source: josm/trunk/src/org/openstreetmap/josm/io/remotecontrol/handler/RequestHandler.java@ 4191

// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.io.remotecontrol.handler;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.util.HashMap;
import java.util.StringTokenizer;

import javax.swing.JOptionPane;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.io.remotecontrol.PermissionPrefWithDefault;

/**
 * This is the parent of all classes that handle a specific remote control command
 *
 * @author Bodo Meissner
 */
public abstract class RequestHandler {
    
    public static final String globalConfirmationKey = "remotecontrol.always-confirm";
    public static final boolean globalConfirmationDefault = false;

    /** The GET request arguments */
    protected HashMap<String,String> args;

    /** The request URL without "GET". */
    protected String request;

    /** default response */
    protected String content = "OK\r\n";
    /** default content type */
    protected String contentType = "text/plain";

    /** will be filled with the command assigned to the subclass */
    protected String myCommand;

    /**
     * Check permission and parameters and handle request.
     *
     * @throws RequestHandlerForbiddenException
     * @throws RequestHandlerBadRequestException
     * @throws RequestHandlerErrorException
     */
    public final void handle() throws RequestHandlerForbiddenException, RequestHandlerBadRequestException, RequestHandlerErrorException
    {
        checkPermission();
        checkMandatoryParams();
        handleRequest();
    }

    /**
     * Handle a specific command sent as remote control.
     *
     * This method of the subclass will do the real work.
     *
     * @throws RequestHandlerErrorException
     * @throws RequestHandlerBadRequestException
     */
    protected abstract void handleRequest() throws RequestHandlerErrorException, RequestHandlerBadRequestException;

    /**
     * Get a specific message to ask the user for permission for the operation
     * requested via remote control.
     *
     * This message will be displayed to the user if the preference
     * remotecontrol.always-confirm is true.
     *
     * @return the message
     */
    abstract public String getPermissionMessage();

    /**
     * Get a PermissionPref object containing the name of a special permission
     * preference to individually allow the requested operation and an error
     * message to be displayed when a disabled operation is requested.
     *
     * Default is not to check any special preference. Override this in a
     * subclass to define permission preference and error message.
     *
     * @return the preference name and error message or null
     */
    public PermissionPrefWithDefault getPermissionPref()
    {
        /* Example:
        return new PermissionPrefWithDefault("fooobar.remotecontrol",
        true
        "RemoteControl: foobar forbidden by preferences");
        */
        return null;
    }

    protected String[] getMandatoryParams()
    {
        return null;
    }

    /**
     * Check permissions in preferences and display error message
     * or ask for permission.
     *
     * @throws RequestHandlerForbiddenException
     */
    final public void checkPermission() throws RequestHandlerForbiddenException
    {
        /*
         * If the subclass defines a specific preference and if this is set
         * to false, abort with an error message.
         *
         * Note: we use the deprecated class here for compatibility with
         * older versions of WMSPlugin.
         */
        PermissionPrefWithDefault permissionPref = getPermissionPref();
        if((permissionPref != null) && (permissionPref.pref != null))
        {
            if (!Main.pref.getBoolean(permissionPref.pref, permissionPref.defaultVal)) {
                System.out.println(permissionPref.message);
                throw new RequestHandlerForbiddenException();
            }
        }

        /* Does the user want to confirm everything?
         * If yes, display specific confirmation message.
         */
        if (Main.pref.getBoolean(globalConfirmationKey, globalConfirmationDefault)) {
            if (JOptionPane.showConfirmDialog(Main.parent,
                "<html>" + getPermissionMessage() +
                "<br>" + tr("Do you want to allow this?"),
                tr("Confirm Remote Control action"),
                JOptionPane.YES_NO_OPTION) != JOptionPane.YES_OPTION) {
                    throw new RequestHandlerForbiddenException();
            }
        }
    }

    /**
     * Set request URL and parse args.
     *
     * @param url The request URL.
     */
    public void setUrl(String url) {
        this.request = url;
        parseArgs();
    }

    /**
     * Parse the request parameters as key=value pairs.
     * The result will be stored in this.args.
     *
     * Can be overridden by subclass.
     */
    protected void parseArgs() {
        StringTokenizer st = new StringTokenizer(this.request, "&?");
        HashMap<String, String> args = new HashMap<String, String>();
        // ignore first token which is the command
        if(st.hasMoreTokens()) st.nextToken();
        while (st.hasMoreTokens()) {
            String param = st.nextToken();
            int eq = param.indexOf("=");
            if (eq > -1)
                args.put(param.substring(0, eq),
                         param.substring(eq + 1));
        }
        this.args = args;
    }

    void checkMandatoryParams() throws RequestHandlerBadRequestException {
        String[] mandatory = getMandatoryParams();
        if(mandatory == null) return;

        boolean error = false;
        for (int i = 0; i < mandatory.length; ++i) {
            String key = mandatory[i];
            String value = args.get(key);
            if ((value == null) || (value.length() == 0)) {
                error = true;
                System.out.println("'" + myCommand + "' remote control request must have '" + key + "' parameter");
            }
        }
        if (error)
            throw new RequestHandlerBadRequestException();
    }

    /**
     * Save command associated with this handler.
     *
     * @param command The command.
     */
    public void setCommand(String command)
    {
        if (command.charAt(0) == '/') {
            command = command.substring(1);
        }
        myCommand = command;
    }

    public String getContent() {
        return content;
    }

    public String getContentType() {
        return contentType;
    }

    public static class RequestHandlerException extends Exception {
    }

    public static class RequestHandlerErrorException extends RequestHandlerException {
    }

    public static class RequestHandlerBadRequestException extends RequestHandlerException {
    }
    
    public static class RequestHandlerForbiddenException extends RequestHandlerException {
        private static final long serialVersionUID = 2263904699747115423L;
    }
}