feat: Add enctype to Form

test-suite-thymeleaf-fieldset/src/test/resources/views/fieldset/form.html

@@ -1 +1 @@
-<form th:fragment="form(form)" xmlns:th="http://www.thymeleaf.org" th:action="${form.action()}" th:method="${form.method()}"><fieldset th:replace="~{fieldset/fieldset :: fieldset(${form.fieldset()})}"></fieldset></form>
+<th:block th:fragment="form(form)" xmlns:th="http://www.thymeleaf.org"><form th:action="${form.action()}" th:method="${form.method()}" th:enctype="${form.enctype()}"><fieldset th:replace="~{fieldset/fieldset :: fieldset(${form.fieldset()})}"></fieldset></form></th:block>

views-fieldset-tck/src/main/java/io/micronaut/views/fields/tck/FormEncTypeRenderTest.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2017-2023 original authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micronaut.views.fields.tck;
+
+import io.micronaut.test.extensions.junit5.annotation.MicronautTest;
+import io.micronaut.views.ViewsRenderer;
+import io.micronaut.views.fields.Fieldset;
+import io.micronaut.views.fields.Form;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+
+@SuppressWarnings({"java:S5960"}) // Assertions are fine, these are tests
+@MicronautTest(startApplication = false)
+class FormEncTypeRenderTest {
+
+    @Test
+    void render(ViewsRenderer<Map<String, Object>, ?> viewsRenderer) throws IOException {
+        assertNotNull(viewsRenderer);
+        Form form = new Form("/foo/bar", "post", new Fieldset(Collections.emptyList(), Collections.emptyList()), "application/x-www-form-urlencoded");
+        assertEquals("""
+                <form action="/foo/bar" method="post" enctype="application/x-www-form-urlencoded">\
+                </form>""",
+                TestUtils.render("fieldset/form.html", viewsRenderer, Map.of("form", form)));
+    }
+}

views-fieldset/src/main/java/io/micronaut/views/fields/Form.java

@@ -17,6 +17,10 @@
 
 import io.micronaut.core.annotation.Experimental;
 import io.micronaut.core.annotation.Introspected;
+import io.micronaut.core.annotation.NonNull;
+import io.micronaut.core.annotation.Nullable;
+import io.micronaut.views.exceptions.ViewRenderingException;
+import jakarta.validation.constraints.Pattern;
 
 /**
  * Representation of an HTML form.
@@ -25,8 +29,41 @@
  * @param action Form Action
  * @param method Form Method. For example `post`
  * @param fieldset Form fields
+ * @param enctype how the form-data should be encoded when submitting it to the server
  */
 @Experimental
 @Introspected
-public record Form(String action, String method, Fieldset fieldset) {
+public record Form(@NonNull String action,
+                   @Nullable @Pattern(regexp = "get|post") String method,
+                   @NonNull Fieldset fieldset,
+                   @Nullable @Pattern(regexp = "application/x-www-form-urlencoded|multipart/form-data|text/plain") String enctype) {
+
+    private static final String POST = "post";
+
+    public Form(@NonNull String action, @NonNull String method, @NonNull Fieldset fieldset) {
+        this(action, method, fieldset, null);
+    }
+
+    public Form(@NonNull String action, @NonNull Fieldset fieldset) {
+        this(action, POST, fieldset, null);
+    }
+
+    public Form(@NonNull String action,
+                @NonNull Fieldset fieldset,
+                @Nullable String enctype) {
+        this(action, POST, fieldset, enctype);
+    }
+
+    public Form(@NonNull String action,
+                @NonNull String method,
+                @NonNull Fieldset fieldset,
+                @Nullable String enctype) {
+        if (enctype != null && !method.equals(POST)) {
+            throw new IllegalArgumentException("enctype attribute can be used only if method equals post");
+        }
+        this.action = action;
+        this.method = method;
+        this.fieldset = fieldset;
+        this.enctype = enctype;
+    }
 }

views-fieldset/src/test/java/io/micronaut/views/fields/FormTest.java

@@ -3,6 +3,8 @@
 import io.micronaut.core.beans.BeanIntrospection;
 import org.junit.jupiter.api.Test;
 
+import java.util.Collections;
+
 import static org.junit.jupiter.api.Assertions.*;
 
 class FormTest {
@@ -11,4 +13,9 @@ void isAnnotatedWithIntrospected() {
         assertDoesNotThrow(() -> BeanIntrospection.getIntrospection(Form.class));
     }
 
+    @Test
+    void formEnctypeMethodGet() {
+        assertThrows(IllegalArgumentException.class, () -> new Form("/foo/bar", "get", new Fieldset(Collections.emptyList(), Collections.emptyList()), "application/x-www-form-urlencoded"));
+        assertDoesNotThrow(() -> new Form("/foo/bar", "post", new Fieldset(Collections.emptyList(), Collections.emptyList()), "application/x-www-form-urlencoded"));
+    }
 }