Add Groovy template engine support for Spring MVC apps

Default suffix .tpl. If groovy-templates is on the classpath user
can now add templates and get them rendered and resolved in an MVC
app.

TODO: Macro helpers for message rendering etc.

See gh-878

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateAutoConfigurationTests.java

@@ -0,0 +1,194 @@
+/*
+ * Copyright 2012-2014 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.groovy.template;
+
+import groovy.text.TemplateEngine;
+
+import java.io.File;
+import java.io.StringWriter;
+import java.io.Writer;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Locale;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.beans.factory.BeanCreationException;
+import org.springframework.boot.autoconfigure.groovy.template.web.GroovyTemplateViewResolver;
+import org.springframework.boot.test.EnvironmentTestUtils;
+import org.springframework.context.i18n.LocaleContextHolder;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.mock.web.MockServletContext;
+import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
+import org.springframework.web.servlet.View;
+import org.springframework.web.servlet.support.RequestContext;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Tests for GroovyTemplateAutoConfiguration.
+ * 
+ * @author Dave Syer
+ */
+public class GroovyTemplateAutoConfigurationTests {
+
+	private AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
+
+	@Before
+	public void setupContext() {
+		this.context.setServletContext(new MockServletContext());
+	}
+
+	@After
+	public void close() {
+		LocaleContextHolder.resetLocaleContext();
+		if (this.context != null) {
+			this.context.close();
+		}
+	}
+
+	@Test
+	public void defaultConfiguration() {
+		registerAndRefreshContext();
+		assertThat(this.context.getBean(GroovyTemplateViewResolver.class), notNullValue());
+	}
+
+	@Test(expected = BeanCreationException.class)
+	public void nonExistentTemplateLocation() {
+		registerAndRefreshContext("spring.groovy.template.prefix:"
+				+ "classpath:/does-not-exist/");
+	}
+
+	@Test
+	public void emptyTemplateLocation() {
+		new File("target/test-classes/templates/empty-directory").mkdir();
+		registerAndRefreshContext("spring.groovy.template.prefix:"
+				+ "classpath:/templates/empty-directory/");
+	}
+
+	@Test
+	public void defaultViewResolution() throws Exception {
+		registerAndRefreshContext();
+		MockHttpServletResponse response = render("home");
+		String result = response.getContentAsString();
+		assertThat(result, containsString("home"));
+		assertThat(response.getContentType(), equalTo("text/html;charset=UTF-8"));
+	}
+
+	@Test
+	public void includesViewResolution() throws Exception {
+		registerAndRefreshContext();
+		MockHttpServletResponse response = render("includes");
+		String result = response.getContentAsString();
+		assertThat(result, containsString("here"));
+		assertThat(response.getContentType(), equalTo("text/html;charset=UTF-8"));
+	}
+
+	@Test
+	public void localeViewResolution() throws Exception {
+		LocaleContextHolder.setLocale(Locale.FRENCH);
+		registerAndRefreshContext();
+		MockHttpServletResponse response = render("includes", Locale.FRENCH);
+		String result = response.getContentAsString();
+		assertThat(result, containsString("voila"));
+		assertThat(response.getContentType(), equalTo("text/html;charset=UTF-8"));
+	}
+
+	@Test
+	public void customContentType() throws Exception {
+		registerAndRefreshContext("spring.groovy.template.contentType:application/json");
+		MockHttpServletResponse response = render("home");
+		String result = response.getContentAsString();
+		assertThat(result, containsString("home"));
+		assertThat(response.getContentType(), equalTo("application/json;charset=UTF-8"));
+	}
+
+	@Test
+	public void customPrefix() throws Exception {
+		registerAndRefreshContext("spring.groovy.template.prefix:classpath:/templates/prefix/");
+		MockHttpServletResponse response = render("prefixed");
+		String result = response.getContentAsString();
+		assertThat(result, containsString("prefixed"));
+	}
+
+	@Test
+	public void customSuffix() throws Exception {
+		registerAndRefreshContext("spring.groovy.template.suffix:.groovytemplate");
+		MockHttpServletResponse response = render("suffixed");
+		String result = response.getContentAsString();
+		assertThat(result, containsString("suffixed"));
+	}
+
+	@Test
+	public void customTemplateLoaderPath() throws Exception {
+		registerAndRefreshContext("spring.groovy.template.prefix:classpath:/custom-templates/");
+		MockHttpServletResponse response = render("custom");
+		String result = response.getContentAsString();
+		assertThat(result, containsString("custom"));
+	}
+
+	@Test
+	public void disableCache() {
+		registerAndRefreshContext("spring.groovy.template.cache:false");
+		assertThat(
+				this.context.getBean(GroovyTemplateViewResolver.class).getCacheLimit(),
+				equalTo(0));
+	}
+
+	@Test
+	public void renderTemplate() throws Exception {
+		registerAndRefreshContext();
+		TemplateEngine engine = this.context.getBean(TemplateEngine.class);
+		Writer writer = new StringWriter();
+		engine.createTemplate(new ClassPathResource("templates/message.tpl").getFile())
+				.make(new HashMap<String, Object>(Collections.singletonMap("greeting",
+						"Hello World"))).writeTo(writer);
+		assertThat(writer.toString(), containsString("Hello World"));
+	}
+
+	private void registerAndRefreshContext(String... env) {
+		EnvironmentTestUtils.addEnvironment(this.context, env);
+		this.context.register(GroovyTemplateAutoConfiguration.class);
+		this.context.refresh();
+	}
+
+	private MockHttpServletResponse render(String viewName) throws Exception {
+		return render(viewName, Locale.UK);
+	}
+
+	private MockHttpServletResponse render(String viewName, Locale locale)
+			throws Exception {
+		GroovyTemplateViewResolver resolver = this.context
+				.getBean(GroovyTemplateViewResolver.class);
+		View view = resolver.resolveViewName(viewName, locale);
+		assertThat(view, notNullValue());
+		HttpServletRequest request = new MockHttpServletRequest();
+		request.setAttribute(RequestContext.WEB_APPLICATION_CONTEXT_ATTRIBUTE,
+				this.context);
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		view.render(null, request, response);
+		return response;
+	}
+}

spring-boot-autoconfigure/src/test/resources/custom-templates/custom.tpl

@@ -0,0 +1 @@
+yield "custom"

spring-boot-autoconfigure/src/test/resources/templates/home.tpl

@@ -0,0 +1 @@
+yield "home"

spring-boot-autoconfigure/src/test/resources/templates/included.tpl

@@ -0,0 +1 @@
+yield "here"

spring-boot-autoconfigure/src/test/resources/templates/included_fr.tpl

@@ -0,0 +1 @@
+yield "voila"

spring-boot-autoconfigure/src/test/resources/templates/includes.tpl

@@ -0,0 +1,2 @@
+yield "include"
+include template: "included.tpl"

spring-boot-autoconfigure/src/test/resources/templates/message.tpl

@@ -0,0 +1 @@
+yield "Message: ${greeting}"

spring-boot-autoconfigure/src/test/resources/templates/prefix/prefixed.tpl

@@ -0,0 +1 @@
+yield "prefixed"

spring-boot-autoconfigure/src/test/resources/templates/suffixed.groovytemplate

@@ -0,0 +1,3 @@
+yield """
+suffixed
+"""