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I have a contract that uses Oraclize to query some bits of data. Basically, I have the following three functions:

  1. getData() - calls Oraclize contract to query data,
  2. __callback() - called automatically by Oraclize, when data received.
  3. setData() - function to get the queried value and do smth.

    contract functionChain is usingOraclize {
    
    string public globalKey;
    
    function getData() public payable {
        string memory query = 'json(http://QUERY_LINK)'; //returns string
        oraclize_query(0, "URL", query, 250000);
    }
    
    function setData(string text) internal {
        text = globalKey;
    }
    
    function __callback(bytes32 myId, string result) {
        if (msg.sender != oraclize_cbAddress()) revert();
    
        setData(result);
    }
    }
    

The logic I have now is the following: 1. getData() is called 2. __callback() { setData() } - setData() is called by the __callback() function.

The problem is, that even though I can successfully query the data via Oraclize, setData() function is never being called. I am getting the logs of success only for the getData() function.

Is this even a legit way to use Oraclize query result in a third function? If not, what would be the best way of linking those functions together, so that SetData() is called after the __callback()?

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1 Answer 1

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Try this:

pragma solidity ^0.4.24;
import './usingOraclize.sol';

contract functionChain is usingOraclize {
    string public globalKey;
    mapping (bytes32 => bool) validIds;

    event LogResult(string result);
    event LogNewOraclizeQuery(string description);
    event LogFundsReceived(address sender, uint amount);

    constructor() public payable {
        OAR = OraclizeAddrResolverI(your oraclize address);
    }

    function() payable {
        LogFundsReceived(msg.sender, msg.value);
    }

    function __callback(bytes32 myid, string result) public {
        require(validIds[myid]);
        require(msg.sender == oraclize_cbAddress());
        globalKey = result;
        LogResult(result);
        delete validIds[myid];
    }

    function setData() public payable {
        if (oraclize_getPrice("URL") > this.balance) {
            LogNewOraclizeQuery("Oraclize query was NOT sent");
        }
        else {
            LogNewOraclizeQuery("Oraclize query was sent");
            bytes32 queryId = oraclize_query("URL", "json(http://QUERY_LINK)");
            validIds[queryId] = true;
        }
    }
}
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