How do I provide a binary attribute value in an AWSCustomResource DynamoDB PutRequest?

Question

Hello.  I am attempting to write CDK code to populate a DynamoDB table.  The table has several attributes, including a binary attribute:

new AwsCustomResource(this, id, {
            onCreate: {
                service: 'DynamoDB',
                action: 'putItem',
                parameters: {
                    TableName: tableName,
                    Item: {
                        A1: { S: "hello" },
                        A2: { B: how do I do this?? },
                        A3: { N: "1" }
                    }
                },
                physicalResourceId: PhysicalResourceId.of(contentKeysInitName)
            }

I've tried various formats that I've seen on the web, and with all of them I get the error "Received response status [FAILED] from custom resource. Message returned: Cannot read properties of undefined (reading 'byteLength')"

I've also seen references to the usage of Uint8array, but no clear examples of how to use it.

Thanks in advance.

Answer

DynamoDB accepts all data parameters as string values, and binary values should be base64 encoded strings:

```
  parameters: {
                TableName: tableName,
                Item: {
                    "A1": { "S": "hello" },
                    "A2": { "B": "aG93IGRvIEkgZG8gdGhpcz8/" },
                    "A3": { "N": "1" }
                }
            }
```

Answer

It doesn't work.  I get the error I previously posted.

How do I provide a binary attribute value in an AWSCustomResource DynamoDB PutRequest?

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