batch treats same query with different request variables as a duplicate

[lerhaupt]

react-relay-network-modern/src/middlewares/batch.js

Line 139 in 331a2f7

requestMap[relayReqId].duplicates.push(requestWrapper);

I have a refetch query in modern that is being run on two instances of the same component, each with different variables on the request. Within the batch middleware, the relayReqId is identical and the same name as the refetch query. However, the fetch variables are different, but any subsequent request in the same batch that has different variables seems to only get treated as a dup and not fetched.

[nodkz]

Confirm the bug!

For backward compatibility needs to write a new middleware with name batch2. Logic should be changed by using arrays (the assumption that server for batched request returns payloads in the same order) instead of Maps (where are responses linked with requests via payload.id).

In the passThroughBatch method

react-relay-network-modern/src/middlewares/batch.js

Lines 110 to 143 in 331a2f7

	return new Promise((resolve, reject) => {
	const relayReqId = req.getID();
	const { requestMap } = singleton.batcher;
	const requestWrapper: RequestWrapper = {
	req,
	completeOk: res => {
	requestWrapper.done = true;
	resolve(res);
	requestWrapper.duplicates.forEach(r => r.completeOk(res));
	},
	completeErr: err => {
	requestWrapper.done = true;
	reject(err);
	requestWrapper.duplicates.forEach(r => r.completeErr(err));
	},
	done: false,
	duplicates: [],
	};
	if (requestMap[relayReqId]) {
	/*
	I've run into a scenario with Relay Classic where if you have 2 components
	that make the exact same query, Relay will dedup the queries and reuse
	the request ids but still make 2 requests. The batch code then loses track
	of all the duplicate requests being made and never resolves or rejects
	the duplicate requests
	https://github.com/nodkz/react-relay-network-layer/pull/52
	*/
	requestMap[relayReqId].duplicates.push(requestWrapper);
	} else {
	requestMap[relayReqId] = requestWrapper;
	}
	});

• relayReqId should be removed
• requestMap renamed to requestList and used push method
• duplicates logic should be removed for simplicity (and may be added in future). Also should be removed in line

  react-relay-network-modern/src/middlewares/batch.js

  Line 172 in 331a2f7

  request.duplicates.forEach(r => r.completeOk(res));

In sendRequests method

• should be changed ids on array order
• payload.id should be removed and also should be rewritten on array order

  react-relay-network-modern/src/middlewares/batch.js

  Lines 198 to 205 in 331a2f7

  	batchResponse.json.forEach((payload: any) => {
  	if (!payload) return;
  	const request = requestMap[payload.id];
  	if (request) {
  	const res = createSingleResponse(batchResponse, payload);
  	request.completeOk(res);
  	}
  	});

---

In my apps I do not use batching (all requests sending in parallel - page loads more progressive and feels more alive). So I'm not redy to write a new batch middleware. But with pleasure review and merge PR if somebody make it. Help wanted!

[modosc]

just curious - why not alter req.getID() to include the request variables as part of the id (json stringified / base64 / hashed / whatever)? seems like that would be more straightforward or is there some edge case that misses?

[codecvlt]

+1

Any chance this will be fixed soon? This middleware is largely unusable because of this issue.

I use with the same graphql fragment to render multiple configurations of the same widget on the same page. All widgets receive the same data which is bad.

[nodkz]

If somebody sends Pull Request with fix I'll merge it.

Sorry, I haven't bandwidth for this issue to do it myself.

[joelvh]

@nodkz this is implemented in #66

[joelvh]

@nodkz can this be closed based on #66 ?

[nodkz]

Sure!