AFUNIXSocketFactory.java
/*
* junixsocket
*
* Copyright 2009-2024 Christian Kohlschütter
*
* Licensed 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
*
* http://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.newsclub.net.unix;
import java.io.File;
import java.io.IOException;
import java.net.Socket;
import java.net.SocketException;
import java.net.URLDecoder;
import java.util.Objects;
import javax.net.SocketFactory;
/**
* The base for a SocketFactory that connects to UNIX sockets.
*
* Typically, the "hostname" is used as a reference to a socketFile on the file system. The actual
* mapping is left to the implementor.
*
* @see AFUNIXSocketFactory.FactoryArg
* @see AFUNIXSocketFactory.SystemProperty
* @see AFUNIXSocketFactory.URIScheme
*/
public abstract class AFUNIXSocketFactory extends AFSocketFactory<AFUNIXSocketAddress> {
/**
* Creates a {@link AFUNIXSocketFactory}.
*/
protected AFUNIXSocketFactory() {
super();
}
@Override
public Socket createSocket() throws SocketException {
return AFUNIXSocket.newInstance(this);
}
@Override
protected AFUNIXSocket connectTo(AFUNIXSocketAddress addr) throws IOException {
return AFUNIXSocket.connectTo(addr);
}
/**
* A socket factory that handles a custom hostname ("localhost", by default, and configured by the
* system property "org.newsclub.net.unix.socket.hostname"), forwarding all other
* requests to the fallback {@link SocketFactory}.
*/
private abstract static class DefaultSocketHostnameSocketFactory extends AFUNIXSocketFactory {
private static final String PROP_SOCKET_HOSTNAME = "org.newsclub.net.unix.socket.hostname";
/**
* Creates a {@link DefaultSocketHostnameSocketFactory}.
*/
public DefaultSocketHostnameSocketFactory() {
super();
}
@Override
public final boolean isHostnameSupported(String host) {
return getDefaultSocketHostname().equals(host);
}
private static String getDefaultSocketHostname() {
return System.getProperty(PROP_SOCKET_HOSTNAME, "localhost");
}
}
/**
* A socket factory that handles a custom hostname ("localhost", by default, and configured by the
* system property "org.newsclub.net.unix.socket.hostname"), forwarding all other
* requests to the fallback {@link SocketFactory}.
*
* The socket path is configured through an argument passed by to the constructor.
*
* This is particularly useful for JDBC drivers that take a "socketFactory" and a
* "socketFactoryArg". The latter will be passed as a constructor argument.
*/
public static final class FactoryArg extends DefaultSocketHostnameSocketFactory {
private final File socketFile;
/**
* Constructs a new {@link FactoryArg} factory using the given socket path.
*
* @param socketPath The path to the socket.
*/
public FactoryArg(String socketPath) {
super();
Objects.requireNonNull(socketPath, "Socket path was null");
this.socketFile = new File(socketPath);
}
/**
* Constructs a new {@link FactoryArg} factory using the given socket path.
*
* @param file The path to the socket.
*/
public FactoryArg(File file) {
super();
Objects.requireNonNull(file, "File was null");
this.socketFile = file;
}
@Override
public AFUNIXSocketAddress addressFromHost(String host, int port) throws SocketException {
return AFUNIXSocketAddress.of(socketFile, port);
}
}
/**
* A socket factory that handles a custom hostname ("junixsocket.localhost", by default, and
* configured by the system property "org.newsclub.net.unix.socket.hostname"),
* forwarding all other requests to the fallback {@link SocketFactory}.
*
* The socket path is configured through a system property,
* "org.newsclub.net.unix.socket.default".
*
* NOTE: While it is technically possible, it is highly discouraged to programmatically change the
* value of the property as it can lead to concurrency issues and undefined behavior.
*/
public static final class SystemProperty extends DefaultSocketHostnameSocketFactory {
private static final String PROP_SOCKET_DEFAULT = "org.newsclub.net.unix.socket.default";
/**
* Creates a {@link SystemProperty} socket factory.
*/
public SystemProperty() {
super();
}
@Override
public AFUNIXSocketAddress addressFromHost(String host, int port) throws SocketException {
String path = System.getProperty(PROP_SOCKET_DEFAULT);
if (path == null || path.isEmpty()) {
throw new IllegalStateException("Property not configured: " + PROP_SOCKET_DEFAULT);
}
File socketFile = new File(path);
return AFUNIXSocketAddress.of(socketFile, port);
}
}
/**
* A socket factory that handles special host names formatted as file:// URIs.
*
* The file:// URI may also be specified in URL-encoded format, i.e., file:%3A%2F%2F etc.
*
* You may also surround the URL with square brackets ("[" and "]"), whereas the closing bracket
* may be omitted.
*
* NOTE: In some circumstances it is recommended to use "<code>[file:%3A%2F%2F</code>(...)", i.e.
* encoded and without the closing bracket. Since this is an invalid hostname, it will not trigger
* a DNS lookup, but can still be used within a JDBC Connection URL.
*/
public static final class URIScheme extends AFUNIXSocketFactory {
private static final String FILE_SCHEME_PREFIX = "file://";
private static final String FILE_SCHEME_PREFIX_ENCODED = "file%";
private static final String FILE_SCHEME_LOCALHOST = "localhost";
/**
* Creates a {@link URIScheme} socket factory.
*/
public URIScheme() {
super();
}
private static String stripBrackets(String host) {
if (host.startsWith("[")) {
if (host.endsWith("]")) {
host = host.substring(1, host.length() - 1);
} else {
host = host.substring(1);
}
}
return host;
}
@Override
public boolean isHostnameSupported(String host) {
host = stripBrackets(host);
return host.startsWith(FILE_SCHEME_PREFIX) || host.startsWith(FILE_SCHEME_PREFIX_ENCODED);
}
@Override
public AFUNIXSocketAddress addressFromHost(String host, int port) throws SocketException {
host = stripBrackets(host);
if (host.startsWith(FILE_SCHEME_PREFIX_ENCODED)) {
try {
host = URLDecoder.decode(host, "UTF-8");
} catch (Exception e) {
throw (SocketException) new SocketException().initCause(e);
}
}
if (!host.startsWith(FILE_SCHEME_PREFIX)) {
throw new SocketException("Unsupported scheme");
}
String path = host.substring(FILE_SCHEME_PREFIX.length());
if (path.startsWith(FILE_SCHEME_LOCALHOST)) {
path = path.substring(FILE_SCHEME_LOCALHOST.length());
}
if (path.isEmpty()) {
throw new SocketException("Path is empty");
}
if (!path.startsWith("/")) {
throw new SocketException("Path must be absolute");
}
File socketFile = new File(path);
return AFUNIXSocketAddress.of(socketFile, port);
}
}
}