Refine Mustache support

Refine Mustache support to provide a cleaner separation between the
reactive and servlet implementations. The views have now moved to the
`spring-boot` project and the auto-configuration has been split into
two distinct `@Imports` to save needing full package declarations.

See gh-8941

spring-boot/pom.xml

@@ -54,6 +54,11 @@
 			<artifactId>jackson-databind</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>com.samskivert</groupId>
+			<artifactId>jmustache</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>com.sendgrid</groupId>
 			<artifactId>sendgrid-java</artifactId>

spring-boot/src/main/java/org/springframework/boot/web/reactive/result/view/MustacheView.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.web.reactive.result.view;
+
+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.Compiler;
+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 Compiler compiler;
+
+	private String charset;
+
+	/**
+	 * Set the JMustache compiler to be used by this view. Typically this property is not
+	 * set directly. Instead a single {@link Compiler} is expected in the Spring
+	 * application context which is used to compile Mustache templates.
+	 * @param compiler the Mustache compiler
+	 */
+	public void setCompiler(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;
+	}
+
+	@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 Resource resolveResource() {
+		Resource resource = getApplicationContext().getResource(getUrl());
+		if (resource == null || !resource.exists()) {
+			return null;
+		}
+		return resource;
+	}
+
+	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 Optional.ofNullable(mediaType != null ? mediaType.getCharset() : null);
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/web/reactive/result/view/MustacheViewResolver.java

@@ -0,0 +1,78 @@
+/*
+ * 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.web.reactive.result.view;
+
+import com.samskivert.mustache.Mustache;
+import com.samskivert.mustache.Mustache.Compiler;
+
+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 Compiler compiler;
+
+	private String charset;
+
+	/**
+	 * Create a {@code MustacheViewResolver} backed by a default instance of a
+	 * {@link Compiler}.
+	 */
+	public MustacheViewResolver() {
+		this.compiler = Mustache.compiler();
+		setViewClass(requiredViewClass());
+	}
+
+	/**
+	 * Create a {@code MustacheViewResolver} backed by a custom instance of a
+	 * {@link Compiler}.
+	 * @param compiler the Mustache compiler used to compile templates
+	 */
+	public MustacheViewResolver(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/src/main/java/org/springframework/boot/web/reactive/result/view/package-info.java

@@ -0,0 +1,21 @@
+/*
+ * 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.
+ */
+
+/**
+ * Additional {@link org.springframework.web.reactive.result.view.View Views} for use with
+ * WebFlux.
+ */
+package org.springframework.boot.web.reactive.result.view;

spring-boot/src/main/java/org/springframework/boot/web/servlet/view/MustacheView.java

@@ -0,0 +1,102 @@
+/*
+ * 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.web.servlet.view;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.util.Locale;
+import java.util.Map;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import com.samskivert.mustache.Mustache.Compiler;
+import com.samskivert.mustache.Template;
+
+import org.springframework.core.io.Resource;
+import org.springframework.web.servlet.View;
+import org.springframework.web.servlet.view.AbstractTemplateView;
+
+/**
+ * Spring MVC {@link View} using the Mustache template engine.
+ *
+ * @author Brian Clozel
+ * @author Dave Syer
+ * @author Phillip Webb
+ * @since 2.0.0
+ */
+public class MustacheView extends AbstractTemplateView {
+
+	private Compiler compiler;
+
+	private String charset;
+
+	/**
+	 * Set the Mustache compiler to be used by this view.
+	 * <p>
+	 * Typically this property is not set directly. Instead a single {@link Compiler} is
+	 * expected in the Spring application context which is used to compile Mustache
+	 * templates.
+	 * @param compiler the Mustache compiler
+	 */
+	public void setCompiler(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 checkResource(Locale locale) throws Exception {
+		Resource resource = getApplicationContext().getResource(this.getUrl());
+		return (resource != null && resource.exists());
+	}
+
+	@Override
+	protected void renderMergedTemplateModel(Map<String, Object> model,
+			HttpServletRequest request, HttpServletResponse response) throws Exception {
+		Template template = createTemplate(
+				getApplicationContext().getResource(this.getUrl()));
+		if (template != null) {
+			template.execute(model, response.getWriter());
+		}
+	}
+
+	private Template createTemplate(Resource resource) throws IOException {
+		Reader reader = getReader(resource);
+		try {
+			return this.compiler.compile(reader);
+		}
+		finally {
+			reader.close();
+		}
+	}
+
+	private Reader getReader(Resource resource) throws IOException {
+		if (this.charset != null) {
+			return new InputStreamReader(resource.getInputStream(), this.charset);
+		}
+		return new InputStreamReader(resource.getInputStream());
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/web/servlet/view/MustacheViewResolver.java

@@ -0,0 +1,78 @@
+/*
+ * 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.web.servlet.view;
+
+import com.samskivert.mustache.Mustache;
+import com.samskivert.mustache.Mustache.Compiler;
+
+import org.springframework.web.servlet.ViewResolver;
+import org.springframework.web.servlet.view.AbstractTemplateViewResolver;
+import org.springframework.web.servlet.view.AbstractUrlBasedView;
+
+/**
+ * Spring MVC {@link ViewResolver} for Mustache.
+ *
+ * @author Brian Clozel
+ * @since 2.0.0
+ */
+public class MustacheViewResolver extends AbstractTemplateViewResolver {
+
+	private final Mustache.Compiler compiler;
+
+	private String charset;
+
+	/**
+	 * Create a {@code MustacheViewResolver} backed by a default instance of a
+	 * {@link Compiler}.
+	 */
+	public MustacheViewResolver() {
+		this.compiler = Mustache.compiler();
+		setViewClass(requiredViewClass());
+	}
+
+	/**
+	 * Create a {@code MustacheViewResolver} backed by a custom instance of a
+	 * {@link Compiler}.
+	 * @param compiler the Mustache compiler used to compile templates
+	 */
+	public MustacheViewResolver(Compiler compiler) {
+		this.compiler = compiler;
+		setViewClass(requiredViewClass());
+	}
+
+	@Override
+	protected Class<?> requiredViewClass() {
+		return MustacheView.class;
+	}
+
+	/**
+	 * Set the charset.
+	 * @param charset the charset
+	 */
+	public void setCharset(String charset) {
+		this.charset = charset;
+	}
+
+	@Override
+	protected AbstractUrlBasedView buildView(String viewName) throws Exception {
+		MustacheView view = (MustacheView) super.buildView(viewName);
+		view.setCompiler(this.compiler);
+		view.setCharset(this.charset);
+		return view;
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/web/servlet/view/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.
+ */
+
+/**
+ * Additional {@link org.springframework.web.servlet.View Views} for use with Web MVC.
+ */
+package org.springframework.boot.web.servlet.view;

spring-boot/src/test/java/org/springframework/boot/web/reactive/result/view/MustacheViewResolverTests.java

@@ -0,0 +1,57 @@
+/*
+ * 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.web.reactive.result.view;
+
+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 MustacheViewResolver}.
+ *
+ * @author Brian Clozel
+ */
+public class MustacheViewResolverTests {
+
+	private final String prefix = "classpath:/"
+			+ getClass().getPackage().getName().replace(".", "/") + "/";
+
+	private MustacheViewResolver resolver = new MustacheViewResolver();
+
+	@Before
+	public void init() {
+		GenericApplicationContext applicationContext = new GenericApplicationContext();
+		applicationContext.refresh();
+		this.resolver.setApplicationContext(applicationContext);
+		this.resolver.setPrefix(this.prefix);
+		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("template", null).block()).isNotNull();
+	}
+
+}

spring-boot/src/test/java/org/springframework/boot/web/reactive/result/view/MustacheViewTests.java

@@ -0,0 +1,66 @@
+/*
+ * 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.web.reactive.result.view;
+
+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 final String templateUrl = "classpath:/"
+			+ getClass().getPackage().getName().replace(".", "/") + "/template.html";
+
+	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(this.templateUrl);
+		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/src/test/java/org/springframework/boot/web/servlet/view/MustacheViewResolverTests.java

@@ -0,0 +1,69 @@
+/*
+ * 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.web.servlet.view;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.context.support.GenericApplicationContext;
+import org.springframework.mock.web.MockServletContext;
+import org.springframework.web.servlet.View;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link MustacheViewResolver}.
+ *
+ * @author Dave Syer
+ * @author Andy Wilkinson
+ */
+public class MustacheViewResolverTests {
+
+	private final String prefix = "classpath:/"
+			+ getClass().getPackage().getName().replace(".", "/") + "/";
+
+	private MustacheViewResolver resolver = new MustacheViewResolver();
+
+	@Before
+	public void init() {
+		GenericApplicationContext applicationContext = new GenericApplicationContext();
+		applicationContext.refresh();
+		this.resolver.setApplicationContext(applicationContext);
+		this.resolver.setServletContext(new MockServletContext());
+		this.resolver.setPrefix(this.prefix);
+		this.resolver.setSuffix(".html");
+	}
+
+	@Test
+	public void resolveNonExistent() throws Exception {
+		assertThat(this.resolver.resolveViewName("bar", null)).isNull();
+	}
+
+	@Test
+	public void resolveExisting() throws Exception {
+		assertThat(this.resolver.resolveViewName("template", null)).isNotNull();
+	}
+
+	@Test
+	public void setsContentType() throws Exception {
+		this.resolver.setContentType("application/octet-stream");
+		View view = this.resolver.resolveViewName("template", null);
+		assertThat(view.getContentType()).isEqualTo("application/octet-stream");
+
+	}
+
+}

spring-boot/src/test/java/org/springframework/boot/web/servlet/view/MustacheViewTests.java

@@ -0,0 +1,70 @@
+/*
+ * 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.web.servlet.view;
+
+import java.util.Collections;
+
+import com.samskivert.mustache.Mustache;
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.mock.web.MockServletContext;
+import org.springframework.web.context.WebApplicationContext;
+import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link MustacheView}.
+ *
+ * @author Dave Syer
+ */
+public class MustacheViewTests {
+
+	private final String templateUrl = "classpath:/"
+			+ getClass().getPackage().getName().replace(".", "/") + "/template.html";
+
+	private MockHttpServletRequest request = new MockHttpServletRequest();
+
+	private MockHttpServletResponse response = new MockHttpServletResponse();
+
+	private AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
+
+	@Before
+	public void init() {
+		this.context.refresh();
+		MockServletContext servletContext = new MockServletContext();
+		this.context.setServletContext(servletContext);
+		servletContext.setAttribute(
+				WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE,
+				this.context);
+	}
+
+	@Test
+	public void viewResolvesHandlebars() throws Exception {
+		MustacheView view = new MustacheView();
+		view.setCompiler(Mustache.compiler());
+		view.setUrl(this.templateUrl);
+		view.setApplicationContext(this.context);
+		view.render(Collections.singletonMap("World", "Spring"), this.request,
+				this.response);
+		assertThat(this.response.getContentAsString()).isEqualTo("Hello Spring");
+	}
+
+}

spring-boot/src/test/resources/org/springframework/boot/web/reactive/result/view/template.html

@@ -0,0 +1 @@
+Hello {{World}}

spring-boot/src/test/resources/org/springframework/boot/web/servlet/view/template.html

@@ -0,0 +1 @@
+Hello {{World}}