问题描述
`pragma solidity ^0.4.22;
import "github.com/provable-things/ethereum-api/provableAPI_0.4.25.sol";
contract ExampleContract is usingProvable {
string public ETHUSD;
event LogConstructorInitiated(string nextStep);
event LogPriceUpdated(string price);
event LogNewProvableQuery(string description);
function ExampleContract() payable {
LogConstructorInitiated("Constructor was initiated. Call 'updatePrice()' to send the Provable Query.");
}
function __callback(bytes32 myid,string result) {
if (msg.sender != provable_cbAddress()) revert();
ETHUSD = result;
LogPriceUpdated(result);
}
function updatePrice() payable {
if (provable_getPrice("URL") > this.balance) {
LogNewProvableQuery("Provable query was NOT sent,please add some ETH to cover for the query fee");
} else {
LogNewProvableQuery("Provable query was sent,standing by for the answer..");
provable_query("URL","json(https://api.pro.coinbase.com/products/ETH-USD/ticker).price");
}
}`
这是代码,我的问题是:
在代码的最后一行,我有一个 provable_query,它包含 URL 和 URL 数据是 [{"Trade_id":103437884,"price":"2674.1","size":"0.12890079","time": "2021-04-28T11:19:29.475452Z","bid":"2673.78","ask":"2674.03","volume":"360649.21208837"} 所以最后我想将价格提取到区块链中。
"但我的问题是,如果此 URL 包含 2 个不同的价格,例如 1 个美元价格和其他欧元价格,例如:{"Trade_id":103437884,"price1":"2674.1","price2": "2222",size":"0.12890079","time":"2021-04-28T11:19:29.475452Z","volume":"360648.237"}
所以现在我的问题是如何从上述 URL 中获取价格 1 和价格 2,如果是,我如何从单个 URL 中获取 2 个价格”。
提前致谢
解决方法
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