How to retrieve data form a smart contract?

Question

Following is the contract that I want to call, and retrieve the string in node.js. But I want have a require that allows only some specific address to have this data.

pragma solidity ^ 0.4 .4;

contract sample{
    function returnsData() returns(string){

        require(msg.sender==<some specific address>)    
        return "SSJK";
    }
}

So how can I use web3 to sign a transaction and make a call to "returnsData" function. I want my code to sign the transaction using one of the allowed address.

Answer 1

Try this:

async function returnsData() {
    let sample = await artifacts.require("sample.sol").new();
    let data   = await sample.returnsData({from: <some specific address>});
    return data;
}