Python Lambda Function Parsing DynamoDB's JSON Format

Question

Python Lambda function that gets invoked for a dynamodb stream has JSON that has DynamoDB format (contains the data types in JSON). I would like to covert DynamoDB JSON to standard JSON. PHP and nodejs have Marshaler that can do this. Please let me know if there are similar or other options for Python.

DynamoDB_format = `{"feas":
    {"M": {
        "fea": {
            "L": [
                {
                    "M": {
                        "pre": {
                            "N": "1"
                        },
                        "Li": {
                            "N": "1"
                        },
                        "Fa": {
                            "N": "0"
                        },
                        "Mo": {
                            "N": "1"
                        },
                        "Ti": {
                            "S": "20160618184156529"
                        },
                        "Fr": {
                            "N": "4088682"
                        }
                    }
                }
                ]
            }   
        }
    }
}`

Answer 1

To easily convert to and from the DynamoDB JSON I recommend using the boto3 dynamodb types serializer and deserializer.

import boto3
from boto3.dynamodb.types import TypeSerializer, TypeDeserializer
ts= TypeSerializer()
td = TypeDeserializer()

data= {"id": "5000"}
serialized_data= ts.serialize(data)
print(serialized_data)
#{'M': {'id': {'S': '5000'}}}
deserialized_data= td.deserialize(serialized_data)
print(deserialized_data)
#{'id': '5000'}

For more details check out the boto3.dynamodb.types classes.