name.martingeisse.webide.nodejs.AbstractNodejsServer.java Source code

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Here is the source code for name.martingeisse.webide.nodejs.AbstractNodejsServer.java

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/**
 * Copyright (c) 2010 Martin Geisse
 *
 * This file is distributed under the terms of the MIT license.
 */

package name.martingeisse.webide.nodejs;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;

import name.martingeisse.webide.application.Configuration;

import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteException;
import org.apache.commons.exec.ExecuteResultHandler;
import org.apache.commons.exec.ExecuteStreamHandler;
import org.apache.commons.exec.Executor;
import org.apache.commons.exec.PumpStreamHandler;
import org.apache.commons.exec.ShutdownHookProcessDestroyer;

/**
 * Base class for NodeJS server processes. Each subclass should
 * have an associated Javascript file (which is inherited and
 * can be overridden) that is passed to the NodeJS command-line
 * tool. The server is started by the start() method.
 */
public abstract class AbstractNodejsServer {

    /**
     * Constructor.
     */
    public AbstractNodejsServer() {
    }

    /**
     * Starts this server.
     */
    public void start() {

        // determine the path of the associated script
        URL url = getScriptUrl();
        if (!url.getProtocol().equals("file")) {
            throw new RuntimeException("unsupported protocol for associated script URL: " + url);
        }
        File scriptFile = new File(url.getPath());

        // build the command line
        CommandLine commandLine = new CommandLine(Configuration.getBashPath());
        commandLine.addArgument("--login");
        commandLine.addArgument("-c");
        commandLine.addArgument("node " + scriptFile.getName(), false);

        // build I/O streams
        ByteArrayInputStream inputStream = null;
        OutputStream outputStream = System.err;
        OutputStream errorStream = System.err;
        ExecuteStreamHandler streamHandler = new PumpStreamHandler(outputStream, errorStream, inputStream);

        // build an environment map that contains the path to the node_modules
        Map<String, String> environment = new HashMap<String, String>();
        environment.put("NODE_PATH", new File("lib/node_modules").getAbsolutePath());

        // run Node.js
        Executor executor = new DefaultExecutor();
        executor.setProcessDestroyer(new ShutdownHookProcessDestroyer());
        executor.setStreamHandler(streamHandler);
        try {
            executor.setWorkingDirectory(scriptFile.getParentFile());
            executor.execute(commandLine, environment, new ExecuteResultHandler() {

                @Override
                public void onProcessFailed(ExecuteException e) {
                }

                @Override
                public void onProcessComplete(int exitValue) {
                }

            });
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

    }

    protected URL getScriptUrl() {
        for (Class<?> c = getClass(); c != null; c = c.getSuperclass()) {
            URL url = c.getResource(c.getSimpleName() + ".js");
            if (url != null) {
                return url;
            }
        }
        throw new RuntimeException("no associated script for NodeJS server could be found");
    }

}