gateway-provider-rewrite/src/main/java/org/apache/knox/gateway/filter/rewrite/impl/html/HtmlFilterReaderBase.java - knox - 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.knox.gateway.filter.rewrite.impl.html;

 import net.htmlparser.jericho.Attribute;
 import net.htmlparser.jericho.Attributes;
 import net.htmlparser.jericho.EndTag;
 import net.htmlparser.jericho.Segment;
 import net.htmlparser.jericho.StartTag;
 import net.htmlparser.jericho.StreamedSource;
 import net.htmlparser.jericho.Tag;
 import org.apache.knox.gateway.filter.rewrite.api.UrlRewriteFilterApplyDescriptor;
 import org.apache.knox.gateway.filter.rewrite.api.UrlRewriteFilterContentDescriptor;
 import org.apache.knox.gateway.filter.rewrite.api.UrlRewriteFilterPathDescriptor;
 import org.apache.knox.gateway.filter.rewrite.i18n.UrlRewriteMessages;
 import org.apache.knox.gateway.filter.rewrite.impl.UrlRewriteFilterReader;
 import org.apache.knox.gateway.filter.rewrite.impl.UrlRewriteUtil;
 import org.apache.knox.gateway.i18n.messages.MessagesFactory;

 import javax.xml.namespace.QName;
 import javax.xml.parsers.ParserConfigurationException;
 import java.io.IOException;
 import java.io.Reader;
 import java.io.StringWriter;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Stack;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;

 public abstract class HtmlFilterReaderBase extends Reader implements
     UrlRewriteFilterReader {

   private static final String SCRIPTTAG = "script";
   private static final UrlRewriteFilterPathDescriptor.Compiler<Pattern> REGEX_COMPILER = new RegexCompiler();

   private static final UrlRewriteMessages LOG = MessagesFactory.get( UrlRewriteMessages.class );

   private Stack<Level> stack;
   private Reader reader;
   private StreamedSource parser;
   private Iterator<Segment> iterator;
   private int lastSegEnd;
   private int offset;
   private StringWriter writer;
   private StringBuffer buffer;
   private UrlRewriteFilterContentDescriptor config;

   protected HtmlFilterReaderBase( Reader reader ) throws IOException, ParserConfigurationException {
     this.reader = reader;
     stack = new Stack<>();
     parser = new StreamedSource( reader );
     iterator = parser.iterator();
     writer = new StringWriter();
     buffer = writer.getBuffer();
     offset = 0;
   }

   protected HtmlFilterReaderBase( Reader reader, UrlRewriteFilterContentDescriptor config ) throws IOException, ParserConfigurationException {
     this(reader);
     this.config = config;
   }

   protected abstract String filterAttribute( QName elementName, QName attributeName, String attributeValue, String ruleName );

   protected abstract String filterText( QName elementName, String text, String ruleName );

   @Override
   public int read( char[] destBuffer, int destOffset, int destCount ) throws IOException {
     int count = 0;
     int available = buffer.length() - offset;

     if( available == 0 ) {
       if( iterator.hasNext() ) {
         iterator.next();
         processCurrentSegment();
         available = buffer.length() - offset;
       } else {
         count = -1;
       }
     }

     if( available > 0 ) {
       count = Math.min( destCount, available );
       buffer.getChars( offset, offset + count, destBuffer, destOffset );
       offset += count;
       if( offset == buffer.length() ) {
         offset = 0;
         buffer.setLength( 0 );
       }
     }

     return count;
   }

   private void processCurrentSegment() {
     Segment segment = parser.getCurrentSegment();
     // If this tag is inside the previous tag (e.g. a server tag) then
     // ignore it as it was already output along with the previous tag.
     if( segment.getEnd() <= lastSegEnd ) {
       return;
     }
     lastSegEnd = segment.getEnd();
     if( segment instanceof Tag ) {
       if( segment instanceof StartTag ) {
         processStartTag( (StartTag)segment );
       } else if ( segment instanceof EndTag ) {
         processEndTag( (EndTag)segment );
       } else {
         writer.write( segment.toString() );
       }
     } else {
       processText( segment );
     }
   }

   private void processEndTag( EndTag tag ) {
     while( !stack.isEmpty() ) {
       Level popped = stack.pop();
       if( popped.getTag().getName().equalsIgnoreCase( tag.getName() ) ) {
         break;
       }
     }
     writer.write( tag.toString() );
   }

   private void processStartTag( StartTag tag ) {
     if( "<".equals( tag.getTagType().getStartDelimiter() ) ) {
       stack.push( new Level( tag ) );
       writer.write( "<" );
       writer.write( tag.getNameSegment().toString() );
       Attributes attributes = tag.getAttributes();
       if( !attributes.isEmpty() ) {
         for( Attribute attribute : attributes ) {
           processAttribute( attribute );
         }
       }
       if( tag.toString().trim().endsWith( "/>" ) || tag.isEmptyElementTag() ) {
         stack.pop();
         writer.write( "/>" );
       } else {
         writer.write( ">" );
       }
     } else {
       writer.write( tag.toString() );
     }
   }

   private void processAttribute( Attribute attribute ) {
     writer.write( " " );
     writer.write( attribute.getName() );
     if(attribute.hasValue()) {
       /*
        * non decoded value, return the raw value of the attribute as it appears
        * in the source document, without decoding, see KNOX-791.
        */
       String inputValue = attribute.getValueSegment().toString();
       String outputValue = inputValue;
       try {
         Level tag = stack.peek();
         String name = getRuleName(inputValue);
         outputValue = filterAttribute( tag.getQName(), tag.getQName( attribute.getName() ), inputValue, name );
         if( outputValue == null ) {
           outputValue = inputValue;
         }
       } catch ( Exception e ) {
         LOG.failedToFilterAttribute( attribute.getName(), e );
       }
       writer.write( "=" );
       writer.write( attribute.getQuoteChar() );
       writer.write( outputValue );
       writer.write( attribute.getQuoteChar() );
     }
   }

   private String getRuleName(String inputValue) {
     if( config != null && !config.getSelectors().isEmpty() ) {
       for( UrlRewriteFilterPathDescriptor selector : config.getSelectors() ) {
         if ( selector instanceof UrlRewriteFilterApplyDescriptor) {
           UrlRewriteFilterApplyDescriptor apply = (UrlRewriteFilterApplyDescriptor)selector;
           Matcher matcher = apply.compiledPath( REGEX_COMPILER ).matcher( inputValue );
             if (matcher.matches()) {
               return apply.rule();
             }
           }
         }
       }
       return null;
     }

   private void processText( Segment segment ) {
     String inputValue = segment.toString();
     String outputValue = inputValue;
     try {
       if( stack.isEmpty() ) {
         // This can happen for whitespace outside of the root element.
         //outputValue = filterText( null, inputValue );
       } else {
         String tagName = stack.peek().getTag().getName();
         if (SCRIPTTAG.equals(tagName) && config != null && !config.getSelectors().isEmpty() ) {
           // embedded javascript content
           outputValue = UrlRewriteUtil.filterJavaScript( inputValue, config, this, REGEX_COMPILER );
         } else {
           outputValue = filterText( stack.peek().getQName(), inputValue, getRuleName(inputValue) );
         }
       }
       if( outputValue == null ) {
         outputValue = inputValue;
       }
     } catch ( Exception e ) {
       LOG.failedToFilterValue( inputValue, null, e );
     }
     writer.write( outputValue );
   }

   @Override
   public void close() throws IOException {
     parser.close();
     reader.close();
     writer.close();
     stack.clear();
   }

   private static class Level {
     private StartTag tag;
     private QName name;
     private Map<String,String> namespaces;

     Level( StartTag tag ) {
       this.tag = tag;
       this.name = null;
       this.namespaces = null;
     }

     private StartTag getTag() {
       return tag;
     }

     private QName getQName() {
       if( name == null ) {
         name = getQName( tag.getName() );
       }
       return name;
     }

     private String getNamespace( String prefix ) {
       return getNamespaces().get( prefix );
     }

     private QName getQName( String name ) {
       String prefix;
       String local;
       int colon = ( name == null ? -1 : name.indexOf( ':' ) );
       if( colon < 0 ) {
         prefix = "";
         local = name;
       } else {
         prefix = name.substring( 0, colon );
         local = ( colon + 1 < name.length() ? name.substring( colon + 1 ) : "" );
       }
       String namespace = getNamespace( prefix );
       return new QName( namespace, local, prefix );
     }

     private Map<String,String> getNamespaces() {
       if( namespaces == null ) {
         namespaces = new HashMap<>();
         parseNamespaces();
       }
       return namespaces;
     }

     private void parseNamespaces() {
       Attributes attributes = tag.getAttributes();
       if( attributes != null ) {
         for( Attribute attribute : tag.getAttributes() ) {
           String name = attribute.getName();
           if( name.toLowerCase(Locale.ROOT).startsWith( "xmlns" ) ) {
             int colon = name.indexOf( ':', 5 );
             String prefix;
             if( colon <= 0 ) {
               prefix = "";
             } else {
               prefix = name.substring( colon );
             }
             namespaces.put( prefix, attribute.getValue() );
           }
         }
       }
     }

   }

 }
	/*
	* 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.knox.gateway.filter.rewrite.impl.html;

	import net.htmlparser.jericho.Attribute;
	import net.htmlparser.jericho.Attributes;
	import net.htmlparser.jericho.EndTag;
	import net.htmlparser.jericho.Segment;
	import net.htmlparser.jericho.StartTag;
	import net.htmlparser.jericho.StreamedSource;
	import net.htmlparser.jericho.Tag;
	import org.apache.knox.gateway.filter.rewrite.api.UrlRewriteFilterApplyDescriptor;
	import org.apache.knox.gateway.filter.rewrite.api.UrlRewriteFilterContentDescriptor;
	import org.apache.knox.gateway.filter.rewrite.api.UrlRewriteFilterPathDescriptor;
	import org.apache.knox.gateway.filter.rewrite.i18n.UrlRewriteMessages;
	import org.apache.knox.gateway.filter.rewrite.impl.UrlRewriteFilterReader;
	import org.apache.knox.gateway.filter.rewrite.impl.UrlRewriteUtil;
	import org.apache.knox.gateway.i18n.messages.MessagesFactory;

	import javax.xml.namespace.QName;
	import javax.xml.parsers.ParserConfigurationException;
	import java.io.IOException;
	import java.io.Reader;
	import java.io.StringWriter;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.Locale;
	import java.util.Map;
	import java.util.Stack;
	import java.util.regex.Matcher;
	import java.util.regex.Pattern;

	public abstract class HtmlFilterReaderBase extends Reader implements
	UrlRewriteFilterReader {

	private static final String SCRIPTTAG = "script";
	private static final UrlRewriteFilterPathDescriptor.Compiler<Pattern> REGEX_COMPILER = new RegexCompiler();

	private static final UrlRewriteMessages LOG = MessagesFactory.get( UrlRewriteMessages.class );

	private Stack<Level> stack;
	private Reader reader;
	private StreamedSource parser;
	private Iterator<Segment> iterator;
	private int lastSegEnd;
	private int offset;
	private StringWriter writer;
	private StringBuffer buffer;
	private UrlRewriteFilterContentDescriptor config;

	protected HtmlFilterReaderBase( Reader reader ) throws IOException, ParserConfigurationException {
	this.reader = reader;
	stack = new Stack<>();
	parser = new StreamedSource( reader );
	iterator = parser.iterator();
	writer = new StringWriter();
	buffer = writer.getBuffer();
	offset = 0;
	}

	protected HtmlFilterReaderBase( Reader reader, UrlRewriteFilterContentDescriptor config ) throws IOException, ParserConfigurationException {
	this(reader);
	this.config = config;
	}

	protected abstract String filterAttribute( QName elementName, QName attributeName, String attributeValue, String ruleName );

	protected abstract String filterText( QName elementName, String text, String ruleName );

	@Override
	public int read( char[] destBuffer, int destOffset, int destCount ) throws IOException {
	int count = 0;
	int available = buffer.length() - offset;

	if( available == 0 ) {
	if( iterator.hasNext() ) {
	iterator.next();
	processCurrentSegment();
	available = buffer.length() - offset;
	} else {
	count = -1;
	}
	}

	if( available > 0 ) {
	count = Math.min( destCount, available );
	buffer.getChars( offset, offset + count, destBuffer, destOffset );
	offset += count;
	if( offset == buffer.length() ) {
	offset = 0;
	buffer.setLength( 0 );
	}
	}

	return count;
	}

	private void processCurrentSegment() {
	Segment segment = parser.getCurrentSegment();
	// If this tag is inside the previous tag (e.g. a server tag) then
	// ignore it as it was already output along with the previous tag.
	if( segment.getEnd() <= lastSegEnd ) {
	return;
	}
	lastSegEnd = segment.getEnd();
	if( segment instanceof Tag ) {
	if( segment instanceof StartTag ) {
	processStartTag( (StartTag)segment );
	} else if ( segment instanceof EndTag ) {
	processEndTag( (EndTag)segment );
	} else {
	writer.write( segment.toString() );
	}
	} else {
	processText( segment );
	}
	}

	private void processEndTag( EndTag tag ) {
	while( !stack.isEmpty() ) {
	Level popped = stack.pop();
	if( popped.getTag().getName().equalsIgnoreCase( tag.getName() ) ) {
	break;
	}
	}
	writer.write( tag.toString() );
	}

	private void processStartTag( StartTag tag ) {
	if( "<".equals( tag.getTagType().getStartDelimiter() ) ) {
	stack.push( new Level( tag ) );
	writer.write( "<" );
	writer.write( tag.getNameSegment().toString() );
	Attributes attributes = tag.getAttributes();
	if( !attributes.isEmpty() ) {
	for( Attribute attribute : attributes ) {
	processAttribute( attribute );
	}
	}
	if( tag.toString().trim().endsWith( "/>" ) \|\| tag.isEmptyElementTag() ) {
	stack.pop();
	writer.write( "/>" );
	} else {
	writer.write( ">" );
	}
	} else {
	writer.write( tag.toString() );
	}
	}

	private void processAttribute( Attribute attribute ) {
	writer.write( " " );
	writer.write( attribute.getName() );
	if(attribute.hasValue()) {
	/*
	* non decoded value, return the raw value of the attribute as it appears
	* in the source document, without decoding, see KNOX-791.
	*/
	String inputValue = attribute.getValueSegment().toString();
	String outputValue = inputValue;
	try {
	Level tag = stack.peek();
	String name = getRuleName(inputValue);
	outputValue = filterAttribute( tag.getQName(), tag.getQName( attribute.getName() ), inputValue, name );
	if( outputValue == null ) {
	outputValue = inputValue;
	}
	} catch ( Exception e ) {
	LOG.failedToFilterAttribute( attribute.getName(), e );
	}
	writer.write( "=" );
	writer.write( attribute.getQuoteChar() );
	writer.write( outputValue );
	writer.write( attribute.getQuoteChar() );
	}
	}

	private String getRuleName(String inputValue) {
	if( config != null && !config.getSelectors().isEmpty() ) {
	for( UrlRewriteFilterPathDescriptor selector : config.getSelectors() ) {
	if ( selector instanceof UrlRewriteFilterApplyDescriptor) {
	UrlRewriteFilterApplyDescriptor apply = (UrlRewriteFilterApplyDescriptor)selector;
	Matcher matcher = apply.compiledPath( REGEX_COMPILER ).matcher( inputValue );
	if (matcher.matches()) {
	return apply.rule();
	}
	}
	}
	}
	return null;
	}

	private void processText( Segment segment ) {
	String inputValue = segment.toString();
	String outputValue = inputValue;
	try {
	if( stack.isEmpty() ) {
	// This can happen for whitespace outside of the root element.
	//outputValue = filterText( null, inputValue );
	} else {
	String tagName = stack.peek().getTag().getName();
	if (SCRIPTTAG.equals(tagName) && config != null && !config.getSelectors().isEmpty() ) {
	// embedded javascript content
	outputValue = UrlRewriteUtil.filterJavaScript( inputValue, config, this, REGEX_COMPILER );
	} else {
	outputValue = filterText( stack.peek().getQName(), inputValue, getRuleName(inputValue) );
	}
	}
	if( outputValue == null ) {
	outputValue = inputValue;
	}
	} catch ( Exception e ) {
	LOG.failedToFilterValue( inputValue, null, e );
	}
	writer.write( outputValue );
	}

	@Override
	public void close() throws IOException {
	parser.close();
	reader.close();
	writer.close();
	stack.clear();
	}

	private static class Level {
	private StartTag tag;
	private QName name;
	private Map<String,String> namespaces;

	Level( StartTag tag ) {
	this.tag = tag;
	this.name = null;
	this.namespaces = null;
	}

	private StartTag getTag() {
	return tag;
	}

	private QName getQName() {
	if( name == null ) {
	name = getQName( tag.getName() );
	}
	return name;
	}

	private String getNamespace( String prefix ) {
	return getNamespaces().get( prefix );
	}

	private QName getQName( String name ) {
	String prefix;
	String local;
	int colon = ( name == null ? -1 : name.indexOf( ':' ) );
	if( colon < 0 ) {
	prefix = "";
	local = name;
	} else {
	prefix = name.substring( 0, colon );
	local = ( colon + 1 < name.length() ? name.substring( colon + 1 ) : "" );
	}
	String namespace = getNamespace( prefix );
	return new QName( namespace, local, prefix );
	}

	private Map<String,String> getNamespaces() {
	if( namespaces == null ) {
	namespaces = new HashMap<>();
	parseNamespaces();
	}
	return namespaces;
	}

	private void parseNamespaces() {
	Attributes attributes = tag.getAttributes();
	if( attributes != null ) {
	for( Attribute attribute : tag.getAttributes() ) {
	String name = attribute.getName();
	if( name.toLowerCase(Locale.ROOT).startsWith( "xmlns" ) ) {
	int colon = name.indexOf( ':', 5 );
	String prefix;
	if( colon <= 0 ) {
	prefix = "";
	} else {
	prefix = name.substring( colon );
	}
	namespaces.put( prefix, attribute.getValue() );
	}
	}
	}
	}

	}

	}