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A minimalist Maven plugin for static site generation
/*
* Copyright © 2019-2020 Metreeca srl
*
* 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.metreeca.mark.steps;
import com.metreeca.mark.Mark;
import com.vladsch.flexmark.util.sequence.SubSequence;
import de.neuland.pug4j.PugConfiguration;
import de.neuland.pug4j.exceptions.ExpressionException;
import de.neuland.pug4j.expression.ExpressionHandler;
import de.neuland.pug4j.model.PugModel;
import de.neuland.pug4j.template.TemplateLoader;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import static java.nio.charset.StandardCharsets.UTF_8;
public final class Pug {
private static final Pattern ExpressionPattern=Pattern.compile("\\\\?\\$\\{([.\\w]+)}");
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
private final PugConfiguration pug;
public Pug(final Mark mark) {
if ( mark == null ) {
throw new NullPointerException("null mark");
}
this.pug=new PugConfiguration();
pug.setPrettyPrint(false); // minified output
pug.setTemplateLoader(new TemplateLoader() {
@Override public long getLastModified(final String name) throws IOException {
return Files.getLastModifiedTime(mark.layout(name)).toMillis();
}
@Override public Reader getReader(final String name) throws IOException {
return Files.newBufferedReader(mark.layout(name), UTF_8);
}
@Override public String getExtension() {
return "pug";
}
@Override public String getBase() {
return "";
}
});
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
public Path write(final Path target, final Map model) {
if ( target == null ) {
throw new NullPointerException("null target");
}
if ( model == null ) {
throw new NullPointerException("null model");
}
final String layout=layout(model).toString();
try ( final BufferedWriter writer=Files.newBufferedWriter(target, UTF_8) ) {
pug.renderTemplate(pug.getTemplate(layout), set(model), writer);
} catch ( final IOException e ) {
throw new UncheckedIOException(e);
}
return target;
}
//// !!! refactor //////////////////////////////////////////////////////////////////////////////////////////////////
private Object layout(final Map model) {
final Object page=model.get("page");
if ( page instanceof Map ) {
return ((Map)page).getOrDefault("layout", "");
} else {
return "";
}
}
private Map set(final Map model) {
final Map _model=new HashMap<>(model);
_model.computeIfPresent("page", (p, page) -> {
if ( page instanceof Map ) {
final Map _page=new HashMap<>((Map)page);
_page.computeIfPresent("body", (b, body) -> evaluate(body.toString(), model));
return _page;
} else {
return page;
}
});
return _model;
}
//// Variable Replacement //////////////////////////////////////////////////////////////////////////////////////////
private String evaluate(final CharSequence body, final Map model) {
final Matcher matcher=ExpressionPattern.matcher(body);
final ExpressionHandler handler=pug.getExpressionHandler();
final StringBuilder builder=new StringBuilder(body.length());
int last=0;
while ( matcher.find() ) {
final int start=matcher.start();
final int end=matcher.end();
builder.append(body.subSequence(last, start)); // leading text
if ( matcher.group().charAt(0) == '\\' ) { // escaped
builder.append(body.subSequence(start+1, end)); // expression text
} else {
try {
final PugModel bindings=new PugModel(pug.getSharedVariables());
bindings.putAll(model);
builder.append(SubSequence.of(handler.evaluateStringExpression(
matcher.group(1), bindings // expression value
)));
} catch ( final ExpressionException e ) {
throw new RuntimeException(e);
}
}
last=end;
}
builder.append(body.subSequence(last, body.length())); // trailing text
return builder.toString();
}
}