# MessageAttribute

A message attribute to add to the SNS message.

- Source: [`aws-stepfunctions-tasks/lib/sns/publish.ts`](https://github.com/aws/aws-cdk/blob/v2.275.0/packages/aws-cdk-lib/aws-stepfunctions-tasks/lib/sns/publish.ts#L47)

## Example

```ts
const topic = new sns.Topic(this, 'Topic');

// Use a field from the execution data as message.
const task1 = new tasks.SnsPublish(this, 'Publish1', {
  topic,
  integrationPattern: sfn.IntegrationPattern.REQUEST_RESPONSE,
  message: sfn.TaskInput.fromDataAt('$.state.message'),
  messageAttributes: {
    place: {
      value: sfn.JsonPath.stringAt('$.place'),
    },
    pic: {
      // BINARY must be explicitly set
      dataType: tasks.MessageAttributeDataType.BINARY,
      value: sfn.JsonPath.stringAt('$.pic'),
    },
    people: {
      value: 4,
    },
    handles: {
      value: ['@kslater', '@jjf', null, '@mfanning'],
    },
  },
});

// Combine a field from the execution data with
// a literal object.
const task2 = new tasks.SnsPublish(this, 'Publish2', {
  topic,
  message: sfn.TaskInput.fromObject({
    field1: 'somedata',
    field2: sfn.JsonPath.stringAt('$.field2'),
  }),
});
```

## Properties

- `dataType`: [MessageAttributeDataType](/cdk/api/v2/docs/aws-cdk-lib.aws_stepfunctions_tasks.MessageAttributeDataType.html) — The data type for the attribute.

  **Default:** determined by type inspection if possible, fallback is String

- `value`: any (required) — The value of the attribute.