deleting messages from a POP3 mailbox based on message size and Subject line
/*
* Copyright (c) 2004 David Flanagan. All rights reserved.
* This code is from the book Java Examples in a Nutshell, 3nd Edition.
* It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
* You may study, use, and modify it for any non-commercial purpose,
* including teaching and use in open-source projects.
* You may distribute it non-commercially as long as you retain this notice.
* For a commercial use license, or to purchase the book,
* please visit http://www.davidflanagan.com/javaexamples3.
*/
//package je3.net;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* A simple utility program for deleting messages from a POP3 mailbox based on
* message size and Subject line. Don't run this program unless you understand
* what it is doing. It deletes e-mail without downloading it: YOU MAY
* PERMANENTLY LOSE DATA!
*
* Typical usage: 1) Look at the subject lines for the big messages you've got
* java PopClean -host host -user user -pass pass -size 100000
*
* 2) Create a regular expression to match viral subject lines, and use it to
* delete large matching messages java PopClean -host h -user u -pass p -delete
* -size 100000 \ -subject 'Thank you!|Re: Your application' This will ask for
* confirmation before proceeding.
*
* 3) If you're confident that all big messages are virus-infected, then you can
* skip the -subject argument and delete on size alone java PopClean -host h
* -user u -pass p -delete -size 100000 This will ask for confirmation before
* proceeding.
*/
public class PopClean {
static Socket s = null; // The connection to the server
static BufferedReader in = null; // To read lines from the server
static PrintWriter out = null; // To write to the server
static boolean debug = false; // Are we in debug mode?
public static void main(String args[]) {
try {
String hostname = null, username = null, password = null;
int port = 110;
int sizelimit = -1;
String subjectPattern = null;
Pattern pattern = null;
Matcher matcher = null;
boolean delete = false;
boolean confirm = true;
// Handle command-line arguments
for (int i = 0; i < args.length; i++) {
if (args[i].equals("-user"))
username = args[++i];
else if (args[i].equals("-pass"))
password = args[++i];
else if (args[i].equals("-host"))
hostname = args[++i];
else if (args[i].equals("-port"))
port = Integer.parseInt(args[++i]);
else if (args[i].equals("-size"))
sizelimit = Integer.parseInt(args[++i]);
else if (args[i].equals("-subject"))
subjectPattern = args[++i];
else if (args[i].equals("-debug"))
debug = true;
else if (args[i].equals("-delete"))
delete = true;
else if (args[i].equals("-force")) // don't confirm
confirm = false;
}
// Verify them
if (hostname == null || username == null || password == null || sizelimit == -1)
usage();
// Make sure the pattern is a valid regexp
if (subjectPattern != null) {
pattern = Pattern.compile(subjectPattern);
matcher = pattern.matcher("");
}
// Say what we are going to do
System.out.println("Connecting to " + hostname + " on port " + port + " with username "
+ username + ".");
if (delete) {
System.out.println("Will delete all messages longer than " + sizelimit + " bytes");
if (subjectPattern != null)
System.out.println("that have a subject matching: [" + subjectPattern + "]");
} else {
System.out.println("Will list subject lines for messages " + "longer than " + sizelimit
+ " bytes");
if (subjectPattern != null)
System.out.println("that have a subject matching: [" + subjectPattern + "]");
}
// If asked to delete, ask for confirmation unless -force is given
if (delete && confirm) {
System.out.println();
System.out.print("Do you want to proceed (y/n) [n]: ");
System.out.flush();
BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
String response = console.readLine();
if (!response.equals("y")) {
System.out.println("No messages deleted.");
System.exit(0);
}
}
// Connect to the server, and set up streams
s = new Socket(hostname, port);
in = new BufferedReader(new InputStreamReader(s.getInputStream()));
out = new PrintWriter(new OutputStreamWriter(s.getOutputStream()));
// Read the welcome message from the server, confirming it is OK.
System.out.println("Connected: " + checkResponse());
// Now log in
send("USER " + username); // Send username, wait for response
send("PASS " + password); // Send password, wait for response
System.out.println("Logged in");
// Check how many messages are waiting, and report it
String stat = send("STAT");
StringTokenizer t = new StringTokenizer(stat);
System.out.println(t.nextToken() + " messages in mailbox.");
System.out.println("Total size: " + t.nextToken());
// Get a list of message numbers and sizes
send("LIST"); // Send LIST command, wait for OK response.
// Now read lines from the server until we get . by itself
List msgs = new ArrayList();
String line;
for (;;) {
line = in.readLine();
if (line == null)
throw new IOException("Unexpected EOF");
if (line.equals("."))
break;
msgs.add(line);
}
// Now loop through the lines we read one at a time.
// Each line should specify the message number and its size.
int nummsgs = msgs.size();
for (int i = 0; i < nummsgs; i++) {
String m = (String) msgs.get(i);
StringTokenizer st = new StringTokenizer(m);
int msgnum = Integer.parseInt(st.nextToken());
int msgsize = Integer.parseInt(st.nextToken());
// If the message is too small, ignore it.
if (msgsize <= sizelimit)
continue;
// If we're listing messages, or matching subject lines
// find the subject line for this message
String subject = null;
if (!delete || pattern != null) {
subject = getSubject(msgnum); // get the subject line
// If we couldn't find a subject, skip the message
if (subject == null)
continue;
// If this subject does not match the pattern, then
// skip the message
if (pattern != null) {
matcher.reset(subject);
if (!matcher.matches())
continue;
}
// If we are listing, list this message
if (!delete) {
System.out.println("Subject " + msgnum + ": " + subject);
continue; // so we never delete it
}
}
// If we were asked to delete, then delete the message
if (delete) {
send("DELE " + msgnum);
if (pattern == null)
System.out.println("Deleted message " + msgnum);
else
System.out.println("Deleted message " + msgnum + ": " + subject);
}
}
// When we're done, log out and shutdown the connection
shutdown();
} catch (Exception e) {
// If anything goes wrong print exception and show usage
System.err.println(e);
usage();
// Always try to shutdown nicely so the server doesn't hang on us
shutdown();
}
}
// Explain how to use the program
public static void usage() {
System.err.println("java PopClean <options>");
System.err.println("Options are:\n" + "-host <hostname> # Required\n"
+ "-port <port> # Optional; default is 110\n" + "-user <username> # Required\n"
+ "-pass <password> # Required and sent as cleartext; APOP not supported\n"
+ "-size <limit> # Message size in bytes. Shorter messages are ignored.\n"
+ "-subject <regexp> # Optional java.util.regex.Pattern regular expression\n"
+ " # only messages with a matching Subject line are deleted\n"
+ "-delete # Delete messages; the default is just to list them\n"
+ "-force # Don't ask for confirmation before deleting\n"
+ "-debug # Display POP3 protocol requests and responses\n");
System.exit(1);
}
// Send a POP3 command to the server and return its response
public static String send(String cmd) throws IOException {
if (debug)
System.out.println(">>>" + cmd);
out.print(cmd); // Send command
out.print("\r\n"); // and line terminator.
out.flush(); // Send it now!
String response = checkResponse(); // Get the response.
if (debug)
System.out.println("<<<+OK " + response);
return response;
}
// Wait for a response and make sure it is an "OK" response.
public static String checkResponse() throws IOException {
String response;
for (;;) {
response = in.readLine();
if (response == null)
throw new IOException("Server unexpectedly closed connection");
else if (response.startsWith("-ERR"))
throw new IOException("Error from server: " + response);
else if (response.startsWith("+OK"))
return response.substring(3);
}
}
// Ask the server to send the headers of the numbered message.
// Look through them for the Subject header and return its content.
public static String getSubject(int msgnum) throws IOException {
send("TOP " + msgnum + " 0");
String subject = null, line;
for (;;) {
line = in.readLine();
if (line == null)
throw new IOException("Unexpected EOF");
if (line.startsWith("Subject: "))
subject = line.substring(9);
if (line.equals("."))
break;
}
return subject;
}
// Disconnect nicely from the POP server.
// This method is called for normal termination and exceptions.
public static void shutdown() {
try {
if (out != null) {
send("QUIT");
out.close();
}
if (in != null)
in.close();
if (s != null)
s.close();
} catch (IOException e) {
}
}
}
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