From: gruban@oocities.com
To: tetractys@oocities.com
Subject: Mail Parser for UNIX

Thanks for your Java Post class. I am using it on my own pages and have written a Java class of my own to filter out the form-generated mail from my UNIX news feed.

Basically I put the line

java ParseMail /var/mail/gruban formMail "Subject: FORM results"

Yes, it likely won't work on non-UNIX systems, but I thought you might be interested.

George Ruban, gruban@oocities.com

import java.io.*;
import java.util.StringTokenizer;

/** Class to pull selected mail messages out of a mail file
 * to a separate file. 
 * It seems that the /var/mail/user-name file is separated by
 * From a@b Date lines. 
 * The post mail example is at the end.
 * A minimal valid mail is the next 2 lines.
 * <PRE>
 * From MAILER-DAEMON@cs.bu.edu Wed Aug  6 10:00:30 1997
 * 
 * </PRE>
 * The following file is treated as 2 valid mails.
 * <PRE>
 * From MAILER-DAEMON@cs.bu.edu Wed Aug  6 10:00:30 1997
 * 
 * From MAILER-DAEMON@cs.bu.edu Wed Aug  6 10:00:30 1997
 * </PRE>
 * @author George Ruban
 * @version 1.0 8/6/97
 */
public class ParseMail
{
  /** Usage:
   * java ParseMail /path/to/mail/file /path/to/new/file "selection string" 
   */
  public static void main(String args[]) throws IOException
  {
    if(args.length!= 3)
    {
      System.err.println("Usage: java ParseMail /path/to/mail/file "
			 + "/path/to/new/file \"selection string\"");
      System.exit(1);
    }

    File mailFile = new File(args[0]);
    RandomAccessFile outFile = new RandomAccessFile(args[1], "rw");
    String searchString = args[2];
    DataInputStream in = new DataInputStream(new FileInputStream(mailFile));
    // holds mails to be left in mail file
    StringBuffer outBuf = new StringBuffer((int)mailFile.length());
    
    // read mail, one line at a time.
    String line = "";
    while(line != null)
    {
      // build up a complete mail, one line at a time
      StringBuffer mailBuf = new StringBuffer(1000);
      mailBuf.append(line);
      while(true)
      {
	line = in.readLine();
	if(line == null) break;
	if(line.startsWith("From "))
	{
	  StringTokenizer tok = new StringTokenizer(line);
	  if(tok.countTokens() == 7)
	  {
	    try
	    {
	      tok.nextToken(); // From
	      if(tok.nextToken().indexOf('@') < 0) // MAILER-DAEMON@cs.bu.edu 
		throw new RuntimeException(); 
	      tok.nextToken(); // Wed 
	      tok.nextToken(); // Aug  
	      Integer.parseInt(tok.nextToken());   // 6 
	      if(tok.nextToken().indexOf(':') != 2) // 10:00:30 
		throw new RuntimeException(); 
	      Integer.parseInt(tok.nextToken());   // 1997
	      break; // yup, it's a From - line
	    }
	    catch(RuntimeException notAFromLine) {}
	  }
	}   
	mailBuf.append(line + '\n');
      }

      // complete mail built up in mailBuf
      // decide whether to parse it out or not
      if(mailBuf.toString().indexOf(searchString) >= 0)
      {
	outFile.seek(outFile.length());
	outFile.writeBytes(mailBuf.toString());
      }
      else
      {
	outBuf.append(mailBuf);
      }
    } // end while(line != null)
    
    // complete mail read, write back the unparsed parts
    in.close();
    in = null;
    outFile.close();
    FileOutputStream out = new FileOutputStream(mailFile);
    byte [] buf = new byte[outBuf.length()];
    outBuf.toString().getBytes(0, buf.length, buf, 0);
    out.write(buf);
  }
}

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