EventCallbackHelper.mustache

{{>licenseInfo}}

package {{invokerPackage}};

import com.dropbox.sign.model.EventCallbackRequest;
import com.dropbox.sign.model.EventCallbackRequestEventMetadata;
import org.apache.commons.codec.digest.HmacAlgorithms;
import org.apache.commons.codec.digest.HmacUtils;

{{>generatedAnnotation}}
public class EventCallbackHelper {
    public static final String EVENT_TYPE_ACCOUNT_CALLBACK = "account_callback";

    public static final String EVENT_TYPE_APP_CALLBACK = "app_callback";

    private EventCallbackHelper() {}

    /**
    * Verify that a callback came from HelloSign.com
    *
    * @param apiKey
    * @param eventCallback
    * @return a boolean value indicating whether the callback event is valid
    */
    public static boolean isValid(String apiKey, EventCallbackRequest eventCallback) {
        return new HmacUtils(HmacAlgorithms.HMAC_SHA_256, apiKey)
            .hmacHex(eventCallback.getEvent().getEventTime() + eventCallback.getEvent().getEventType())
            .equals(eventCallback.getEvent().getEventHash());
    }

    /**
     * Identifies the callback type, one of "account_callback" or
     * "app_callback".
     *
     * "app_callback" will always include a value for "reported_for_app_id"
     *
     * @param eventCallback
     */
    public static String getCallbackType(EventCallbackRequest eventCallback) {
        EventCallbackRequestEventMetadata metadata = eventCallback.getEvent().getEventMetadata();

        if (metadata.getReportedForAppId() == null || metadata.getReportedForAppId().isEmpty()) {
            return EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK;
        }

        return EventCallbackHelper.EVENT_TYPE_APP_CALLBACK;
    }
}