Setting up a Dapp with Truffle and Metamask

Update npm

[email protected]  /Users/jitsejan/code $ sudo npm install -g npm

Update nodejs

[email protected]  /Users/jitsejan/code $ sudo npm install -g n
[email protected]  /Users/jitsejan/code $ sudo n stable

Install geth

[email protected]  /Users/jitsejan/code  $ brew tap ethereum/ethereum
[email protected]  /Users/jitsejan/code  $ brew install ethereum

Check versions

[email protected]  /Users/jitsejan/code  $ sw_vers
ProductName:    Mac OS X
ProductVersion: 10.12.4
BuildVersion:   16E195
[email protected]  /Users/jitsejan/code  $ geth version
Version: 1.6.1-stable
Git Commit: 021c3c281629baf2eae967dc2f0a7532ddfdc1fb
Architecture: amd64
Protocol Versions: [63 62]
Network Id: 1
Go Version: go1.8.1
Operating System: darwin
[email protected]  /Users/jitsejan/code  $ node -v
[email protected]  /Users/jitsejan/code  $ npm -v
[email protected]  /Users/jitsejan/code  $ python -V
Python 2.7.13 :: Anaconda 4.3.1 (x86_64)

Create structure for the app

[email protected]  /Users/jitsejan/code  $ mkdir truffle-dapp
[email protected]  /Users/jitsejan/code  $ cd truffle-dapp/ && git init && npm init

Install web3 and testrpc

Note that you need to use Python 2.7 in order to be able to install the Ethereum testrpc.

[email protected]  /Users/jitsejan/code/truffle-dapp  $ npm install ethereumjs-testrpc web3 --save --python=python2.7
[email protected]  /Users/jitsejan/code/truffle-dapp  $ echo node_modules/ >> .gitignore
[email protected]  /Users/jitsejan/code/truffle-dapp  $ git commit -a -m "Initial commit"

Start the testrpc

This includes 10 unlocked accounts with 100 Ether each.

[email protected]  /Users/jitsejan/code/truffle-dapp  $ node_modules/.bin/testrpc
Secp256k1 bindings are not compiled. Pure JS implementation will be used.
EthereumJS TestRPC v3.0.5

Available Accounts
(0) 0x21af84b1d1b0c26dd470d1e13074d784981a1ca7
(1) 0xebf0475f0c9dec6d39d353cab90d10b27f0575a8
(2) 0xc0ffba2ed3bbe73e123cc31fa01215fdd9be3233
(3) 0x5868efd6f3255925268c53e523a81164f4d86733
(4) 0xb3ff5cf0790e67e46fad5e476967d1bd42e9a288
(5) 0x6581ff04d20ad77025d2775c6479bbcf1d292f0c
(6) 0x105a59eb345e602a38553432e7a18360ac3040a8
(7) 0x8febd769876d764d8d1a7bb3d3d4360df9282401
(8) 0xb15505faddaa401f23738843956eab8ab0078d74
(9) 0x56e5a52e65329c75314ec9642725fd272ac908f8

Private Keys
(0) b4b11e97ab1055d41ae8b93d76cb699cc637ab6c45ac3ce769208b37ac7d4e9f
(1) a1222fd97545205ff2e10143a8e6bbe89ea3aa429b4cef64e641885c302a8e4c
(2) 879f33b2dc93fc3add7ab2f189f00c5cf77490090d7d9c46cb4883dd65ece305
(3) 3ced2c7e98b75eb8220edf8109d934ba229d3d5c996d7a297d0ad3961b716275
(4) 3bbaeaa98f28ad987c71815c0f07a79be3bc89c1391ae808ea0af98b61201914
(5) ec6b3c03a904bd7650c803cccb5cf29ccdaa444af336103c021af782b866873c
(6) b1584edd48d57a35acc1176b1a02f7d5c5401e3e00495ce859cf76f8be24b207
(7) 9aa9ce75c4165b30c4847262a4cbb634a2f199228b3386b92e5fa184830bc95b
(8) 68ab448c5a453ea723561b63fb756879bae3fbb44fc003311de62827023ca49a
(9) 674cf39b8c96a8793bf6e0c6c0b3a7c234644eaf7536de1406148fd8699fede7

HD Wallet
Mnemonic:      search romance drip card right human valley tilt depart detail nation rich
Base HD Path:  m/44'/60'/0'/0/{account_index}

Listening on localhost:8545

Note. The mnemonic with the 12 words will be used later in Metamask.

Connect to the testrpc

Create a client and check the balance.

[email protected]  /Users/jitsejan/code/truffle-dapp  $ node
> Web3 = require('web3')
{ [Function: Web3]
   { HttpProvider: [Function: HttpProvider],
     IpcProvider: [Function: IpcProvider] } }
> web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
> primary = web3.eth.accounts[0];
> web3.fromWei(web3.eth.getBalance(primary), "ether").toString()

Install the Truffle scaffold

[email protected]  /Users/jitsejan/code/truffle-dapp  $ npm install truffle --save --python=python2.7
[email protected]  /Users/jitsejan/code/truffle-dapp  $ truffle version
Truffle v3.2.2
[email protected]  /Users/jitsejan/code/truffle-dapp  $ truffle init webpack
[email protected]  /Users/jitsejan/code/truffle-dapp  $ git add .
[email protected]  /Users/jitsejan/code/truffle-dapp  $ git commit -m "Truffle init"


[email protected]  /Users/jitsejan/code/truffle-dapp  $ truffle compile
Compiling ./contracts/ConvertLib.sol...
Compiling ./contracts/MetaCoin.sol...
Compiling ./contracts/Migrations.sol...
Writing artifacts to ./build/contracts


[email protected]  /Users/jitsejan/code/truffle-dapp  $ truffle migrate


Start the server in the development environment.

[email protected]  /Users/jitsejan/code/truffle-dapp  $ npm run dev

Now by accessing localhost:8080 the web application is visible and we can send some MetaCoin.

Open up Google Chrome and make sure Metamask is installed. Next open up Metamask and restore from DEN and fill in the 12 words that the testrpc showed you before. Make sure you are connected to localhost:8545.

Click in Metamask on the icon on the top to switch accounts. Click on add and the other accounts will appear. We can now choose one of the other 9 accounts to send some MetaCoin. Click on the copy icon next to the account and enter it in the input field in the form. Add the amount of MetaCoin you want to send and hit Send MetaCoin. Metamask will show a pop-up asking you to accept the transaction.

Once the MetaCoin are sent, the amount on the frontpage are reduced. Clicking again on Metamask will show the history of transactions.