Add Mustache support for Spring WebFlux apps

This commit moves the existing Spring MVC Mustache support to its own
`servlet` package and adds a new one under `reactive` for the WebFlux
web applications.

New `MustacheView` and `MustacheViewResolver` types resolve and render
Mustache views for WebFlux applications.

Since this templating engine is now supported by two flavors of Spring
web apps, the `spring-boot-starter-mustache` does not depend anymore on
the `spring-boot-starter-web` one: it's up to the developer to add the
relevant starter `web` or `webflux` to their application.

Fixes gh-8648

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mobile/DeviceDelegatingViewResolverAutoConfiguration.java

@@ -28,7 +28,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplicat
 import org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration;
 import org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration;
 import org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration;
-import org.springframework.boot.autoconfigure.mustache.web.MustacheViewResolver;
+import org.springframework.boot.autoconfigure.mustache.servlet.MustacheViewResolver;
 import org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mustache/MustacheAutoConfiguration.java

@@ -30,7 +30,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
-import org.springframework.boot.autoconfigure.mustache.web.MustacheViewResolver;
+import org.springframework.boot.autoconfigure.mustache.servlet.MustacheViewResolver;
 import org.springframework.boot.autoconfigure.template.TemplateLocation;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.ApplicationContext;
@@ -43,6 +43,7 @@ import org.springframework.core.env.Environment;
  * {@link EnableAutoConfiguration Auto-configuration} for Mustache.
  *
  * @author Dave Syer
+ * @author Brian Clozel
  * @since 1.2.2
  */
 @Configuration
@@ -123,4 +124,34 @@ public class MustacheAutoConfiguration {
 
 	}
 
+	@Configuration
+	@ConditionalOnWebApplication(type = Type.REACTIVE)
+	protected static class MustacheReactiveWebConfiguration {
+
+		private final MustacheProperties mustache;
+
+		protected MustacheReactiveWebConfiguration(MustacheProperties mustache) {
+			this.mustache = mustache;
+		}
+
+		@Bean
+		@ConditionalOnMissingBean(org.springframework.boot.autoconfigure
+				.mustache.reactive.MustacheViewResolver.class)
+		public org.springframework.boot.autoconfigure
+				.mustache.reactive.MustacheViewResolver mustacheViewResolver(Compiler mustacheCompiler) {
+			org.springframework.boot.autoconfigure
+					.mustache.reactive.MustacheViewResolver resolver
+					= new org.springframework.boot.autoconfigure
+					.mustache.reactive.MustacheViewResolver(mustacheCompiler);
+			resolver.setPrefix(this.mustache.getPrefix());
+			resolver.setSuffix(this.mustache.getSuffix());
+			resolver.setViewNames(this.mustache.getViewNames());
+			resolver.setRequestContextAttribute(this.mustache.getRequestContextAttribute());
+			resolver.setCharset(this.mustache.getCharsetName());
+			resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 10);
+			return resolver;
+		}
+
+	}
+
 }

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mustache/reactive/MustacheView.java

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2012-2017 the original author or 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
+ *
+ *      http://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 org.springframework.boot.autoconfigure.mustache.reactive;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.Reader;
+import java.io.Writer;
+import java.nio.charset.Charset;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Optional;
+
+import com.samskivert.mustache.Mustache;
+import com.samskivert.mustache.Template;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.http.MediaType;
+import org.springframework.web.reactive.result.view.AbstractUrlBasedView;
+import org.springframework.web.reactive.result.view.View;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * Spring WebFlux {@link View} using the Mustache template engine.
+ *
+ * @author Brian Clozel
+ * @since 2.0.0
+ */
+public class MustacheView extends AbstractUrlBasedView {
+
+	private Mustache.Compiler compiler;
+
+	private String charset;
+
+	/**
+	 * Set the JMustache compiler to be used by this view.
+	 * <p>Typically this property is not set directly. Instead a single
+	 * {@link Mustache.Compiler} is expected in the Spring application context
+	 * which is used to compile Mustache templates.
+	 * @param compiler the Mustache compiler
+	 */
+	public void setCompiler(Mustache.Compiler compiler) {
+		this.compiler = compiler;
+	}
+
+	/**
+	 * Set the charset used for reading Mustache template files.
+	 * @param charset the charset to use for reading template files
+	 */
+	public void setCharset(String charset) {
+		this.charset = charset;
+	}
+
+	@Override
+	public boolean checkResourceExists(Locale locale) throws Exception {
+		return resolveResource() != null;
+	}
+
+	private Resource resolveResource() {
+		Resource resource = getApplicationContext().getResource(getUrl());
+		if (resource == null || !resource.exists()) {
+			return null;
+		}
+		return resource;
+	}
+
+	@Override
+	protected Mono<Void> renderInternal(Map<String, Object> model,
+			MediaType contentType, ServerWebExchange exchange) {
+		Resource resource = resolveResource();
+		if (resource == null) {
+			return Mono.error(new IllegalStateException("Could not find Mustache template with URL ["
+					+ getUrl() + "]"));
+		}
+		DataBuffer dataBuffer = exchange.getResponse().bufferFactory().allocateBuffer();
+		try (Reader reader = getReader(resource)) {
+			Template template = this.compiler.compile(reader);
+			Charset charset = getCharset(contentType).orElse(getDefaultCharset());
+			try (Writer writer = new OutputStreamWriter(dataBuffer.asOutputStream(), charset)) {
+				template.execute(model, writer);
+				writer.flush();
+			}
+		}
+		catch (Throwable exc) {
+			return Mono.error(exc);
+		}
+		return exchange.getResponse().writeWith(Flux.just(dataBuffer));
+	}
+
+	private Reader getReader(Resource resource) throws IOException {
+		if (this.charset != null) {
+			return new InputStreamReader(resource.getInputStream(), this.charset);
+		}
+		return new InputStreamReader(resource.getInputStream());
+	}
+
+	private Optional<Charset> getCharset(MediaType mediaType) {
+		return (mediaType != null ? Optional.ofNullable(mediaType.getCharset()) : Optional.empty());
+	}
+}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mustache/reactive/MustacheViewResolver.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2012-2017 the original author or 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
+ *
+ *      http://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 org.springframework.boot.autoconfigure.mustache.reactive;
+
+import com.samskivert.mustache.Mustache;
+
+import org.springframework.web.reactive.result.view.AbstractUrlBasedView;
+import org.springframework.web.reactive.result.view.UrlBasedViewResolver;
+import org.springframework.web.reactive.result.view.ViewResolver;
+
+/**
+ * Spring WebFlux {@link ViewResolver} for Mustache.
+ *
+ * @author Brian Clozel
+ * @since 2.0.0
+ */
+public class MustacheViewResolver extends UrlBasedViewResolver {
+
+	private final Mustache.Compiler compiler;
+
+	private String charset;
+
+	/**
+	 * Create a {@code MustacheViewResolver} backed by a default
+	 * instance of a {@link Mustache.Compiler}.
+	 */
+	public MustacheViewResolver() {
+		this.compiler = Mustache.compiler();
+		setViewClass(requiredViewClass());
+	}
+
+	/**
+	 * Create a {@code MustacheViewResolver} backed by a custom
+	 * instance of a {@link Mustache.Compiler}.
+	 * @param compiler the Mustache compiler used to compile templates
+	 */
+	public MustacheViewResolver(Mustache.Compiler compiler) {
+		this.compiler = compiler;
+		setViewClass(requiredViewClass());
+	}
+
+	/**
+	 * Set the charset.
+	 * @param charset the charset
+	 */
+	public void setCharset(String charset) {
+		this.charset = charset;
+	}
+
+	@Override
+	protected Class<?> requiredViewClass() {
+		return MustacheView.class;
+	}
+
+	@Override
+	protected AbstractUrlBasedView createUrlBasedView(String viewName) {
+		MustacheView view = (MustacheView) super.createUrlBasedView(viewName);
+		view.setCompiler(this.compiler);
+		view.setCharset(this.charset);
+		return view;
+	}
+
+}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mustache/reactive/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-2017 the original author or 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
+ *
+ *      http://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.
+ */
+
+/**
+ * Auto-configuration for Mustache with Spring WebFlux.
+ */
+package org.springframework.boot.autoconfigure.mustache.reactive;

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mustache/servlet/MustacheView.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.autoconfigure.mustache.web;
+package org.springframework.boot.autoconfigure.mustache.servlet;
 
 import java.util.Map;
 

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mustache/servlet/MustacheViewResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.autoconfigure.mustache.web;
+package org.springframework.boot.autoconfigure.mustache.servlet;
 
 import java.io.IOException;
 import java.io.InputStreamReader;

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mustache/servlet/package-info.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,4 +17,4 @@
 /**
  * Auto-configuration for Mustache with Spring MVC.
  */
-package org.springframework.boot.autoconfigure.mustache.web;
+package org.springframework.boot.autoconfigure.mustache.servlet;

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mobile/DeviceDelegatingViewResolverAutoConfigurationTests.java

@@ -34,7 +34,7 @@ import org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfigura
 import org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration;
 import org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration;
 import org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration;
-import org.springframework.boot.autoconfigure.mustache.web.MustacheViewResolver;
+import org.springframework.boot.autoconfigure.mustache.servlet.MustacheViewResolver;
 import org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration;
 import org.springframework.boot.test.util.EnvironmentTestUtils;

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mustache/MustacheAutoConfigurationIntegrationTests.java

@@ -1,122 +0,0 @@
-/*
- * Copyright 2012-2017 the original author or 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
- *
- *      http://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 org.springframework.boot.autoconfigure.mustache;
-
-import java.lang.annotation.Documented;
-import java.lang.annotation.ElementType;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.lang.annotation.Target;
-import java.util.Date;
-import java.util.Map;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.SpringApplication;
-import org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration;
-import org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration;
-import org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration;
-import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
-import org.springframework.boot.test.web.client.TestRestTemplate;
-import org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.context.annotation.Import;
-import org.springframework.stereotype.Controller;
-import org.springframework.test.annotation.DirtiesContext;
-import org.springframework.test.context.junit4.SpringRunner;
-import org.springframework.web.bind.annotation.RequestMapping;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-/**
- * Integration tests for {@link MustacheAutoConfiguration}.
- *
- * @author Dave Syer
- */
-@RunWith(SpringRunner.class)
-@DirtiesContext
-@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT, properties = {
-		"spring.mustache.prefix:classpath:/mustache-templates/" })
-public class MustacheAutoConfigurationIntegrationTests {
-
-	@Autowired
-	private ServletWebServerApplicationContext context;
-
-	private int port;
-
-	@Before
-	public void init() {
-		this.port = this.context.getWebServer().getPort();
-	}
-
-	@Test
-	public void testHomePage() throws Exception {
-		String body = new TestRestTemplate().getForObject("http://localhost:" + this.port,
-				String.class);
-		assertThat(body.contains("Hello World")).isTrue();
-	}
-
-	@Test
-	public void testPartialPage() throws Exception {
-		String body = new TestRestTemplate()
-				.getForObject("http://localhost:" + this.port + "/partial", String.class);
-		assertThat(body.contains("Hello World")).isTrue();
-	}
-
-	@Configuration
-	@MinimalWebConfiguration
-	@Controller
-	public static class Application {
-
-		@RequestMapping("/")
-		public String home(Map<String, Object> model) {
-			model.put("time", new Date());
-			model.put("message", "Hello World");
-			model.put("title", "Hello App");
-			return "home";
-		}
-
-		@RequestMapping("/partial")
-		public String layout(Map<String, Object> model) {
-			model.put("time", new Date());
-			model.put("message", "Hello World");
-			model.put("title", "Hello App");
-			return "partial";
-		}
-
-		public static void main(String[] args) {
-			SpringApplication.run(Application.class, args);
-		}
-
-	}
-
-	@Target(ElementType.TYPE)
-	@Retention(RetentionPolicy.RUNTIME)
-	@Documented
-	@Import({ MustacheAutoConfiguration.class,
-			ServletWebServerFactoryAutoConfiguration.class,
-			DispatcherServletAutoConfiguration.class,
-			PropertyPlaceholderAutoConfiguration.class })
-	protected @interface MinimalWebConfiguration {
-
-	}
-
-}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mustache/MustacheAutoConfigurationTests.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2012-2017 the original author or 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
+ *
+ *      http://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 org.springframework.boot.autoconfigure.mustache;
+
+import com.samskivert.mustache.Mustache;
+import org.junit.Test;
+
+import org.springframework.boot.autoconfigure.mustache.servlet.MustacheViewResolver;
+import org.springframework.boot.test.util.EnvironmentTestUtils;
+import org.springframework.boot.web.reactive.context.GenericReactiveWebApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link MustacheAutoConfiguration}.
+ *
+ * @author Brian Clozel
+ */
+public class MustacheAutoConfigurationTests {
+
+	private AnnotationConfigWebApplicationContext webContext;
+
+	private GenericReactiveWebApplicationContext reactiveWebContext;
+
+	@Test
+	public void registerBeansForServletApp() {
+		loadWithServlet(null);
+		assertThat(this.webContext.getBeansOfType(Mustache.Compiler.class)).hasSize(1);
+		assertThat(this.webContext.getBeansOfType(MustacheResourceTemplateLoader.class)).hasSize(1);
+		assertThat(this.webContext.getBeansOfType(MustacheViewResolver.class)).hasSize(1);
+	}
+
+	@Test
+	public void registerCompilerForServletApp() {
+		loadWithServlet(CustomCompilerConfiguration.class);
+		assertThat(this.webContext.getBeansOfType(MustacheResourceTemplateLoader.class)).hasSize(1);
+		assertThat(this.webContext.getBeansOfType(MustacheViewResolver.class)).hasSize(1);
+		assertThat(this.webContext.getBeansOfType(Mustache.Compiler.class)).hasSize(1);
+		assertThat(this.webContext.getBean(Mustache.Compiler.class).standardsMode).isTrue();
+	}
+
+	@Test
+	public void registerBeansForReactiveApp() {
+		loadWithReactive(null);
+		assertThat(this.reactiveWebContext.getBeansOfType(Mustache.Compiler.class)).hasSize(1);
+		assertThat(this.reactiveWebContext.getBeansOfType(MustacheResourceTemplateLoader.class)).hasSize(1);
+		assertThat(this.reactiveWebContext.getBeansOfType(MustacheViewResolver.class)).isEmpty();
+		assertThat(this.reactiveWebContext
+				.getBeansOfType(org.springframework.boot.autoconfigure.mustache.reactive.MustacheViewResolver.class)
+		).hasSize(1);
+	}
+
+
+	@Test
+	public void registerCompilerForReactiveApp() {
+		loadWithReactive(CustomCompilerConfiguration.class);
+		assertThat(this.reactiveWebContext.getBeansOfType(Mustache.Compiler.class)).hasSize(1);
+		assertThat(this.reactiveWebContext.getBeansOfType(MustacheResourceTemplateLoader.class)).hasSize(1);
+		assertThat(this.reactiveWebContext.getBeansOfType(MustacheViewResolver.class)).isEmpty();
+		assertThat(this.reactiveWebContext
+				.getBeansOfType(org.springframework.boot.autoconfigure.mustache.reactive.MustacheViewResolver.class)
+		).hasSize(1);
+		assertThat(this.reactiveWebContext.getBean(Mustache.Compiler.class).standardsMode).isTrue();
+	}
+
+	private void loadWithServlet(Class<?> config) {
+		this.webContext = new AnnotationConfigWebApplicationContext();
+		EnvironmentTestUtils.addEnvironment(this.webContext,
+				"spring.mustache.prefix=classpath:/mustache-templates/");
+		if (config != null) {
+			this.webContext.register(config);
+		}
+		this.webContext.register(BaseConfiguration.class);
+		this.webContext.refresh();
+	}
+
+	private void loadWithReactive(Class<?> config) {
+		this.reactiveWebContext = new GenericReactiveWebApplicationContext();
+		EnvironmentTestUtils.addEnvironment(this.reactiveWebContext,
+				"spring.mustache.prefix=classpath:/mustache-templates/");
+		if (config != null) {
+			this.reactiveWebContext.register(config);
+		}
+		this.reactiveWebContext.register(BaseConfiguration.class);
+		this.reactiveWebContext.refresh();
+	}
+
+	@Configuration
+	@Import({MustacheAutoConfiguration.class})
+	protected static class BaseConfiguration {
+
+	}
+
+	@Configuration
+	protected static class CustomCompilerConfiguration {
+
+		@Bean
+		public Mustache.Compiler compiler(Mustache.TemplateLoader mustacheTemplateLoader) {
+			return Mustache.compiler().standardsMode(true).withLoader(mustacheTemplateLoader);
+		}
+	}
+
+}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mustache/reactive/MustacheViewResolverTests.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2012-2017 the original author or 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
+ *
+ *      http://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 org.springframework.boot.autoconfigure.mustache.reactive;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.context.support.GenericApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link org.springframework.boot.autoconfigure.mustache.reactive.MustacheViewResolver}.
+ *
+ * @author Brian Clozel
+ */
+public class MustacheViewResolverTests {
+
+	private MustacheViewResolver resolver = new MustacheViewResolver();
+
+	@Before
+	public void init() {
+		GenericApplicationContext applicationContext = new GenericApplicationContext();
+		applicationContext.refresh();
+		this.resolver.setApplicationContext(applicationContext);
+		this.resolver.setPrefix("classpath:/mustache-templates/");
+		this.resolver.setSuffix(".html");
+	}
+
+	@Test
+	public void resolveNonExistent() throws Exception {
+		assertThat(this.resolver.resolveViewName("bar", null).block()).isNull();
+	}
+
+	@Test
+	public void resolveExisting() throws Exception {
+		assertThat(this.resolver.resolveViewName("foo", null).block()).isNotNull();
+	}
+
+}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mustache/reactive/MustacheViewTests.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2012-2017 the original author or 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
+ *
+ *      http://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 org.springframework.boot.autoconfigure.mustache.reactive;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
+
+import com.samskivert.mustache.Mustache;
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.context.support.GenericApplicationContext;
+import org.springframework.http.MediaType;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.MockServerWebExchange;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link MustacheView}.
+ *
+ * @author Brian Clozel
+ */
+public class MustacheViewTests {
+
+	private GenericApplicationContext context = new GenericApplicationContext();
+
+	private MockServerWebExchange exchange;
+
+	@Before
+	public void init() {
+		this.context.refresh();
+	}
+
+	@Test
+	public void viewResolvesHandlebars() throws Exception {
+		this.exchange = MockServerHttpRequest.get("/test").toExchange();
+		MustacheView view = new MustacheView();
+		view.setCompiler(Mustache.compiler());
+		view.setUrl("classpath:/mustache-templates/foo.html");
+		view.setCharset(StandardCharsets.UTF_8.displayName());
+		view.setApplicationContext(this.context);
+		view.render(Collections.singletonMap("World", "Spring"), MediaType.TEXT_HTML, this.exchange).block();
+		assertThat(this.exchange.getResponse().getBodyAsString().block()).isEqualTo("Hello Spring");
+	}
+
+}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mustache/reactive/MustacheWebIntegrationTests.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright 2012-2017 the original author or 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
+ *
+ *      http://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 org.springframework.boot.autoconfigure.mustache.reactive;
+
+import java.util.Date;
+
+import com.samskivert.mustache.Mustache;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration;
+import org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration;
+import org.springframework.boot.autoconfigure.mustache.MustacheResourceTemplateLoader;
+import org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration;
+import org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerAutoConfiguration;
+import org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.stereotype.Controller;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration Tests for {@link MustacheAutoConfiguration}, {@link MustacheViewResolver}
+ * and {@link MustacheView}.
+ *
+ * @author Brian Clozel
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT,
+		properties = "spring.main.web-application-type=reactive")
+public class MustacheWebIntegrationTests {
+
+	@Autowired
+	private WebTestClient client;
+
+	@Test
+	public void testHomePage() throws Exception {
+		String result = (String) this.client.get().uri("/").exchange()
+				.expectStatus().isOk()
+				.expectBody(String.class).returnResult().getResponseBody();
+		assertThat(result).contains("Hello App").contains("Hello World");
+	}
+
+	@Test
+	public void testPartialPage() throws Exception {
+		String result = (String) this.client.get().uri("/partial").exchange()
+				.expectStatus().isOk()
+				.expectBody(String.class).returnResult().getResponseBody();
+		assertThat(result).contains("Hello App").contains("Hello World");
+	}
+
+	@Configuration
+	@Import({ReactiveWebServerAutoConfiguration.class,
+			WebFluxAutoConfiguration.class,
+			HttpHandlerAutoConfiguration.class,
+			PropertyPlaceholderAutoConfiguration.class})
+	@Controller
+	public static class Application {
+
+		@RequestMapping("/")
+		public String home(Model model) {
+			model.addAttribute("time", new Date());
+			model.addAttribute("message", "Hello World");
+			model.addAttribute("title", "Hello App");
+			return "home";
+		}
+
+		@RequestMapping("/partial")
+		public String layout(Model model) {
+			model.addAttribute("time", new Date());
+			model.addAttribute("message", "Hello World");
+			model.addAttribute("title", "Hello App");
+			return "partial";
+		}
+
+		@Bean
+		public MustacheViewResolver viewResolver() {
+			Mustache.Compiler compiler = Mustache.compiler().withLoader(
+					new MustacheResourceTemplateLoader("classpath:/mustache-templates/", ".html"));
+			MustacheViewResolver resolver = new MustacheViewResolver(compiler);
+			resolver.setPrefix("classpath:/mustache-templates/");
+			resolver.setSuffix(".html");
+			return resolver;
+		}
+
+		public static void main(String[] args) {
+			SpringApplication application = new SpringApplication(Application.class);
+			application.setWebApplicationType(WebApplicationType.REACTIVE);
+			application.run(args);
+		}
+
+	}
+
+}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mustache/servlet/MustacheViewResolverTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.autoconfigure.mustache.web;
+package org.springframework.boot.autoconfigure.mustache.servlet;
 
 import java.io.ByteArrayInputStream;
 import java.io.InputStream;

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mustache/servlet/MustacheViewTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.autoconfigure.mustache.web;
+package org.springframework.boot.autoconfigure.mustache.servlet;
 
 import java.util.Collections;
 

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mustache/servlet/MustacheWebIntegrationTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.autoconfigure.mustache.web;
+package org.springframework.boot.autoconfigure.mustache.servlet;
 
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;

spring-boot-samples/spring-boot-sample-web-mustache/pom.xml

@@ -21,6 +21,10 @@
 	</properties>
 	<dependencies>
 		<!-- Compile -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-mustache</artifactId>

spring-boot-starters/spring-boot-starter-mustache/pom.xml

@@ -8,7 +8,7 @@
 	</parent>
 	<artifactId>spring-boot-starter-mustache</artifactId>
 	<name>Spring Boot Mustache Starter</name>
-	<description>Starter for building MVC web applications using Mustache views</description>
+	<description>Starter for building web applications using Mustache views</description>
 	<url>http://projects.spring.io/spring-boot/</url>
 	<organization>
 		<name>Pivotal Software, Inc.</name>
@@ -22,10 +22,6 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter</artifactId>
 		</dependency>
-		<dependency>
-			<groupId>org.springframework.boot</groupId>
-			<artifactId>spring-boot-starter-web</artifactId>
-		</dependency>
 		<dependency>
 			<groupId>com.samskivert</groupId>
 			<artifactId>jmustache</artifactId>