a simple robotsParser.

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@652 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/data/robotsParser.java

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+// robotsParser.java 
+// -------------------------------------
+// part of YACY
+// (C) by Michael Peter Christen; mc@anomic.de
+// first published on http://www.anomic.de
+// Frankfurt, Germany, 2004
+//
+// This file ist contributed by Alexander Schier
+// last major change: 05.09.2005
+//
+// 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.
+
+import java.lang.String;
+import java.util.Vector;
+import java.util.Iterator;
+import java.io.IOException;
+import java.io.File;
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.net.URL;
+
+/*
+ * A class for Parsing robots.txt files.
+ * It only parses the Deny Part, yet.
+ * TODO: Allow, Do not deny if User-Agent: != yacy
+ *
+ * Use:
+ * robotsParser rp=new Robotsparser(robotsfile);
+ * if(rp.isAllowedRobots("/test")){
+ *   System.out.println("/test is allowed");
+ * }
+ */
+public class robotsParser{
+	String robotstxt="";
+	Vector deny;
+	/*
+	 * constructor with a robots.txt as string
+	 */
+	public robotsParser(String robots){
+		robotstxt=robots;
+		parse();
+	}
+	/*
+	 * constructor with a robots.txt as Filehandle
+	 */
+	public robotsParser(File robotsFile){
+		String robots="";
+		String line="";
+		try{
+			BufferedReader br=new BufferedReader(new FileReader(robotsFile));
+			while( (line=br.readLine()) != null){
+				robots+=line+"\n";
+			}
+		}catch(IOException e){
+			System.out.println("File Error");
+		}
+		robotstxt=robots;
+		parse();
+	}
+	/*public robotsParser(URL robotsUrl){
+	}*/
+	/*
+	 * this parses the robots.txt.
+	 * at the Moment it only creates a list of Deny Paths
+	 */
+	private void parse(){
+		deny=new Vector();
+		String[] lines = robotstxt.split("\n");
+		String line;
+		for(int i=0;i<lines.length;i++){
+			line=lines[i];
+			if(line.startsWith("Disallow:")){
+				line=line.substring(9);
+				if(line.startsWith(" ")){
+					line=line.substring(1);
+				}
+				deny.add(line);
+			}
+		}
+	}
+	/*
+	 * Check if a url is allowed.
+	 */
+	public boolean isAllowedRobots(String url){
+		boolean allowed=false;
+		if(deny !=null){
+			Iterator it=deny.iterator();
+			allowed=true;
+			while(it.hasNext()){
+				if(url.indexOf((String)it.next()) >= 0){
+					allowed=false;
+					break;
+				}
+			}
+		}
+		return allowed;
+	}
+
+	/*
+	 * Test the class with a file robots.txt in the workdir and a testpath as argument.
+	 */
+	public static void main(String[] args){
+		robotsParser rp=new robotsParser(new File("robots.txt"));
+		for(int i=0;i<args.length;i++){
+			if(rp.isAllowedRobots(args[i])){
+				System.out.println(args[i]+" is allowed.");
+			}else{
+				System.out.println(args[i]+" is NOT allowed.");
+			}
+		}
+	}
+}