链接Kaleido合同汇编

Question

我正在尝试重新编译在Kaleido样本库中找到的ChainlinkEthPrice合同，这里是：https://kaleido-io.github.io/kaleido-samples-gallery/#/kaleido-samples-gallery/chainlink。

守则如下：

pragma solidity ^0.4.24;

import "./Chainlinked.sol";

contract ChainlinkEthPrice is Chainlinked {

    struct EthPriceAtBlock
    {
        uint    blockNumber;
        uint    blockTimestamp;
        bytes32 requestId;
        uint256 reportedPrice;
    }

    EthPriceAtBlock[] public ethPrices;
    bytes32 jobId;

    constructor(bytes32 _jobId, address linkTokenAddr, address oracleAddr)
        public
    {
        jobId = _jobId;
        setLinkToken(linkTokenAddr);
        setOracle(oracleAddr);
    }

    function requestEthereumPrice(string _currency)
        public returns (bytes32 requestId)
    {
        ChainlinkLib.Run memory run = newRun(jobId, this, "fulfillEthereumPrice(bytes32,uint256)");
        run.add("url", "https://min-api.cryptocompare.com/data/price?fsym=ETH&tsyms=USD,EUR,JPY");
        run.add("path", _currency);
        run.addInt("times", 100);
        requestId = chainlinkRequest(run, LINK(0));
    }

    function fulfillEthereumPrice(bytes32 _requestId, uint256 _reportedPrice)
        public checkChainlinkFulfillment(_requestId)
    {
        ethPrices.push(EthPriceAtBlock({
            blockNumber: block.number,
            blockTimestamp: block.timestamp,
            requestId: _requestId,
            reportedPrice: _reportedPrice
        }));
       emit RequestEthereumPriceFulfilled(_requestId, _reportedPrice, block.number, block.timestamp);
    }

    event RequestEthereumPriceFulfilled(
        bytes32 indexed requestId,
        uint256 indexed reportedPrice,
        uint256 blockNumber,
        uint256 blockTimestamp
    );

    function getDataCount()
        public view returns (uint length)
    {
        return ethPrices.length;
    }

    function getData(uint idx)
        public view returns (uint blockNumber, uint256 reportedPrice)
    {
        return (ethPrices[idx].blockNumber, ethPrices[idx].reportedPrice);
    }
}

收到下列错误：

browser/chainlink.sol:27:59: TypeError: Invalid type for argument in function call. Invalid implicit conversion from literal_string "fulfillEthereumPrice(bytes32,uint256)" to bytes4 requested.
    ChainlinkLib.Run memory run = newRun(jobId, this, "fulfillEthereumPrice(bytes32,uint256)");
                                                      ^-------------------------------------^

browser/chainlink.sol:31:43: TypeError: Type is not callable
    requestId = chainlinkRequest(run, LINK(0));
                                      ^-----^

browser/chainlink.sol:31:43: TypeError: Invalid type for argument in function call. Invalid implicit conversion from tuple() to uint256 requested.
    requestId = chainlinkRequest(run, LINK(0));
                                      ^-----^

想知道是否有人能帮上忙。谢谢!

Answer 1

感谢那些建议Oraclize的人--这就是我在公共区块链项目中一直使用的东西。我在这里使用Chainlink，因为它与Kaleido.io一起工作，这是我在我的项目中使用的一个私有区块链平台。

不管怎么说，ChainLink的托马斯·霍奇斯帮了我这个忙。这些都是他所做的改变：

发自：

ChainlinkLib.Run memory run = newRun(jobId, this,"fulfillEthereumPrice(bytes32,uint256)");

至：

ChainlinkLib.Run memory run = newRun(jobId, this, this.fulfillEthereumPrice.selector);

来自：

requestId = chainlinkRequest(run, LINK(0));

至：

requestId = chainlinkRequest(run, 0);

现在它的工作方式正是它应该做的。

Answer 2

虽然我无法具体地帮助解决这些错误，但我可以帮助创建一个智能合同，通过Oraclize对您的问题的评论获得ETH的当前价格(以美元计)：

pragma solidity 0.5.0;

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

contract EthPriceTicker is usingOraclize {

    string public ethPriceUSD;

    event LogEthPrice(string priceUSD);

    function __callback(bytes32 myid, string memory result, bytes memory proof) public {
        require(msg.sender == oraclize_cbAddress());
        ethPriceUSD = result;
        emit LogEthPrice(result);
    }

    function getEthPriceInUSD() public payable {
        oraclize_query("URL", "json(https://min-api.cryptocompare.com/data/price?fsym=ETH&tsyms=USD,EUR,JPY).USD");
    }
}

指令：

• 复制并粘贴到混炼 (一个坚实的IDE)
• 确保您的solc编译器版本大于所选的0.5。
• 编制合同
• 从右上角的settings选项卡加载Oraclize插件
• 切换到run选项卡并单击deploy
• 部署完毕后，展开下面显示的选项卡，查看合同中的函数。然后点击getEthPrice&观看Oraclize插件所做的事情。