Tomcat example source code file (HostManagerServlet.java)

This example Tomcat source code file (HostManagerServlet.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

file, file, host, host, http, io, ioexception, ioexception, lifecycle, printwriter, request, response, servlet, servletexception, standardhost, string, string, throwable, unavailableexception, util

The Tomcat HostManagerServlet.java source code

/*
 * 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 org.apache.catalina.manager.host;


import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;

import javax.management.MBeanServer;
import javax.servlet.ServletException;
import javax.servlet.UnavailableException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.catalina.Container;
import org.apache.catalina.ContainerServlet;
import org.apache.catalina.Context;
import org.apache.catalina.Engine;
import org.apache.catalina.Globals;
import org.apache.catalina.Host;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.Wrapper;
import org.apache.catalina.core.StandardHost;
import org.apache.catalina.startup.HostConfig;
import org.apache.catalina.util.StringManager;
import org.apache.tomcat.util.modeler.Registry;
import org.apache.catalina.core.ContainerBase;


/**
 * Servlet that enables remote management of the virtual hosts installed
 * on the server.  Normally, this functionality will be protected by 
 * a security constraint in the web application deployment descriptor.  
 * However, this requirement can be relaxed during testing.
 * <p>
 * This servlet examines the value returned by <code>getPathInfo()
 * and related query parameters to determine what action is being requested.
 * The following actions and parameters (starting after the servlet path)
 * are supported:
 * <ul>
 * <li>/add?name={host-name}&aliases={host-aliases}&manager={manager} -
 *     Create and add a new virtual host. The <code>host-name attribute
 *     indicates the name of the new host. The <code>host-aliases 
 *     attribute is a comma separated list of the host alias names. 
 *     The <code>manager attribute is a boolean value indicating if the
 *     webapp manager will be installed in the newly created host (optional, 
 *     false by default).</li>
 * <li>/remove?name={host-name} - Remove a virtual host. 
 *     The <code>host-name attribute indicates the name of the host.
 *     </li>
 * <li>/list - List the virtual hosts installed on the server.
 *     Each host will be listed with the following format 
 *     <code>host-name#host-aliases.
 * <li>/start?name={host-name} - Start the virtual host.
 * <li>/stop?name={host-name} - Stop the virtual host.
 * </ul>
 * <p>
 * <b>NOTE - Attempting to stop or remove the host containing
 * this servlet itself will not succeed.  Therefore, this servlet should
 * generally be deployed in a separate virtual host.
 * <p>
 * <b>NOTE - For security reasons, this application will not operate
 * when accessed via the invoker servlet.  You must explicitly map this servlet
 * with a servlet mapping, and you will always want to protect it with
 * appropriate security constraints as well.
 * <p>
 * The following servlet initialization parameters are recognized:
 * <ul>
 * <li>debug - The debugging detail level that controls the amount
 *     of information that is logged by this servlet.  Default is zero.
 * </ul>
 *
 * @author Craig R. McClanahan
 * @author Remy Maucherat
 * @version $Revision: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 */

public class HostManagerServlet
    extends HttpServlet implements ContainerServlet {


    // ----------------------------------------------------- Instance Variables


    /**
     * Path where context descriptors should be deployed.
     */
    protected File configBase = null;


    /**
     * The Context container associated with our web application.
     */
    protected Context context = null;


    /**
     * The debugging detail level for this servlet.
     */
    protected int debug = 1;


    /**
     * The associated host.
     */
    protected Host host = null;

    
    /**
     * The associated engine.
     */
    protected Engine engine = null;

    
    /**
     * MBean server.
     */
    protected MBeanServer mBeanServer = null;


    /**
     * The string manager for this package.
     */
    protected static StringManager sm =
        StringManager.getManager(Constants.Package);


    /**
     * The Wrapper container associated with this servlet.
     */
    protected Wrapper wrapper = null;


    // ----------------------------------------------- ContainerServlet Methods


    /**
     * Return the Wrapper with which we are associated.
     */
    public Wrapper getWrapper() {

        return (this.wrapper);

    }


    /**
     * Set the Wrapper with which we are associated.
     *
     * @param wrapper The new wrapper
     */
    public void setWrapper(Wrapper wrapper) {

        this.wrapper = wrapper;
        if (wrapper == null) {
            context = null;
            host = null;
            engine = null;
        } else {
            context = (Context) wrapper.getParent();
            host = (Host) context.getParent();
            engine = (Engine) host.getParent();
        }

        // Retrieve the MBean server
        mBeanServer = Registry.getRegistry(null, null).getMBeanServer();
        
    }


    // --------------------------------------------------------- Public Methods


    /**
     * Finalize this servlet.
     */
    public void destroy() {

        ;       // No actions necessary

    }


    /**
     * Process a GET request for the specified resource.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet-specified error occurs
     */
    public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
        throws IOException, ServletException {

        // Verify that we were not accessed using the invoker servlet
        if (request.getAttribute(Globals.INVOKED_ATTR) != null)
            throw new UnavailableException
                (sm.getString("hostManagerServlet.cannotInvoke"));

        // Identify the request parameters that we need
        String command = request.getPathInfo();
        if (command == null)
            command = request.getServletPath();
        String name = request.getParameter("name");
  
        // Prepare our output writer to generate the response message
        response.setContentType("text/plain; charset=" + Constants.CHARSET);
        PrintWriter writer = response.getWriter();

        // Process the requested command
        if (command == null) {
            writer.println(sm.getString("hostManagerServlet.noCommand"));
        } else if (command.equals("/add")) {
            add(request, writer, name, false);
        } else if (command.equals("/remove")) {
            remove(writer, name);
        } else if (command.equals("/list")) {
            list(writer);
        } else if (command.equals("/start")) {
            start(writer, name);
        } else if (command.equals("/stop")) {
            stop(writer, name);
        } else {
            writer.println(sm.getString("hostManagerServlet.unknownCommand",
                                        command));
        }

        // Finish up the response
        writer.flush();
        writer.close();

    }


    /**
     * Add host with the given parameters.
     *
     * @param request The request
     * @param writer The output writer
     * @param name The host name
     * @param htmlMode Flag value
     */
    protected void add(HttpServletRequest request, PrintWriter writer, String name, boolean htmlMode ) {
        String aliases = request.getParameter("aliases");
        String appBase = request.getParameter("appBase");
        boolean manager = booleanParameter(request, "manager", false, htmlMode);
        boolean autoDeploy = booleanParameter(request, "autoDeploy", true, htmlMode);
        boolean deployOnStartup = booleanParameter(request, "deployOnStartup", true, htmlMode);
        boolean deployXML = booleanParameter(request, "deployXML", true, htmlMode);
        boolean unpackWARs = booleanParameter(request, "unpackWARs", true, htmlMode);
        boolean xmlNamespaceAware = booleanParameter(request, "xmlNamespaceAware", false, htmlMode);
        boolean xmlValidation = booleanParameter(request, "xmlValidation", false, htmlMode);
        add(writer, name, aliases, appBase, manager,
            autoDeploy,
            deployOnStartup,
            deployXML,                                       
            unpackWARs,
            xmlNamespaceAware,
            xmlValidation);
    }


    /**
     * extract boolean value from checkbox with default
     * @param request
     * @param parameter
     * @param theDefault
     * @param htmlMode
     * @return
     */
    protected boolean booleanParameter(HttpServletRequest request,
            String parameter, boolean theDefault, boolean htmlMode) {
        String value = request.getParameter(parameter);
        boolean booleanValue = theDefault;
        if (value != null) {
            if (htmlMode) {
                if (value.equals("on")) {
                    booleanValue = true;
                }
            } else if (theDefault) {
                if (value.equals("false")) {
                    booleanValue = false;
                }
            } else if (value.equals("true")) {
                booleanValue = true;
            }
        } else if (htmlMode)
            booleanValue = false;
        return booleanValue;
    }


    /**
     * Initialize this servlet.
     */
    public void init() throws ServletException {

        // Ensure that our ContainerServlet properties have been set
        if ((wrapper == null) || (context == null))
            throw new UnavailableException
                (sm.getString("hostManagerServlet.noWrapper"));

        // Verify that we were not accessed using the invoker servlet
        String servletName = getServletConfig().getServletName();
        if (servletName == null)
            servletName = "";
        if (servletName.startsWith("org.apache.catalina.INVOKER."))
            throw new UnavailableException
                (sm.getString("hostManagerServlet.cannotInvoke"));

        // Set our properties from the initialization parameters
        String value = null;
        try {
            value = getServletConfig().getInitParameter("debug");
            debug = Integer.parseInt(value);
        } catch (Throwable t) {
            ;
        }

    }



    // -------------------------------------------------------- Private Methods


    /**
     * Add a host using the specified parameters.
     *
     * @param writer Writer to render results to
     * @param name host name
     * @param aliases comma separated alias list
     * @param appBase application base for the host
     * @param manager should the manager webapp be deployed to the new host ?
     */
    protected synchronized void add
        (PrintWriter writer, String name, String aliases, String appBase, 
         boolean manager,
         boolean autoDeploy,
         boolean deployOnStartup,
         boolean deployXML,                                       
         boolean unpackWARs,
         boolean xmlNamespaceAware,
         boolean xmlValidation) {
        if (debug >= 1) {
            log("add: Adding host '" + name + "'");
        }

        // Validate the requested host name
        if ((name == null) || name.length() == 0) {
            writer.println(sm.getString("hostManagerServlet.invalidHostName", name));
            return;
        }

        // Check if host already exists
        if (engine.findChild(name) != null) {
            writer.println
                (sm.getString("hostManagerServlet.alreadyHost", name));
            return;
        }

        // Validate and create appBase
        File appBaseFile = null;
        if (appBase == null || appBase.length() == 0) {
            appBase = name;
        }
        File file = new File(appBase);
        if (!file.isAbsolute())
            file = new File(System.getProperty("catalina.base"), appBase);
        try {
            appBaseFile = file.getCanonicalFile();
        } catch (IOException e) {
            appBaseFile = file;
        }
        if (!appBaseFile.exists()) {
            appBaseFile.mkdirs();
        }
        
        // Create base for config files
        File configBaseFile = getConfigBase(name);
        
        // Copy manager.xml if requested
        if (manager) {
            InputStream is = null;
            OutputStream os = null;
            try {
                is = getServletContext().getResourceAsStream("/manager.xml");
                os = new FileOutputStream(new File(configBaseFile, "manager.xml"));
                byte buffer[] = new byte[512];
                int len = buffer.length;
                while (true) {
                    len = is.read(buffer);
                    if (len == -1)
                        break;
                    os.write(buffer, 0, len);
                }
            } catch (IOException e) {
                writer.println
                    (sm.getString("hostManagerServlet.managerXml"));
                return;
            } finally {
                if (is != null) {
                    try {
                        is.close();
                    } catch (IOException e) {
                    }
                }
                if (os != null) {
                    try {
                        os.close();
                    } catch (IOException e) {
                    }
                }
            }
        }
        
        StandardHost host = new StandardHost();
        host.setAppBase(appBase);
        host.setName(name);

        host.addLifecycleListener(new HostConfig());

        // Add host aliases
        if ((aliases != null) && !("".equals(aliases))) {
            StringTokenizer tok = new StringTokenizer(aliases, ", ");
            while (tok.hasMoreTokens()) {
                host.addAlias(tok.nextToken());
            }
        }
        host.setAutoDeploy(autoDeploy);
        host.setDeployOnStartup(deployOnStartup);
        host.setDeployXML(deployXML);
        host.setUnpackWARs(unpackWARs);
        host.setXmlNamespaceAware(xmlNamespaceAware);
        host.setXmlValidation(xmlValidation);
        
        // Add new host
        try {
            engine.addChild(host);
        } catch (Exception e) {
            writer.println(sm.getString("hostManagerServlet.exception",
                                        e.toString()));
            return;
        }
        
        host = (StandardHost) engine.findChild(name);
        if (host != null) {
            writer.println(sm.getString("hostManagerServlet.add", name));
        } else {
            // Something failed
            writer.println(sm.getString("hostManagerServlet.addFailed", name));
        }
        
    }


    /**
     * Remove the specified host.
     *
     * @param writer Writer to render results to
     * @param name host name
     */
    protected synchronized void remove(PrintWriter writer, String name) {

        if (debug >= 1) {
            log("remove: Removing host '" + name + "'");
        }

        // Validate the requested host name
        if ((name == null) || name.length() == 0) {
            writer.println(sm.getString("hostManagerServlet.invalidHostName", name));
            return;
        }

        // Check if host exists
        if (engine.findChild(name) == null) {
            writer.println
                (sm.getString("hostManagerServlet.noHost", name));
            return;
        }

        // Prevent removing our own host
        if (engine.findChild(name) == host) {
            writer.println
                (sm.getString("hostManagerServlet.cannotRemoveOwnHost", name));
            return;
        }

        // Remove host
        // Note that the host will not get physically removed
        try {
            Container child = engine.findChild(name);
            engine.removeChild(child);
            if ( child instanceof ContainerBase ) ((ContainerBase)child).destroy();
        } catch (Exception e) {
            writer.println(sm.getString("hostManagerServlet.exception",
                                        e.toString()));
            return;
        }
        
        Host host = (StandardHost) engine.findChild(name);
        if (host == null) {
            writer.println(sm.getString("hostManagerServlet.remove", name));
        } else {
            // Something failed
            writer.println(sm.getString("hostManagerServlet.removeFailed", name));
        }
        
    }


    /**
     * Render a list of the currently active Contexts in our virtual host.
     *
     * @param writer Writer to render to
     */
    protected void list(PrintWriter writer) {

        if (debug >= 1)
            log("list: Listing hosts for engine '" 
                + engine.getName() + "'");

        writer.println(sm.getString("hostManagerServlet.listed",
                                    engine.getName()));
        Container[] hosts = engine.findChildren();
        for (int i = 0; i < hosts.length; i++) {
            Host host = (Host) hosts[i];
            String name = host.getName();
            String[] aliases = host.findAliases();
            StringBuffer buf = new StringBuffer();
            if (aliases.length > 0) {
                buf.append(aliases[0]);
                for (int j = 1; j < aliases.length; j++) {
                    buf.append(',').append(aliases[j]);
                }
            }
            writer.println(sm.getString("hostManagerServlet.listitem",
                                        name, buf.toString()));
        }
    }


    /**
     * Start the host with the specified name.
     *
     * @param writer Writer to render to
     * @param name Host name
     */
    protected void start(PrintWriter writer, String name) {

        if (debug >= 1)
            log("start: Starting host with name '" + name + "'");

        // Validate the requested host name
        if ((name == null) || name.length() == 0) {
            writer.println(sm.getString("hostManagerServlet.invalidHostName", name));
            return;
        }

        // Check if host exists
        if (engine.findChild(name) == null) {
            writer.println
                (sm.getString("hostManagerServlet.noHost", name));
            return;
        }

        // Prevent starting our own host
        if (engine.findChild(name) == host) {
            writer.println
                (sm.getString("hostManagerServlet.cannotStartOwnHost", name));
            return;
        }

        // Start host
        try {
            ((Lifecycle) engine.findChild(name)).start();
            writer.println
                (sm.getString("hostManagerServlet.started", name));
        } catch (Throwable t) {
            getServletContext().log
                (sm.getString("hostManagerServlet.startFailed", name), t);
            writer.println
                (sm.getString("hostManagerServlet.startFailed", name));
            writer.println(sm.getString("hostManagerServlet.exception",
                                        t.toString()));
            return;
        }
        
    }


    /**
     * Start the host with the specified name.
     *
     * @param writer Writer to render to
     * @param name Host name
     */
    protected void stop(PrintWriter writer, String name) {

        if (debug >= 1)
            log("stop: Stopping host with name '" + name + "'");

        // Validate the requested host name
        if ((name == null) || name.length() == 0) {
            writer.println(sm.getString("hostManagerServlet.invalidHostName", name));
            return;
        }

        // Check if host exists
        if (engine.findChild(name) == null) {
            writer.println
                (sm.getString("hostManagerServlet.noHost", name));
            return;
        }

        // Prevent starting our own host
        if (engine.findChild(name) == host) {
            writer.println
                (sm.getString("hostManagerServlet.cannotStopOwnHost", name));
            return;
        }

        // Start host
        try {
            ((Lifecycle) engine.findChild(name)).stop();
            writer.println
                (sm.getString("hostManagerServlet.stopped", name));
        } catch (Throwable t) {
            getServletContext().log
                (sm.getString("hostManagerServlet.stopFailed", name), t);
            writer.println
                (sm.getString("hostManagerServlet.stopFailed", name));
            writer.println(sm.getString("hostManagerServlet.exception",
                                        t.toString()));
            return;
        }
        
    }


    // -------------------------------------------------------- Support Methods


    /**
     * Get config base.
     */
    protected File getConfigBase(String hostName) {
        File configBase = 
            new File(System.getProperty("catalina.base"), "conf");
        if (!configBase.exists()) {
            return null;
        }
        if (engine != null) {
            configBase = new File(configBase, engine.getName());
        }
        if (host != null) {
            configBase = new File(configBase, hostName);
        }
        configBase.mkdirs();
        return configBase;
    }


}