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# Kafka Connect HeaderFrom SMT Usage Reference for Confluent Cloud

This topic describes the Apache Kafka® Single Message
Transformation (SMT) `org.apache.kafka.connect.transforms.HeaderFrom`.

## Description

The `HeaderFrom` SMT moves or copies fields in a record key or value into the
record header. Use the concrete transformation type designed for the record key
(`org.apache.kafka.connect.transforms.HeaderFrom$Key`) or value
(`org.apache.kafka.connect.transforms.HeaderFrom$Value`).

#### SEE ALSO
For the inverse transformation that moves header fields into the record
value, see [Kafka Connect HeaderToValue (Debezium) SMT Usage Reference for Confluent Cloud](headertovalue.md#headertovalue).

## Example

This configuration snippet shows how to use `HeaderFrom` to move the fields
`id` and `ts` in the record value into the record header. The transform
removes the fields from the record value. If you want to keep the fields in the
record value, use the operation `copy` instead of `move`.

```json
"transforms": "moveFieldsToHeader",
"transforms.moveFieldsToHeader.type": "org.apache.kafka.connect.transforms.HeaderFrom$Value",
"transforms.moveFieldsToHeader.fields": "id,ts",
"transforms.moveFieldsToHeader.headers": "record_id,event_timestamp",
"transforms.moveFieldsToHeader.operation": "move"
```

**Before:**

* **Record value**
  ```json
  {
      "id": 24,
      "ts": 1626102708861,
      "name": "John Smith",
      "book": "Kafka: The Definitive Guide"
  }
  ```
* **Record header**
  ```json
  {
      "source": "RedditSource"
  }
  ```

**After:**

* **Record value**
  ```json
  {
      "name": "John Smith",
      "book": "Kafka: The Definitive Guide"
  }
  ```
* **Record header**
  ```json
  {
      "source": "RedditSource",
      "record_id": 24,
      "event_timestamp": 1626102708861
  }
  ```

## Properties

All properties are required.

| Name        | Description                                                                                                                                                                                      | Type   | Default   | Valid Values   | Importance   |
|-------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|-----------|----------------|--------------|
| `fields`    | A comma-separated list of field names that the transform moves or copies to the record header.                                                                                                   | list   | None      | non-empty list | high         |
| `headers`   | A comma-separated list of header names. The number of `headers` listed must be the same as the number of `fields` listed. The `headers` listed must be in the same order as the `fields` listed. | list   | None      | non-empty list | high         |
| `operation` | - `move`: Moves fields into the record header and removes these<br/>  fields from the record value.<br/>- `copy`: Adds the header entries but keeps the fields in the record<br/>  value.        | string | None      | `move`, `copy` | high         |

## Predicates

Transformations can be configured with *predicates* so that the transformation
is applied only to records which satisfy a condition. You can use predicates in
a transformation chain and, when combined with the [Kafka Connect Filter (Kafka) SMT Usage Reference for Confluent Cloud](filter-ak.md#ak-filter), predicates
can conditionally filter out specific records. For details and examples, see [Predicates](filter-ak.md#predicates).