com.googlecode.htmlcompressor.velocity.HtmlCompressorDirective Maven / Gradle / Ivy

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HtmlCompressor is a small, fast and very easy to use Java library that minifies given HTML or XML source by removing extra whitespaces, comments and other unneeded characters without breaking the content structure. As a result pages become smaller in size and load faster. A command-line version of the compressor is also available.
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/*
 *    Copyright 2009-2022 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 com.googlecode.htmlcompressor.velocity;

import com.google.javascript.jscomp.CompilationLevel;
import com.googlecode.htmlcompressor.compressor.ClosureJavaScriptCompressor;
import com.googlecode.htmlcompressor.compressor.HtmlCompressor;

import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;

import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.TemplateInitException;
import org.apache.velocity.runtime.RuntimeServices;
import org.apache.velocity.runtime.directive.Directive;
import org.apache.velocity.runtime.parser.node.Node;

/**
 * Velocity directive that compresses an HTML content within #compressHtml ... #end block. Compression parameters are
 * set by default (no JavaScript and CSS compression).
 *
 * @author Sergiy Kovalchuk
 *
 * @see HtmlCompressor
 */
public class HtmlCompressorDirective extends Directive {

    /** The Constant htmlCompressor. */
    private static final HtmlCompressor htmlCompressor = new HtmlCompressor();

    @Override
    public String getName() {
        return "compressHtml";
    }

    @Override
    public int getType() {
        return BLOCK;
    }

    @Override
    public void init(RuntimeServices rs, InternalContextAdapter context, Node node) throws TemplateInitException {
        super.init(rs, context, node);
        log = rs.getLog();

        boolean compressJavaScript = rs.getBoolean("userdirective.compressHtml.compressJavaScript", false);

        // set compressor properties
        htmlCompressor.setEnabled(rs.getBoolean("userdirective.compressHtml.enabled", true));
        htmlCompressor.setRemoveComments(rs.getBoolean("userdirective.compressHtml.removeComments", true));
        htmlCompressor.setRemoveMultiSpaces(rs.getBoolean("userdirective.compressHtml.removeMultiSpaces", true));
        htmlCompressor.setRemoveIntertagSpaces(rs.getBoolean("userdirective.compressHtml.removeIntertagSpaces", false));
        htmlCompressor.setRemoveQuotes(rs.getBoolean("userdirective.compressHtml.removeQuotes", false));
        htmlCompressor.setPreserveLineBreaks(rs.getBoolean("userdirective.compressHtml.preserveLineBreaks", false));
        htmlCompressor.setCompressJavaScript(compressJavaScript);
        htmlCompressor.setCompressCss(rs.getBoolean("userdirective.compressHtml.compressCss", false));
        htmlCompressor.setYuiJsNoMunge(rs.getBoolean("userdirective.compressHtml.yuiJsNoMunge", false));
        htmlCompressor.setYuiJsPreserveAllSemiColons(
                rs.getBoolean("userdirective.compressHtml.yuiJsPreserveAllSemiColons", false));
        htmlCompressor.setYuiJsLineBreak(rs.getInt("userdirective.compressHtml.yuiJsLineBreak", -1));
        htmlCompressor.setYuiCssLineBreak(rs.getInt("userdirective.compressHtml.yuiCssLineBreak", -1));
        htmlCompressor.setSimpleDoctype(rs.getBoolean("userdirective.compressHtml.simpleDoctype", false));
        htmlCompressor
                .setRemoveScriptAttributes(rs.getBoolean("userdirective.compressHtml.removeScriptAttributes", false));
        htmlCompressor
                .setRemoveStyleAttributes(rs.getBoolean("userdirective.compressHtml.removeStyleAttributes", false));
        htmlCompressor.setRemoveLinkAttributes(rs.getBoolean("userdirective.compressHtml.removeLinkAttributes", false));
        htmlCompressor.setRemoveFormAttributes(rs.getBoolean("userdirective.compressHtml.removeFormAttributes", false));
        htmlCompressor
                .setRemoveInputAttributes(rs.getBoolean("userdirective.compressHtml.removeInputAttributes", false));
        htmlCompressor
                .setSimpleBooleanAttributes(rs.getBoolean("userdirective.compressHtml.simpleBooleanAttributes", false));
        htmlCompressor.setRemoveJavaScriptProtocol(
                rs.getBoolean("userdirective.compressHtml.removeJavaScriptProtocol", false));
        htmlCompressor.setRemoveHttpProtocol(rs.getBoolean("userdirective.compressHtml.removeHttpProtocol", false));
        htmlCompressor.setRemoveHttpsProtocol(rs.getBoolean("userdirective.compressHtml.removeHttpsProtocol", false));

        if (compressJavaScript
                && rs.getString("userdirective.compressHtml.jsCompressor", HtmlCompressor.JS_COMPRESSOR_YUI)
                        .equalsIgnoreCase(HtmlCompressor.JS_COMPRESSOR_CLOSURE)) {
            String closureOptLevel = rs.getString("userdirective.compressHtml.closureOptLevel",
                    ClosureJavaScriptCompressor.COMPILATION_LEVEL_SIMPLE);

            ClosureJavaScriptCompressor closureCompressor = new ClosureJavaScriptCompressor();
            if (closureOptLevel.equalsIgnoreCase(ClosureJavaScriptCompressor.COMPILATION_LEVEL_ADVANCED)) {
                closureCompressor.setCompilationLevel(CompilationLevel.ADVANCED_OPTIMIZATIONS);
            } else if (closureOptLevel.equalsIgnoreCase(ClosureJavaScriptCompressor.COMPILATION_LEVEL_WHITESPACE)) {
                closureCompressor.setCompilationLevel(CompilationLevel.WHITESPACE_ONLY);
            } else {
                closureCompressor.setCompilationLevel(CompilationLevel.SIMPLE_OPTIMIZATIONS);
            }

            htmlCompressor.setJavaScriptCompressor(closureCompressor);
        }
    }

    @Override
    public boolean render(InternalContextAdapter context, Writer writer, Node node)
            throws IOException, MethodInvocationException {

        // render content
        StringWriter content = new StringWriter();
        node.jjtGetChild(0).render(context, content);

        // compress
        try {
            writer.write(htmlCompressor.compress(content.toString()));
        } catch (Exception e) {
            writer.write(content.toString());
            String msg = "Failed to compress content: " + content.toString();
            log.error(msg, e);
            throw new RuntimeException(msg, e);

        }
        return true;

    }

}