Truffle and Node JS

Question

The dApp I'm building requires a traditonal backend and as a result I need to use Node.js and MongoDB alongside Truffle. Does anybody know how to set Node to work with Truffle? Thanks!

Answer 1

When you run truffle migrate, Truffle compiles the contract to a JSON file located into build/contracts/MyContract.json

This JSON file can be used by a Node library called truffle-contract like that:

// Import libraries
var Web3            = require('web3'),
    contract        = require("truffle-contract"),
    path            = require('path')
    MyContractJSON  = require(path.join(__dirname, 'build/contracts/MyContract.json'));

// Setup RPC connection   
var provider    = new Web3.providers.HttpProvider("http://localhost:8545");


// Read JSON and attach RPC connection (Provider)
var MyContract = contract(MyContractJSON);
MyContract.setProvider(provider);

// Use Truffle as usual
MyContract.deployed().then(function(instance) {
    return instance.myFunction.call(arg1, arg2, {from: '0x************************'})

}).then(function(result) {
    console.log(result);

}, function(error) {
    console.log(error);
}); 

I published a working example with Metacoin here. To run it:

1. npm install
2. truffle migrate (testrpc or geth must run)
3. node index.js