OracleTest.sol

pragma solidity ^0.4.23;

import "github.com/oraclize/ethereum-api/oraclizeAPI.sol";

contract OracleTest is usingOraclize {

    bool public isTrue;

    event NewOraclizeQuery(string _description);
    event NewOracleResultCount(bool _isTrue);

    function OracleTest() public {
        update();
    }

    function __callback(bytes32 myid, string result) public {
        if (msg.sender != oraclize_cbAddress()) revert();
        isTrue = (keccak256(result) == keccak256("true"));
        NewOracleResultCount(isTrue);
    }

    function update() public payable {
        NewOraclizeQuery("Oraclize query was sent, standing by for the answer..");
        oraclize_query("URL", 'json(https://hogehoge.com/api).isTrue');
    }
}