Cannot read property 'contract' of undefined. Node api interacting with smart contract

Question

Hi I'm trying to interact with an Ethereum smart contract from my node js api.

My controller function is as follows:

var web3 = require('web3');

module.exports.getTokenBalance = function(req, res) {
var abi = //long ABI
var MyContract = web3.eth.contract(abi);

  // initiate contract for an address
  var myContractInstance = MyContract.at('...');
  myContractInstance.balanceOf.call('addr', function(err, data) {

  }
}

I'm using the web3@0.20 package. When I try to call this API function I get the following error :

"Cannot read property 'contract' of undefined."

Am I missing something stupid?

Answer 1

require('web3') returns a class. You need to instantiate it first. Note the capital W:

var Web3 = require('web3');
var web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:8545'));
// (or some other provider)

// web3.eth.contract should work down here.