Merge pull request #36 from smartcontractkit/txwait

Author: KuphJr

.changeset/three-seas-beam.md

@@ -0,0 +1,5 @@
+---
+'@chainlink/functions-toolkit': patch
+---
+
+Added ResponseListener.listenForResponseFromTransaction() method to handle listening for responses if the request was reorged and the requestId changed

README.md

@@ -450,9 +450,27 @@ provider,
 functionsRouterAddress,
 })
 
-To listen for the response to a single Functions request by request ID, use the the `listenForResponse()` method. Optionally, you can provide a custom timeout after which the listener will throw an error indicating that the time limit was exceeded. If no timeout is provided, the default timeout is 300 seconds.
+To listen for a response to a single Functions request, use the `listenForResponseFromTransaction()` method.
+Optionally, you can provide:
+- timeout after which the listener will throw an error indicating that the time limit was exceeded (default 5 minutes) 
+- number of block confirmations (default 2)
+- frequency of checking if the request is already included on-chain (or if it got moved after a chain re-org) (default 2 seconds)
 
-**Note:** Listening for multiple responses simultaneously is not supported by the `listenForResponse()` method and will lead to undefined behavior.
+```
+const response: FunctionsResponse = await responseListener.listenForResponseFromTransaction(
+  txHash: string,
+  timeout?: number,
+  confirmations?: number,
+  checkInterval?: number,
+)
+```
+
+Alternatively, to listen using a request ID, use the `listenForResponse()` method.
+
+**Notes:** 
+1. Request ID can change during a chain re-org so it's less reliable than a request transaction hash.
+2. If the methods are called after the response is already on chain, it won't be returned correctly.
+3. Listening for multiple responses simultaneously is not supported by the above methods and will lead to undefined behavior.
 
 ```
 const response: FunctionsResponse = await responseListener.listenForResponse(
@@ -479,13 +497,9 @@ The possible fulfillment codes are shown below.
 
 ```
 {
-  FULFILLED = 0, // Indicates that calling the consumer contract's handleOracleFulfill method was successful
+  FULFILLED = 0, // Indicates that a Function was executed and calling the consumer contract's handleOracleFulfill method was successful
   USER_CALLBACK_ERROR = 1, // Indicates that the consumer contract's handleOracleFulfill method reverted
-  INVALID_REQUEST_ID = 2, // Internal error
-  COST_EXCEEDS_COMMITMENT = 3, // Indicates that the request was not fulfilled because the cost of fulfillment is higher than the estimated cost due to an increase in gas prices
-  INSUFFICIENT_GAS_PROVIDED = 4, // Internal error
-  SUBSCRIPTION_BALANCE_INVARIANT_VIOLATION, // Internal error
-  INVALID_COMMITMENT = 6, // Internal error
+  // all other codes indicate internal errors
 }
 ```
 

src/ResponseListener.ts

@@ -8,6 +8,7 @@ import { FulfillmentCode, type FunctionsResponse } from './types'
 
 export class ResponseListener {
   private functionsRouter: Contract
+  private provider: providers.Provider
 
   constructor({
     provider,
@@ -16,6 +17,7 @@ export class ResponseListener {
     provider: providers.Provider
     functionsRouterAddress: string
   }) {
+    this.provider = provider
     this.functionsRouter = new Contract(functionsRouterAddress, FunctionsRouterSource.abi, provider)
   }
 
@@ -55,7 +57,45 @@ export class ResponseListener {
       )
     })
 
-    return await responsePromise
+    return responsePromise
+  }
+
+  public async listenForResponseFromTransaction(
+    txHash: string,
+    timeout = 3000000,
+    confirmations = 2,
+    checkInterval = 2000,
+  ): Promise<FunctionsResponse> {
+    return new Promise<FunctionsResponse>((resolve, reject) => {
+      ;(async () => {
+        let requestID: string
+        // eslint-disable-next-line prefer-const
+        let checkTimeout: NodeJS.Timeout
+        const expirationTimeout = setTimeout(() => {
+          reject('Response not received within timeout period')
+        }, timeout)
+
+        const check = async () => {
+          const receipt = await this.provider.waitForTransaction(txHash, confirmations, timeout)
+          const updatedID = receipt.logs[0].topics[1]
+          if (updatedID !== requestID) {
+            requestID = updatedID
+            const response = await this.listenForResponse(receipt.logs[0].topics[1], timeout)
+            if (updatedID === requestID) {
+              // Resolve only if the ID hasn't changed in the meantime
+              clearTimeout(expirationTimeout)
+              clearInterval(checkTimeout)
+              resolve(response)
+            }
+          }
+        }
+
+        // Check periodically if the transaction has been re-orged and requestID changed
+        checkTimeout = setInterval(check, checkInterval)
+
+        check()
+      })()
+    })
   }
 
   public listenForResponses(

test/integration/ResponseListener.test.ts

@@ -101,6 +101,78 @@ describe('Functions toolkit classes', () => {
       expect(errResponse.fulfillmentCode).toBe(FulfillmentCode.FULFILLED)
     })
 
+    it('Successfully waits for single response from transaction hash', async () => {
+      const subscriptionManager = new SubscriptionManager({
+        signer: allowlistedUser_A,
+        linkTokenAddress,
+        functionsRouterAddress,
+      })
+      await subscriptionManager.initialize()
+
+      const subscriptionId = await subscriptionManager.createSubscription()
+      await subscriptionManager.fundSubscription({
+        juelsAmount: utils.parseUnits('1', 'ether').toString(),
+        subscriptionId,
+      })
+      await subscriptionManager.addConsumer({
+        subscriptionId,
+        consumerAddress: exampleClient.address,
+        txOptions: {
+          confirmations: 1,
+        },
+      })
+
+      const functionsListener = new ResponseListener({
+        provider: allowlistedUser_A.provider,
+        functionsRouterAddress,
+      })
+
+      const succReqTx = await exampleClient.sendRequest(
+        'return Functions.encodeUint256(1)',
+        1,
+        [],
+        [],
+        [],
+        subscriptionId,
+        100_000,
+      )
+
+      const succReq = await succReqTx.wait()
+      const succResponse = await functionsListener.listenForResponseFromTransaction(
+        succReq.transactionHash,
+        1000000,
+        0,
+      )
+
+      expect(succResponse.responseBytesHexstring).toBe(
+        '0x0000000000000000000000000000000000000000000000000000000000000001',
+      )
+      expect(succResponse.errorString).toBe('')
+      expect(succResponse.returnDataBytesHexstring).toBe('0x')
+      expect(succResponse.fulfillmentCode).toBe(FulfillmentCode.FULFILLED)
+
+      const errReqTx = await exampleClient.sendRequest(
+        'return Functions.encodeUint256(1',
+        1,
+        [],
+        [],
+        [],
+        subscriptionId,
+        100_000,
+      )
+
+      const errReq = await errReqTx.wait(1)
+      const errRequestId = errReq.events[0].topics[1]
+
+      const errResponse = await functionsListener.listenForResponse(errRequestId)
+
+      expect(errResponse.requestId).toBe(errRequestId)
+      expect(errResponse.responseBytesHexstring).toBe('0x')
+      expect(errResponse.errorString).toBe('syntax error, RAM exceeded, or other error')
+      expect(errResponse.returnDataBytesHexstring).toBe('0x')
+      expect(errResponse.fulfillmentCode).toBe(FulfillmentCode.FULFILLED)
+    })
+
     it('Successfully listens for responses', async () => {
       const subscriptionManager = new SubscriptionManager({
         signer: allowlistedUser_A,