Reactive routes - set content-type from Route#produces()

- if no content-type header is set try to use
RoutingContext#getAcceptableContentType()
- resolves quarkusio#10465

extensions/vertx-web/deployment/src/main/java/io/quarkus/vertx/web/deployment/Methods.java

@@ -19,6 +19,7 @@
 import io.quarkus.vertx.web.runtime.MultiJsonArraySupport;
 import io.quarkus.vertx.web.runtime.MultiSseSupport;
 import io.quarkus.vertx.web.runtime.MultiSupport;
+import io.quarkus.vertx.web.runtime.RouteHandlers;
 import io.smallrye.mutiny.Multi;
 import io.smallrye.mutiny.Uni;
 import io.smallrye.mutiny.groups.UniSubscribe;
@@ -136,6 +137,9 @@ class Methods {
                     CreationalContext.class);
     static final MethodDescriptor OBJECT_CONSTRUCTOR = MethodDescriptor.ofConstructor(Object.class);
 
+    static final MethodDescriptor ROUTE_HANDLERS_SET_CONTENT_TYPE = MethodDescriptor
+            .ofMethod(RouteHandlers.class, "setContentType", void.class, RoutingContext.class);
+
     private Methods() {
         // Avoid direct instantiation
     }

extensions/vertx-web/deployment/src/main/java/io/quarkus/vertx/web/deployment/VertxWebProcessor.java

@@ -530,10 +530,13 @@ void implementInvoke(HandlerDescriptor descriptor, BeanInfo bean, MethodInfo met
         // Invoke the business method handler
         ResultHandle res = invoke.invokeVirtualMethod(methodDescriptor, beanInstanceHandle, paramHandles);
 
+        // If no content-type header is set then try to use the most acceptable content type
+        invoke.invokeStaticMethod(Methods.ROUTE_HANDLERS_SET_CONTENT_TYPE, routingContext);
+
         // Get the response: HttpServerResponse response = rc.response()
-        ResultHandle response = invoke.invokeInterfaceMethod(Methods.RESPONSE, routingContext);
         MethodDescriptor end = Methods.getEndMethodForContentType(descriptor);
         if (descriptor.isReturningUni()) {
+            ResultHandle response = invoke.invokeInterfaceMethod(Methods.RESPONSE, routingContext);
             // The method returns a Uni.
             // We subscribe to this Uni and write the provided item in the HTTP response
             // If the method returned null, we fail
@@ -568,7 +571,7 @@ void implementInvoke(HandlerDescriptor descriptor, BeanInfo bean, MethodInfo met
 
         } else if (descriptor.getContentType() != null) {
             // The method returns "something" in a synchronous manner, write it into the response
-
+            ResultHandle response = invoke.invokeInterfaceMethod(Methods.RESPONSE, routingContext);
             // If the method returned null, we fail
             // If the method returns string or buffer, the response.end method is used to write the response
             // If the method returns an object, the result is mapped to JSON and written into the response

extensions/vertx-web/runtime/src/main/java/io/quarkus/vertx/web/Route.java

@@ -10,6 +10,7 @@
 import io.vertx.core.Handler;
 import io.vertx.core.http.HttpMethod;
 import io.vertx.ext.web.Router;
+import io.vertx.ext.web.RoutingContext;
 
 /**
  * This annotation can be used to configure a reactive route in a declarative way.
@@ -74,8 +75,11 @@
 
     /**
      * Used for content-based routing.
+     * <p>
+     * If no {@code Content-Type} header is set then try to use the most acceptable content type.
      * 
      * @see io.vertx.ext.web.Route#produces(String)
+     * @see RoutingContext#getAcceptableContentType()
      * @return the produced content types
      */
     String[] produces() default {};

extensions/vertx-web/runtime/src/main/java/io/quarkus/vertx/web/runtime/RouteHandlers.java

@@ -5,12 +5,29 @@
 import io.quarkus.arc.Arc;
 import io.quarkus.arc.impl.LazyValue;
 import io.quarkus.security.identity.SecurityIdentity;
+import io.vertx.core.http.HttpServerResponse;
+import io.vertx.ext.web.RoutingContext;
 
-final class RouteHandlers {
+public final class RouteHandlers {
+
+    private RouteHandlers() {
+    }
+
+    static final String CONTENT_TYPE = "content-type";
 
     private static final LazyValue<Event<SecurityIdentity>> SECURITY_IDENTITY_EVENT = new LazyValue<>(
             RouteHandlers::createEvent);
 
+    public static void setContentType(RoutingContext context) {
+        HttpServerResponse response = context.response();
+        if (response.headers().get(CONTENT_TYPE) == null) {
+            String acceptableContentType = context.getAcceptableContentType();
+            if (acceptableContentType != null) {
+                response.putHeader(CONTENT_TYPE, acceptableContentType);
+            }
+        }
+    }
+
     static void fireSecurityIdentity(SecurityIdentity identity) {
         SECURITY_IDENTITY_EVENT.get().fire(identity);
     }