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Groovy: A powerful, dynamic language for the JVM
/*
* 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
*
* 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 groovy.ui;
import groovy.lang.GroovyCodeSource;
import groovy.lang.GroovyRuntimeException;
import groovy.lang.GroovyShell;
import groovy.lang.Script;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.regex.Pattern;
/**
* Simple server that executes supplied script against a socket.
*
* Typically this is used from the groovy command line agent but it can be
* invoked programmatically. To run this program from the command line please
* refer to the command line documentation at
*
* Running Groovy from the commandline.
*
* Here is an example of how to use this class to open a listening socket on the server,
* listen for incoming data, and then echo the data back to the client in reverse order:
*
* new GroovySocketServer(
* new GroovyShell(), // evaluator
* false, // is not a file
* "println line.reverse()", // script to evaluate
* true, // return result to client
* 1960) //port
*
* There are several variables in the script binding:
*
* - line - The data from the socket
* - out - The output PrintWriter, should you need it for some reason.
* - socket - The socket, should you need it for some reason.
*
*
* @author Jeremy Rayner
*/
public class GroovySocketServer implements Runnable {
private URL url;
private GroovyShell groovy;
private GroovyCodeSource source;
private boolean autoOutput;
private static int counter;
/**
* This creates and starts the socket server on a new Thread. There is no need to call run or spawn
* a new thread yourself.
* @param groovy
* The GroovyShell object that evaluates the incoming text. If you need additional classes in the
* classloader then configure that through this object.
* @param isScriptFile
* Whether the incoming socket data String will be a script or a file path.
* @param scriptFilenameOrText
* This will be a groovy script or a file location depending on the argument isScriptFile.
* @param autoOutput
* whether output should be automatically echoed back to the client
* @param port
* the port to listen on
*
*/
public GroovySocketServer(GroovyShell groovy, boolean isScriptFile, String scriptFilenameOrText, boolean autoOutput, int port) {
this(groovy, getCodeSource(isScriptFile, scriptFilenameOrText), autoOutput, port);
}
private static GroovyCodeSource getCodeSource(boolean scriptFile, String scriptFilenameOrText) {
if (scriptFile) {
try {
if (uriPattern.matcher(scriptFilenameOrText).matches()) {
return new GroovyCodeSource(new URI(scriptFilenameOrText));
} else {
return new GroovyCodeSource(GroovyMain.searchForGroovyScriptFile(scriptFilenameOrText));
}
} catch (IOException e) {
throw new GroovyRuntimeException("Unable to get script from: " + scriptFilenameOrText, e);
} catch (URISyntaxException e) {
throw new GroovyRuntimeException("Unable to get script from URI: " + scriptFilenameOrText, e);
}
} else {
// We could jump through some hoops to have GroovyShell make our script name, but that seems unwarranted.
// If we *did* jump through that hoop then we should probably change the run loop to not recompile
// the script on every iteration since the script text can't change (the reason for the recompilation).
return new GroovyCodeSource(scriptFilenameOrText, generateScriptName(), GroovyShell.DEFAULT_CODE_BASE);
}
}
private static synchronized String generateScriptName() {
return "ServerSocketScript" + (++counter) + ".groovy";
}
// RFC2396
// scheme = alpha *( alpha | digit | "+" | "-" | "." )
private static final Pattern uriPattern = Pattern.compile("\\p{Alpha}[-+.\\p{Alnum}]*:.*");
/**
* This creates and starts the socket server on a new Thread. There is no need to call run or spawn
* a new thread yourself.
* @param groovy
* The GroovyShell object that evaluates the incoming text. If you need additional classes in the
* classloader then configure that through this object.
* @param source
* GroovyCodeSource for the Groovy script
* @param autoOutput
* whether output should be automatically echoed back to the client
* @param port
* the port to listen on
* @since 2.3.0
*/
public GroovySocketServer(GroovyShell groovy, GroovyCodeSource source, boolean autoOutput, int port) {
this.groovy = groovy;
this.source = source;
this.autoOutput = autoOutput;
try {
url = new URL("http", InetAddress.getLocalHost().getHostAddress(), port, "/");
System.out.println("groovy is listening on port " + port);
} catch (IOException e) {
e.printStackTrace();
}
new Thread(this).start();
}
/**
* Runs this server. There is typically no need to call this method, as the object's constructor
* creates a new thread and runs this object automatically.
*/
public void run() {
try {
ServerSocket serverSocket = new ServerSocket(url.getPort());
while (true) {
// Create one script per socket connection.
// This is purposefully not caching the Script
// so that the script source file can be changed on the fly,
// as each connection is made to the server.
//FIXME: Groovy has other mechanisms specifically for watching to see if source code changes.
// We should probably be using that here.
// See also the comment about the fact we recompile a script that can't change.
Script script = groovy.parse(source);
new GroovyClientConnection(script, autoOutput, serverSocket.accept());
}
} catch (Exception e) {
e.printStackTrace();
}
}
class GroovyClientConnection implements Runnable {
private Script script;
private Socket socket;
private BufferedReader reader;
private PrintWriter writer;
private boolean autoOutputFlag;
GroovyClientConnection(Script script, boolean autoOutput,Socket socket) throws IOException {
this.script = script;
this.autoOutputFlag = autoOutput;
this.socket = socket;
reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
writer = new PrintWriter(socket.getOutputStream());
new Thread(this, "Groovy client connection - " + socket.getInetAddress().getHostAddress()).start();
}
public void run() {
try {
String line = null;
script.setProperty("out", writer);
script.setProperty("socket", socket);
script.setProperty("init", Boolean.TRUE);
while ((line = reader.readLine()) != null) {
// System.out.println(line);
script.setProperty("line", line);
Object o = script.run();
script.setProperty("init", Boolean.FALSE);
if (o != null) {
if ("success".equals(o)) {
break; // to close sockets gracefully etc...
} else {
if (autoOutputFlag) {
writer.println(o);
}
}
}
writer.flush();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
writer.flush();
writer.close();
} finally {
try {
socket.close();
} catch (IOException e3) {
e3.printStackTrace();
}
}
}
}
}
}