如何返回一个 struct ?

[Demian101]

https://0x74d15156b20f6e79eb62a73d1c23cf71d86adfa8.5.w3link.io/flag?returns=(struct)

• 报错 Return attribute: Invalid type: struct

---

合约如下：

    struct Flag {
        uint256 id; 
        address flager;
        string flag;
        address[] bettors;    // up to 100 bettors
    }

    function flag() public view returns(Flag memory) {
        address[] memory bettors = new address[](5); // Placeholder for up to 100 bettors
        // bettors.push(msg.sender);
        bettors[0] = msg.sender;
        Flag memory newFlag = Flag({
            id: 1, // This is an example id
            flag: "EAT ALL!",
            flager: msg.sender, // The person who calls the function is the 'flager'
            bettors: bettors // Empty array of 'bettors'
        });

        return newFlag;
    }

---

如果直接访问 https://0x74d15156b20f6e79eb62a73d1c23cf71d86adfa8.5.w3link.io/flag

• 会返回一个文件，但是文件里面只有 0x02 这个标识，不知道怎么来的

[Demian101]

使用

https://0x74d15156b20f6e79eb62a73d1c23cf71d86adfa8.5.w3link.io/flag?returns=()

返回了一堆字节码，不知道咋看 lol

[Demian101]

感觉我走了个弯路，如果把合约当后端的话，是不是用 web3.js 这种请求会更好?

[qzhodl]

解析复杂数据类型比如struct或者array应该也可以支持，比如类似这样https://0x74d15156b20f6e79eb62a73d1c23cf71d86adfa8.5.w3link.io/flag?returns=(uint,string,address,address[])，但是现在spec里面应该还不支持

[qizhou]

ERC-6860应该支持复杂结构的

[qzhodl]

做了一个测试，返回一个结构体，是可以支持的，比如这个 https://0x6a019daa1c05fe89e274801d9f164316a1ad46bf.5.w3link.io/testFn?returns=(uint256,uint256,uint256) , 源码如下：

struct MiningInfo {
    uint256 lastMineTime;
    uint256 difficulty;
    uint256 blockMined;
}
contract Test {
    function testFn() public pure returns (MiningInfo memory) {
        return MiningInfo({
            lastMineTime: 1,
            difficulty: 2,
            blockMined: 3
        });
    }
}

[qzhodl]

https://0x74d15156b20f6e79eb62a73d1c23cf71d86adfa8.5.w3link.io/flag?returns=(struct)

• 报错 Return attribute: Invalid type: struct

合约如下：

    function flag() public view returns(Flag memory) {
        address[] memory bettors = new address[](5); // Placeholder for up to 100 bettors
        // bettors.push(msg.sender);
        bettors[0] = msg.sender;
        Flag memory newFlag = Flag({
            id: 1, // This is an example id
            flag: "EAT ALL!",
            flager: msg.sender, // The person who calls the function is the 'flager'
            bettors: bettors // Empty array of 'bettors'
        });

        return newFlag;
    }

如果直接访问 https://0x74d15156b20f6e79eb62a73d1c23cf71d86adfa8.5.w3link.io/flag

• 会返回一个文件，但是文件里面只有 0x02 这个标识，不知道怎么来的

Flag的定义可以贴一下吗？

[Demian101]

更新到在最上面的合约里面了

    struct Flag {
        uint256 id; 
        address flager;
        string flag;
        address[] bettors;    // up to 100 bettors
    }
        Flag memory newFlag = Flag({
            id: 1, // This is an example id
            flag: "EAT ALL!",
            flager: msg.sender, // The person who calls the function is the 'flager'
            bettors: bettors // Empty array of 'bettors'
        });

[qzhodl]

这样拼URL: https://0x74d15156b20f6e79eb62a73d1c23cf71d86adfa8.5.w3link.io/flag?returns=(uint256,address,string,(address[]))