gerrit-httpd/src/main/java/com/google/gerrit/httpd/HtmlDomUtil.java - gerrit - Git at Google

 // Copyright (C) 2008 The Android Open Source Project
 //
 // 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 com.google.gerrit.httpd;

 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 import org.xml.sax.SAXException;

 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.StringWriter;
 import java.io.UnsupportedEncodingException;
 import java.util.zip.GZIPOutputStream;

 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.transform.OutputKeys;
 import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerConfigurationException;
 import javax.xml.transform.TransformerException;
 import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.stream.StreamResult;
 import javax.xml.xpath.XPathConstants;
 import javax.xml.xpath.XPathExpression;
 import javax.xml.xpath.XPathExpressionException;
 import javax.xml.xpath.XPathFactory;

 /** Utility functions to deal with HTML using W3C DOM operations. */
 public class HtmlDomUtil {
   /** Standard character encoding we prefer (UTF-8). */
   public static final String ENC = "UTF-8";

   /** DOCTYPE for a standards mode HTML document. */
   public static final String HTML_STRICT =
       "-//W3C//DTD HTML 4.01//EN\" \"http://www.w3.org/TR/REC-html40/strict.dtd";

   /** Convert a document to a UTF-8 byte sequence. */
   public static byte[] toUTF8(final Document hostDoc) throws IOException {
     return toString(hostDoc).getBytes(ENC);
   }

   /** Compress the document. */
   public static byte[] compress(final byte[] raw) throws IOException {
     final ByteArrayOutputStream out = new ByteArrayOutputStream();
     final GZIPOutputStream gz = new GZIPOutputStream(out);
     gz.write(raw);
     gz.finish();
     gz.flush();
     return out.toByteArray();
   }

   /** Convert a document to a String, assuming later encoding to UTF-8. */
   public static String toString(final Document hostDoc) throws IOException {
     try {
       final StringWriter out = new StringWriter();
       final DOMSource domSource = new DOMSource(hostDoc);
       final StreamResult streamResult = new StreamResult(out);
       final TransformerFactory tf = TransformerFactory.newInstance();
       final Transformer serializer = tf.newTransformer();
       serializer.setOutputProperty(OutputKeys.ENCODING, ENC);
       serializer.setOutputProperty(OutputKeys.METHOD, "html");
       serializer.setOutputProperty(OutputKeys.INDENT, "no");
       serializer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC,
           HtmlDomUtil.HTML_STRICT);
       serializer.transform(domSource, streamResult);
       return out.toString();
     } catch (TransformerConfigurationException e) {
       final IOException r = new IOException("Error transforming page");
       r.initCause(e);
       throw r;
     } catch (TransformerException e) {
       final IOException r = new IOException("Error transforming page");
       r.initCause(e);
       throw r;
     }
   }

   /** Find an element by its "id" attribute; null if no element is found. */
   public static Element find(final Node parent, final String name) {
     final NodeList list = parent.getChildNodes();
     for (int i = 0; i < list.getLength(); i++) {
       final Node n = list.item(i);
       if (n instanceof Element) {
         final Element e = (Element) n;
         if (name.equals(e.getAttribute("id"))) {
           return e;
         }
       }
       final Element r = find(n, name);
       if (r != null) {
         return r;
       }
     }
     return null;
   }

   /** Append an HTML &lt;input type="hidden"&gt; to the form. */
   public static void addHidden(final Element form, final String name,
       final String value) {
     final Element in = form.getOwnerDocument().createElement("input");
     in.setAttribute("type", "hidden");
     in.setAttribute("name", name);
     in.setAttribute("value", value);
     form.appendChild(in);
   }

   /** Construct a new empty document. */
   public static Document newDocument() {
     try {
       return newBuilder().newDocument();
     } catch (ParserConfigurationException e) {
       throw new RuntimeException("Cannot create new document", e);
     }
   }

   /** Clone a document so it can be safely modified on a per-request basis. */
   public static Document clone(final Document doc) throws IOException {
     final Document d;
     try {
       d = newBuilder().newDocument();
     } catch (ParserConfigurationException e) {
       throw new IOException("Cannot clone document");
     }
     final Node n = d.importNode(doc.getDocumentElement(), true);
     d.appendChild(n);
     return d;
   }

   /** Parse an XHTML file from our CLASSPATH and return the instance. */
   public static Document parseFile(final Class<?> context, final String name)
       throws IOException {
     final InputStream in;

     in = context.getResourceAsStream(name);
     if (in == null) {
       return null;
     }
     try {
       try {
         try {
           final Document doc = newBuilder().parse(in);
           compact(doc);
           return doc;
         } catch (SAXException e) {
           throw new IOException("Error reading " + name, e);
         } catch (ParserConfigurationException e) {
           throw new IOException("Error reading " + name, e);
         }
       } finally {
         in.close();
       }
     } catch (IOException e) {
       throw new IOException("Error reading " + name, e);
     }
   }

   private static void compact(final Document doc) {
     try {
       final String expr = "//text()[normalize-space(.) = '']";
       final XPathFactory xp = XPathFactory.newInstance();
       final XPathExpression e = xp.newXPath().compile(expr);
       NodeList empty = (NodeList) e.evaluate(doc, XPathConstants.NODESET);
       for (int i = 0; i < empty.getLength(); i++) {
         Node node = empty.item(i);
         node.getParentNode().removeChild(node);
       }
     } catch (XPathExpressionException e) {
       // Don't do the whitespace removal.
     }
   }

   /** Read a Read a UTF-8 text file from our CLASSPATH and return it. */
   public static String readFile(final Class<?> context, final String name)
       throws IOException {
     final InputStream in = context.getResourceAsStream(name);
     if (in == null) {
       return null;
     }
     try {
       return asString(in);
     } catch (IOException e) {
       throw new IOException("Error reading " + name, e);
     }
   }

   /** Parse an XHTML file from the local drive and return the instance. */
   public static Document parseFile(final File path) throws IOException {
     try {
       final InputStream in = new FileInputStream(path);
       try {
         try {
           final Document doc = newBuilder().parse(in);
           compact(doc);
           return doc;
         } catch (SAXException e) {
           throw new IOException("Error reading " + path, e);
         } catch (ParserConfigurationException e) {
           throw new IOException("Error reading " + path, e);
         }
       } finally {
         in.close();
       }
     } catch (FileNotFoundException e) {
       return null;
     } catch (IOException e) {
       throw new IOException("Error reading " + path, e);
     }
   }

   /** Read a UTF-8 text file from the local drive. */
   public static String readFile(final File parentDir, final String name)
       throws IOException {
     if (parentDir == null) {
       return null;
     }
     final File path = new File(parentDir, name);
     try {
       return asString(new FileInputStream(path));
     } catch (FileNotFoundException e) {
       return null;
     } catch (IOException e) {
       throw new IOException("Error reading " + path, e);
     }
   }

   private static String asString(final InputStream in)
       throws UnsupportedEncodingException, IOException {
     try {
       final StringBuilder w = new StringBuilder();
       final InputStreamReader r = new InputStreamReader(in, ENC);
       final char[] buf = new char[512];
       int n;
       while ((n = r.read(buf)) > 0) {
         w.append(buf, 0, n);
       }
       return w.toString();
     } finally {
       in.close();
     }
   }

   private static DocumentBuilder newBuilder()
       throws ParserConfigurationException {
     final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
     factory.setValidating(false);
     factory.setExpandEntityReferences(false);
     factory.setIgnoringComments(true);
     factory.setCoalescing(true);
     final DocumentBuilder parser = factory.newDocumentBuilder();
     return parser;
   }
 }
	// Copyright (C) 2008 The Android Open Source Project
	//
	// 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 com.google.gerrit.httpd;

	import org.w3c.dom.Document;
	import org.w3c.dom.Element;
	import org.w3c.dom.Node;
	import org.w3c.dom.NodeList;
	import org.xml.sax.SAXException;

	import java.io.ByteArrayOutputStream;
	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileNotFoundException;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.InputStreamReader;
	import java.io.StringWriter;
	import java.io.UnsupportedEncodingException;
	import java.util.zip.GZIPOutputStream;

	import javax.xml.parsers.DocumentBuilder;
	import javax.xml.parsers.DocumentBuilderFactory;
	import javax.xml.parsers.ParserConfigurationException;
	import javax.xml.transform.OutputKeys;
	import javax.xml.transform.Transformer;
	import javax.xml.transform.TransformerConfigurationException;
	import javax.xml.transform.TransformerException;
	import javax.xml.transform.TransformerFactory;
	import javax.xml.transform.dom.DOMSource;
	import javax.xml.transform.stream.StreamResult;
	import javax.xml.xpath.XPathConstants;
	import javax.xml.xpath.XPathExpression;
	import javax.xml.xpath.XPathExpressionException;
	import javax.xml.xpath.XPathFactory;

	/** Utility functions to deal with HTML using W3C DOM operations. */
	public class HtmlDomUtil {
	/** Standard character encoding we prefer (UTF-8). */
	public static final String ENC = "UTF-8";

	/** DOCTYPE for a standards mode HTML document. */
	public static final String HTML_STRICT =
	"-//W3C//DTD HTML 4.01//EN\" \"http://www.w3.org/TR/REC-html40/strict.dtd";

	/** Convert a document to a UTF-8 byte sequence. */
	public static byte[] toUTF8(final Document hostDoc) throws IOException {
	return toString(hostDoc).getBytes(ENC);
	}

	/** Compress the document. */
	public static byte[] compress(final byte[] raw) throws IOException {
	final ByteArrayOutputStream out = new ByteArrayOutputStream();
	final GZIPOutputStream gz = new GZIPOutputStream(out);
	gz.write(raw);
	gz.finish();
	gz.flush();
	return out.toByteArray();
	}

	/** Convert a document to a String, assuming later encoding to UTF-8. */
	public static String toString(final Document hostDoc) throws IOException {
	try {
	final StringWriter out = new StringWriter();
	final DOMSource domSource = new DOMSource(hostDoc);
	final StreamResult streamResult = new StreamResult(out);
	final TransformerFactory tf = TransformerFactory.newInstance();
	final Transformer serializer = tf.newTransformer();
	serializer.setOutputProperty(OutputKeys.ENCODING, ENC);
	serializer.setOutputProperty(OutputKeys.METHOD, "html");
	serializer.setOutputProperty(OutputKeys.INDENT, "no");
	serializer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC,
	HtmlDomUtil.HTML_STRICT);
	serializer.transform(domSource, streamResult);
	return out.toString();
	} catch (TransformerConfigurationException e) {
	final IOException r = new IOException("Error transforming page");
	r.initCause(e);
	throw r;
	} catch (TransformerException e) {
	final IOException r = new IOException("Error transforming page");
	r.initCause(e);
	throw r;
	}
	}

	/** Find an element by its "id" attribute; null if no element is found. */
	public static Element find(final Node parent, final String name) {
	final NodeList list = parent.getChildNodes();
	for (int i = 0; i < list.getLength(); i++) {
	final Node n = list.item(i);
	if (n instanceof Element) {
	final Element e = (Element) n;
	if (name.equals(e.getAttribute("id"))) {
	return e;
	}
	}
	final Element r = find(n, name);
	if (r != null) {
	return r;
	}
	}
	return null;
	}

	/** Append an HTML <input type="hidden"> to the form. */
	public static void addHidden(final Element form, final String name,
	final String value) {
	final Element in = form.getOwnerDocument().createElement("input");
	in.setAttribute("type", "hidden");
	in.setAttribute("name", name);
	in.setAttribute("value", value);
	form.appendChild(in);
	}

	/** Construct a new empty document. */
	public static Document newDocument() {
	try {
	return newBuilder().newDocument();
	} catch (ParserConfigurationException e) {
	throw new RuntimeException("Cannot create new document", e);
	}
	}

	/** Clone a document so it can be safely modified on a per-request basis. */
	public static Document clone(final Document doc) throws IOException {
	final Document d;
	try {
	d = newBuilder().newDocument();
	} catch (ParserConfigurationException e) {
	throw new IOException("Cannot clone document");
	}
	final Node n = d.importNode(doc.getDocumentElement(), true);
	d.appendChild(n);
	return d;
	}

	/** Parse an XHTML file from our CLASSPATH and return the instance. */
	public static Document parseFile(final Class<?> context, final String name)
	throws IOException {
	final InputStream in;

	in = context.getResourceAsStream(name);
	if (in == null) {
	return null;
	}
	try {
	try {
	try {
	final Document doc = newBuilder().parse(in);
	compact(doc);
	return doc;
	} catch (SAXException e) {
	throw new IOException("Error reading " + name, e);
	} catch (ParserConfigurationException e) {
	throw new IOException("Error reading " + name, e);
	}
	} finally {
	in.close();
	}
	} catch (IOException e) {
	throw new IOException("Error reading " + name, e);
	}
	}

	private static void compact(final Document doc) {
	try {
	final String expr = "//text()[normalize-space(.) = '']";
	final XPathFactory xp = XPathFactory.newInstance();
	final XPathExpression e = xp.newXPath().compile(expr);
	NodeList empty = (NodeList) e.evaluate(doc, XPathConstants.NODESET);
	for (int i = 0; i < empty.getLength(); i++) {
	Node node = empty.item(i);
	node.getParentNode().removeChild(node);
	}
	} catch (XPathExpressionException e) {
	// Don't do the whitespace removal.
	}
	}

	/** Read a Read a UTF-8 text file from our CLASSPATH and return it. */
	public static String readFile(final Class<?> context, final String name)
	throws IOException {
	final InputStream in = context.getResourceAsStream(name);
	if (in == null) {
	return null;
	}
	try {
	return asString(in);
	} catch (IOException e) {
	throw new IOException("Error reading " + name, e);
	}
	}

	/** Parse an XHTML file from the local drive and return the instance. */
	public static Document parseFile(final File path) throws IOException {
	try {
	final InputStream in = new FileInputStream(path);
	try {
	try {
	final Document doc = newBuilder().parse(in);
	compact(doc);
	return doc;
	} catch (SAXException e) {
	throw new IOException("Error reading " + path, e);
	} catch (ParserConfigurationException e) {
	throw new IOException("Error reading " + path, e);
	}
	} finally {
	in.close();
	}
	} catch (FileNotFoundException e) {
	return null;
	} catch (IOException e) {
	throw new IOException("Error reading " + path, e);
	}
	}

	/** Read a UTF-8 text file from the local drive. */
	public static String readFile(final File parentDir, final String name)
	throws IOException {
	if (parentDir == null) {
	return null;
	}
	final File path = new File(parentDir, name);
	try {
	return asString(new FileInputStream(path));
	} catch (FileNotFoundException e) {
	return null;
	} catch (IOException e) {
	throw new IOException("Error reading " + path, e);
	}
	}

	private static String asString(final InputStream in)
	throws UnsupportedEncodingException, IOException {
	try {
	final StringBuilder w = new StringBuilder();
	final InputStreamReader r = new InputStreamReader(in, ENC);
	final char[] buf = new char[512];
	int n;
	while ((n = r.read(buf)) > 0) {
	w.append(buf, 0, n);
	}
	return w.toString();
	} finally {
	in.close();
	}
	}

	private static DocumentBuilder newBuilder()
	throws ParserConfigurationException {
	final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
	factory.setValidating(false);
	factory.setExpandEntityReferences(false);
	factory.setIgnoringComments(true);
	factory.setCoalescing(true);
	final DocumentBuilder parser = factory.newDocumentBuilder();
	return parser;
	}
	}