Cannot construct instance of IntentResponse, problem: The response from the Lambda function has an empty content field for one of the messages.

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I'm getting an error like this: "message": "Invalid Lambda Response: Received invalid response from Lambda: Cannot construct instance of IntentResponse, problem: The response from the Lambda function has an empty content field for one of the messages. Your Lambda function should make sure that it always returns a valid content field for a message. at [Source: (String)"Response structure is exactly what it should be. using the same structure getting response for else condition but not for if condition of the lambda

asked 11 days ago36 views
2 Answers
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The error you're encountering suggests that your Lambda function is returning an invalid response format for Amazon Lex V2. This typically happens when the response structure doesn't match what Lex expects, particularly when closing an intent or when the content field for a message is empty.

To resolve this issue:

  1. Ensure your Lambda function always returns a valid content field for messages. Even if you're using an SSML audio response, you should include a text content as a fallback.

  2. When closing an intent, make sure to include the intent information in the sessionState. The dialogAction type "Close" requires an intent to be specified.

  3. Double-check your response structure. It should include a "sessionState" object with "dialogAction" and "intent" nested within it, as well as a "messages" array.

  4. If you're using SSML for audio responses, ensure the SSML tags are properly formatted and enclosed.

Here's a basic structure your Lambda response should follow:

{
  "sessionState": {
    "dialogAction": {
      "type": "Close"
    },
    "intent": {
      "name": "YourIntentName",
      "state": "Fulfilled"
    }
  },
  "messages": [
    {
      "contentType": "PlainText",
      "content": "Your message here"
    }
  ]
}

If you're still having issues, try simplifying your response to only include the essential elements, then gradually add complexity back in to identify where the problem occurs. Also, ensure that all content fields in your messages array have valid, non-empty values.

Sources
[Invalid Lambda Response: Received invalid response from Lambda: Cannot construct instance of IntentResponse, problem: The validated object is null at Source: (String)" | AWS re:Post
Lex chatbot response for Polly speech file | AWS re:Post

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answered 11 days ago
0

Hi,

Kindly review the Lambda response format and ensure that it follows the format mentioned in the documentation below:

[+] https://docs.aws.amazon.com/lexv2/latest/dg/lambda-response-format.html

I would also suggest implementing error handling for the lambda function in order to narrow down where exactly you are getting the error from.

If the error still persists after implementing the above, please reach out to AWS Support, and we would be happy to take a closer look.

AWS
answered 10 days ago

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