SocketClient.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.net;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.Socket;
import java.net.SocketException;
import java.nio.charset.Charset;
import java.util.Objects;
import javax.net.ServerSocketFactory;
import javax.net.SocketFactory;
import org.apache.commons.io.IOUtils;
/**
* The SocketClient provides the basic operations that are required of client objects accessing sockets. It is meant to be subclassed to avoid having to rewrite
* the same code over and over again to open a socket, close a socket, set timeouts, etc. Of special note is the {@link #setSocketFactory setSocketFactory}
* method, which allows you to control the type of Socket the SocketClient creates for initiating network connections. This is especially useful for adding SSL
* or proxy support as well as better support for applets. For example, you could create a {@link javax.net.SocketFactory} that requests browser security
* capabilities before creating a socket. All classes derived from SocketClient should use the {@link #_socketFactory_ _socketFactory_} member variable to
* create Socket and ServerSocket instances rather than instantiating them by directly invoking a constructor. By honoring this contract you guarantee that a
* user will always be able to provide his own Socket implementations by substituting his own SocketFactory.
*
* @see SocketFactory
*/
public abstract class SocketClient {
/**
* The end of line character sequence used by most IETF protocols. That is a carriage return followed by a newline: "\r\n"
*/
public static final String NETASCII_EOL = "\r\n";
/** The default SocketFactory shared by all SocketClient instances. */
private static final SocketFactory DEFAULT_SOCKET_FACTORY = SocketFactory.getDefault();
/** The default {@link ServerSocketFactory} */
private static final ServerSocketFactory DEFAULT_SERVER_SOCKET_FACTORY = ServerSocketFactory.getDefault();
/** The socket's connect timeout (0 = infinite timeout) */
private static final int DEFAULT_CONNECT_TIMEOUT = 60000;
/**
* Gets the IP address string of the given Socket in textual presentation.
*
* @param socket the socket to query.
* @return the raw IP address in a string format.
* @since 3.12.0
*/
protected static String getHostAddress(final Socket socket) {
return getHostAddress(socket.getInetAddress());
}
/**
* Gets the IP address string of the given InetAddress in textual presentation.
*
* @param inetAddress Internet Protocol (IP) address to query.
* @return the raw IP address in a string format.
* @since 3.12.0
*/
protected static String getHostAddress(final InetAddress inetAddress) {
return inetAddress != null ? inetAddress.getHostAddress() : null;
}
/**
* A ProtocolCommandSupport object used to manage the registering of ProtocolCommandListeners and the firing of ProtocolCommandEvents.
*/
private ProtocolCommandSupport commandSupport;
/** The timeout to use after opening a socket. */
protected int _timeout_;
/** The socket used for the connection. */
protected Socket _socket_;
/** The hostname used for the connection (null = no hostname supplied). */
protected String _hostname_;
/** The remote socket address used for the connection. */
protected InetSocketAddress remoteInetSocketAddress;
/** The default port the client should connect to. */
protected int _defaultPort_;
/** The socket's InputStream. */
protected InputStream _input_;
/** The socket's OutputStream. */
protected OutputStream _output_;
/** The socket's SocketFactory. */
protected SocketFactory _socketFactory_;
/** The socket's ServerSocket Factory. */
protected ServerSocketFactory _serverSocketFactory_;
/**
* Defaults to {@link #DEFAULT_CONNECT_TIMEOUT}.
*/
protected int connectTimeout = DEFAULT_CONNECT_TIMEOUT;
/** Hint for SO_RCVBUF size */
private int receiveBufferSize = -1;
/** Hint for SO_SNDBUF size */
private int sendBufferSize = -1;
/** The proxy to use when connecting. */
private Proxy connProxy;
/**
* Charset to use for byte IO.
*/
private Charset charset = Charset.defaultCharset();
/**
* Default constructor for SocketClient. Initializes _socket_ to null, _timeout_ to 0, _defaultPort to 0, _isConnected_ to false, charset to
* {@code Charset.defaultCharset()} and _socketFactory_ to a shared instance of {@link org.apache.commons.net.DefaultSocketFactory}.
*/
public SocketClient() {
_socket_ = null;
_hostname_ = null;
_input_ = null;
_output_ = null;
_timeout_ = 0;
_defaultPort_ = 0;
_socketFactory_ = DEFAULT_SOCKET_FACTORY;
_serverSocketFactory_ = DEFAULT_SERVER_SOCKET_FACTORY;
}
// helper method to allow code to be shared with connect(String,...) methods
private void _connect(final InetSocketAddress remoteInetSocketAddress, final InetAddress localAddr, final int localPort) throws IOException {
this.remoteInetSocketAddress = remoteInetSocketAddress;
_socket_ = _socketFactory_.createSocket();
if (receiveBufferSize != -1) {
_socket_.setReceiveBufferSize(receiveBufferSize);
}
if (sendBufferSize != -1) {
_socket_.setSendBufferSize(sendBufferSize);
}
if (localAddr != null) {
_socket_.bind(new InetSocketAddress(localAddr, localPort));
}
_socket_.connect(remoteInetSocketAddress, connectTimeout);
_connectAction_();
}
/**
* Because there are so many connect() methods, the _connectAction_() method is provided as a means of performing some action immediately after establishing
* a connection, rather than reimplementing all the connect() methods. The last action performed by every connect() method after opening a socket is to
* call this method.
* <p>
* This method sets the timeout on the just opened socket to the default timeout set by {@link #setDefaultTimeout setDefaultTimeout()}, sets _input_ and
* _output_ to the socket's InputStream and OutputStream respectively, and sets _isConnected_ to true.
* <p>
* Subclasses overriding this method should start by calling {@code super._connectAction_()} first to ensure the initialization of the aforementioned
* protected variables.
*
* @throws IOException (SocketException) if a problem occurs with the socket
*/
protected void _connectAction_() throws IOException {
applySocketAttributes();
_input_ = _socket_.getInputStream();
_output_ = _socket_.getOutputStream();
}
/**
* Adds a ProtocolCommandListener.
*
* @param listener The ProtocolCommandListener to add.
* @since 3.0
*/
public void addProtocolCommandListener(final ProtocolCommandListener listener) {
getCommandSupport().addProtocolCommandListener(listener);
}
/**
* Applies socket attributes.
*
* @throws SocketException if there is an error in the underlying protocol, such as a TCP error.
* @since 3.8.0
*/
protected void applySocketAttributes() throws SocketException {
_socket_.setSoTimeout(_timeout_);
}
/**
* Gets the non-null OutputStream or throws {@link NullPointerException}.
*
* <p>
* This method does not allocate resources.
* </p>
*
* @return the non-null OutputStream.
* @since 3.11.0
*/
protected OutputStream checkOpenOutputStream() {
return Objects.requireNonNull(_output_, "OutputStream");
}
/**
* Opens a Socket connected to a remote host at the current default port and originating from the current host at a system assigned port. Before returning,
* {@link #_connectAction_ _connectAction_()} is called to perform connection initialization actions.
*
* @param host The remote host.
* @throws SocketException If the socket timeout could not be set.
* @throws IOException If the socket could not be opened. In most cases you will only want to catch IOException since SocketException is derived from
* it.
*/
public void connect(final InetAddress host) throws SocketException, IOException {
_hostname_ = null;
connect(host, _defaultPort_);
}
/**
* Opens a Socket connected to a remote host at the specified port and originating from the current host at a system assigned port. Before returning,
* {@link #_connectAction_ _connectAction_()} is called to perform connection initialization actions.
*
* @param host The remote host.
* @param port The port to connect to on the remote host.
* @throws SocketException If the socket timeout could not be set.
* @throws IOException If the socket could not be opened. In most cases you will only want to catch IOException since SocketException is derived from
* it.
*/
public void connect(final InetAddress host, final int port) throws SocketException, IOException {
_hostname_ = null;
_connect(new InetSocketAddress(host, port), null, -1);
}
/**
* Opens a Socket connected to a remote host at the specified port and originating from the specified local address and port. Before returning,
* {@link #_connectAction_ _connectAction_()} is called to perform connection initialization actions.
*
* @param host The remote host.
* @param port The port to connect to on the remote host.
* @param localAddr The local address to use.
* @param localPort The local port to use.
* @throws SocketException If the socket timeout could not be set.
* @throws IOException If the socket could not be opened. In most cases you will only want to catch IOException since SocketException is derived from
* it.
*/
public void connect(final InetAddress host, final int port, final InetAddress localAddr, final int localPort) throws SocketException, IOException {
_hostname_ = null;
_connect(new InetSocketAddress(host, port), localAddr, localPort);
}
/**
* Opens a Socket connected to a remote host at the current default port and originating from the current host at a system assigned port. Before returning,
* {@link #_connectAction_ _connectAction_()} is called to perform connection initialization actions.
*
* @param hostname The name of the remote host.
* @throws SocketException If the socket timeout could not be set.
* @throws IOException If the socket could not be opened. In most cases you will only want to catch IOException since SocketException is
* derived from it.
* @throws java.net.UnknownHostException If the hostname cannot be resolved.
*/
public void connect(final String hostname) throws SocketException, IOException {
connect(hostname, _defaultPort_);
}
/**
* Opens a Socket connected to a remote host at the specified port and originating from the current host at a system assigned port. Before returning,
* {@link #_connectAction_ _connectAction_()} is called to perform connection initialization actions.
*
* @param hostname The name of the remote host.
* @param port The port to connect to on the remote host.
* @throws SocketException If the socket timeout could not be set.
* @throws IOException If the socket could not be opened. In most cases you will only want to catch IOException since SocketException is
* derived from it.
* @throws java.net.UnknownHostException If the hostname cannot be resolved.
*/
public void connect(final String hostname, final int port) throws SocketException, IOException {
connect(hostname, port, null, -1);
}
/**
* Opens a Socket connected to a remote host at the specified port and originating from the specified local address and port. Before returning,
* {@link #_connectAction_ _connectAction_()} is called to perform connection initialization actions.
*
* @param hostname The name of the remote host.
* @param port The port to connect to on the remote host.
* @param localAddr The local address to use.
* @param localPort The local port to use.
* @throws SocketException If the socket timeout could not be set.
* @throws IOException If the socket could not be opened. In most cases you will only want to catch IOException since SocketException is
* derived from it.
* @throws java.net.UnknownHostException If the hostname cannot be resolved.
*/
public void connect(final String hostname, final int port, final InetAddress localAddr, final int localPort) throws SocketException, IOException {
_hostname_ = hostname;
_connect(new InetSocketAddress(hostname, port), localAddr, localPort);
}
/**
* Create the CommandSupport instance if required
*/
protected void createCommandSupport() {
commandSupport = new ProtocolCommandSupport(this);
}
/**
* Disconnects the socket connection. You should call this method after you've finished using the class instance and also before you call {@link #connect
* connect()} again. _isConnected_ is set to false, _socket_ is set to null, _input_ is set to null, and _output_ is set to null.
*
* @throws IOException not thrown, subclasses may throw.
*/
@SuppressWarnings("unused") // subclasses may throw IOException
public void disconnect() throws IOException {
IOUtils.closeQuietly(_socket_);
IOUtils.closeQuietly(_input_);
IOUtils.closeQuietly(_output_);
_socket_ = null;
_hostname_ = null;
_input_ = null;
_output_ = null;
}
/**
* If there are any listeners, send them the command details.
*
* @param command the command name
* @param message the complete message, including command name
* @since 3.0
*/
protected void fireCommandSent(final String command, final String message) {
if (getCommandSupport().getListenerCount() > 0) {
getCommandSupport().fireCommandSent(command, message);
}
}
/**
* If there are any listeners, send them the reply details.
*
* @param replyCode the code extracted from the reply
* @param reply the full reply text
* @since 3.0
*/
protected void fireReplyReceived(final int replyCode, final String reply) {
if (getCommandSupport().getListenerCount() > 0) {
getCommandSupport().fireReplyReceived(replyCode, reply);
}
}
/**
* Gets the charset.
*
* @return the charset.
* @since 3.3
*/
public Charset getCharset() {
return charset;
}
/**
* Gets the charset name.
*
* @return the charset.
* @since 3.3
* @deprecated Since the code now requires Java 1.6 as a minimum
*/
@Deprecated
public String getCharsetName() {
return charset.name();
}
/**
* Subclasses can override this if they need to provide their own instance field for backwards compatibility.
*
* @return the CommandSupport instance, may be {@code null}
* @since 3.0
*/
protected ProtocolCommandSupport getCommandSupport() {
return commandSupport;
}
/**
* Gets the underlying socket connection timeout.
*
* @return timeout (in ms)
* @since 2.0
*/
public int getConnectTimeout() {
return connectTimeout;
}
/**
* Gets the current value of the default port (stored in {@link #_defaultPort_ _defaultPort_}).
*
* @return The current value of the default port.
*/
public int getDefaultPort() {
return _defaultPort_;
}
/**
* Gets the default timeout in milliseconds that is used when opening a socket.
*
* @return The default timeout in milliseconds that is used when opening a socket.
*/
public int getDefaultTimeout() {
return _timeout_;
}
/**
* Gets the current value of the SO_KEEPALIVE flag on the currently opened socket. Delegates to {@link Socket#getKeepAlive()}
*
* @return True if SO_KEEPALIVE is enabled.
* @throws SocketException if there is a problem with the socket
* @throws NullPointerException if the socket is not currently open
* @since 2.2
*/
public boolean getKeepAlive() throws SocketException {
return _socket_.getKeepAlive();
}
/**
* Gets the local address to which the client's socket is bound. Delegates to {@link Socket#getLocalAddress()}
*
* @return The local address to which the client's socket is bound.
* @throws NullPointerException if the socket is not currently open
*/
public InetAddress getLocalAddress() {
return _socket_.getLocalAddress();
}
/**
* Gets the port number of the open socket on the local host used for the connection. Delegates to {@link Socket#getLocalPort()}
*
* @return The port number of the open socket on the local host used for the connection.
* @throws NullPointerException if the socket is not currently open
*/
public int getLocalPort() {
return _socket_.getLocalPort();
}
/**
* Gets the proxy for use with all the connections.
*
* @return the current proxy for connections.
*/
public Proxy getProxy() {
return connProxy;
}
/**
* Gets the current receivedBuffer size
*
* @return the size, or -1 if not initialized
* @since 3.0
*/
protected int getReceiveBufferSize() {
return receiveBufferSize;
}
/**
* Gets the address to which the socket is connected.
*
* @return The remote address to which the client is connected. Delegates to {@link Socket#getInetAddress()}
* @throws NullPointerException if the socket is not currently open
*/
public InetAddress getRemoteAddress() {
return _socket_.getInetAddress();
}
/**
* Gets the remote socket address used for the connection.
*
* @return the remote socket address used for the connection
* @since 3.10.0
*/
protected InetSocketAddress getRemoteInetSocketAddress() {
return remoteInetSocketAddress;
}
/**
* Gets the port number of the remote host to which the client is connected. Delegates to {@link Socket#getPort()}
*
* @return The port number of the remote host to which the client is connected.
* @throws NullPointerException if the socket is not currently open
*/
public int getRemotePort() {
return _socket_.getPort();
}
/**
* Gets the current sendBuffer size
*
* @return the size, or -1 if not initialized
* @since 3.0
*/
protected int getSendBufferSize() {
return sendBufferSize;
}
/**
* Gets the underlying {@link ServerSocketFactory}
*
* @return The server socket factory
* @since 2.2
*/
public ServerSocketFactory getServerSocketFactory() {
return _serverSocketFactory_;
}
/**
* Gets the current SO_LINGER timeout of the currently opened socket.
*
* @return The current SO_LINGER timeout. If SO_LINGER is disabled returns -1.
* @throws SocketException If the operation fails.
* @throws NullPointerException if the socket is not currently open
*/
public int getSoLinger() throws SocketException {
return _socket_.getSoLinger();
}
/**
* Gets the timeout in milliseconds of the currently opened socket.
*
* @return The timeout in milliseconds of the currently opened socket.
* @throws SocketException If the operation fails.
* @throws NullPointerException if the socket is not currently open
*/
public int getSoTimeout() throws SocketException {
return _socket_.getSoTimeout();
}
/**
* Gets true if Nagle's algorithm is enabled on the currently opened socket.
*
* @return True if Nagle's algorithm is enabled on the currently opened socket, false otherwise.
* @throws SocketException If the operation fails.
* @throws NullPointerException if the socket is not currently open
*/
public boolean getTcpNoDelay() throws SocketException {
return _socket_.getTcpNoDelay();
}
/**
* Tests the socket to test if it is available for use. Note that the only sure test is to use it, but these checks may help in some cases.
*
* @see <a href="https://issues.apache.org/jira/browse/NET-350">NET-350</a>
* @return {@code true} if the socket appears to be available for use
* @since 3.0
*/
@SuppressWarnings("resource")
public boolean isAvailable() {
if (isConnected()) {
try {
if (_socket_.getInetAddress() == null) {
return false;
}
if (_socket_.getPort() == 0) {
return false;
}
if (_socket_.getRemoteSocketAddress() == null) {
return false;
}
if (_socket_.isClosed()) {
return false;
}
/*
* these aren't exact checks (a Socket can be half-open), but since we usually require two-way data transfer, we check these here too:
*/
if (_socket_.isInputShutdown()) {
return false;
}
if (_socket_.isOutputShutdown()) {
return false;
}
/* ignore the result, catch exceptions: */
// No need to close
_socket_.getInputStream();
// No need to close
_socket_.getOutputStream();
} catch (final IOException ioex) {
return false;
}
return true;
}
return false;
}
/**
* Tests whether the client is currently connected to a server.
*
* Delegates to {@link Socket#isConnected()}
*
* @return True if the client is currently connected to a server, false otherwise.
*/
public boolean isConnected() {
if (_socket_ == null) {
return false;
}
return _socket_.isConnected();
}
/**
* Removes a ProtocolCommandListener.
*
* @param listener The ProtocolCommandListener to remove.
* @since 3.0
*/
public void removeProtocolCommandListener(final ProtocolCommandListener listener) {
getCommandSupport().removeProtocolCommandListener(listener);
}
/**
* Sets the charset.
*
* @param charset the charset.
* @since 3.3
*/
public void setCharset(final Charset charset) {
this.charset = charset;
}
/**
* Sets the connection timeout in milliseconds, which will be passed to the {@link Socket} object's connect() method.
*
* @param connectTimeout The connection timeout to use (in ms)
* @since 2.0
*/
public void setConnectTimeout(final int connectTimeout) {
this.connectTimeout = connectTimeout;
}
/**
* Sets the default port the SocketClient should connect to when a port is not specified. The {@link #_defaultPort_ _defaultPort_} variable stores this
* value. If never set, the default port is equal to zero.
*
* @param port The default port to set.
*/
public void setDefaultPort(final int port) {
_defaultPort_ = port;
}
/**
* Sets the default timeout in milliseconds to use when opening a socket. This value is only used previous to a call to {@link #connect connect()} and
* should not be confused with {@link #setSoTimeout setSoTimeout()} which operates on the currently opened socket. _timeout_ contains the new timeout value.
*
* @param timeout The timeout in milliseconds to use for the socket connection.
*/
public void setDefaultTimeout(final int timeout) {
_timeout_ = timeout;
}
/**
* Sets the SO_KEEPALIVE flag on the currently opened socket.
*
* From the Javadocs, the default keepalive time is 2 hours (although this is implementation dependent). It looks as though the Windows WSA sockets
* implementation allows a specific keepalive value to be set, although this seems not to be the case on other systems.
*
* @param keepAlive If true, keepAlive is turned on
* @throws SocketException if there is a problem with the socket
* @throws NullPointerException if the socket is not currently open
* @since 2.2
*/
public void setKeepAlive(final boolean keepAlive) throws SocketException {
_socket_.setKeepAlive(keepAlive);
}
/**
* Sets the proxy for use with all the connections. The proxy is used for connections established after the call to this method.
*
* @param proxy the new proxy for connections.
* @since 3.2
*/
public void setProxy(final Proxy proxy) {
setSocketFactory(new DefaultSocketFactory(proxy));
connProxy = proxy;
}
/**
* Sets the underlying socket receive buffer size.
*
* @param size The size of the buffer in bytes.
* @throws SocketException never (but subclasses may wish to do so)
* @since 2.0
*/
@SuppressWarnings("unused") // subclasses may throw SocketException
public void setReceiveBufferSize(final int size) throws SocketException {
receiveBufferSize = size;
}
/**
* Sets the underlying socket send buffer size.
*
* @param size The size of the buffer in bytes.
* @throws SocketException never thrown, but subclasses might want to do so
* @since 2.0
*/
@SuppressWarnings("unused") // subclasses may throw SocketException
public void setSendBufferSize(final int size) throws SocketException {
sendBufferSize = size;
}
/**
* Sets the ServerSocketFactory used by the SocketClient to open ServerSocket connections. If the factory value is null, then a default factory is used
* (only do this to reset the factory after having previously altered it).
*
* @param factory The new ServerSocketFactory the SocketClient should use.
* @since 2.0
*/
public void setServerSocketFactory(final ServerSocketFactory factory) {
if (factory == null) {
_serverSocketFactory_ = DEFAULT_SERVER_SOCKET_FACTORY;
} else {
_serverSocketFactory_ = factory;
}
}
/**
* Sets the SocketFactory used by the SocketClient to open socket connections. If the factory value is null, then a default factory is used (only do this to
* reset the factory after having previously altered it). Any proxy setting is discarded.
*
* @param factory The new SocketFactory the SocketClient should use.
*/
public void setSocketFactory(final SocketFactory factory) {
if (factory == null) {
_socketFactory_ = DEFAULT_SOCKET_FACTORY;
} else {
_socketFactory_ = factory;
}
}
/**
* Sets the SO_LINGER timeout on the currently opened socket.
*
* @param on True if linger is to be enabled, false if not.
* @param val The {@code linger} timeout (in hundredths of a second?)
* @throws SocketException If the operation fails.
* @throws NullPointerException if the socket is not currently open
*/
public void setSoLinger(final boolean on, final int val) throws SocketException {
_socket_.setSoLinger(on, val);
}
/**
* Sets the timeout in milliseconds of a currently open connection. Only call this method after a connection has been opened by {@link #connect connect()}.
* <p>
* To set the initial timeout, use {@link #setDefaultTimeout(int)} instead.
*
* @param timeout The timeout in milliseconds to use for the currently open socket connection.
* @throws SocketException If the operation fails.
* @throws NullPointerException if the socket is not currently open
*/
public void setSoTimeout(final int timeout) throws SocketException {
_socket_.setSoTimeout(timeout);
}
/**
* Enables or disables the Nagle's algorithm (TCP_NODELAY) on the currently opened socket.
*
* @param on True if Nagle's algorithm is to be enabled, false if not.
* @throws SocketException If the operation fails.
* @throws NullPointerException if the socket is not currently open
*/
public void setTcpNoDelay(final boolean on) throws SocketException {
_socket_.setTcpNoDelay(on);
}
/**
* Verifies that the remote end of the given socket is connected to the same host that the SocketClient is currently connected to. This is useful for
* doing a quick security check when a client needs to accept a connection from a server, such as an FTP data connection or a BSD R command standard error
* stream.
*
* @param socket the item to check against
* @return True if the remote hosts are the same, false if not.
*/
public boolean verifyRemote(final Socket socket) {
return socket != null && Objects.equals(socket.getInetAddress(), getRemoteAddress());
}
/*
* Fields cannot be pulled up into a super-class without breaking binary compatibility, so the abstract method is needed to pass the instance to the
* methods which were moved here.
*/
}