feature: v0.4.2 ViewContextContainer to compose pages from multiple c…

…omponents -> support htmx out of band response

README.md

@@ -51,9 +51,7 @@ class Router(
     val homeViewComponent: HomeViewComponent
 ) {
     @GetMapping("/")
-    fun homeComponent(): Any {
-        return homeViewComponent.render()
-    }
+    fun homeComponent() = homeViewComponent.render()
 }
 ```
 
@@ -128,6 +126,25 @@ If we now access the root url path of our spring application we can see that the
 
 ![viewcomponent-parameter](https://user-images.githubusercontent.com/33346637/222275688-7f301ff7-4a69-4062-ae69-1dd6c9983a7a.png)
 
+### Composing pages from components
+
+If you want to compose a page/response from multiple components you can use the `ViewContextContainer` as response in your controller, this can be used for [htmx out of band responses](https://htmx.org/examples/update-other-content/#oob).
+
+```kotlin
+@Controller
+class Router(
+    private val homeViewComponent: HomeViewComponent,
+    private val navigationViewComponent: NavigationViewComponent,
+) {
+
+    @GetMapping("/multi-component")
+    fun multipleComponent() = ViewContextContainer(
+        navigationViewComponent.render(),
+        homeViewComponent.render()
+    )
+}
+```
+
 ### Local Development
 
 To enable live reload of the components on each save without rebuilding the application add this configuration:
@@ -206,15 +223,15 @@ We can then call the render method in our Controller
 // Router.java
 @Controller
 public class Router {
-    private final HomeViewComponent HomeViewComponent;
+    private final HomeViewComponent homeViewComponent;
 
-    public Router(HomeViewComponent HomeViewComponent) {
-        this.HomeViewComponent = HomeViewComponent;
+    public Router(HomeViewComponent homeViewComponent) {
+        this.HomeViewComponent = homeViewComponent;
     }
 
     @GetMapping("/")
     ViewContext homeView(){
-        return HomeViewComponent.render();
+        return homeViewComponent.render();
     }
 }
 ```
@@ -304,6 +321,31 @@ If we now access the root url path of our spring application we can see that the
 
 ![viewcomponent-parameter](https://user-images.githubusercontent.com/33346637/222275688-7f301ff7-4a69-4062-ae69-1dd6c9983a7a.png)
 
+### Composing pages from components
+
+If you want to compose a page/response from multiple components you can use the `ViewContextContainer` as response in your controller, this can be used for [htmx out of band responses](https://htmx.org/examples/update-other-content/#oob).
+
+```java
+// Router.java
+@Controller
+public class Router {
+    private final NavigationViewComponent navigationViewComponent;
+    private final TableViewComponent tableViewComponent;
+
+    public Router(NavigationViewComponent navigationViewComponent, TableViewComponent tableViewComponent) {
+        this.navigationViewComponent = navigationViewComponent;
+        this.tableViewComponent = tableViewComponent;
+    }
+
+    @GetMapping("/multi-component")
+    ViewContextContainer multipleComponent() {
+        return new ViewContextContainer(
+                this.navigationViewComponent.render(),
+                this.tableViewComponent.render()
+        );
+    }
+}
+```
 
 ### Local Development
 

build.gradle.kts

@@ -10,7 +10,7 @@ plugins {
 }
 
 group = "de.tschuehly"
-version = "0.4.0"
+version = "0.4.2"
 java.sourceCompatibility = JavaVersion.VERSION_17
 
 repositories {

src/main/kotlin/de/tschuehly/thymeleafviewcomponent/ViewComponentMvcConfigurer.kt

@@ -5,10 +5,13 @@ import org.springframework.web.method.support.HandlerMethodReturnValueHandler
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer
 
 @Component
-class ViewComponentMvcConfigurer : WebMvcConfigurer {
+class ViewComponentMvcConfigurer(
+    private val viewContextContainerMethodReturnValueHandler: ViewContextContainerMethodReturnValueHandler
+) : WebMvcConfigurer {
 
     override fun addReturnValueHandlers(handlers: MutableList<HandlerMethodReturnValueHandler>) {
-        handlers.add(ViewComponentMethodReturnValueHandler())
+        handlers.add(viewContextContainerMethodReturnValueHandler)
+        handlers.add(ViewContextMethodReturnValueHandler())
         super.addReturnValueHandlers(handlers)
     }
 }

src/main/kotlin/de/tschuehly/thymeleafviewcomponent/ViewContextContainer.kt

@@ -0,0 +1,5 @@
+package de.tschuehly.thymeleafviewcomponent
+
+class ViewContextContainer(
+    vararg val viewContexts: ViewContext
+)

src/main/kotlin/de/tschuehly/thymeleafviewcomponent/ViewContextContainerMethodReturnValueHandler.kt

@@ -0,0 +1,42 @@
+package de.tschuehly.thymeleafviewcomponent
+
+import jakarta.servlet.http.HttpServletRequest
+import jakarta.servlet.http.HttpServletResponse
+import org.springframework.core.MethodParameter
+import org.springframework.stereotype.Component
+import org.springframework.web.context.request.NativeWebRequest
+import org.springframework.web.context.support.WebApplicationObjectSupport
+import org.springframework.web.method.support.HandlerMethodReturnValueHandler
+import org.springframework.web.method.support.ModelAndViewContainer
+import org.thymeleaf.spring6.view.ThymeleafView
+import org.thymeleaf.spring6.view.ThymeleafViewResolver
+import java.util.*
+
+@Component
+class ViewContextContainerMethodReturnValueHandler(
+    private val thymeleafViewResolver: ThymeleafViewResolver
+) : HandlerMethodReturnValueHandler, WebApplicationObjectSupport() {
+
+    override fun supportsReturnType(returnType: MethodParameter): Boolean {
+        return ViewContextContainer::class.java.isAssignableFrom(returnType.parameterType)
+    }
+
+    override fun handleReturnValue(
+        returnValue: Any?,
+        returnType: MethodParameter,
+        mavContainer: ModelAndViewContainer,
+        webRequest: NativeWebRequest
+    ) {
+        val request = webRequest.getNativeRequest(HttpServletRequest::class.java)!!
+        val response = webRequest.getNativeResponse(HttpServletResponse::class.java)!!
+        val viewContextContainer = returnValue as ViewContextContainer
+        viewContextContainer.viewContexts.forEach { viewContext ->
+            val view: ThymeleafView =
+                thymeleafViewResolver.resolveViewName(viewContext.componentTemplate!!, Locale.GERMAN) as ThymeleafView
+            view.render(viewContext.contextAttributes.toMap(), request, response)
+
+        }
+        mavContainer.isRequestHandled = true
+    }
+
+}

src/main/kotlin/de/tschuehly/thymeleafviewcomponent/ViewComponentMethodReturnValueHandler.kt → src/main/kotlin/de/tschuehly/thymeleafviewcomponent/ViewContextMethodReturnValueHandler.kt

@@ -6,7 +6,7 @@ import org.springframework.web.method.support.HandlerMethodReturnValueHandler
 import org.springframework.web.method.support.ModelAndViewContainer
 
 
-class ViewComponentMethodReturnValueHandler : HandlerMethodReturnValueHandler {
+class ViewContextMethodReturnValueHandler : HandlerMethodReturnValueHandler {
 
     override fun supportsReturnType(returnType: MethodParameter): Boolean {
         return ViewContext::class.java.isAssignableFrom(returnType.parameterType)