How do you format Python using json.dumps, to make your Lambda function respond correctly to API Gateway?

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This is my first post on Stack Overflow, so hope I'm being specific enough. I am trying to integrate a Lambda function (coded in Python) with DynamoDB and API Gateway. I want the API to return a single item from DynamoDB, but I'm getting an Internal server error message when I navigate to the API endpoint. I have looked at the CloudWatch Logs and they say it's caused by a malformed Lambda proxy response.

Having further investigated, I am fairly sure this has to do with formatting the Lambda responseBody using json.dumps. But I don't know the correct syntax to do this having tried dozens of different combinations (I don't have any Python experience).

Here is my Lambda function:

def lambda_handler(event, context):

    ddbResponse = table.update_item(
        Key={
            "id": "user1"
        },
        UpdateExpression='ADD clicks :inc',
        ExpressionAttributeValues={
            ':inc': 1
        },
        ReturnValues="UPDATED_NEW"
    )

    responseBody = json.dumps(XXXXXXXXXX)

    apiResponse = {
        "isBase64Encoded": False,
        "statusCode": 200,
        "body": responseBody
    }

    return apiResponse

If I just want the API response to be the number of clicks returned from the DynamoDB table, what would I have to put in the XXXX's between the json.dumps bracket? Thanks in advance

aws-api-gateway amazon-dynamodb aws-lambda python
1 Answers

ddbResponse['Attributes']['clicks']) will give you clicks. we can return

return {
    'statusCode': 200,
    'body': json.dumps({'clicks': int(ddbResponse['Attributes']['clicks'])})
}

To return only clicks

{
    'statusCode': 200,
    'body': int(response['Attributes']['clicks'])
}
user_101868080
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