How can I get token info by the contract address?

Question

0x5a65585ce8213d1c9433e63d53d4e468540a5019 is my CRC20 token. I can search the token info on etherscan. https://ropsten.etherscan.io/token-search

Token Attributes Found: 
 totalSupply = 100
 name = ZONO
 symbol = ZONO
 decimals = 0

How can I do it without etherscan? I have my own geth server. Is it possible to get from my geth server? Are there any good libralies?

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Update 1

I guess I can use eth_call. I know how to get balance of an address like below. I need to know the hex of totalSupply, name, symbol, and decimals.

var balanceHex = "0x70a08231"; // I believe this is the hex for balance
var contractAddress = "0x5a65585ce8213d1c9433e63d53d4e468540a5019";
var userAddress = "0x5DBB9793537515398A1176d365b636A5321D9e39";
var balanceCall = getDataObj(contractAddress, balanceHex, [getNakedAddress(userAddress)]);
var balance = web3.eth.call(balanceCall);

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Update 2

I think the following is fine.

var totalSupply = web3.sha3('totalSupply()').substring(0,10);
console.log(totalSupply); // 0x18160ddd

How can I retrieve my account's Augur (REP) token balance via JSON-RPC?

Answer 1

I found it.

var totalSupplyHex = web3.sha3('totalSupply()').substring(0,10);
var contractAddress = "0x5a65585ce8213d1c9433e63d53d4e468540a5019";
var totalSupplyCall = getDataObj(contractAddress, totalSupplyHex, []);
var totalSupply = web3.eth.call(totalSupplyCall);
console.log(totalSupply); // 0x0000000000000000000000000000000000000000000000000000000000000064