//robotsParser.java
//-------------------------------------
//part of YACY
//
//(C) 2005, 2006 by Alexander Schier
// Martin Thelian
//
//last change: $LastChangedDate$ by $LastChangedBy$
//Revision: $LastChangedRevision$
//
//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
//
//Using this software in any meaning (reading, learning, copying, compiling,
//running) means that you agree that the Author(s) is (are) not responsible
//for cost, loss of data or any harm that may be caused directly or indirectly
//by usage of this softare or this documentation. The usage of this software
//is on your own risk. The installation and usage (starting/running) of this
//software may allow other people or application to access your computer and
//any attached devices and is highly dependent on the configuration of the
//software which must be done by the user of the software; the author(s) is
//(are) also not responsible for proper configuration and usage of the
//software, even if provoked by documentation provided together with
//the software.
//
//Any changes to this file according to the GPL as documented in the file
//gpl.txt aside this file in the shipment you received can be done to the
//lines that follows this copyright notice here, but changes must not be
//done inside the copyright notive above. A re-distribution must contain
//the intact and unchanged copyright notice.
//Contributions and changes to the program code must be marked as such.
package de.anomic.data;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Date;
import de.anomic.http.HttpClient;
import de.anomic.http.JakartaCommonsHttpClient;
import de.anomic.http.JakartaCommonsHttpResponse;
import de.anomic.http.httpHeader;
import de.anomic.plasma.plasmaCrawlRobotsTxt;
import de.anomic.plasma.plasmaSwitchboard;
import de.anomic.server.serverByteBuffer;
import de.anomic.server.serverFileUtils;
import de.anomic.server.logging.serverLog;
import de.anomic.yacy.yacyURL;
/*
* A class for Parsing robots.txt files.
* It only parses the Deny Part, yet.
*
* Robots RFC
* http://www.robotstxt.org/wc/norobots-rfc.html
*
* TODO:
* - On the request attempt resulted in temporary failure a robot
* should defer visits to the site until such time as the resource
* can be retrieved.
*
* - Extended Standard for Robot Exclusion
* See: http://www.conman.org/people/spc/robots2.html
*
* - Robot Exclusion Standard Revisited
* See: http://www.kollar.com/robots.html
*/
public final class robotsParser{
public static final int DOWNLOAD_ACCESS_RESTRICTED = 0;
public static final int DOWNLOAD_ROBOTS_TXT = 1;
public static final int DOWNLOAD_ETAG = 2;
public static final int DOWNLOAD_MODDATE = 3;
public static final String ROBOTS_USER_AGENT = "User-agent:".toUpperCase();
public static final String ROBOTS_DISALLOW = "Disallow:".toUpperCase();
public static final String ROBOTS_ALLOW = "Allow:".toUpperCase();
public static final String ROBOTS_COMMENT = "#";
public static final String ROBOTS_SITEMAP = "Sitemap:".toUpperCase();
public static final String ROBOTS_CRAWL_DELAY = "Crawl-Delay:".toUpperCase();
/*public robotsParser(URL robotsUrl){
}*/
/*
* this parses the robots.txt.
* at the Moment it only creates a list of Deny Paths
*/
public static Object[] parse(File robotsFile) throws IOException {
BufferedReader reader = null;
try {
reader = new BufferedReader(new FileReader(robotsFile));
return parse(reader);
} finally {
if (reader != null) try{reader.close();}catch(Exception e){/* ignore this */}
}
}
@SuppressWarnings("unchecked")
public static Object[] parse(byte[] robotsTxt) throws IOException {
if ((robotsTxt == null)||(robotsTxt.length == 0)) return new Object[]{new ArrayList(0),null,null};
ByteArrayInputStream bin = new ByteArrayInputStream(robotsTxt);
BufferedReader reader = new BufferedReader(new InputStreamReader(bin));
return parse(reader);
}
public static Object[] parse(BufferedReader reader) throws IOException{
ArrayList<String> deny4AllAgents = new ArrayList<String>();
ArrayList<String> deny4YaCyAgent = new ArrayList<String>();
int pos;
String line = null, lineUpper = null, sitemap = null;
Integer crawlDelay = null;
boolean isRuleBlock4AllAgents = false,
isRuleBlock4YaCyAgent = false,
rule4YaCyFound = false,
inBlock = false;
while ((line = reader.readLine()) != null) {
line = line.trim();
lineUpper = line.toUpperCase();
if (line.length() == 0) {
// OLD: we have reached the end of the rule block
// rule4Yacy = false; inBlock = false;
// NEW: just ignore it
} else if (line.startsWith(ROBOTS_COMMENT)) {
// we can ignore this. Just a comment line
} else if (lineUpper.startsWith(ROBOTS_SITEMAP)) {
pos = line.indexOf(" ");
if (pos != -1) {
sitemap = line.substring(pos).trim();
}
} else if (lineUpper.startsWith(ROBOTS_USER_AGENT)) {
if (inBlock) {
// we have detected the start of a new block
inBlock = false;
isRuleBlock4AllAgents = false;
isRuleBlock4YaCyAgent = false;
crawlDelay = null; // each block has a separate delay
}
// cutting off comments at the line end
pos = line.indexOf(ROBOTS_COMMENT);
if (pos != -1) line = line.substring(0,pos).trim();
// replacing all tabs with spaces
line = line.replaceAll("\t"," ");
// getting out the robots name
pos = line.indexOf(" ");
if (pos != -1) {
String userAgent = line.substring(pos).trim();
isRuleBlock4AllAgents |= userAgent.equals("*");
isRuleBlock4YaCyAgent |= userAgent.toLowerCase().indexOf("yacy") >=0;
if (isRuleBlock4YaCyAgent) rule4YaCyFound = true;
}
} else if (lineUpper.startsWith(ROBOTS_CRAWL_DELAY)) {
pos = line.indexOf(" ");
if (pos != -1) {
try {
crawlDelay = Integer.valueOf(line.substring(pos).trim());
} catch (NumberFormatException e) {
// invalid crawling delay
}
}
} else if (lineUpper.startsWith(ROBOTS_DISALLOW) ||
lineUpper.startsWith(ROBOTS_ALLOW)) {
inBlock = true;
boolean isDisallowRule = lineUpper.startsWith(ROBOTS_DISALLOW);
if (isRuleBlock4YaCyAgent || isRuleBlock4AllAgents) {
// cutting off comments at the line end
pos = line.indexOf(ROBOTS_COMMENT);
if (pos != -1) line = line.substring(0,pos).trim();
// cutting of tailing *
if (line.endsWith("*")) line = line.substring(0,line.length()-1);
// replacing all tabs with spaces
line = line.replaceAll("\t"," ");
// getting the path
pos = line.indexOf(" ");
if (pos != -1) {
// getting the path
String path = line.substring(pos).trim();
// unencoding all special charsx
try {
path = URLDecoder.decode(path,"UTF-8");
} catch (Exception e) {
/*
* url decoding failed. E.g. because of
* "Incomplete trailing escape (%) pattern"
*/
}
// escaping all occurences of ; because this char is used as special char in the Robots DB
path = path.replaceAll(plasmaCrawlRobotsTxt.ROBOTS_DB_PATH_SEPARATOR,"%3B");
// adding it to the pathlist
if (!isDisallowRule) path = "!" + path;
if (isRuleBlock4AllAgents) deny4AllAgents.add(path);
if (isRuleBlock4YaCyAgent) deny4YaCyAgent.add(path);
}
}
}
}
ArrayList<String> denyList = (rule4YaCyFound) ? deny4YaCyAgent : deny4AllAgents;
return new Object[]{denyList,sitemap,crawlDelay};
}
private static final int getPort(yacyURL theURL) {
int port = theURL.getPort();
if (port == -1) {
if (theURL.getProtocol().equalsIgnoreCase("http")) {
port = 80;
} else if (theURL.getProtocol().equalsIgnoreCase("https")) {
port = 443;
}
}
return port;
}
private static final String getHostPort(yacyURL theURL) {
String urlHostPort = null;
int port = getPort(theURL);
urlHostPort = theURL.getHost() + ":" + port;
urlHostPort = urlHostPort.toLowerCase().intern();
return urlHostPort;
}
public static yacyURL getSitemapURL(yacyURL theURL) {
if (theURL == null) throw new IllegalArgumentException();
yacyURL sitemapURL = null;
// generating the hostname:poart string needed to do a DB lookup
String urlHostPort = getHostPort(theURL);
plasmaCrawlRobotsTxt.Entry robotsTxt4Host = null;
synchronized(urlHostPort) {
// doing a DB lookup to determine if the robots data is already available
robotsTxt4Host = plasmaSwitchboard.robots.getEntry(urlHostPort);
}
if (robotsTxt4Host == null) return null;
try {
String sitemapUrlStr = robotsTxt4Host.getSitemap();
if (sitemapUrlStr != null) sitemapURL = new yacyURL(sitemapUrlStr, null);
} catch (MalformedURLException e) {/* ignore this */}
return sitemapURL;
}
public static Integer getCrawlDelay(yacyURL theURL) {
if (theURL == null) throw new IllegalArgumentException();
Integer crawlDelay = null;
// generating the hostname:poart string needed to do a DB lookup
String urlHostPort = getHostPort(theURL);
plasmaCrawlRobotsTxt.Entry robotsTxt4Host = null;
synchronized(urlHostPort) {
// doing a DB lookup to determine if the robots data is already available
robotsTxt4Host = plasmaSwitchboard.robots.getEntry(urlHostPort);
}
if (robotsTxt4Host == null) return null;
try {
crawlDelay = robotsTxt4Host.getCrawlDelay();
} catch (NumberFormatException e) {/* ignore this */}
return crawlDelay;
}
@SuppressWarnings("unchecked")
public static boolean isDisallowed(yacyURL nexturl) {
if (nexturl == null) throw new IllegalArgumentException();
// generating the hostname:poart string needed to do a DB lookup
String urlHostPort = getHostPort(nexturl);
plasmaCrawlRobotsTxt.Entry robotsTxt4Host = null;
synchronized(urlHostPort) {
// doing a DB lookup to determine if the robots data is already available
robotsTxt4Host = plasmaSwitchboard.robots.getEntry(urlHostPort);
// if we have not found any data or the data is older than 7 days, we need to load it from the remote server
if (
(robotsTxt4Host == null) ||
(robotsTxt4Host.getLoadedDate() == null) ||
(System.currentTimeMillis() - robotsTxt4Host.getLoadedDate().getTime() > 7*24*60*60*1000)
) {
yacyURL robotsURL = null;
// generating the proper url to download the robots txt
try {
robotsURL = new yacyURL(nexturl.getProtocol(),nexturl.getHost(),getPort(nexturl),"/robots.txt");
} catch (MalformedURLException e) {
serverLog.logSevere("ROBOTS","Unable to generate robots.txt URL for URL '" + nexturl.toString() + "'.");
return false;
}
Object[] result = null;
boolean accessCompletelyRestricted = false;
byte[] robotsTxt = null;
String eTag = null;
Date modDate = null;
try {
serverLog.logFine("ROBOTS","Trying to download the robots.txt file from URL '" + robotsURL + "'.");
result = downloadRobotsTxt(robotsURL,5,robotsTxt4Host);
if (result != null) {
accessCompletelyRestricted = ((Boolean)result[DOWNLOAD_ACCESS_RESTRICTED]).booleanValue();
robotsTxt = (byte[])result[DOWNLOAD_ROBOTS_TXT];
eTag = (String) result[DOWNLOAD_ETAG];
modDate = (Date) result[DOWNLOAD_MODDATE];
} else if (robotsTxt4Host != null) {
robotsTxt4Host.setLoadedDate(new Date());
plasmaSwitchboard.robots.addEntry(robotsTxt4Host);
}
} catch (Exception e) {
serverLog.logSevere("ROBOTS","Unable to download the robots.txt file from URL '" + robotsURL + "'. " + e.getMessage());
}
if ((robotsTxt4Host==null)||((robotsTxt4Host!=null)&&(result!=null))) {
ArrayList<String> denyPath = null;
String sitemap = null;
Integer crawlDelay = null;
if (accessCompletelyRestricted) {
denyPath = new ArrayList<String>();
denyPath.add("/");
} else {
// parsing the robots.txt Data and converting it into an arraylist
try {
Object[] parserResult = robotsParser.parse(robotsTxt);
denyPath = (ArrayList<String>) parserResult[0];
sitemap = (String) parserResult[1];
crawlDelay = (Integer) parserResult[2];
} catch (IOException e) {
serverLog.logSevere("ROBOTS","Unable to parse the robots.txt file from URL '" + robotsURL + "'.");
}
}
// storing the data into the robots DB
robotsTxt4Host = plasmaSwitchboard.robots.addEntry(urlHostPort,denyPath,new Date(),modDate,eTag,sitemap,crawlDelay);
}
}
}
if (robotsTxt4Host.isDisallowed(nexturl.getFile())) {
return true;
}
return false;
}
static Object[] downloadRobotsTxt(yacyURL robotsURL, int redirectionCount, plasmaCrawlRobotsTxt.Entry entry) throws Exception {
if (redirectionCount < 0) return new Object[]{Boolean.FALSE,null,null};
redirectionCount--;
boolean accessCompletelyRestricted = false;
byte[] robotsTxt = null;
long downloadStart, downloadEnd;
String eTag=null, oldEtag = null;
Date lastMod=null;
downloadStart = System.currentTimeMillis();
// if we previously have downloaded this robots.txt then we can set the if-modified-since header
httpHeader reqHeaders = new httpHeader();
// adding referer
reqHeaders.put(httpHeader.REFERER, (yacyURL.newURL(robotsURL,"/")).toNormalform(true, true));
if (entry != null) {
oldEtag = entry.getETag();
reqHeaders = new httpHeader();
Date modDate = entry.getModDate();
if (modDate != null) reqHeaders.put(httpHeader.IF_MODIFIED_SINCE,HttpClient.dateString(entry.getModDate()));
}
// setup http-client
//TODO: adding Traffic statistic for robots download?
JakartaCommonsHttpClient client = new JakartaCommonsHttpClient(10000, reqHeaders, null);
JakartaCommonsHttpResponse res = null;
try {
// sending the get request
res = client.GET(robotsURL.toString());
// check for interruption
if (Thread.currentThread().isInterrupted()) throw new InterruptedException("Shutdown in progress.");
// check the response status
if (res.getStatusLine().startsWith("2")) {
if (!res.getResponseHeader().mime().startsWith("text/plain")) {
robotsTxt = null;
serverLog.logFinest("ROBOTS","Robots.txt from URL '" + robotsURL + "' has wrong mimetype '" + res.getResponseHeader().mime() + "'.");
} else {
// getting some metadata
eTag = res.getResponseHeader().containsKey(httpHeader.ETAG)?((String)res.getResponseHeader().get(httpHeader.ETAG)).trim():null;
lastMod = res.getResponseHeader().lastModified();
// if the robots.txt file was not changed we break here
if ((eTag != null) && (oldEtag != null) && (eTag.equals(oldEtag))) {
serverLog.logFinest("ROBOTS","Robots.txt from URL '" + robotsURL + "' was not modified. Abort downloading of new version.");
return null;
}
// downloading the content
serverByteBuffer sbb = new serverByteBuffer();
try {
serverFileUtils.copyToStream(new BufferedInputStream(res.getDataAsStream()), new BufferedOutputStream(sbb));
} finally {
res.closeStream();
}
robotsTxt = sbb.getBytes();
downloadEnd = System.currentTimeMillis();
serverLog.logFinest("ROBOTS","Robots.txt successfully loaded from URL '" + robotsURL + "' in " + (downloadEnd-downloadStart) + " ms.");
}
} else if (res.getStatusCode() == 304) {
return null;
} else if (res.getStatusLine().startsWith("3")) {
// getting redirection URL
String redirectionUrlString = (String) res.getResponseHeader().get(httpHeader.LOCATION);
if (redirectionUrlString==null) {
serverLog.logFinest("ROBOTS","robots.txt could not be downloaded from URL '" + robotsURL + "' because of missing redirecton header. [" + res.getStatusLine() + "].");
robotsTxt = null;
}
redirectionUrlString = redirectionUrlString.trim();
// generating the new URL object
yacyURL redirectionUrl = yacyURL.newURL(robotsURL, redirectionUrlString);
// following the redirection
serverLog.logFinest("ROBOTS","Redirection detected for robots.txt with URL '" + robotsURL + "'." +
"\nRedirecting request to: " + redirectionUrl);
return downloadRobotsTxt(redirectionUrl,redirectionCount,entry);
} else if (res.getStatusCode() == 401 || res.getStatusCode() == 403) {
accessCompletelyRestricted = true;
serverLog.logFinest("ROBOTS","Access to Robots.txt not allowed on URL '" + robotsURL + "'.");
} else {
serverLog.logFinest("ROBOTS","robots.txt could not be downloaded from URL '" + robotsURL + "'. [" + res.getStatusLine() + "].");
robotsTxt = null;
}
} catch (Exception e) {
throw e;
} finally {
if(res != null) {
// release connection
res.closeStream();
}
}
return new Object[]{new Boolean(accessCompletelyRestricted),robotsTxt,eTag,lastMod};
}
}