src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsDomainDnsSetupHostingAssetValidator.java

@@ -5,6 +5,7 @@ import net.hostsharing.hsadminng.hs.hosting.asset.HsHostingAssetType;
 
 import java.util.regex.Pattern;
 
+import static java.util.Arrays.stream;
 import static net.hostsharing.hsadminng.hs.validation.ArrayProperty.arrayOf;
 import static net.hostsharing.hsadminng.hs.validation.BooleanProperty.booleanProperty;
 import static net.hostsharing.hsadminng.hs.validation.IntegerProperty.integerProperty;
@@ -53,4 +54,21 @@ class HsDomainDnsSetupHostingAssetValidator extends HsHostingAssetEntityValidato
         // FIXME: should be auto-initialized
         return  Pattern.compile("^" + assetEntity.getParentAsset().getIdentifier() + "$");
     }
+
+    String toZonefileString(final HsHostingAssetEntity assetEntity) {
+        return """
+              $ORIGIN {domain}.
+              $TTL {ttl}
+
+              ; these records are just placeholders to create a valid zonefile for the validation
+              @        1814400  IN  SOA     {domain}. root.{domain} ( 1999010100 10800 900 604800 86400 )
+              @                 IN  NS      ns
+  
+              {userRRs}
+              """
+                    .replace("{domain}", assetEntity.getIdentifier())
+                    .replace("{ttl}", getPropertyValue(assetEntity, "TTL"))
+                    .replace("{userRRs}", getPropertyValues(assetEntity, "user-RR") );
+    }
+
 }

src/main/java/net/hostsharing/hsadminng/hs/validation/HsEntityValidator.java

@@ -6,7 +6,9 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.function.Supplier;
+import java.util.stream.Collectors;
 
 import static java.util.Arrays.stream;
 import static java.util.Collections.emptyList;
@@ -41,6 +43,12 @@ public abstract class HsEntityValidator<E extends PropertiesProvider> {
                 .toList();
     }
 
+    public final Map<String, Map<String, Object>> propertiesMap() {
+        return Arrays.stream(propertyValidators)
+                .map(ValidatableProperty::toOrderedMap)
+                .collect(Collectors.toMap(p -> p.get("propertyName").toString(), p -> p));
+    }
+
     protected ArrayList<String> validateProperties(final PropertiesProvider propsProvider) {
         final var result = new ArrayList<String>();
 
@@ -109,4 +117,20 @@ public abstract class HsEntityValidator<E extends PropertiesProvider> {
         });
         return copy;
     }
+
+    protected String getPropertyValue(final PropertiesProvider entity, final String propertyName) {
+        final var rawValue = entity.getDirectValue(propertyName, Object.class);
+        if (rawValue != null) {
+            return rawValue.toString();
+        }
+        return Objects.toString(propertiesMap().get(propertyName).get("defaultValue"));
+    }
+
+    protected String getPropertyValues(final PropertiesProvider entity, final String propertyName) {
+        final var rawValue = entity.getDirectValue(propertyName, Object[].class);
+        if (rawValue != null) {
+            return stream(rawValue).map(Object::toString).collect(Collectors.joining("\n"));
+        }
+        return "";
+    }
 }

src/test/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsDomainDnsSetupHostingAssetValidatorUnitTest.java

@@ -126,4 +126,29 @@ class HsDomainDnsSetupHostingAssetValidatorUnitTest {
 
         assertThat("; whatever ; \" really anything").matches(RR_COMMENT);
     }
+
+    @Test
+    void generatesZonefile() {
+        // given
+        final var givenEntity = validEntityBuilder().identifier("example.org").build();
+        final var validator = (HsDomainDnsSetupHostingAssetValidator) HsHostingAssetEntityValidatorRegistry.forType(givenEntity.getType());
+
+        // when
+        final var zonefile = validator.toZonefileString(givenEntity);
+
+        // then
+        assertThat(zonefile).isEqualTo("""
+                $ORIGIN example.org.
+                $TTL 21600
+
+                ; these records are just placeholders to create a valid zonefile for the validation
+                @        1814400  IN  SOA     example.org. root.example.org ( 1999010100 10800 900 604800 86400 )
+                @                 IN  NS      ns
+
+                www            IN          CNAME example.com. ; www.example.com is an alias for example.com
+                test1          IN 1h30m    CNAME example.com.
+                test2 1h30m    IN          CNAME example.com.
+                ns             IN          A     192.0.2.2; IPv4 address for ns.example.com
+                """);
+    }
 }