org.apache.shindig.gadgets.parse.nekohtml.NekoSimplifiedHtmlParser Maven / Gradle / Ivy

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Renders gadgets, provides the gadget metadata service, and serves all javascript required by the OpenSocial specification.
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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.shindig.gadgets.parse.nekohtml;

import org.apache.commons.lang3.StringUtils;
import org.apache.shindig.common.xml.DomUtil;
import org.apache.shindig.gadgets.GadgetException;
import org.apache.shindig.gadgets.parse.GadgetHtmlParser;
import org.apache.shindig.gadgets.parse.SocialDataTags;
import org.apache.xerces.xni.Augmentations;
import org.apache.xerces.xni.NamespaceContext;
import org.apache.xerces.xni.QName;
import org.apache.xerces.xni.XMLAttributes;
import org.apache.xerces.xni.XMLDocumentHandler;
import org.apache.xerces.xni.XMLLocator;
import org.apache.xerces.xni.XMLResourceIdentifier;
import org.apache.xerces.xni.XMLString;
import org.apache.xerces.xni.XNIException;
import org.apache.xerces.xni.parser.XMLDocumentSource;
import org.apache.xerces.xni.parser.XMLInputSource;

import com.google.inject.Inject;
import com.google.inject.Singleton;
import org.cyberneko.html.HTMLConfiguration;
import org.cyberneko.html.HTMLElements;
import org.cyberneko.html.HTMLEntities;
import org.cyberneko.html.HTMLScanner;
import org.cyberneko.html.HTMLTagBalancer;
import org.cyberneko.html.filters.NamespaceBinder;
import org.w3c.dom.DOMException;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentFragment;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import java.io.IOException;
import java.io.StringReader;
import java.util.Stack;

/**
 * Supports parsing of social markup blocks inside gadget content.
 * <script> elements with types of either "text/os-template"
 * or "text/os-data" are parsed inline into contained DOM hierarchies
 * for subsequent processing by the pipeline and template rewriters.
 */
@Singleton
public class NekoSimplifiedHtmlParser extends GadgetHtmlParser {

  private static final HTMLElements.Element OSML_TEMPLATE_ELEMENT;
  private static final HTMLElements.Element OSML_DATA_ELEMENT;

  static {
    HTMLElements.Element unknown = HTMLElements.getElement(HTMLElements.UNKNOWN);
    OSML_TEMPLATE_ELEMENT = new HTMLElements.Element(unknown.code,
        SocialDataTags.OSML_TEMPLATE_TAG, unknown.flags, HTMLElements.BODY, unknown.closes);
    // Passing parent in constructor is ignored.
    // Only allow template tags in BODY
    OSML_TEMPLATE_ELEMENT.parent =
        new HTMLElements.Element[]{HTMLElements.getElement(HTMLElements.BODY)};

    // data tags are allowed in BODY only, since Neko disallows HEAD elements from
    // having child elements of their own.
    OSML_DATA_ELEMENT = new HTMLElements.Element(unknown.code,
        SocialDataTags.OSML_TEMPLATE_TAG, unknown.flags, HTMLElements.BODY, unknown.closes);
    OSML_DATA_ELEMENT.parent = new HTMLElements.Element[]{
        HTMLElements.getElement(HTMLElements.BODY)};
  }


  @Inject
  public NekoSimplifiedHtmlParser(DOMImplementation documentFactory) {
    super(documentFactory);
  }

  @Override
  protected Document parseDomImpl(String source) throws GadgetException {
    DocumentHandler handler;

    HTMLConfiguration config = newConfiguration();
    try {
      handler = parseHtmlImpl(source, config, new NormalizingTagBalancer());
    } catch (IOException ioe) {
      return null;
    }

    Document document = handler.getDocument();
    document.appendChild(DomUtil.getFirstNamedChildNode(handler.getFragment(), "html"));
    fixNekoWeirdness(document);
    return document;
  }

  @Override
  protected DocumentFragment parseFragmentImpl(String source) throws GadgetException {
    DocumentHandler handler;

    HTMLConfiguration config = newConfiguration();
    // http://cyberneko.org/html/features/balance-tags/document-fragment
    // deprecated http://cyberneko.org/html/features/document-fragment
    config.setFeature("http://cyberneko.org/html/features/balance-tags/document-fragment", true);
    config.setProperty("http://cyberneko.org/html/properties/balance-tags/fragment-context-stack",
        new QName[]{new QName(null, "HTML", "HTML", null), new QName(null, "BODY", "BODY", null)});

    try {
      handler = parseHtmlImpl(source, config, new NekoPatchTagBalancer());
    } catch (IOException ioe) {
      return null;
    }

    return handler.getFragment();
  }

  /**
   * Parse HTML source.
   *
   * @return a document handler containing the parsed source
   */
  private DocumentHandler parseHtmlImpl(String source, HTMLConfiguration config,
      NormalizingTagBalancer tagBalancer)
      throws IOException {

    HTMLScanner htmlScanner = new HTMLScanner();
    tagBalancer.setScanner(htmlScanner);

    DocumentHandler handler = newDocumentHandler(source);

    NamespaceBinder namespaceBinder = new NamespaceBinder();
    namespaceBinder.setDocumentHandler(handler);
    namespaceBinder.setDocumentSource(tagBalancer);
    namespaceBinder.reset(config);
    tagBalancer.setDocumentHandler(namespaceBinder);

    // Order of filter is Scanner -> OSMLFilter -> Tag Balancer
    tagBalancer.setDocumentSource(htmlScanner);
    htmlScanner.setDocumentHandler(tagBalancer);

    tagBalancer.reset(config);
    htmlScanner.reset(config);

    XMLInputSource inputSource = new XMLInputSource(null, null, null);
    inputSource.setEncoding("UTF-8");
    inputSource.setCharacterStream(new StringReader(source));
    htmlScanner.setInputSource(inputSource);
    htmlScanner.scanDocument(true);
    return handler;
  }
  
  private void fixNekoWeirdness(Document document) {
    // Neko as of versions > 1.9.13 stuffs all leading  will break due to both
    //