DynamicFrameDecodeBase64.java

public class DynamicFrameDecodeBase64 {

  public static DynamicFrame unBase64(
    DynamicFrame df,
    final String base64ColumnName,
    final String dataColumnName
  ) {
    RDD unboxRecords = df
      .records()
      .mapPartitions(
        new MapFunctionUnbase64(base64ColumnName, dataColumnName),
        true,
        scala.reflect.ClassTag$.MODULE$.apply(DynamicRecord.class)
      );
    return DynamicFrame.newFrameWithErrors(
      df,
      unboxRecords,
      df.getName(),
      "",
      null,
      0,
      0
    );
  }
}

MapFunctionUnbase64.java

public class MapFunctionUnbase64
  extends scala.runtime.AbstractFunction1<scala.collection.Iterator<DynamicRecord>, scala.collection.Iterator<DynamicRecord>>
  implements scala.Serializable {

  public final scala.collection.Iterator<DynamicRecord> apply(
    scala.collection.Iterator<DynamicRecord> iter
  ) {
    Base64.Decoder base64decoder = Base64.getDecoder();
    return iter.map(
      new scala.runtime.AbstractFunction1<com.amazonaws.services.glue.DynamicRecord, DynamicRecord>() {

        public final DynamicRecord apply(DynamicRecord record) {
          String base64ColumnName = "base64";
          String raw = record
            .dropField(base64ColumnName)
            .get()
            .getValue()
            .toString();
          byte[] decodedString;
          String data;
          try {
            decodedString =
              base64decoder.decode(new String(raw).getBytes("UTF-8"));
            data = new String(decodedString, StandardCharsets.UTF_8);
          } catch (java.io.UnsupportedEncodingException e) {
            data = "";
          }
          record.addField(
            "data",
            com.amazonaws.services.glue.types.StringNode.apply(data)
          );
          return record;
        }
      }
    );
  }
}