/*
* Copyright 2002-2008 Andy Clark
*
* 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.cyberneko.html.filters;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import org.cyberneko.html.HTMLConfiguration;
import org.cyberneko.html.HTMLElements;
import org.cyberneko.html.HTMLEntities;
import org.cyberneko.html.filters.DefaultFilter;
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.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.XMLDocumentFilter;
import org.apache.xerces.xni.parser.XMLInputSource;
import org.apache.xerces.xni.parser.XMLParserConfiguration;
/**
* An HTML writer written as a filter. Besides serializing the HTML
* event stream, the writer also passes the document events to the next
* stage in the pipeline. This allows applications to insert writer
* filters between other custom filters for debugging purposes.
* <p>
* Since an HTML document may have specified its encoding using the
* <META> tag and http-equiv/content attributes, the writer will
* automatically change any character set specified in this tag to
* match the encoding of the output stream. Therefore, the character
* encoding name used to construct the writer should be an official
* <a href='http://www.iana.org/assignments/character-sets'>IANA</a>
* encoding name and not a Java encoding name.
* <p>
* <strong>Note:</strong>
* The modified character set in the <META> tag is <em>not</em>
* propagated to the next stage in the pipeline. The changed value is
* only output to the stream; the original value is sent to the next
* stage in the pipeline.
*
* @author Andy Clark
*
* @version $Id: Writer.java,v 1.7 2005/02/14 04:01:33 andyc Exp $
*/
public class Writer
extends DefaultFilter {
//
// Constants
//
/** Notify character entity references. */
public static final String NOTIFY_CHAR_REFS = "http://apache.org/xml/features/scanner/notify-char-refs";
/** Notify built-in entity references. */
public static final String NOTIFY_HTML_BUILTIN_REFS = "http://cyberneko.org/html/features/scanner/notify-builtin-refs";
/** Augmentations feature identifier. */
protected static final String AUGMENTATIONS = "http://cyberneko.org/html/features/augmentations";
/** Filters property identifier. */
protected static final String FILTERS = "http://cyberneko.org/html/properties/filters";
//
// Data
//
/** The encoding. */
protected String fEncoding;
/**
* The print writer used for serializing the document with the
* appropriate character encoding.
*/
protected PrintWriter fPrinter;
// state
/** Seen root element. */
protected boolean fSeenRootElement;
/** Seen http-equiv directive. */
protected boolean fSeenHttpEquiv;
/** Element depth. */
protected int fElementDepth;
/** Normalize character content. */
protected boolean fNormalize;
/** Print characters. */
protected boolean fPrintChars;
//
// Constructors
//
/** Constructs a writer filter that prints to standard out. */
public Writer() {
// Note: UTF-8 should *always* be a supported encoding. Although,
// I've heard of the old M$ JVM not supporting it! Amazing. -Ac
try {
fEncoding = "UTF-8";
fPrinter = new PrintWriter(new OutputStreamWriter(System.out, fEncoding));
}
catch (UnsupportedEncodingException e) {
throw new RuntimeException(e.getMessage());
}
} // <init>()
/**
* Constructs a writer filter using the specified output stream and
* encoding.
*
* @param outputStream The output stream to write to.
* @param encoding The encoding to be used for the output. The encoding name
* should be an official IANA encoding name.
*/
public Writer(OutputStream outputStream, String encoding)
throws UnsupportedEncodingException {
this(new OutputStreamWriter(outputStream, encoding), encoding);
} // <init>(OutputStream,String)
/**
* Constructs a writer filter using the specified Java writer and
* encoding.
*
* @param writer The Java writer to write to.
* @param encoding The encoding to be used for the output. The encoding name
* should be an official IANA encoding name.
*/
public Writer(java.io.Writer writer, String encoding) {
fEncoding = encoding;
if (writer instanceof PrintWriter) {
fPrinter = (PrintWriter)writer;
}
else {
fPrinter = new PrintWriter(writer);
}
} // <init>(java.io.Writer,String)
//
// XMLDocumentHandler methods
//
// since Xerces-J 2.2.0
/** Start document. */
public void startDocument(XMLLocator locator, String encoding,
NamespaceContext nscontext, Augmentations augs)
throws XNIException {
fSeenRootElement = false;
fSeenHttpEquiv = false;
fElementDepth = 0;
fNormalize = true;
fPrintChars = true;
super.startDocument(locator, encoding, nscontext, augs);
} // startDocument(XMLLocator,String,NamespaceContext,Augmentations)
// old methods
/** Start document. */
public void startDocument(XMLLocator locator, String encoding, Augmentations augs)
throws XNIException {
startDocument(locator, encoding, null, augs);
} // startDocument(XMLLocator,String,Augmentations)
/** Comment. */
public void comment(XMLString text, Augmentations augs)
throws XNIException {
if (fSeenRootElement && fElementDepth <= 0) {
fPrinter.println();
}
fPrinter.print("<!--");
printCharacters(text, false);
fPrinter.print("-->");
if (!fSeenRootElement) {
fPrinter.println();
}
fPrinter.flush();
} // comment(XMLString,Augmentations)
/** Start element. */
public void startElement(QName element, XMLAttributes attributes, Augmentations augs)
throws XNIException {
fSeenRootElement = true;
fElementDepth++;
fNormalize = !HTMLElements.getElement(element.rawname).isSpecial();
printStartElement(element, attributes);
super.startElement(element, attributes, augs);
} // startElement(QName,XMLAttributes,Augmentations)
/** Empty element. */
public void emptyElement(QName element, XMLAttributes attributes, Augmentations augs)
throws XNIException {
fSeenRootElement = true;
printStartElement(element, attributes);
super.emptyElement(element, attributes, augs);
} // emptyElement(QName,XMLAttributes,Augmentations)
/** Characters. */
public void characters(XMLString text, Augmentations augs)
throws XNIException {
if (fPrintChars) {
printCharacters(text, fNormalize);
}
super.characters(text, augs);
} // characters(XMLString,Augmentations)
/** End element. */
public void endElement(QName element, Augmentations augs)
throws XNIException {
fElementDepth--;
fNormalize = true;
/***
// NOTE: Not sure if this is what should be done in the case where
// the encoding is not explitly declared within the HEAD. So
// I'm leaving it commented out for now. -Ac
if (element.rawname.equalsIgnoreCase("head") && !fSeenHttpEquiv) {
boolean capitalize = Character.isUpperCase(element.rawname.charAt(0));
String ename = capitalize ? "META" : "meta";
QName qname = new QName(null, ename, ename, null);
XMLAttributes attrs = new XMLAttributesImpl();
QName aname = new QName(null, "http-equiv", "http-equiv", null);
attrs.addAttribute(aname, "CDATA", "Content-Type");
aname.setValues(null, "content", "content", null);
attrs.addAttribute(aname, "CDATA", "text/html; charset="+fEncoding);
super.emptyElement(qname, attrs, null);
}
/***/
printEndElement(element);
super.endElement(element, augs);
} // endElement(QName,Augmentations)
/** Start general entity. */
public void startGeneralEntity(String name, XMLResourceIdentifier id, String encoding, Augmentations augs)
throws XNIException {
fPrintChars = false;
if (name.startsWith("#")) {
try {
boolean hex = name.startsWith("#x");
int offset = hex ? 2 : 1;
int base = hex ? 16 : 10;
int value = Integer.parseInt(name.substring(offset), base);
String entity = HTMLEntities.get(value);
if (entity != null) {
name = entity;
}
}
catch (NumberFormatException e) {
// ignore
}
}
printEntity(name);
super.startGeneralEntity(name, id, encoding, augs);
} // startGeneralEntity(String,XMLResourceIdentifier,String,Augmentations)
/** End general entity. */
public void endGeneralEntity(String name, Augmentations augs)
throws XNIException {
fPrintChars = true;
super.endGeneralEntity(name, augs);
} // endGeneralEntity(String,Augmentations)
//
// Protected methods
//
/** Print attribute value. */
protected void printAttributeValue(String text) {
int length = text.length();
for (int j = 0; j < length; j++) {
char c = text.charAt(j);
if (c == '"') {
fPrinter.print(""");
}
else {
fPrinter.print(c);
}
}
fPrinter.flush();
} // printAttributeValue(String)
/** Print characters. */
protected void printCharacters(XMLString text, boolean normalize) {
if (normalize) {
for (int i = 0; i < text.length; i++) {
char c = text.ch[text.offset + i];
if (c != '\n') {
String entity = HTMLEntities.get(c);
if (entity != null) {
printEntity(entity);
}
else {
fPrinter.print(c);
}
}
else {
fPrinter.println();
}
}
}
else {
for (int i = 0; i < text.length; i++) {
char c = text.ch[text.offset + i];
fPrinter.print(c);
}
}
fPrinter.flush();
} // printCharacters(XMLString,boolean)
/** Print start element. */
protected void printStartElement(QName element, XMLAttributes attributes) {
// modify META[@http-equiv='content-type']/@content value
int contentIndex = -1;
String originalContent = null;
if (element.rawname.toLowerCase().equals("meta")) {
String httpEquiv = null;
int length = attributes.getLength();
for (int i = 0; i < length; i++) {
String aname = attributes.getQName(i).toLowerCase();
if (aname.equals("http-equiv")) {
httpEquiv = attributes.getValue(i);
}
else if (aname.equals("content")) {
contentIndex = i;
}
}
if (httpEquiv != null && httpEquiv.toLowerCase().equals("content-type")) {
fSeenHttpEquiv = true;
String content = null;
if (contentIndex != -1) {
originalContent = attributes.getValue(contentIndex);
content = originalContent.toLowerCase();
}
if (content != null) {
int charsetIndex = content.indexOf("charset=");
if (charsetIndex != -1) {
content = content.substring(0, charsetIndex + 8);
}
else {
content += ";charset=";
}
content += fEncoding;
attributes.setValue(contentIndex, content);
}
}
}
// print element
fPrinter.print('<');
fPrinter.print(element.rawname);
int attrCount = attributes != null ? attributes.getLength() : 0;
for (int i = 0; i < attrCount; i++) {
String aname = attributes.getQName(i);
String avalue = attributes.getValue(i);
fPrinter.print(' ');
fPrinter.print(aname);
fPrinter.print("=\"");
printAttributeValue(avalue);
fPrinter.print('"');
}
fPrinter.print('>');
fPrinter.flush();
// return original META[@http-equiv]/@content value
if (contentIndex != -1) {
attributes.setValue(contentIndex, originalContent);
}
} // printStartElement(QName,XMLAttributes)
/** Print end element. */
protected void printEndElement(QName element) {
fPrinter.print("</");
fPrinter.print(element.rawname);
fPrinter.print('>');
fPrinter.flush();
} // printEndElement(QName)
/** Print entity. */
protected void printEntity(String name) {
fPrinter.print('&');
fPrinter.print(name);
fPrinter.print(';');
fPrinter.flush();
} // printEntity(String)
//
// MAIN
//
/** Main. */
public static void main(String[] argv) throws Exception {
if (argv.length == 0) {
printUsage();
System.exit(1);
}
XMLParserConfiguration parser = new HTMLConfiguration();
parser.setFeature(NOTIFY_CHAR_REFS, true);
parser.setFeature(NOTIFY_HTML_BUILTIN_REFS, true);
String iencoding = null;
String oencoding = "Windows-1252";
boolean identity = false;
boolean purify = false;
for (int i = 0; i < argv.length; i++) {
String arg = argv[i];
if (arg.equals("-ie")) {
iencoding = argv[++i];
continue;
}
if (arg.equals("-e") || arg.equals("-oe")) {
oencoding = argv[++i];
continue;
}
if (arg.equals("-i")) {
identity = true;
continue;
}
if (arg.equals("-p")) {
purify = true;
continue;
}
if (arg.equals("-h")) {
printUsage();
System.exit(1);
}
java.util.Vector filtersVector = new java.util.Vector(2);
if (identity) {
filtersVector.addElement(new Identity());
}
else if (purify) {
filtersVector.addElement(new Purifier());
}
filtersVector.addElement(new Writer(System.out, oencoding));
XMLDocumentFilter[] filters =
new XMLDocumentFilter[filtersVector.size()];
filtersVector.copyInto(filters);
parser.setProperty(FILTERS, filters);
XMLInputSource source = new XMLInputSource(null, arg, null);
source.setEncoding(iencoding);
parser.parse(source);
}
} // main(String[])
/** Print usage. */
private static void printUsage() {
System.err.println("usage: java "+Writer.class.getName()+" (options) file ...");
System.err.println();
System.err.println("options:");
System.err.println(" -ie name Specify IANA name of input encoding.");
System.err.println(" -oe name Specify IANA name of output encoding.");
System.err.println(" -i Perform identity transform.");
System.err.println(" -p Purify output to ensure XML well-formedness.");
System.err.println(" -h Display help screen.");
System.err.println();
System.err.println("notes:");
System.err.println(" The -i and -p options are mutually exclusive.");
System.err.println(" The -e option has been replaced with -oe.");
} // printUsage()
} // class Writer