mirror of
https://github.com/yacy/yacy_search_server.git
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727dd9b193
- moved storage of robots.txt entries to WorkTables, so it is now possible to browse the robots entries with the table browser git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@6710 6c8d7289-2bf4-0310-a012-ef5d649a1542
258 lines
10 KiB
Java
258 lines
10 KiB
Java
//robotsParser.java
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//-------------------------------------
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//part of YACY
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//
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//(C) 2005, 2006 by Alexander Schier
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// Martin Thelian
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//
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//last change: $LastChangedDate$ by $LastChangedBy$
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//Revision: $LastChangedRevision$
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//
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//This program is free software; you can redistribute it and/or modify
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//it under the terms of the GNU General Public License as published by
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//the Free Software Foundation; either version 2 of the License, or
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//(at your option) any later version.
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//
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//This program is distributed in the hope that it will be useful,
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//but WITHOUT ANY WARRANTY; without even the implied warranty of
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//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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//GNU General Public License for more details.
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//
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//You should have received a copy of the GNU General Public License
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//along with this program; if not, write to the Free Software
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//Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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// extended to return structured objects instead of a Object[] and
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// extended to return a Allow-List by Michael Christen, 21.07.2008
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package de.anomic.crawler;
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import java.io.BufferedReader;
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import java.io.ByteArrayInputStream;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.net.URLDecoder;
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import java.util.ArrayList;
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/*
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* A class for Parsing robots.txt files.
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* It only parses the Deny Part, yet.
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*
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* Robots RFC
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* http://www.robotstxt.org/wc/norobots-rfc.html
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*
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* TODO:
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* - On the request attempt resulted in temporary failure a robot
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* should defer visits to the site until such time as the resource
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* can be retrieved.
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*
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* - Extended Standard for Robot Exclusion
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* See: http://www.conman.org/people/spc/robots2.html
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*
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* - Robot Exclusion Standard Revisited
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* See: http://www.kollar.com/robots.html
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*/
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public final class robotsParser {
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public static final String ROBOTS_USER_AGENT = "User-agent:".toUpperCase();
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public static final String ROBOTS_DISALLOW = "Disallow:".toUpperCase();
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public static final String ROBOTS_ALLOW = "Allow:".toUpperCase();
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public static final String ROBOTS_COMMENT = "#";
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public static final String ROBOTS_SITEMAP = "Sitemap:".toUpperCase();
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public static final String ROBOTS_CRAWL_DELAY = "Crawl-delay:".toUpperCase();
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private ArrayList<String> allowList;
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private ArrayList<String> denyList;
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private String sitemap;
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private long crawlDelayMillis;
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public robotsParser(final byte[] robotsTxt) {
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if ((robotsTxt == null)||(robotsTxt.length == 0)) {
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allowList = new ArrayList<String>(0);
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denyList = new ArrayList<String>(0);
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sitemap = "";
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crawlDelayMillis = 0;
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} else {
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final ByteArrayInputStream bin = new ByteArrayInputStream(robotsTxt);
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final BufferedReader reader = new BufferedReader(new InputStreamReader(bin));
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parse(reader);
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}
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}
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public robotsParser(final BufferedReader reader) {
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if (reader == null) {
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allowList = new ArrayList<String>(0);
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denyList = new ArrayList<String>(0);
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sitemap = "";
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crawlDelayMillis = 0;
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} else {
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parse(reader);
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}
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}
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private void parse(final BufferedReader reader) {
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final ArrayList<String> deny4AllAgents = new ArrayList<String>();
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final ArrayList<String> deny4YaCyAgent = new ArrayList<String>();
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final ArrayList<String> allow4AllAgents = new ArrayList<String>();
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final ArrayList<String> allow4YaCyAgent = new ArrayList<String>();
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int pos;
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String line = null, lineUpper = null;
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sitemap = null;
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crawlDelayMillis = 0;
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boolean isRule4AllAgents = false,
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isRule4YaCyAgent = false,
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rule4YaCyFound = false,
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inBlock = false;
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try {
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lineparser: while ((line = reader.readLine()) != null) {
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// replacing all tabs with spaces
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line = line.replaceAll("\t"," ").trim();
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lineUpper = line.toUpperCase();
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// parse empty line
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if (line.length() == 0) {
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// we have reached the end of the rule block
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if (rule4YaCyFound) {
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// stop here because other robot blocks are either not for YaCy
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// or global settings which shall not overwrite YaCys settings.
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break lineparser;
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}
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continue lineparser;
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}
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// parse comment
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if (line.startsWith(ROBOTS_COMMENT)) {
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// we can ignore this. Just a comment line
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continue lineparser;
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}
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// parse sitemap
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if (lineUpper.startsWith(ROBOTS_SITEMAP)) {
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pos = line.indexOf(' ');
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if (pos != -1) {
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sitemap = line.substring(pos).trim();
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}
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continue lineparser;
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}
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// parse user agent
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if (lineUpper.startsWith(ROBOTS_USER_AGENT)) {
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if (inBlock) {
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// we have detected the start of a new block
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if (rule4YaCyFound) {
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// stop here because other robot blocks are either not for YaCy
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// or global settings which shall not overwrite YaCys settings.
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break lineparser;
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}
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inBlock = false;
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isRule4AllAgents = false;
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isRule4YaCyAgent = false;
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crawlDelayMillis = 0; // each block has a separate delay
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}
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// cutting off comments at the line end
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pos = line.indexOf(ROBOTS_COMMENT);
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if (pos != -1) line = line.substring(0,pos).trim();
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// getting out the robots name
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pos = line.indexOf(' ');
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if (pos != -1) {
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final String userAgent = line.substring(pos).trim();
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isRule4AllAgents |= userAgent.equals("*");
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isRule4YaCyAgent |= userAgent.toLowerCase().indexOf("yacy") >=0;
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isRule4YaCyAgent |= userAgent.toLowerCase().indexOf("yacybot") >=0;
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if (isRule4YaCyAgent) rule4YaCyFound = true;
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}
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continue lineparser;
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}
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// parse crawl delay
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if (lineUpper.startsWith(ROBOTS_CRAWL_DELAY)) {
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inBlock = true;
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if (isRule4YaCyAgent || isRule4AllAgents) {
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pos = line.indexOf(' ');
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if (pos != -1) {
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try {
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// the crawl delay can be a float number and means number of seconds
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crawlDelayMillis = (long) (1000.0 * Float.parseFloat(line.substring(pos).trim()));
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} catch (final NumberFormatException e) {
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// invalid crawling delay
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}
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}
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}
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continue lineparser;
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}
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// parse disallow
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if (lineUpper.startsWith(ROBOTS_DISALLOW) || lineUpper.startsWith(ROBOTS_ALLOW)) {
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inBlock = true;
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final boolean isDisallowRule = lineUpper.startsWith(ROBOTS_DISALLOW);
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if (isRule4YaCyAgent || isRule4AllAgents) {
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// cutting off comments at the line end
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pos = line.indexOf(ROBOTS_COMMENT);
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if (pos != -1) line = line.substring(0,pos).trim();
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// cut off tailing *
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if (line.endsWith("*")) line = line.substring(0,line.length()-1);
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// parse the path
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pos = line.indexOf(' ');
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if (pos >= 0) {
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// getting the path
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String path = line.substring(pos).trim();
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// unencoding all special charsx
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try {
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path = URLDecoder.decode(path, "UTF-8");
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} catch (final Exception e) {
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/*
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* url decoding failed. E.g. because of
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* "Incomplete trailing escape (%) pattern"
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*/
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}
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// escaping all occurences of ; because this char is used as special char in the Robots DB
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path = path.replaceAll(RobotsTxt.ROBOTS_DB_PATH_SEPARATOR,"%3B");
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// adding it to the pathlist
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if (isDisallowRule) {
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if (isRule4AllAgents) deny4AllAgents.add(path);
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if (isRule4YaCyAgent) deny4YaCyAgent.add(path);
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} else {
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if (isRule4AllAgents) allow4AllAgents.add(path);
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if (isRule4YaCyAgent) allow4YaCyAgent.add(path);
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}
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}
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}
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continue lineparser;
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}
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}
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} catch (final IOException e) {}
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allowList = (rule4YaCyFound) ? allow4YaCyAgent : allow4AllAgents;
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denyList = (rule4YaCyFound) ? deny4YaCyAgent : deny4AllAgents;
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}
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public long crawlDelayMillis() {
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return this.crawlDelayMillis;
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}
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public String sitemap() {
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return this.sitemap;
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}
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public ArrayList<String> allowList() {
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return this.allowList;
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}
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public ArrayList<String> denyList() {
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return this.denyList;
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}
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}
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