panda.net.pop3.POP3Client Maven / Gradle / Ivy
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package panda.net.pop3;
import java.io.IOException;
import java.io.Reader;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ListIterator;
import java.util.StringTokenizer;
import panda.net.io.DotTerminatedMessageReader;
/***
* The POP3Client class implements the client side of the Internet POP3 Protocol defined in RFC
* 1939. All commands are supported, including the APOP command which requires MD5 encryption. See
* RFC 1939 for more details on the POP3 protocol.
*
* Rather than list it separately for each method, we mention here that every method communicating
* with the server and throwing an IOException can also throw a
* {@link panda.net.MalformedServerReplyException} , which is a subclass of IOException. A
* MalformedServerReplyException will be thrown when the reply received from the server deviates
* enough from the protocol specification that it cannot be interpreted in a useful manner despite
* attempts to be as lenient as possible.
*
* @see POP3MessageInfo
* @see panda.net.io.DotTerminatedMessageReader
* @see panda.net.MalformedServerReplyException
***/
public class POP3Client extends POP3 {
private static POP3MessageInfo __parseStatus(String line) {
int num, size;
StringTokenizer tokenizer;
tokenizer = new StringTokenizer(line);
if (!tokenizer.hasMoreElements()) {
return null;
}
num = size = 0;
try {
num = Integer.parseInt(tokenizer.nextToken());
if (!tokenizer.hasMoreElements()) {
return null;
}
size = Integer.parseInt(tokenizer.nextToken());
}
catch (NumberFormatException e) {
return null;
}
return new POP3MessageInfo(num, size);
}
private static POP3MessageInfo __parseUID(String line) {
int num;
StringTokenizer tokenizer;
tokenizer = new StringTokenizer(line);
if (!tokenizer.hasMoreElements()) {
return null;
}
num = 0;
try {
num = Integer.parseInt(tokenizer.nextToken());
if (!tokenizer.hasMoreElements()) {
return null;
}
line = tokenizer.nextToken();
}
catch (NumberFormatException e) {
return null;
}
return new POP3MessageInfo(num, line);
}
/***
* Send a CAPA command to the POP3 server.
*
* @return True if the command was successful, false if not.
* @exception IOException If a network I/O error occurs in the process of sending the CAPA
* command.
***/
public boolean capa() throws IOException {
if (sendCommand(POP3Command.CAPA) == POP3Reply.OK) {
getAdditionalReply();
return true;
}
return false;
}
/***
* Login to the POP3 server with the given username and password. You must first connect to the
* server with {@link panda.net.SocketClient#connect connect } before attempting to login. A
* login attempt is only valid if the client is in the
* {@link panda.net.pop3.POP3#AUTHORIZATION_STATE AUTHORIZATION_STATE } . After logging in, the
* client enters the {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } .
*
* @param username The account name being logged in to.
* @param password The plain text password of the account.
* @return True if the login attempt was successful, false if not.
* @exception IOException If a network I/O error occurs in the process of logging in.
***/
public boolean login(String username, String password) throws IOException {
if (getState() != AUTHORIZATION_STATE) {
return false;
}
if (sendCommand(POP3Command.USER, username) != POP3Reply.OK) {
return false;
}
if (sendCommand(POP3Command.PASS, password) != POP3Reply.OK) {
return false;
}
setState(TRANSACTION_STATE);
return true;
}
/***
* Login to the POP3 server with the given username and authentication information. Use this
* method when connecting to a server requiring authentication using the APOP command. Because
* the timestamp produced in the greeting banner varies from server to server, it is not
* possible to consistently extract the information. Therefore, after connecting to the server,
* you must call {@link panda.net.pop3.POP3#getReplyString getReplyString } and parse out the
* timestamp information yourself.
*
* You must first connect to the server with {@link panda.net.SocketClient#connect connect }
* before attempting to login. A login attempt is only valid if the client is in the
* {@link panda.net.pop3.POP3#AUTHORIZATION_STATE AUTHORIZATION_STATE } . After logging in, the
* client enters the {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } . After
* connecting, you must parse out the server specific information to use as a timestamp, and
* pass that information to this method. The secret is a shared secret known to you and the
* server. See RFC 1939 for more details regarding the APOP command.
*
* @param username The account name being logged in to.
* @param timestamp The timestamp string to combine with the secret.
* @param secret The shared secret which produces the MD5 digest when combined with the
* timestamp.
* @return True if the login attempt was successful, false if not.
* @exception IOException If a network I/O error occurs in the process of logging in.
* @exception NoSuchAlgorithmException If the MD5 encryption algorithm cannot be instantiated by
* the Java runtime system.
***/
public boolean login(String username, String timestamp, String secret) throws IOException, NoSuchAlgorithmException {
int i;
byte[] digest;
StringBuilder buffer, digestBuffer;
MessageDigest md5;
if (getState() != AUTHORIZATION_STATE) {
return false;
}
md5 = MessageDigest.getInstance("MD5");
timestamp += secret;
digest = md5.digest(timestamp.getBytes(getCharsetName())); // Java 1.6 can use getCharset()
digestBuffer = new StringBuilder(128);
for (i = 0; i < digest.length; i++) {
int digit = digest[i] & 0xff;
if (digit <= 15) { // Add leading zero if necessary (NET-351)
digestBuffer.append("0");
}
digestBuffer.append(Integer.toHexString(digit));
}
buffer = new StringBuilder(256);
buffer.append(username);
buffer.append(' ');
buffer.append(digestBuffer.toString());
if (sendCommand(POP3Command.APOP, buffer.toString()) != POP3Reply.OK) {
return false;
}
setState(TRANSACTION_STATE);
return true;
}
/***
* Logout of the POP3 server. To fully disconnect from the server you must call
* {@link panda.net.pop3.POP3#disconnect disconnect }. A logout attempt is valid in any state.
* If the client is in the {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } , it
* enters the {@link panda.net.pop3.POP3#UPDATE_STATE UPDATE_STATE } on a successful logout.
*
* @return True if the logout attempt was successful, false if not.
* @exception IOException If a network I/O error occurs in the process of logging out.
***/
public boolean logout() throws IOException {
if (getState() == TRANSACTION_STATE) {
setState(UPDATE_STATE);
}
sendCommand(POP3Command.QUIT);
return (_replyCode == POP3Reply.OK);
}
/***
* Send a NOOP command to the POP3 server. This is useful for keeping a connection alive since
* most POP3 servers will timeout after 10 minutes of inactivity. A noop attempt will only
* succeed if the client is in the {@link panda.net.pop3.POP3#TRANSACTION_STATE
* TRANSACTION_STATE } .
*
* @return True if the noop attempt was successful, false if not.
* @exception IOException If a network I/O error occurs in the process of sending the NOOP
* command.
***/
public boolean noop() throws IOException {
if (getState() == TRANSACTION_STATE) {
return (sendCommand(POP3Command.NOOP) == POP3Reply.OK);
}
return false;
}
/***
* Delete a message from the POP3 server. The message is only marked for deletion by the server.
* If you decide to unmark the message, you must issuse a {@link #reset reset } command.
* Messages marked for deletion are only deleted by the server on {@link #logout logout }. A
* delete attempt can only succeed if the client is in the
* {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } .
*
* @param messageId The message number to delete.
* @return True if the deletion attempt was successful, false if not.
* @exception IOException If a network I/O error occurs in the process of sending the delete
* command.
***/
public boolean deleteMessage(int messageId) throws IOException {
if (getState() == TRANSACTION_STATE) {
return (sendCommand(POP3Command.DELE, Integer.toString(messageId)) == POP3Reply.OK);
}
return false;
}
/***
* Reset the POP3 session. This is useful for undoing any message deletions that may have been
* performed. A reset attempt can only succeed if the client is in the
* {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } .
*
* @return True if the reset attempt was successful, false if not.
* @exception IOException If a network I/O error occurs in the process of sending the reset
* command.
***/
public boolean reset() throws IOException {
if (getState() == TRANSACTION_STATE) {
return (sendCommand(POP3Command.RSET) == POP3Reply.OK);
}
return false;
}
/***
* Get the mailbox status. A status attempt can only succeed if the client is in the
* {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } . Returns a POP3MessageInfo
* instance containing the number of messages in the mailbox and the total size of the messages
* in bytes. Returns null if the status the attempt fails.
*
* @return A POP3MessageInfo instance containing the number of messages in the mailbox and the
* total size of the messages in bytes. Returns null if the status the attempt fails.
* @exception IOException If a network I/O error occurs in the process of sending the status
* command.
***/
public POP3MessageInfo status() throws IOException {
if (getState() != TRANSACTION_STATE) {
return null;
}
if (sendCommand(POP3Command.STAT) != POP3Reply.OK) {
return null;
}
return __parseStatus(_lastReplyLine.substring(3));
}
/***
* List an individual message. A list attempt can only succeed if the client is in the
* {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } . Returns a POP3MessageInfo
* instance containing the number of the listed message and the size of the message in bytes.
* Returns null if the list attempt fails (e.g., if the specified message number does not
* exist).
*
* @param messageId The number of the message list.
* @return A POP3MessageInfo instance containing the number of the listed message and the size
* of the message in bytes. Returns null if the list attempt fails.
* @exception IOException If a network I/O error occurs in the process of sending the list
* command.
***/
public POP3MessageInfo listMessage(int messageId) throws IOException {
if (getState() != TRANSACTION_STATE) {
return null;
}
if (sendCommand(POP3Command.LIST, Integer.toString(messageId)) != POP3Reply.OK) {
return null;
}
return __parseStatus(_lastReplyLine.substring(3));
}
/***
* List all messages. A list attempt can only succeed if the client is in the
* {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } . Returns an array of
* POP3MessageInfo instances, each containing the number of a message and its size in bytes. If
* there are no messages, this method returns a zero length array. If the list attempt fails, it
* returns null.
*
* @return An array of POP3MessageInfo instances representing all messages in the order they
* appear in the mailbox, each containing the number of a message and its size in bytes.
* If there are no messages, this method returns a zero length array. If the list
* attempt fails, it returns null.
* @exception IOException If a network I/O error occurs in the process of sending the list
* command.
***/
public POP3MessageInfo[] listMessages() throws IOException {
if (getState() != TRANSACTION_STATE) {
return null;
}
if (sendCommand(POP3Command.LIST) != POP3Reply.OK) {
return null;
}
getAdditionalReply();
// This could be a zero length array if no messages present
POP3MessageInfo[] messages = new POP3MessageInfo[_replyLines.size() - 2]; // skip first and
// last lines
ListIterator en = _replyLines.listIterator(1); // Skip first line
// Fetch lines.
for (int line = 0; line < messages.length; line++) {
messages[line] = __parseStatus(en.next());
}
return messages;
}
/***
* List the unique identifier for a message. A list attempt can only succeed if the client is in
* the {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } . Returns a
* POP3MessageInfo instance containing the number of the listed message and the unique
* identifier for that message. Returns null if the list attempt fails (e.g., if the specified
* message number does not exist).
*
* @param messageId The number of the message list.
* @return A POP3MessageInfo instance containing the number of the listed message and the unique
* identifier for that message. Returns null if the list attempt fails.
* @exception IOException If a network I/O error occurs in the process of sending the list
* unique identifier command.
***/
public POP3MessageInfo listUniqueIdentifier(int messageId) throws IOException {
if (getState() != TRANSACTION_STATE) {
return null;
}
if (sendCommand(POP3Command.UIDL, Integer.toString(messageId)) != POP3Reply.OK) {
return null;
}
return __parseUID(_lastReplyLine.substring(3));
}
/***
* List the unique identifiers for all messages. A list attempt can only succeed if the client
* is in the {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE } . Returns an array
* of POP3MessageInfo instances, each containing the number of a message and its unique
* identifier. If there are no messages, this method returns a zero length array. If the list
* attempt fails, it returns null.
*
* @return An array of POP3MessageInfo instances representing all messages in the order they
* appear in the mailbox, each containing the number of a message and its unique
* identifier If there are no messages, this method returns a zero length array. If the
* list attempt fails, it returns null.
* @exception IOException If a network I/O error occurs in the process of sending the list
* unique identifier command.
***/
public POP3MessageInfo[] listUniqueIdentifiers() throws IOException {
if (getState() != TRANSACTION_STATE) {
return null;
}
if (sendCommand(POP3Command.UIDL) != POP3Reply.OK) {
return null;
}
getAdditionalReply();
// This could be a zero length array if no messages present
POP3MessageInfo[] messages = new POP3MessageInfo[_replyLines.size() - 2]; // skip first and
// last lines
ListIterator en = _replyLines.listIterator(1); // skip first line
// Fetch lines.
for (int line = 0; line < messages.length; line++) {
messages[line] = __parseUID(en.next());
}
return messages;
}
/**
* Retrieve a message from the POP3 server. A retrieve message attempt can only succeed if the
* client is in the {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE }
*
* You must not issue any commands to the POP3 server (i.e., call any other methods) until you
* finish reading the message from the returned BufferedReader instance. The POP3 protocol uses
* the same stream for issuing commands as it does for returning results. Therefore the returned
* BufferedReader actually reads directly from the POP3 connection. After the end of message has
* been reached, new commands can be executed and their replies read. If you do not follow these
* requirements, your program will not work properly.
*
* @param messageId The number of the message to fetch.
* @return A DotTerminatedMessageReader instance from which the entire message can be read. This
* can safely be cast to a {@link java.io.BufferedReader BufferedReader} in order to use
* the {@link java.io.BufferedReader#readLine() BufferedReader#readLine()} method.
* Returns null if the retrieval attempt fails (e.g., if the specified message number
* does not exist).
* @exception IOException If a network I/O error occurs in the process of sending the retrieve
* message command.
*/
public Reader retrieveMessage(int messageId) throws IOException {
if (getState() != TRANSACTION_STATE) {
return null;
}
if (sendCommand(POP3Command.RETR, Integer.toString(messageId)) != POP3Reply.OK) {
return null;
}
return new DotTerminatedMessageReader(_reader);
}
/**
* Retrieve only the specified top number of lines of a message from the POP3 server. A retrieve
* top lines attempt can only succeed if the client is in the
* {@link panda.net.pop3.POP3#TRANSACTION_STATE TRANSACTION_STATE }
*
* You must not issue any commands to the POP3 server (i.e., call any other methods) until you
* finish reading the message from the returned BufferedReader instance. The POP3 protocol uses
* the same stream for issuing commands as it does for returning results. Therefore the returned
* BufferedReader actually reads directly from the POP3 connection. After the end of message has
* been reached, new commands can be executed and their replies read. If you do not follow these
* requirements, your program will not work properly.
*
* @param messageId The number of the message to fetch.
* @param numLines The top number of lines to fetch. This must be >= 0.
* @return A DotTerminatedMessageReader instance from which the specified top number of lines of
* the message can be read. This can safely be cast to a {@link java.io.BufferedReader
* BufferedReader} in order to use the {@link java.io.BufferedReader#readLine()
* BufferedReader#readLine()} method. Returns null if the retrieval attempt fails (e.g.,
* if the specified message number does not exist).
* @exception IOException If a network I/O error occurs in the process of sending the top
* command.
*/
public Reader retrieveMessageTop(int messageId, int numLines) throws IOException {
if (numLines < 0 || getState() != TRANSACTION_STATE) {
return null;
}
if (sendCommand(POP3Command.TOP, Integer.toString(messageId) + " " + Integer.toString(numLines)) != POP3Reply.OK) {
return null;
}
return new DotTerminatedMessageReader(_reader);
}
}