/**
* Default constructor. Create a new FTP client and connect to a specified server.
*
* @param server Address of an FTP server
*/
public Ftp(String server) {
serverAddr = server;
debug = true;
try {
sock = new Socket(server, 21);
System.out.println("Connected to " + server);
out = new PrintWriter(sock.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(sock.getInputStream()));
System.out.println(getResponse());
} catch (IOException e) {
System.err.println(e.getMessage());
System.exit(1);
}
}
/**
* Main method which is in charge of parsing and interpreting user input and interacting with the
* FTP client.
*
* @param args Command line arguments; should only contain the server
*/
public static void main(String args[]) {
boolean eof = false;
String input = null;
Scanner in = new Scanner(System.in);
if (args.length != 1) {
System.err.println("Usage: java Ftp <server>");
System.exit(1);
}
/* Create a new FTP client */
Ftp client = new Ftp(args[0]);
do {
try {
System.out.print(prompt);
input = in.nextLine();
} catch (NoSuchElementException e) {
eof = true;
}
/* Keep going if we have not hit end of file */
if (!eof && input.length() > 0) {
int cmd = -1;
String argv[] = input.split("\\s+");
for (int i = 0; i < commands.length && cmd == -1; i++)
if (commands[i].equalsIgnoreCase(argv[0])) cmd = i;
/* Execute the command */
switch (cmd) {
case ASCII:
client.ascii();
break;
case BINARY:
client.binary();
break;
case CD:
client.cd(argv[1]);
break;
case CDUP:
client.cdup();
break;
case DEBUG:
client.toggleDebug();
break;
case DIR:
client.dir();
break;
case GET:
client.get(argv[1]);
break;
case HELP:
for (int i = 0; i < HELP_MESSAGE.length; i++) System.out.println(HELP_MESSAGE[i]);
break;
case PASSIVE:
client.pasv();
break;
case PWD:
client.pwd();
break;
case QUIT:
eof = true;
break;
case USER:
client.user(argv[1]);
String password = PasswordField.getPassword("Password: "******"Invalid command");
}
}
} while (!eof);
/* Clean up */
client.close();
}
/** * A basic implementation of the FTP client protocol (RFC959). * * @author Luke Macken ([email protected]) */ public class Ftp { public static final String prompt = ">> "; public static final String line_sep = System.getProperties().getProperty("line.separator"); public static final String commands[] = { "ascii", "binary", "cd", "cdup", "debug", "dir", "get", "help", "passive", "put", "pwd", "quit", "user", "pass", "pasv", "list" }; public static final int ASCII = 0; public static final int BINARY = 1; public static final int CD = 2; public static final int CDUP = 3; public static final int DEBUG = 4; public static final int DIR = 5; public static final int GET = 6; public static final int HELP = 7; public static final int PASSIVE = 8; public static final int PUT = 9; public static final int PWD = 10; public static final int QUIT = 11; public static final int USER = 12; public static final int PASS = 13; public static final int PASV = 14; public static final int LIST = 15; public static final String[] HELP_MESSAGE = { "ascii --> Set ASCII transfer type", "binary --> Set binary transfer type", "cd <path> --> Change the remote working directory", "cdup --> Change the remote working directory to the", " parent directory (i.e., cd ..)", "debug --> Toggle debug mode", "dir --> List the contents of the remote directory", "get <path> --> Get a remote file", "help --> Displays this text", "passive --> Toggle passive/active mode", "put <path> --> Transfer the specified file to the server", "pwd --> Print the working directory on the server", "quit --> Close the connection to the server and terminate", "user <login> --> Specify the user name (will prompt for password)" }; /* The IP/hostname of the FTP server we are connecting to */ private String serverAddr; /* Debugging mode */ private boolean debug; /* ASCII transfer mode */ private boolean ascii = true; /* If we are in passive or active mode */ private boolean passive = true; /* I/O communication objects */ private Socket sock; private Socket pasvSock = null; private ServerSocket activeSock = null; private BufferedReader pasvIn; private BufferedReader in; private PrintWriter out; /** * Default constructor. Create a new FTP client and connect to a specified server. * * @param server Address of an FTP server */ public Ftp(String server) { serverAddr = server; debug = true; try { sock = new Socket(server, 21); System.out.println("Connected to " + server); out = new PrintWriter(sock.getOutputStream(), true); in = new BufferedReader(new InputStreamReader(sock.getInputStream())); System.out.println(getResponse()); } catch (IOException e) { System.err.println(e.getMessage()); System.exit(1); } } /** Toggle debugging mode. */ public void toggleDebug() { if (debug) { debug("Debugging output off"); debug = false; } else { debug = true; debug("Debugging output on"); } } /** Close the client connect to the server. */ public void close() { try { debug("Closing connect to server"); System.out.println("=> QUIT"); out.println("QUIT"); System.out.println(getResponse()); out.close(); in.close(); sock.close(); if (pasvSock != null && !pasvSock.isClosed()) { pasvIn.close(); pasvSock.close(); } if (activeSock != null && !activeSock.isClosed()) { activeSock.close(); } } catch (IOException e) { System.err.println(e.getMessage()); } } /** * Receive a single line response from the server. * * @return the response from the server */ private String getResponse() { try { return in.readLine(); } catch (IOException e) { System.err.println("Error reading server response: " + e.getMessage()); } return null; } /** * Log a debugging message to the console if the user has specified that debug mode should be * enabled. If it is not, then this method is essentially a nop. * * @param msg the debugging message to log */ private void debug(String msg) { if (debug) System.err.println(msg); } /** * Send a given username to the server. * * @param username the username to login with */ public void user(String username) { out.println(commands[USER] + " " + username); System.out.println(getResponse()); } /** * Send a given password to the server. * * @param password the password for the user. */ public void pass(String password) { out.println(commands[PASS] + " " + password); System.out.println(getResponse()); } /** Request a directory listing from the server. */ public void dir() { String userInput; BufferedReader srvIn; Socket srv = null; /* Setup the appropriate sockets */ setupTransferMode(); out.println(commands[LIST]); System.out.println("=> LIST"); System.out.println(getResponse()); try { /* Setup the proper input streams based on the transfer mode */ if (passive) { srvIn = pasvIn; } else { srv = activeSock.accept(); srvIn = new BufferedReader(new InputStreamReader(srv.getInputStream())); } /* Display the directory listing */ while ((userInput = srvIn.readLine()) != null) { System.out.println(userInput); } srvIn.close(); if (srv != null) { srv.close(); } } catch (IOException e) { System.err.println("Error recieving data from server: " + e.getMessage()); } /* Clean up */ closeTransferMode(); System.out.println(getResponse()); } /** Set the transfer type to ASCII. */ public void ascii() { ascii = true; System.out.println("=> TYPE A"); out.println("TYPE A"); System.out.println(getResponse()); } /** Toggle passive/active modes. */ public void pasv() { passive = (passive) ? false : true; System.out.println(((passive) ? "Passive" : "Active") + " mode enabled"); } /** Close any sockets associated with the current transfer mode. */ private void closeTransferMode() { try { if (passive) { if (pasvSock != null && !pasvSock.isClosed()) { debug("Closing passive connection"); pasvIn.close(); pasvSock.close(); } } else { if (activeSock != null && !activeSock.isClosed()) { debug("Closing active connection"); activeSock.close(); } } } catch (IOException e) { System.err.println("Error closing transfer mode: " + e.getMessage()); } } /** Setup the sockets needed for the given transfer mode (either passive or active). */ private void setupTransferMode() { String resp = ""; if (passive) { debug("Switching to passive mode"); System.out.println("=> PASV"); out.println(commands[PASV]); resp = getResponse(); System.out.println(resp); /* If we've successfully entered passive mode, setup the socket */ if (resp.startsWith("227")) { String[] foo = resp.split(","); int pasvPort = new Integer(foo[4]) * 256 + new Integer(foo[5].replaceAll("[a-zA-Z).]+", "")); debug("Opening passive socket on " + serverAddr + ":" + pasvPort); try { pasvSock = new Socket(serverAddr, pasvPort, null, sock.getLocalPort() + 1); pasvIn = new BufferedReader(new InputStreamReader(pasvSock.getInputStream())); } catch (IOException e) { System.err.println(e.getMessage()); } } else { debug("Got invalid response from PASV command"); } } else { /* Active mode */ debug("Switching to active mode"); try { activeSock = new ServerSocket(0); } catch (IOException e) { System.err.println("Error creating active socket: " + e.getMessage()); } byte[] addr = sock.getLocalAddress().getAddress(); debug("Listening on local port " + activeSock.getLocalPort()); String portCmd = "PORT " + ((int) addr[0] & 0xFF) + "," + ((int) addr[1] & 0xFF) + "," + ((int) addr[2] & 0xFF) + "," + ((int) addr[3] & 0xFF) + "," + activeSock.getLocalPort() / 256 + "," + activeSock.getLocalPort() % 256; System.out.println("=> " + portCmd); out.println(portCmd); System.out.println(getResponse()); } } /** Print out the current working directory on the server. */ public void pwd() { System.out.println("=> PWD"); out.println("PWD"); System.out.println(getResponse()); } /** Set the transfer type to binary. */ public void binary() { ascii = false; System.out.println("=> TYPE I"); out.println("TYPE I"); System.out.println(getResponse()); } /** * Tell the server to change working directories. * * @param dir the directory to change to. if dir is '..', then this function will call cdup() * instead. */ public void cd(String dir) { System.out.println("=> CWD " + dir); out.println("CWD " + dir); System.out.println(getResponse()); } /** Tell the server to go up a directory. */ public void cdup() { System.out.println("=> CDUP"); out.println("CDUP"); System.out.println(getResponse()); } /** * Request a specified file from the server. * * @param path The path to the file to acquire */ public void get(String path) { String userInput, resp; BufferedReader srvIn; InputStream inStr; Socket srv = null; /* Initialize the appropriate transfer mode */ setupTransferMode(); /* Request the file */ System.out.println("=> RETR " + path); out.println("RETR " + path); /* Spit out the response */ resp = getResponse(); System.out.println(resp); /* Validate response */ if (!resp.startsWith("150")) { debug("Invalid response from RETR command; aborting transfer"); closeTransferMode(); return; } try { /* Point to the appropriate input streams based on transfer mode */ if (passive) { srvIn = pasvIn; inStr = pasvSock.getInputStream(); } else { srv = activeSock.accept(); inStr = srv.getInputStream(); } /* ASCII transfer */ if (ascii) { FileWriter outFile = new FileWriter(new File(path).getName()); srvIn = new BufferedReader(new InputStreamReader(inStr)); while ((userInput = srvIn.readLine()) != null) { outFile.write(userInput + line_sep); } outFile.close(); srvIn.close(); } else { /* Binary transfer */ int bytesRead = 0; byte[] buf = new byte[512]; FileOutputStream outFile = new FileOutputStream(new File(path).getName()); BufferedInputStream binIn = new BufferedInputStream(inStr); while ((bytesRead = binIn.read(buf, 0, 512)) != -1) { outFile.write(buf, 0, bytesRead); } outFile.close(); binIn.close(); } if (srv != null) { srv.close(); } } catch (IOException e) { System.err.println("Error acquiring file: " + e.getMessage()); } /* Clean up */ closeTransferMode(); System.out.println(getResponse()); } /** * Main method which is in charge of parsing and interpreting user input and interacting with the * FTP client. * * @param args Command line arguments; should only contain the server */ public static void main(String args[]) { boolean eof = false; String input = null; Scanner in = new Scanner(System.in); if (args.length != 1) { System.err.println("Usage: java Ftp <server>"); System.exit(1); } /* Create a new FTP client */ Ftp client = new Ftp(args[0]); do { try { System.out.print(prompt); input = in.nextLine(); } catch (NoSuchElementException e) { eof = true; } /* Keep going if we have not hit end of file */ if (!eof && input.length() > 0) { int cmd = -1; String argv[] = input.split("\\s+"); for (int i = 0; i < commands.length && cmd == -1; i++) if (commands[i].equalsIgnoreCase(argv[0])) cmd = i; /* Execute the command */ switch (cmd) { case ASCII: client.ascii(); break; case BINARY: client.binary(); break; case CD: client.cd(argv[1]); break; case CDUP: client.cdup(); break; case DEBUG: client.toggleDebug(); break; case DIR: client.dir(); break; case GET: client.get(argv[1]); break; case HELP: for (int i = 0; i < HELP_MESSAGE.length; i++) System.out.println(HELP_MESSAGE[i]); break; case PASSIVE: client.pasv(); break; case PWD: client.pwd(); break; case QUIT: eof = true; break; case USER: client.user(argv[1]); String password = PasswordField.getPassword("Password: "******"Invalid command"); } } } while (!eof); /* Clean up */ client.close(); } }