使用Chainlink大型响应示例从任何API获取字符串 [英] Get a string from any API using Chainlink Large Response Example

问题描述

我只需要从这个json中获取一个字符串，例如：https://filesamples.com/samples/code/json/sample1.json

我采用了Chainlink示例，只更改了URL和路径。该示例运行良好，但如果使用不同的json o jobid，则无法运行。

链接到链接示例：https://docs.chain.link/docs/large-responses/

有什么办法可以解决这个问题吗？

使用的代码：

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

import "@chainlink/contracts/src/v0.8/ChainlinkClient.sol";

/**
 * @notice DO NOT USE THIS CODE IN PRODUCTION. This is an example contract. 
 */
contract GenericLargeResponse is ChainlinkClient {
  using Chainlink for Chainlink.Request;

  // variable bytes returned in a signle oracle response
  bytes public data;
  string public dataS;

  /**
   * @notice Initialize the link token and target oracle
   * @dev The oracle address must be an Operator contract for multiword response
   *
   *
   * Kovan Testnet details: 
   * Link Token: 0xa36085F69e2889c224210F603D836748e7dC0088
   * Oracle: 0xc57B33452b4F7BB189bB5AfaE9cc4aBa1f7a4FD8 (Chainlink DevRel)
   *
   */
  constructor(
  ) {
    setChainlinkToken(0xa36085F69e2889c224210F603D836748e7dC0088);
    setChainlinkOracle(0xc57B33452b4F7BB189bB5AfaE9cc4aBa1f7a4FD8);
  }

  /**
   * @notice Request variable bytes from the oracle
   */
  function requestBytes(
  )
    public
  {
    bytes32 specId = "7a97ff8493ec406d90621b2531f9251a";
    uint256 payment = 100000000000000000;
    Chainlink.Request memory req = buildChainlinkRequest(specId, address(this), this.fulfillBytes.selector);
    req.add("get","https://filesamples.com/samples/code/json/sample1.json");
    req.add("path", "fruit");
    requestOracleData(req, payment);
  }

  event RequestFulfilled(
    bytes32 indexed requestId,
    bytes indexed data
  );

  /**
   * @notice Fulfillment function for variable bytes
   * @dev This is called by the oracle. recordChainlinkFulfillment must be used.
   */
  function fulfillBytes(
    bytes32 requestId,
    bytes memory bytesData
  )
    public
    recordChainlinkFulfillment(requestId)
  {
    emit RequestFulfilled(requestId, bytesData);
    data = bytesData;
    dataS = string(data);
  }

}

推荐答案

该接口返回：

{
  "fruit": "Apple",
  "size": "Large",
  "color": "Red"
}

fruit的值为Apple。您需要让API返回Apple的字节版本。

您会注意到该示例返回如下所示的JSON：

{
  "image": "0x68747470733a2f2f697066732e696f2f697066732f516d5358416257356b716e3259777435444c336857354d736a654b4a4839724c654c6b51733362527579547871313f66696c656e616d653d73756e2d636861696e6c696e6b2e676966"
}

哪个是图像URL的十六进制版本。

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