Java tutorial
/* * 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.esigate.esi; import java.io.IOException; import java.io.Writer; import java.util.Map; import java.util.regex.Pattern; import org.apache.http.HttpStatus; import org.esigate.HttpErrorPage; import org.esigate.Parameters; import org.esigate.Renderer; import org.esigate.impl.DriverRequest; import org.esigate.parser.Parser; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Retrieves a resource from the provider application and parses it to find ESI tags to be replaced by contents from * other applications. * * For more information about ESI language specification, see <a href="http://www.w3.org/TR/esi-lang">Edge Side * Include</a> * * @author Francois-Xavier Bonnet */ public class EsiRenderer implements Renderer, Appendable { private static final Logger LOG = LoggerFactory.getLogger(EsiRenderer.class); private static final Pattern PATTERN = Pattern.compile( "(<esi:\\w+((\\s+\\w+(\\s*=\\s*(?:\".*?\"|'.*?'|[^'\">\\s]+))?)+\\s*|\\s*)/?>)|(</esi:[^>]*>)"); private static final Pattern PATTERN_COMMENTS = Pattern.compile("(<!--esi)|(-->)"); private final Parser parser = new Parser(PATTERN, IncludeElement.TYPE, CommentElement.TYPE, RemoveElement.TYPE, VarsElement.TYPE, ChooseElement.TYPE, WhenElement.TYPE, OtherwiseElement.TYPE, TryElement.TYPE, AttemptElement.TYPE, ExceptElement.TYPE, InlineElement.TYPE, ReplaceElement.TYPE, FragmentElement.TYPE); private final Parser parserComments = new Parser(PATTERN_COMMENTS, Comment.TYPE); private Writer out; private Map<String, CharSequence> fragmentsToReplace; private final String page; private final String name; private boolean write = true; private boolean found = false; public String getName() { return name; } public void setWrite(boolean write) { this.write = write; } /** * Constructor used to render a complete page. */ public EsiRenderer() { page = null; name = null; } /** * Constructor used to render a fragment Retrieves a fragment inside a page.<br /> * * Extracts html between <code><esi:fragment name="myFragment"></code> and <code></esi:fragment></code> * * @param page * @param name */ public EsiRenderer(String page, String name) { this.page = page; this.name = name; write = false; } public Map<String, CharSequence> getFragmentsToReplace() { return fragmentsToReplace; } public void setFragmentsToReplace(Map<String, CharSequence> fragmentsToReplace) { this.fragmentsToReplace = fragmentsToReplace; } @Override public void render(DriverRequest originalRequest, String content, Writer outWriter) throws IOException, HttpErrorPage { if (name != null) { LOG.debug("Rendering fragment {} in page {}", name, page); } this.out = outWriter; if (content == null) { return; } // Pass 1. Remove esi comments StringBuilder contentWithoutComments = new StringBuilder(Parameters.DEFAULT_BUFFER_SIZE); parserComments.setHttpRequest(originalRequest); parserComments.parse(content, contentWithoutComments); // Pass 2. Process ESI parser.setHttpRequest(originalRequest); parser.parse(contentWithoutComments, this); if (name != null && !this.found) { throw new HttpErrorPage(HttpStatus.SC_BAD_GATEWAY, "Fragment " + name + " not found", "Fragment " + name + " not found"); } } @Override public Appendable append(CharSequence csq) throws IOException { if (write) { out.append(csq); } return this; } @Override public Appendable append(char c) throws IOException { if (write) { out.append(c); } return this; } @Override public Appendable append(CharSequence csq, int start, int end) throws IOException { if (write) { out.append(csq, start, end); } return this; } public boolean isWrite() { return this.write; } public void setFound(boolean found) { this.found = found; } }