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yacy_search_server/source/net/yacy/document/parser/html/ContentScraper.java

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// ContentScraper.java
// -----------------------------
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
//
// Contains contributions by Marc Nause [MN]
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package net.yacy.document.parser.html;
import java.io.ByteArrayInputStream;
import java.io.CharArrayReader;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.net.MalformedURLException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import javax.swing.event.EventListenerList;
import net.yacy.document.parser.htmlParser;
import net.yacy.kelondro.data.meta.DigestURI;
import net.yacy.kelondro.io.CharBuffer;
import net.yacy.kelondro.logging.Log;
import net.yacy.kelondro.util.FileUtils;
import net.yacy.kelondro.util.ISO639;
public class ContentScraper extends AbstractScraper implements Scraper {
// statics: for initialization of the HTMLFilterAbstractScraper
private static final HashSet<String> linkTags0 = new HashSet<String>(9,0.99f);
private static final HashSet<String> linkTags1 = new HashSet<String>(7,0.99f);
// all these tags must be given in lowercase, because the tags from the files are compared in lowercase
static {
linkTags0.add("html"); // scraped as tag 0 to get attached properties like 'lang'
linkTags0.add("img");
linkTags0.add("base");
linkTags0.add("frame");
linkTags0.add("meta");
linkTags0.add("area");
linkTags0.add("link");
linkTags0.add("embed"); //added by [MN]
linkTags0.add("param"); //added by [MN]
linkTags1.add("a");
linkTags1.add("h1");
linkTags1.add("h2");
linkTags1.add("h3");
linkTags1.add("h4");
linkTags1.add("title");
}
// class variables: collectors for links
private HashMap<DigestURI, String> anchors;
private HashMap<String, ImageEntry> images; // urlhash/image relation
private final HashMap<String, String> metas;
private String title;
//private String headline;
private List<String>[] headlines;
private CharBuffer content;
private final EventListenerList htmlFilterEventListeners;
/**
* {@link DigestURI} to the favicon that belongs to the document
*/
private DigestURI favicon;
/**
* The document root {@link DigestURI}
*/
private DigestURI root;
@SuppressWarnings("unchecked")
public ContentScraper(final DigestURI root) {
// the root value here will not be used to load the resource.
// it is only the reference for relative links
super(linkTags0, linkTags1);
this.root = root;
this.anchors = new HashMap<DigestURI, String>();
this.images = new HashMap<String, ImageEntry>();
this.metas = new HashMap<String, String>();
this.title = "";
this.headlines = new ArrayList[4];
for (int i = 0; i < 4; i++) headlines[i] = new ArrayList<String>();
this.content = new CharBuffer(1024);
this.htmlFilterEventListeners = new EventListenerList();
}
public final static boolean punctuation(final char c) {
return c == '.' || c == '!' || c == '?';
}
public void scrapeText(final char[] newtext, final String insideTag) {
// System.out.println("SCRAPE: " + new String(newtext));
String b = cleanLine(super.stripAll(new String(newtext)));
if ((insideTag != null) && (!(insideTag.equals("a")))) {
// texts inside tags sometimes have no punctuation at the line end
// this is bad for the text sematics, because it is not possible for the
// condenser to distinguish headlines from text beginnings.
// to make it easier for the condenser, a dot ('.') is appended in case that
// no punctuation is part of the newtext line
if ((b.length() != 0) && (!(punctuation(b.charAt(b.length() - 1))))) b = b + '.';
//System.out.println("*** Appended dot: " + b.toString());
}
if (b.length() != 0) content.append(b).append(32);
}
private DigestURI absolutePath(final String relativePath) {
try {
return DigestURI.newURL(root, relativePath);
} catch (final Exception e) {
return null;
}
}
public void scrapeTag0(final String tagname, final Properties tagopts) {
if (tagname.equalsIgnoreCase("img")) {
try {
final int width = Integer.parseInt(tagopts.getProperty("width", "-1"));
final int height = Integer.parseInt(tagopts.getProperty("height", "-1"));
if (width > 15 && height > 15) {
final float ratio = (float) Math.min(width, height) / Math.max(width, height);
if (ratio > 0.4) {
final DigestURI url = absolutePath(tagopts.getProperty("src", ""));
final ImageEntry ie = new ImageEntry(url, tagopts.getProperty("alt", ""), width, height, -1);
addImage(images, ie);
}
// i think that real pictures have witdth & height tags - thq
// } else if (width < 0 && height < 0) { // add or to ignore !?
// final yacyURL url = absolutePath(tagopts.getProperty("src", ""));
// final htmlFilterImageEntry ie = new htmlFilterImageEntry(url, tagopts.getProperty("alt", ""), width, height);
// addImage(images, ie);
}
} catch (final NumberFormatException e) {}
}
if (tagname.equalsIgnoreCase("base")) try {
root = new DigestURI(tagopts.getProperty("href", ""), null);
} catch (final MalformedURLException e) {}
if (tagname.equalsIgnoreCase("frame")) {
anchors.put(absolutePath(tagopts.getProperty("src", "")), tagopts.getProperty("name",""));
}
if (tagname.equalsIgnoreCase("meta")) {
String name = tagopts.getProperty("name", "");
if (name.length() > 0) {
metas.put(name.toLowerCase(), CharacterCoding.html2unicode(tagopts.getProperty("content","")));
} else {
name = tagopts.getProperty("http-equiv", "");
if (name.length() > 0) {
metas.put(name.toLowerCase(), CharacterCoding.html2unicode(tagopts.getProperty("content","")));
}
}
}
if (tagname.equalsIgnoreCase("area")) {
final String areatitle = cleanLine(tagopts.getProperty("title",""));
//String alt = tagopts.getProperty("alt","");
final String href = tagopts.getProperty("href", "");
if (href.length() > 0) anchors.put(absolutePath(href), areatitle);
}
if (tagname.equalsIgnoreCase("link")) {
final DigestURI newLink = absolutePath(tagopts.getProperty("href", ""));
if (newLink != null) {
final String type = tagopts.getProperty("rel", "");
final String linktitle = tagopts.getProperty("title", "");
if (type.equalsIgnoreCase("shortcut icon")) {
final ImageEntry ie = new ImageEntry(newLink, linktitle, -1, -1, -1);
images.put(new String(ie.url().hash()), ie);
this.favicon = newLink;
} else if (!type.equalsIgnoreCase("stylesheet") && !type.equalsIgnoreCase("alternate stylesheet")) {
anchors.put(newLink, linktitle);
}
}
}
//start contrib [MN]
if (tagname.equalsIgnoreCase("embed")) {
anchors.put(absolutePath(tagopts.getProperty("src", "")), tagopts.getProperty("name",""));
}
if (tagname.equalsIgnoreCase("param")) {
final String name = tagopts.getProperty("name", "");
if (name.equalsIgnoreCase("movie")) {
anchors.put(absolutePath(tagopts.getProperty("value", "")),name);
}
}
//end contrib [MN]
// fire event
fireScrapeTag0(tagname, tagopts);
}
public void scrapeTag1(final String tagname, final Properties tagopts, final char[] text) {
// System.out.println("ScrapeTag1: tagname=" + tagname + ", opts=" + tagopts.toString() + ", text=" + new String(text));
if (tagname.equalsIgnoreCase("a") && text.length < 2048) {
final String href = tagopts.getProperty("href", "");
DigestURI url;
if ((href.length() > 0) && ((url = absolutePath(href)) != null)) {
final String f = url.getFile();
final int p = f.lastIndexOf('.');
final String type = (p < 0) ? "" : f.substring(p + 1);
if (type.equals("png") || type.equals("gif") || type.equals("jpg") || type.equals("jpeg")) {
// special handling of such urls: put them to the image urls
final ImageEntry ie = new ImageEntry(url, recursiveParse(text), -1, -1, -1);
addImage(images, ie);
} else {
anchors.put(url, recursiveParse(text));
}
}
}
String h;
if ((tagname.equalsIgnoreCase("h1")) && (text.length < 1024)) {
h = recursiveParse(text);
if (h.length() > 0) headlines[0].add(h);
}
if ((tagname.equalsIgnoreCase("h2")) && (text.length < 1024)) {
h = recursiveParse(text);
if (h.length() > 0) headlines[1].add(h);
}
if ((tagname.equalsIgnoreCase("h3")) && (text.length < 1024)) {
h = recursiveParse(text);
if (h.length() > 0) headlines[2].add(h);
}
if ((tagname.equalsIgnoreCase("h4")) && (text.length < 1024)) {
h = recursiveParse(text);
if (h.length() > 0) headlines[3].add(h);
}
if ((tagname.equalsIgnoreCase("title")) && (text.length < 1024)) {
title = recursiveParse(text);
}
// fire event
fireScrapeTag1(tagname, tagopts, text);
}
private String recursiveParse(char[] inlineHtml) {
if (inlineHtml.length < 14) return cleanLine(super.stripAll(new String(inlineHtml)));
// start a new scraper to parse links inside this text
// parsing the content
final ContentScraper scraper = new ContentScraper(this.root);
final TransformerWriter writer = new TransformerWriter(null, null, scraper, null, false);
try {
FileUtils.copy(new CharArrayReader(inlineHtml), writer);
writer.close();
} catch (IOException e) {
Log.logException(e);
return cleanLine(super.stripAll(new String(inlineHtml)));
}
this.anchors.putAll(scraper.getAnchors());
this.images.putAll(scraper.images);
return cleanLine(super.stripAll(new String(scraper.content.getChars())));
}
private static String cleanLine(String s) {
StringBuilder sb = new StringBuilder(s.length());
char c, l = ' ';
for (int i = 0; i < s.length(); i++) {
c = s.charAt(i);
if (c < ' ') c = ' ';
if (c == ' ') {
if (l != ' ') sb.append(c);
} else {
sb.append(c);
}
l = c;
}
// return result
return sb.toString().trim();
}
public String getTitle() {
// construct a title string, even if the document has no title
// some documents have a title tag as meta tag
String s = metas.get("title");
// try to construct the title with the content of the title tag
if (title.length() > 0) {
if (s == null) {
return title;
}
if ((title.compareToIgnoreCase(s) == 0) || (title.indexOf(s) >= 0)) return s;
return title + ": " + s;
}
if (s != null) {
return s;
}
// otherwise take any headline
for (int i = 0; i < 4; i++) {
if (!headlines[i].isEmpty()) return headlines[i].get(0);
}
// take description tag
s = getDescription();
if (s.length() > 0) return s;
// extract headline from content
if (content.length() > 80) {
return cleanLine(new String(content.getChars(), 0, 80));
}
return cleanLine(content.trim().toString());
}
public String[] getHeadlines(final int i) {
assert ((i >= 1) && (i <= 4));
final String[] s = new String[headlines[i - 1].size()];
for (int j = 0; j < headlines[i - 1].size(); j++) s[j] = headlines[i - 1].get(j);
return s;
}
public byte[] getText() {
return this.getText("UTF-8");
}
public byte[] getText(final String charSet) {
try {
return content.getBytes(charSet);
} catch (final UnsupportedEncodingException e) {
return content.getBytes();
}
}
public Map<DigestURI, String> getAnchors() {
// returns a url (String) / name (String) relation
return anchors;
}
/**
* get all images
* @return a map of <urlhash, ImageEntry>
*/
public HashMap<String, ImageEntry> getImages() {
// this resturns a String(absolute url)/htmlFilterImageEntry - relation
return images;
}
public Map<String, String> getMetas() {
return metas;
}
/**
* @return the {@link DigestURI} to the favicon that belongs to the document
*/
public DigestURI getFavicon() {
return this.favicon;
}
/*
DC in html example:
<meta name="DC.title" lang="en" content="Expressing Dublin Core in HTML/XHTML meta and link elements" />
<meta name="DC.creator" content="Andy Powell, UKOLN, University of Bath" />
<meta name="DC.identifier" scheme="DCTERMS.URI" content="http://dublincore.org/documents/dcq-html/" />
<meta name="DC.format" scheme="DCTERMS.IMT" content="text/html" />
<meta name="DC.type" scheme="DCTERMS.DCMIType" content="Text" />
*/
public boolean indexingDenied() {
String s = metas.get("robots");
if (s == null) return false;
if (s.indexOf("noindex") >= 0) return true;
return false;
}
public String getDescription() {
String s = metas.get("description");
if (s == null) s = metas.get("dc.description");
if (s == null) return "";
return s;
}
public String getContentType() {
final String s = metas.get("content-type");
if (s == null) return "";
return s;
}
public String getAuthor() {
String s = metas.get("author");
if (s == null) s = metas.get("copyright");
if (s == null) s = metas.get("dc.creator");
if (s == null) return "";
return s;
}
public HashSet<String> getContentLanguages() {
// i.e. <meta name="DC.language" content="en" scheme="DCTERMS.RFC3066">
// or <meta http-equiv="content-language" content="en">
String s = metas.get("content-language");
if (s == null) s = metas.get("dc.language");
if (s == null) return null;
HashSet<String> hs = new HashSet<String>();
String[] cl = s.split(" |,");
int p;
for (int i = 0; i < cl.length; i++) {
cl[i] = cl[i].toLowerCase();
p = cl[i].indexOf('-');
if (p > 0) cl[i] = cl[i].substring(0, p);
if (ISO639.exists(cl[i])) hs.add(cl[i]);
}
if (hs.isEmpty()) return null;
return hs;
}
public String[] getKeywords() {
String s = metas.get("keywords");
if (s == null) s = metas.get("dc.description");
if (s == null) s = "";
if (s.length() == 0) {
return DigestURI.splitpattern.split(getTitle().toLowerCase());
}
if (s.contains(",")) return s.split(" |,");
if (s.contains(";")) return s.split(" |;");
return s.split("\\s");
}
public int getRefreshSeconds() {
final String s = metas.get("refresh");
if (s == null) return 9999;
try {
final int pos = s.indexOf(';');
if (pos < 0) return 9999;
final int i = Integer.parseInt(s.substring(0, pos));
return i;
} catch (final NumberFormatException e) {
return 9999;
}
}
public String getRefreshPath() {
String s = metas.get("refresh");
if (s == null) return "";
final int pos = s.indexOf(';');
if (pos < 0) return "";
s = s.substring(pos + 1);
if (s.toLowerCase().startsWith("url=")) return s.substring(4).trim();
return "";
}
/*
* (non-Javadoc)
* @see de.anomic.htmlFilter.htmlFilterScraper#close()
*/
@Override
public void close() {
// free resources
super.close();
anchors = null;
images = null;
title = null;
headlines = null;
content = null;
root = null;
}
public void print() {
System.out.println("TITLE :" + title);
for (int i = 0; i < 4; i++) {
System.out.println("HEADLINE" + i + ":" + headlines[i].toString());
}
System.out.println("ANCHORS :" + anchors.toString());
System.out.println("IMAGES :" + images.toString());
System.out.println("METAS :" + metas.toString());
System.out.println("TEXT :" + content.toString());
}
public void registerHtmlFilterEventListener(final ScraperListener listener) {
if (listener != null) {
this.htmlFilterEventListeners.add(ScraperListener.class, listener);
}
}
public void deregisterHtmlFilterEventListener(final ScraperListener listener) {
if (listener != null) {
this.htmlFilterEventListeners.remove(ScraperListener.class, listener);
}
}
private void fireScrapeTag0(final String tagname, final Properties tagopts) {
final Object[] listeners = this.htmlFilterEventListeners.getListenerList();
for (int i=0; i<listeners.length; i+=2) {
if (listeners[i]==ScraperListener.class) {
((ScraperListener)listeners[i+1]).scrapeTag0(tagname, tagopts);
}
}
}
private void fireScrapeTag1(final String tagname, final Properties tagopts, final char[] text) {
final Object[] listeners = this.htmlFilterEventListeners.getListenerList();
for (int i=0; i<listeners.length; i+=2) {
if (listeners[i]==ScraperListener.class) {
((ScraperListener)listeners[i+1]).scrapeTag1(tagname, tagopts, text);
}
}
}
public static ContentScraper parseResource(final File file) throws IOException {
// load page
final byte[] page = FileUtils.read(file);
if (page == null) throw new IOException("no content in file " + file.toString());
// scrape document to look up charset
final ScraperInputStream htmlFilter = new ScraperInputStream(new ByteArrayInputStream(page),"UTF-8",new DigestURI("http://localhost", null),null,false);
final String charset = htmlParser.patchCharsetEncoding(htmlFilter.detectCharset());
// scrape content
final ContentScraper scraper = new ContentScraper(new DigestURI("http://localhost", null));
final Writer writer = new TransformerWriter(null, null, scraper, null, false);
FileUtils.copy(new ByteArrayInputStream(page), writer, Charset.forName(charset));
return scraper;
}
public static void addAllImages(final HashMap<String, ImageEntry> a, final HashMap<String, ImageEntry> b) {
final Iterator<Map.Entry<String, ImageEntry>> i = b.entrySet().iterator();
Map.Entry<String, ImageEntry> ie;
while (i.hasNext()) {
ie = i.next();
addImage(a, ie.getValue());
}
}
public static void addImage(final HashMap<String, ImageEntry> a, final ImageEntry ie) {
if (a.containsKey(new String(ie.url().hash()))) {
// in case of a collision, take that image that has the better image size tags
if ((ie.height() > 0) && (ie.width() > 0)) a.put(new String(ie.url().hash()), ie);
} else {
a.put(new String(ie.url().hash()), ie);
}
}
}
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