1 /**
2 * This file Copyright (c) 2015-2018 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.cms.util;
35
36 import info.magnolia.context.Context;
37
38 import java.io.IOException;
39 import java.io.Writer;
40 import java.util.Map;
41
42 import freemarker.cache.ClassTemplateLoader;
43 import freemarker.ext.beans.BeansWrapper;
44 import freemarker.ext.beans.MapModel;
45 import freemarker.ext.util.ModelFactory;
46 import freemarker.template.Configuration;
47 import freemarker.template.DefaultObjectWrapper;
48 import freemarker.template.ObjectWrapper;
49 import freemarker.template.TemplateException;
50 import freemarker.template.TemplateExceptionHandler;
51 import freemarker.template.TemplateModel;
52 import freemarker.template.TemplateModelException;
53 import freemarker.template.Version;
54
55 /**
56 * A simple utility to render FreeMarker templates for those rare cases in magnolia-core that can't be extracted (yet),
57 * and thus can't use {@link info.magnolia.freemarker.FreemarkerHelper} of magnolia-freemarker-support or
58 * {@link info.magnolia.rendering.engine.RenderingEngine} of magnolia-rendering.
59 *
60 * <p>It only loads templates on the classpath and, unlike FreemarkerHelper, is simply not configurable.
61 * It does not put _any_ variables in the templateContext, so you have to add them all explicitly.
62 * This class might disappear if its current uses can be split out of core.</p>
63 *
64 * @see <a href="https://wiki.magnolia-cms.com/display/DEV/Core+split">Core split</a>
65 * @see <a href="https://jira.magnolia-cms.com/browse/MAGNOLIA-6253">MAGNOLIA-6253</a>
66 */
67 public class SimpleFreemarkerHelper {
68
69 private final Configuration cfg;
70
71 /**
72 * If relative is true, templates will be loaded from the base class' package; if false, the paths will be relative to the root of the classpath.
73 */
74 public SimpleFreemarkerHelper(Class<?> baseClass, boolean relative) {
75 final String basePath = relative ? "" : "/"; // "" will start at current class, "/" will start at root
76 cfg = new Configuration(Configuration.VERSION_2_3_28);
77 cfg.setObjectWrapper(new SimpleFreemarkerHelperObjectWrapper(Configuration.VERSION_2_3_28));
78 cfg.setTemplateLoader(new ClassTemplateLoader(baseClass, basePath));
79 cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
80 cfg.setTagSyntax(Configuration.AUTO_DETECT_TAG_SYNTAX);
81 cfg.setDefaultEncoding("UTF-8");
82 cfg.setURLEscapingCharset("UTF-8");
83 }
84
85 public void render(String template, Map<String, ?> templateContext, Writer out) throws IOException, TemplateException {
86 cfg.getTemplate(template).process(templateContext, out);
87 }
88
89 /**
90 * Custom {@link DefaultObjectWrapper} that enables us to wrap the {@link Context} in order to make it "available"
91 * in templates.
92 */
93 private static class SimpleFreemarkerHelperObjectWrapper extends DefaultObjectWrapper {
94
95 public SimpleFreemarkerHelperObjectWrapper(Version version) {
96 super(version);
97 }
98
99 /**
100 * In order to use a custom model factory for {@link Context} we need to intercept the call to
101 * {@link DefaultObjectWrapper#wrap(Object)} because wrap would otherwise return a
102 * {@link freemarker.template.SimpleHash} for our context as it implements a {@link java.util.Map}.
103 *
104 * <p><i>Note</i>: we only want to use {@link #handleUnknownType(Object)} for our custom
105 * {@link ModelFactory ModelFactories} which is why we introduce/use {@link #getCustomModelFactory(Class)}.</p>
106 *
107 * <p>This behavior is heavily based on what happens in
108 * {@link info.magnolia.freemarker.models.MagnoliaObjectWrapper}.</p>
109 */
110 @Override
111 public TemplateModel wrap(Object obj) throws TemplateModelException {
112 if (obj != null) {
113 final Class<?> clazz = obj.getClass();
114 final ModelFactory modelFactory = getCustomModelFactory(clazz);
115 if (modelFactory != null) {
116 return handleUnknownType(obj);
117 }
118 }
119
120 return super.wrap(obj);
121 }
122
123 @Override
124 protected ModelFactory getModelFactory(Class clazz) {
125 final ModelFactory customModelFactory = getCustomModelFactory(clazz);
126 if (customModelFactory != null) {
127 return customModelFactory;
128 }
129 return super.getModelFactory(clazz);
130 }
131
132 /**
133 * This method returns any additional, custom {@link ModelFactory}. It allows us to bypass
134 * {@link DefaultObjectWrapper#wrap(Object)} *only* for our customs types returned here.
135 *
136 * @see #wrap(Object)
137 */
138 private ModelFactory getCustomModelFactory(Class clazz) {
139 if (Context.class.isAssignableFrom(clazz)) {
140 return CONTEXT_MODEL_FACTORY;
141 }
142 return null;
143 }
144
145 /**
146 * @see info.magnolia.freemarker.models.ContextModelFactory
147 */
148 static final ModelFactory CONTEXT_MODEL_FACTORY = new ModelFactory() {
149 @Override
150 public TemplateModel create(Object object, ObjectWrapper wrapper) {
151 return new MapModel((Map) object, (BeansWrapper) wrapper);
152 }
153 };
154
155 }
156 }