Chainlink- Issue when fetching an API in form of `bytes32` - api

Question

I've been learning the chainlink API and trying to modify the example from the Chainlin's documentation to get a byets32 value from an API. The original code of the example works well, but since the API I was hitting is returning a byets32 foem, the Chainlink job need to be configured to handle this type of return. The node is given here with Kovan testnet. Here is my code
pragma solidity ^0.8.7;
import "#chainlink/contracts/src/v0.8/ChainlinkClient.sol";
/**
* Request testnet LINK and ETH here: https://faucets.chain.link/
* Find information on LINK Token Contracts and get the latest ETH and LINK faucets here: https://docs.chain.link/docs/link-token-contracts/
*/
/**
* THIS IS AN EXAMPLE CONTRACT WHICH USES HARDCODED VALUES FOR CLARITY.
* PLEASE DO NOT USE THIS CODE IN PRODUCTION.
*/
contract APIConsumer is ChainlinkClient {
using Chainlink for Chainlink.Request;
//Result of the api
bytes32 public martket;
address private oracle;
bytes32 private jobId;
uint256 private fee;
/**
* Get -> bytes32
* Network: Kovan
* Oracle: 0xc57B33452b4F7BB189bB5AfaE9cc4aBa1f7a4FD8 (Chainlink Devrel
* Node)
* Job ID: 7401f318127148a894c00c292e486ffd
* Fee: 0.1 LINK
*/
constructor() {
setPublicChainlinkToken();
// Get -> bytes32 node taken from documentation
oracle = 0xc57B33452b4F7BB189bB5AfaE9cc4aBa1f7a4FD8;
jobId = "7401f318127148a894c00c292e486ffd";
fee = 0.1 * 10 ** 18; // (Varies by network and job)
}
/**
* Create a Chainlink request to retrieve API response, find the target
* data, then multiply by 1000000000000000000 (to remove decimal places from data).
*/
function requestVolumeData() public returns (bytes32 requestId)
{
Chainlink.Request memory request = buildChainlinkRequest(jobId, address(this), this.fulfill.selector);
// Set the URL to perform the GET request on
request.add("get", "https://min-api.cryptocompare.com/data/pricemultifull?fsyms=ETH&tsyms=USD");
// Set the path to find the desired data in the API response, where the response format is:
// {"RAW":
// {"ETH":
// {"USD":
// {
// "MARKET": "CCCAGG",
// }
// }
// }
// }
//Get the MARKET field of API
request.add("path", "RAW,ETH,USD,MARKET"); // Chainlink nodes 1.0.0 and later support this format
// Sends the request
return sendChainlinkRequestTo(oracle, request, fee);
}
/**
* Receive the response in the form of bytes32
*/
function fulfill(bytes32 _requestId, bytes32 _market) public recordChainlinkFulfillment(_requestId)
{
martket = _market;
}
// function withdrawLink() external {} - Implement a withdraw function to avoid locking your LINK in the contract
}
The value of market should be a byets32 reprsenting "CCCAGG" as shown in the API. But what I got was just 0x0...00 all the time, which means market has not been modified yet. I've checked this various ways and found out that the fulfill function never get rans. Then same thing happens when I changed the jobId and oracle to handle get-> int256, get -> bool (of course I did change the return type of the variable such that it's consistent with the returning form of API). I also noticed that only the job get -> uint256 works well (the example from documentation also used this job). Does anyon know why? Was my code wrong or the problem came from the node/job? Since I was able the get the example right, I don't think the problem cam from my wallet.
Any help would be appreciated!

Answer 1

You can test with a GET>STRING JOB
Go to this link: https://docs.chain.link/docs/any-api-testnet-oracles/
Take the Oracle contract address relevant to your network. For instance: 0xCC79157eb46F5624204f47AB42b3906cAA40eaB7 for Goerli
Use a Get>String job: 7d80a6386ef543a3abb52817f6707e3b
Make sure that your callback function expects to receive a string. (see a full example here: https://docs.chain.link/docs/api-array-response/)