Chainlink request not returning the integer at the followed path - google-search-api

Question

I have a very simple smart contract which creates and sends a Chainlink request to the Kovan Linkpool node using the get>uint256 job. The contract looks like this (API private key removed).
contract OracleChainlink is ChainlinkClient {
using Chainlink for Chainlink.Request;
uint256 public H_Index;
address private Oracle;
bytes32 private JobId;
uint256 private Fee = .1 * 10 ** 18; //kovan is .1 link per call
constructor() public {
setPublicChainlinkToken();
Oracle = 0x56dd6586DB0D08c6Ce7B2f2805af28616E082455; //Chainlink linkpool node on Kovan
JobId = "b6602d14e4734c49a5e1ce19d45a4632";
}
function getChainlinkToken() public view returns (address) {
return chainlinkTokenAddress();
}
function RequestH_index() public returns (bytes32 Reqid) {
Chainlink.Request memory Req = buildChainlinkRequest(JobId, address(this), this.fulfill.selector);
Req.add("get", "https://serpapi.com/.....");
Req.add("path", "cited_by.table.1.h_index.all");
return sendChainlinkRequestTo(Oracle, Req, Fee);
}
function fulfill(bytes32 Reqid, uint256 _Hindex) public recordChainlinkFulfillment(Reqid) {
H_Index = _Hindex;
}
The Google Scholar Author API https://serpapi.com/google-scholar-author-api returns a pretty large json, seen at the link if you scroll down. The snippet/path I need to follow is shown below (cited_by is at the top level of the json).
"cited_by": {
"table": [
{
"citations": {
"all": 23351,
"since_2016": 13660
}
},
{
"h_index": {
"all": 46,
"since_2016": 37
}
},
{
"i10_index": {
"all": 60,
"since_2016": 53
}
}
],
When ran, I get logs of Chainlink request events, but the public H_Index value remains 0. Am I missing something in terms of adapters? I have tried all sorts of path formats through the JSON with no luck. I have also tried different nodes and jobs. Is there any way to ensure that the API is even being called? What am I missing?

Answer 1

Your JSON Path should look like this:
Req.add("path", "cited_by.table.1.h_index.all");
Looking at the Etherscan activity, it looks like the node you are using may be inactive. Try this node and jobId:
Oracle = 0xc57B33452b4F7BB189bB5AfaE9cc4aBa1f7a4FD8;
JobId = "d5270d1c311941d0b08bead21fea7747";
These were taken from the Chainlink Official Docs.
To check to see if a node is running or not, check out the oracle address in a block explorer. You can see here that the original node you tried to use hasn't posted a transaction in quite a long time.
If a node is inactive you will need to find a new one or host one yourself. To find more nodes and jobs, you can check market.link or use the one found in the docs as mentioned earlier.