LambdaHandler.java

public class LambdaHandler implements RequestHandler<APIGatewayV2HTTPEvent, LambdaResponse> {

  private static final Gson mapper = new Gson();

  private static final AstraClient astraClient = newAstraClientFromEnv();

  private static AstraClient newAstraClientFromEnv() {
    String astraUrl = System.getenv("ASTRA_URL");
    String astraToken = System.getenv("ASTRA_TOKEN");
    String astraNamespace = System.getenv("ASTRA_NAMESPACE");
    return new AstraClient(URI.create(astraUrl), astraToken, astraNamespace);
  }

  @Override
  public LambdaResponse handleRequest(APIGatewayV2HTTPEvent input, Context context) {
    if (input.getRouteKey().startsWith("GET")) {
      String orderIdRaw = input.getPathParameters().get("orderId");
      UUID orderId = UUID.fromString(orderIdRaw);
      Optional<Order> order = astraClient.getOrder(orderId);
      if (order.isEmpty()) {
        return new LambdaResponse();
      }
      return new LambdaResponse(order.get());

    } else if (input.getRouteKey().startsWith("POST")) {
      Order requestOrder = null;
      try {
        byte[] decodedRequest = base64DecodeApiGatewayEvent(input);
        requestOrder = mapper.fromJson(new String(decodedRequest), Order.class);
        Order savedOrder = astraClient.saveOrder(requestOrder);
        LambdaResponse lambdaResponse = new LambdaResponse(savedOrder);
        return lambdaResponse;
      } catch (Exception e) {
        logger.log("Could not save input '" + input + "' as order '" + requestOrder);
        logger.log("Exception was: " + e.getLocalizedMessage());
        return new LambdaResponse(
          "{ \"message\": \"Order could not be saved.\" }",
          SC_BAD_REQUEST);
  	}
    } else {
      return new LambdaResponse(
        "{ \"message\": \"HTTP method is not supported.\" }",
        SC_BAD_REQUEST);
    }
  }

  private byte[] base64DecodeApiGatewayEvent(APIGatewayV2HTTPEvent input) {
    byte[] decodedRequest;
    if (input.getIsBase64Encoded()) {
      decodedRequest = Base64.decodeBase64(input.getBody());
    } else {
      String body = input.getBody();
      decodedRequest = body != null ? body.getBytes(UTF_8) : null;
    }
    return decodedRequest;
  }
}