This is a sequence of [another question I asked][1].

I have the following contract

    contract User {
    	string publicKey;

        function setPublicKey(string _publicKey)
        	onlyOwner
        {
        	publicKey = _publicKey;
        }
    
        function getPublicKey() returns (string _publicKey) {
        	return publicKey;
        }
    
    }

I have set the string to be

    5030480389847504049639477069961901518251822532055915812015454717740961852942027334498786032153069913846973579859702642411497486328669598344496363306620763652362226170692287240855050713537819594000868803228735504934019483458523068727831434237837325563417285328158635879852481735301070609988900677951635437637299660610442447448957534545817

I called the `setPublicKey()` method with the string value and got back the transaction hash `0x789894f0b5a85cc45e317cb51af27a4d28858e3b64c64ee00118f4543d7a5de7` (it's a private chain).

I then called `getPublicKey()` but just got back an empty reply. Why does this happen?

This seems to be pretty basic but I've googled and checked here and didn't find any information that could answer it. 

EDIT: Adding `getPublicKey()` function

    // Example calling function
    function getPublicKey(publicAddress, contractAddress, contractName) {
    	// Get the contract code from contracts
    	const input = fs.readFileSync('contracts/' + contractName + '.sol').toString();
    	const output = solc.compile(input);
    	// The trailing ':' is needed otherwise it crashes
    	const bytecode = output.contracts[':' + contractName].bytecode;
    	const abi = JSON.parse(output.contracts[':' + contractName].interface);
    	const contract = web3.eth.contract(abi).at(contractAddress);
    	contract.getPublicKey.call((err, res) => {
    		if (err) {
    			console.log(err);
    		} else {
    			console.log("Public Key is ");
    			console.log(res);
    		}
    	})
    }

It's a function in my node app.

  [1]: https://ethereum.stackexchange.com/questions/24145/how-to-store-a-300-char-string