tika-core/src/main/java/org/apache/tika/sax/XHTMLContentHandler.java - tika - Git at Google

 /*
  * 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.tika.sax;

 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;

 import org.apache.tika.metadata.Metadata;
 import org.apache.tika.metadata.TikaCoreProperties;
 import org.xml.sax.Attributes;
 import org.xml.sax.ContentHandler;
 import org.xml.sax.SAXException;
 import org.xml.sax.helpers.AttributesImpl;

 /**
  * Content handler decorator that simplifies the task of producing XHTML
  * events for Tika content parsers.
  */
 public class XHTMLContentHandler extends SafeContentHandler {

     /**
      * The XHTML namespace URI
      */
     public static final String XHTML = "http://www.w3.org/1999/xhtml";

     /**
      * The newline character that gets inserted after block elements.
      */
     private static final char[] NL = new char[] { '\n' };

     /**
      * The tab character gets inserted before table cells and list items.
      */
     private static final char[] TAB = new char[] { '\t' };

     /**
      * The elements that are in the <head> section.
      */
     private static final Set<String> HEAD =
         unmodifiableSet("title", "link", "base", "meta", "script");

     /**
      * The elements that are automatically emitted by lazyStartHead, so
      * skip them if they get sent to startElement/endElement by mistake.
      */
     private static final Set<String> AUTO =
         unmodifiableSet("head", "frameset");

     /**
      * The elements that get prepended with the {@link #TAB} character.
      */
     private static final Set<String> INDENT =
         unmodifiableSet("li", "dd", "dt", "td", "th", "frame");

     /**
      * The elements that get appended with the {@link #NL} character.
      */
     public static final Set<String> ENDLINE = unmodifiableSet(
             "p", "h1", "h2", "h3", "h4", "h5", "h6", "div", "ul", "ol", "dl",
             "pre", "hr", "blockquote", "address", "fieldset", "table", "form",
             "noscript", "li", "dt", "dd", "noframes", "br", "tr", "select",
             "option", "link", "script");

     private static final Attributes EMPTY_ATTRIBUTES = new AttributesImpl();

     private static Set<String> unmodifiableSet(String... elements) {
         return Collections.unmodifiableSet(
                 new HashSet<String>(Arrays.asList(elements)));
     }

     /**
      * Metadata associated with the document. Used to fill in the
      * &lt;head/&gt; section.
      */
     private final Metadata metadata;

     /**
      * Flag to indicate whether the document has been started.
      */
     private boolean documentStarted = false;

     /**
      * Flags to indicate whether the document head element has been started/ended.
      */
     private boolean headStarted = false;
     private boolean headEnded = false;
     private boolean useFrameset = false;

     public XHTMLContentHandler(ContentHandler handler, Metadata metadata) {
         super(handler);
         this.metadata = metadata;
     }

     /**
      * Starts an XHTML document by setting up the namespace mappings
      * when called for the first time.
      * The standard XHTML prefix is generated lazily when the first
      * element is started.
      */
     @Override
     public void startDocument() throws SAXException {
     	if(!documentStarted){
     		documentStarted = true;
             super.startDocument();
             startPrefixMapping("", XHTML);
     	}
     }

     /**
      * Generates the following XHTML prefix when called for the first time:
      * <pre>
      * &lt;html&gt;
      *   &lt;head&gt;
      *     &lt;title&gt;...&lt;/title&gt;
      *   &lt;/head&gt;
      *   &lt;body&gt;
      * </pre>
      */
     private void lazyStartHead() throws SAXException {
         if (!headStarted) {
             headStarted = true;

             // Call directly, so we don't go through our startElement(), which will
             // ignore these elements.
             AttributesImpl htmlAttrs = new AttributesImpl();
             String lang = metadata.get(Metadata.CONTENT_LANGUAGE);
             if (lang != null) {
                 htmlAttrs.addAttribute("", "lang", "lang", "CDATA", lang);
             }
             super.startElement(XHTML, "html", "html", htmlAttrs);
             newline();
             super.startElement(XHTML, "head", "head", EMPTY_ATTRIBUTES);
             newline();
         }
     }

     /**
      * Generates the following XHTML prefix when called for the first time:
      * <pre>
      * &lt;html&gt;
      *   &lt;head&gt;
      *     &lt;title&gt;...&lt;/title&gt;
      *   &lt;/head&gt;
      *   &lt;body&gt; (or &lt;frameset&gt;
      * </pre>
      */
     private void lazyEndHead(boolean isFrameset) throws SAXException {
         lazyStartHead();

         if (!headEnded) {
             headEnded = true;
             useFrameset = isFrameset;

             // TIKA-478: Emit all metadata values (other than title). We have to call
             // startElement() and characters() directly to avoid recursive problems.
             for (String name : metadata.names()) {
                 if (name.equals("title")) {
                     continue;
                 }

                 for (String value : metadata.getValues(name)) {
                     // Putting null values into attributes causes problems, but is
                     // allowed by Metadata, so guard against that.
                     if (value != null) {
                         AttributesImpl attributes = new AttributesImpl();
                         attributes.addAttribute("", "name", "name", "CDATA", name);
                         attributes.addAttribute("", "content", "content", "CDATA", value);
                         super.startElement(XHTML, "meta", "meta", attributes);
                         super.endElement(XHTML, "meta", "meta");
                         newline();
                     }
                 }
             }

             super.startElement(XHTML, "title", "title", EMPTY_ATTRIBUTES);
             String title = metadata.get(TikaCoreProperties.TITLE);
             if (title != null && title.length() > 0) {
                 char[] titleChars = title.toCharArray();
                 super.characters(titleChars, 0, titleChars.length);
             } else {
                 // TIKA-725: Prefer <title></title> over <title/>
                 super.characters(new char[0], 0, 0);
             }
             super.endElement(XHTML, "title", "title");
             newline();

             super.endElement(XHTML, "head", "head");
             newline();

             if (useFrameset) {
                 super.startElement(XHTML, "frameset", "frameset", EMPTY_ATTRIBUTES);
             } else {
                 super.startElement(XHTML, "body", "body", EMPTY_ATTRIBUTES);
             }
         }
     }

     /**
      * Ends the XHTML document by writing the following footer and
      * clearing the namespace mappings:
      * <pre>
      *   &lt;/body&gt;
      * &lt;/html&gt;
      * </pre>
      */
     @Override
     public void endDocument() throws SAXException {
         lazyEndHead(useFrameset);

         if (useFrameset) {
             super.endElement(XHTML, "frameset", "frameset");
         } else {
             super.endElement(XHTML, "body", "body");
         }

         super.endElement(XHTML, "html", "html");

         endPrefixMapping("");
         super.endDocument();
     }

     /**
      * Starts the given element. Table cells and list items are automatically
      * indented by emitting a tab character as ignorable whitespace.
      */
     @Override
     public void startElement(
             String uri, String local, String name, Attributes attributes)
             throws SAXException {

         if (name.equals("frameset")) {
             lazyEndHead(true);
         } else if (!AUTO.contains(name)) {
             if (HEAD.contains(name)) {
                 lazyStartHead();
             } else {
                 lazyEndHead(false);
             }

             if (XHTML.equals(uri) && INDENT.contains(name)) {
                 ignorableWhitespace(TAB, 0, TAB.length);
             }

             super.startElement(uri, local, name, attributes);
         }
     }

     /**
      * Ends the given element. Block elements are automatically followed
      * by a newline character.
      */
     @Override
     public void endElement(String uri, String local, String name) throws SAXException {
         if (!AUTO.contains(name)) {
             super.endElement(uri, local, name);
             if (XHTML.equals(uri) && ENDLINE.contains(name)) {
                 newline();
             }
         }
     }

     /**
      * @see <a href="https://issues.apache.org/jira/browse/TIKA-210">TIKA-210</a>
      */
     @Override
     public void characters(char[] ch, int start, int length) throws SAXException {
         lazyEndHead(useFrameset);
         super.characters(ch, start, length);
     }

     //------------------------------------------< public convenience methods >

     public void startElement(String name) throws SAXException {
         startElement(XHTML, name, name, EMPTY_ATTRIBUTES);
     }

     public void startElement(String name, String attribute, String value)
             throws SAXException {
         AttributesImpl attributes = new AttributesImpl();
         attributes.addAttribute("", attribute, attribute, "CDATA", value);
         startElement(XHTML, name, name, attributes);
     }

     public void startElement(String name, AttributesImpl attributes)
             throws SAXException {
         startElement(XHTML, name, name, attributes);
     }

     public void endElement(String name) throws SAXException {
         endElement(XHTML, name, name);
     }

     public void characters(String characters) throws SAXException {
         if (characters != null && characters.length() > 0) {
             characters(characters.toCharArray(), 0, characters.length());
         }
     }

     public void newline() throws SAXException {
         ignorableWhitespace(NL, 0, NL.length);
     }

     /**
      * Emits an XHTML element with the given text content. If the given
      * text value is null or empty, then the element is not written.
      *
      * @param name XHTML element name
      * @param value element value, possibly <code>null</code>
      * @throws SAXException if the content element could not be written
      */
     public void element(String name, String value) throws SAXException {
         if (value != null && value.length() > 0) {
             startElement(name);
             characters(value);
             endElement(name);
         }
     }

     @Override
     protected boolean isInvalid(int ch) {
         if(super.isInvalid(ch)) return true;
         // These control chars are  invalid in XHTML.
         if(0x7F <= ch && ch <=0x9F) {
             return true;
         }
         return false;
     }

 }
	/*
	* 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.tika.sax;

	import java.util.Arrays;
	import java.util.Collections;
	import java.util.HashSet;
	import java.util.Set;

	import org.apache.tika.metadata.Metadata;
	import org.apache.tika.metadata.TikaCoreProperties;
	import org.xml.sax.Attributes;
	import org.xml.sax.ContentHandler;
	import org.xml.sax.SAXException;
	import org.xml.sax.helpers.AttributesImpl;

	/**
	* Content handler decorator that simplifies the task of producing XHTML
	* events for Tika content parsers.
	*/
	public class XHTMLContentHandler extends SafeContentHandler {

	/**
	* The XHTML namespace URI
	*/
	public static final String XHTML = "http://www.w3.org/1999/xhtml";

	/**
	* The newline character that gets inserted after block elements.
	*/
	private static final char[] NL = new char[] { '\n' };

	/**
	* The tab character gets inserted before table cells and list items.
	*/
	private static final char[] TAB = new char[] { '\t' };

	/**
	* The elements that are in the <head> section.
	*/
	private static final Set<String> HEAD =
	unmodifiableSet("title", "link", "base", "meta", "script");

	/**
	* The elements that are automatically emitted by lazyStartHead, so
	* skip them if they get sent to startElement/endElement by mistake.
	*/
	private static final Set<String> AUTO =
	unmodifiableSet("head", "frameset");

	/**
	* The elements that get prepended with the {@link #TAB} character.
	*/
	private static final Set<String> INDENT =
	unmodifiableSet("li", "dd", "dt", "td", "th", "frame");

	/**
	* The elements that get appended with the {@link #NL} character.
	*/
	public static final Set<String> ENDLINE = unmodifiableSet(
	"p", "h1", "h2", "h3", "h4", "h5", "h6", "div", "ul", "ol", "dl",
	"pre", "hr", "blockquote", "address", "fieldset", "table", "form",
	"noscript", "li", "dt", "dd", "noframes", "br", "tr", "select",
	"option", "link", "script");

	private static final Attributes EMPTY_ATTRIBUTES = new AttributesImpl();

	private static Set<String> unmodifiableSet(String... elements) {
	return Collections.unmodifiableSet(
	new HashSet<String>(Arrays.asList(elements)));
	}

	/**
	* Metadata associated with the document. Used to fill in the
	* <head/> section.
	*/
	private final Metadata metadata;

	/**
	* Flag to indicate whether the document has been started.
	*/
	private boolean documentStarted = false;

	/**
	* Flags to indicate whether the document head element has been started/ended.
	*/
	private boolean headStarted = false;
	private boolean headEnded = false;
	private boolean useFrameset = false;

	public XHTMLContentHandler(ContentHandler handler, Metadata metadata) {
	super(handler);
	this.metadata = metadata;
	}

	/**
	* Starts an XHTML document by setting up the namespace mappings
	* when called for the first time.
	* The standard XHTML prefix is generated lazily when the first
	* element is started.
	*/
	@Override
	public void startDocument() throws SAXException {
	if(!documentStarted){
	documentStarted = true;
	super.startDocument();
	startPrefixMapping("", XHTML);
	}
	}

	/**
	* Generates the following XHTML prefix when called for the first time:
	* <pre>
	* <html>
	* <head>
	* <title>...</title>
	* </head>
	* <body>
	* </pre>
	*/
	private void lazyStartHead() throws SAXException {
	if (!headStarted) {
	headStarted = true;

	// Call directly, so we don't go through our startElement(), which will
	// ignore these elements.
	AttributesImpl htmlAttrs = new AttributesImpl();
	String lang = metadata.get(Metadata.CONTENT_LANGUAGE);
	if (lang != null) {
	htmlAttrs.addAttribute("", "lang", "lang", "CDATA", lang);
	}
	super.startElement(XHTML, "html", "html", htmlAttrs);
	newline();
	super.startElement(XHTML, "head", "head", EMPTY_ATTRIBUTES);
	newline();
	}
	}

	/**
	* Generates the following XHTML prefix when called for the first time:
	* <pre>
	* <html>
	* <head>
	* <title>...</title>
	* </head>
	* <body> (or <frameset>
	* </pre>
	*/
	private void lazyEndHead(boolean isFrameset) throws SAXException {
	lazyStartHead();

	if (!headEnded) {
	headEnded = true;
	useFrameset = isFrameset;

	// TIKA-478: Emit all metadata values (other than title). We have to call
	// startElement() and characters() directly to avoid recursive problems.
	for (String name : metadata.names()) {
	if (name.equals("title")) {
	continue;
	}

	for (String value : metadata.getValues(name)) {
	// Putting null values into attributes causes problems, but is
	// allowed by Metadata, so guard against that.
	if (value != null) {
	AttributesImpl attributes = new AttributesImpl();
	attributes.addAttribute("", "name", "name", "CDATA", name);
	attributes.addAttribute("", "content", "content", "CDATA", value);
	super.startElement(XHTML, "meta", "meta", attributes);
	super.endElement(XHTML, "meta", "meta");
	newline();
	}
	}
	}

	super.startElement(XHTML, "title", "title", EMPTY_ATTRIBUTES);
	String title = metadata.get(TikaCoreProperties.TITLE);
	if (title != null && title.length() > 0) {
	char[] titleChars = title.toCharArray();
	super.characters(titleChars, 0, titleChars.length);
	} else {
	// TIKA-725: Prefer <title></title> over <title/>
	super.characters(new char[0], 0, 0);
	}
	super.endElement(XHTML, "title", "title");
	newline();

	super.endElement(XHTML, "head", "head");
	newline();

	if (useFrameset) {
	super.startElement(XHTML, "frameset", "frameset", EMPTY_ATTRIBUTES);
	} else {
	super.startElement(XHTML, "body", "body", EMPTY_ATTRIBUTES);
	}
	}
	}

	/**
	* Ends the XHTML document by writing the following footer and
	* clearing the namespace mappings:
	* <pre>
	* </body>
	* </html>
	* </pre>
	*/
	@Override
	public void endDocument() throws SAXException {
	lazyEndHead(useFrameset);

	if (useFrameset) {
	super.endElement(XHTML, "frameset", "frameset");
	} else {
	super.endElement(XHTML, "body", "body");
	}

	super.endElement(XHTML, "html", "html");

	endPrefixMapping("");
	super.endDocument();
	}

	/**
	* Starts the given element. Table cells and list items are automatically
	* indented by emitting a tab character as ignorable whitespace.
	*/
	@Override
	public void startElement(
	String uri, String local, String name, Attributes attributes)
	throws SAXException {

	if (name.equals("frameset")) {
	lazyEndHead(true);
	} else if (!AUTO.contains(name)) {
	if (HEAD.contains(name)) {
	lazyStartHead();
	} else {
	lazyEndHead(false);
	}

	if (XHTML.equals(uri) && INDENT.contains(name)) {
	ignorableWhitespace(TAB, 0, TAB.length);
	}

	super.startElement(uri, local, name, attributes);
	}
	}

	/**
	* Ends the given element. Block elements are automatically followed
	* by a newline character.
	*/
	@Override
	public void endElement(String uri, String local, String name) throws SAXException {
	if (!AUTO.contains(name)) {
	super.endElement(uri, local, name);
	if (XHTML.equals(uri) && ENDLINE.contains(name)) {
	newline();
	}
	}
	}

	/**
	* @see <a href="https://issues.apache.org/jira/browse/TIKA-210">TIKA-210</a>
	*/
	@Override
	public void characters(char[] ch, int start, int length) throws SAXException {
	lazyEndHead(useFrameset);
	super.characters(ch, start, length);
	}

	//------------------------------------------< public convenience methods >

	public void startElement(String name) throws SAXException {
	startElement(XHTML, name, name, EMPTY_ATTRIBUTES);
	}

	public void startElement(String name, String attribute, String value)
	throws SAXException {
	AttributesImpl attributes = new AttributesImpl();
	attributes.addAttribute("", attribute, attribute, "CDATA", value);
	startElement(XHTML, name, name, attributes);
	}

	public void startElement(String name, AttributesImpl attributes)
	throws SAXException {
	startElement(XHTML, name, name, attributes);
	}

	public void endElement(String name) throws SAXException {
	endElement(XHTML, name, name);
	}

	public void characters(String characters) throws SAXException {
	if (characters != null && characters.length() > 0) {
	characters(characters.toCharArray(), 0, characters.length());
	}
	}

	public void newline() throws SAXException {
	ignorableWhitespace(NL, 0, NL.length);
	}

	/**
	* Emits an XHTML element with the given text content. If the given
	* text value is null or empty, then the element is not written.
	*
	* @param name XHTML element name
	* @param value element value, possibly <code>null</code>
	* @throws SAXException if the content element could not be written
	*/
	public void element(String name, String value) throws SAXException {
	if (value != null && value.length() > 0) {
	startElement(name);
	characters(value);
	endElement(name);
	}
	}

	@Override
	protected boolean isInvalid(int ch) {
	if(super.isInvalid(ch)) return true;
	// These control chars are invalid in XHTML.
	if(0x7F <= ch && ch <=0x9F) {
	return true;
	}
	return false;
	}

	}