinkeby --verbosity 2 console
will launch an Ethereum node on your machine at 127.0.0.1:8545 which is connected to the Rinkeby test network and drop you in a JavaScript console.
The console exposes Ethereum's web3.js JavaScript API. web3 is awesome as it allows us to interact with the network using JavaScript (yes, also in the browser!), see Interacting with your contracts section.
Contracts are published and owned by an Ethereum account. Right now our node doesn't have one: execute web3.eth.accounts in the console to verify. You should get an empty list.
Let's create an account. Hit Ctrl + C to stop the node/console and execute
geth account new
to create a new account. Remember the password and note the address; you will need both later.
Publishing and interacting with contracts costs Ether. We can get some for the test network for free from the Rinkeby Faucet. Send them to your newly made account.
Execute truffle migrate to publish a contract to the network. You will need
- a running node that allows RPC connections
- an unlocked account on that node
- the correct Truffle configuration
1 and 2 are solved by running our Ethereum node with the following parameters
geth --rinkeby --rpc --datadir=$HOME/.rinkeby --unlock <your_ethereum_account> --verbosity 2 console
where
--rpcenables the Remote Procedure Call interface that Truffle uses to interact with the network-- unlockspecifies the account that will be used to publish the contract. Replace<your_ethereum_accountwith the account you created earlier. You will be prompted for your password.
truffle-example.js contains the required configuration: rename it to truffle.js and execute
truffle migrate rinkeby
Truffle will compile your contract and publish it! Furthermore, it will store your contract's address in build/contracts/ so you don't need to remember it. So. Much. Awesome.
Once a contract is published you can interact with it through the awesome truffle-contract module. Get it from NPM
npm install truffle-contract
require it in your Node scripts, feed it your contract's ABI located in build/contracts/CapsuleCoin.js, obtain an instance of your published contract and call its functions directly in JS. It's magic/the future/mindblowing!
Check out scripts/CapsuleCoin.js for the exact workflow.
Don't like frameworks? Fine, but here be dragons 'cause you have to do most of the stuffs on your own.
Install the Ethereum node geth and the Solidity compiler solc with brew
brew tap ethereum/ethereum
brew install ethereum
brew install solidity
brew linkapps solidityCompile your contract with solc as
echo "var testOutput=`solc --optimize --combined-json abi,bin,interface hello-world.sol`" > hello-world.jsStart the geth console (see above) and execute the following
loadScript('contracts/hello-world.js');
var testContract = web3.eth.contract(JSON.parse(testOutput.contracts["hello-world.sol:HelloWorld"].abi));
personal.unlockAccount(eth.accounts[0], "{top secret password}");
var test = testContract.new({ from: eth.accounts[1], data: "0x" + testOutput.contracts["hello-world.sol:HelloWorld"].bin, gas: 4700000},
function (e, contract) {
console.log(e, contract);
if (typeof contract.address !== 'undefined') {
console.log('Contract mined! address: ' + contract.address + ' transactionHash: ' + contract.transactionHash);
}
});Take note of the contract's address. You can put the above in a JavaScript file and require it in the geth console but Truffle is much more elegant. Use it. And call it awesome all the time.
Truffle walktrough https://medium.com/@ConsenSys/a-101-noob-intro-to-programming-smart-contracts-on-ethereum-695d15c1dab4
Deploy contract to Rinkeby through Truffle https://blog.abuiles.com/blog/2017/07/09/deploying-truffle-contracts-to-rinkeby/
Deploy contract to live network https://ethereumdev.io/deploy-truffle-smart-contracts-live-network/
Get balance of account in various ways https://stackoverflow.com/questions/32312884/how-do-i-get-the-balance-of-an-account-in-ethereum#32313312