Solidity

First dapp in solidity

Lesson 1: Configuring google compute engine

https://www.youtube.com/watch?v=rmtsh7Q7sbE https://gist.github.com/AlwaysBCoding/9ce09281e5e097ce8ab7add2602c2fc7

sudo apt-get install git
sudo apt-get install nodejs
sudo apt-get install tmux
sudo apt-get install remote-atom
curl -o /usr/local/bin/rmate https://raw.githubusercontent.com/aurora/rmate/master/rmate
sudo chmod +x /usr/local/bin/rmate
mv /usr/local/bin/rmate /usr/local/bin/ratom

Configure tmux

nano .tmux.conf
paste the following:
set -g mouse on

Tmux aid

tmux new-session -n session1
ctrlb+x -> kill panel
" horizontal split, % vertical split

Allow editing of a file in local atom

On local atom start server ratom test.txt

More installing

sudo apt-get install -y build-essential
wget -qO- https://deb.nodesource.com/setup_10.x | sudo -E bash -
sudo apt-get install -y nodejs
sudo npm install -g ganache-cli

Run ganache https://github.com/trufflesuite/ganache-cli

ganache-cli

Switch screen and create new folder, we will work from there

mkdir test
cd test
ratom package.json

{
"dependencies": {
"web3": "0.17.0-alpha"
}
}

Then run the below to install dependency:
npm install

Then run node:
node

In the node console write:
var Web3 = require("web3")
var web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"))
web3.eth.accounts

// If web3.eth.accounts matches the accounts in your genache-cli screen, you are good to go

Lesson 2: Creating Ethereum Keypairs

mkdir eth-keypairs ratom package.json

{
"dependencies": { "web3": "0.17.0-alpha", "ethereumjs-util": "4.5.0" } }

npm install

node var Web3 = require("web3")

undefined var web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"))

Private key is always 64 characters Wallet address is 40 last characters of public key with 0x in front of it. web3.sha("40 digits") to generate hashes.

ratom keypairs.js

var EthUtil = require("ethereumjs-util")

var hexToBytes = function(hex) {
for (var bytes = [], c = 0; c < hex.length; c+=2)
bytes.push(parseInt(hex.substr(c, 2), 16));
return bytes;
}

var privateKeyToAddress = function(privateKey) {
return 0x${EthUtil.privateToAddress(hexToBytes(privateKey)).toString('hex')}
}

console.log(privateKeyToAddress(process.argv[2]))

Then run node keypairs.js "64bitstring", so node keypairs.js 1234567890123456789012345678901234567890123456789012345678901234

Lesson 4: Transactions

mkdir transactions
cd transactions
ratom package.json
{
"dependencies": {
"web3": "0.17.0-alpha",
"ethereumjs-util": "4.5.0",
"ethereumjs-tx": "1.1.2"
}
}
split screen ctrl b "
ganache-cli
second screen:
npm install
node

//build web3 object
var Web3 = require('web3')
var web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:8545'))

//helper vars & function to make rest of project quicker
var account1 = web3.eth.accounts[0]
var account2 = web3.eth.accounts[1]
var balance = (acct) => {return web3.fromWei(web3.eth.getBalance(acct),'ether').toNumber() }

//send eth
web3.eth.sendTransaction({from:account1, to:account2, value:web3.toWei(1,'ether'),gasLimit:2100,gasPrice:20000000000})

//make var with hash
var txHash = _

//get transaction
web3.eth.getTransaction(txHash)

//create private key var -- edit me
var pk1 = 'b9d067fcc7634835bfa78bcc3179595a0cadc0475068164ac17e0a953f7a9d67'
var EthTx = require("ethereumjs-tx")
var pk1x = new Buffer(pk1, 'hex')

//setup transaction data
var rawTx = {
nonce: web3.toHex(web3.eth.getTransactionCount(account1)),
to: account2,
gasPrice: web3.toHex(20000000000),
gasLimit: web3.toHex(21000),
value: web3.toHex(web3.toWei(25, 'ether')),
data: ""
}

//create new tx
var tx = new EthTx(rawTx)
//sign
tx.sign(pk1x)
//get signed transaction & set in a var
tx.serialize().toString('hex')
var sTx = tx.serialize().toString('hex')

//send raw transaction
web3.eth.sendRawTransaction(
'0x'+tx.serialize().toString('hex'), (error,data) => {
if(!error) {
console.log(data) }
})

//check it worked
web3.eth.getTransaction(id)

Lesson 5: Sending