commandresolver.java

jspwiki source code,jspwiki source code

/* 
    JSPWiki - a JSP-based WikiWiki clone.

    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 com.ecyrd.jspwiki.ui;

import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;

import javax.servlet.http.HttpServletRequest;

import org.apache.log4j.Logger;

import com.ecyrd.jspwiki.InternalWikiException;
import com.ecyrd.jspwiki.TextUtil;
import com.ecyrd.jspwiki.WikiEngine;
import com.ecyrd.jspwiki.WikiPage;
import com.ecyrd.jspwiki.WikiProvider;
import com.ecyrd.jspwiki.auth.GroupPrincipal;
import com.ecyrd.jspwiki.parser.MarkupParser;
import com.ecyrd.jspwiki.providers.ProviderException;
import com.ecyrd.jspwiki.url.URLConstructor;

/**
 * <p>Resolves special pages, JSPs and Commands on behalf of a
 * WikiEngine. CommandResolver will automatically resolve page names
 * with singular/plural variants. It can also detect the correct Command
 * based on parameters supplied in an HTTP request, or due to the
 * JSP being accessed.</p>
 * <p>
 * <p>CommandResolver's static {@link #findCommand(String)} method is
 * the simplest method; it looks up and returns the Command matching
 * a supplied wiki context. For example, looking up the request context
 * <code>view</code> returns {@link PageCommand#VIEW}. Use this method
 * to obtain static Command instances that aren't targeted at a particular
 * page or group.</p>
 * <p>For more complex lookups in which the caller supplies an HTTP
 * request, {@link #findCommand(HttpServletRequest, String)} will
 * look up and return the correct Command. The String parameter
 * <code>defaultContext</code> supplies the request context to use
 * if it cannot be detected. However, note that the default wiki
 * context may be over-ridden if the request was for a "special page."</p>
 * <p>For example, suppose the WikiEngine's properties specify a
 * special page called <code>UserPrefs</code>
 * that redirects to <code>UserPreferences.jsp</code>. The ordinary
 * lookup method {@linkplain #findCommand(String)} using a supplied
 * context <code>view</code> would return {@link PageCommand#VIEW}. But
 * the {@linkplain #findCommand(HttpServletRequest, String)} method,
 * when passed the same context (<code>view</code>) and an HTTP request
 * containing the page parameter value <code>UserPrefs</code>,
 * will instead return {@link WikiCommand#PREFS}.</p>
 * @author Andrew Jaquith
 * @since 2.4.22
 */
public final class CommandResolver
{
    /** Prefix in jspwiki.properties signifying special page keys. */
    private static final String PROP_SPECIALPAGE = "jspwiki.specialPage.";

    /** Private map with request contexts as keys, Commands as values */
    private static final Map<String, Command>    CONTEXTS;

    /** Private map with JSPs as keys, Commands as values */
    private static final Map<String, Command>    JSPS;

    /** Store the JSP-to-Command and context-to-Command mappings */
    static
    {
        CONTEXTS = new HashMap<String, Command>();
        JSPS = new HashMap<String, Command>();
        Command[] commands = AbstractCommand.allCommands();
        for( int i = 0; i < commands.length; i++ )
        {
            JSPS.put( commands[i].getJSP(), commands[i] );
            CONTEXTS.put( commands[i].getRequestContext(), commands[i] );
        }
    }

    private final Logger        m_log = Logger.getLogger( CommandResolver.class );

    private final WikiEngine    m_engine;

    /** If true, we'll also consider english plurals (+s) a match. */
    private final boolean       m_matchEnglishPlurals;

    /** Stores special page names as keys, and Commands as values. */
    private final Map<String, Command> m_specialPages;

    /**
     * Constructs a CommandResolver for a given WikiEngine. This constructor
     * will extract the special page references for this wiki and store them in
     * a cache used for resolution.
     * @param engine the wiki engine
     * @param properties the properties used to initialize the wiki
     */
    public CommandResolver( WikiEngine engine, Properties properties )
    {
        m_engine = engine;
        m_specialPages = new HashMap<String, Command>();

        // Skim through the properties and look for anything with
        // the "special page" prefix. Create maps that allow us
        // look up the correct Command based on special page name.
        // If a matching command isn't found, create a RedirectCommand.
        for( Iterator i = properties.entrySet().iterator(); i.hasNext(); )
        {
            Map.Entry entry = (Map.Entry) i.next();
            String key = (String) entry.getKey();
            if ( key.startsWith( PROP_SPECIALPAGE ) )
            {
                String specialPage = key.substring( PROP_SPECIALPAGE.length() );
                String jsp = (String) entry.getValue();
                if ( specialPage != null && jsp != null )
                {
                    specialPage = specialPage.trim();
                    jsp = jsp.trim();
                    Command command = JSPS.get( jsp );
                    if ( command == null )
                    {
                        Command redirect = RedirectCommand.REDIRECT;
                        command = redirect.targetedCommand( jsp );
                    }
                    m_specialPages.put( specialPage, command );
                }
            }
        }

        // Do we match plurals?
        m_matchEnglishPlurals = TextUtil.getBooleanProperty( properties, WikiEngine.PROP_MATCHPLURALS, true );
    }

    /**
     * Attempts to locate a wiki command for a supplied request context.
     * The resolution technique is simple: we examine the list of
     * Commands returned by {@link AbstractCommand#allCommands()} and
     * return the one whose <code>requestContext</code> matches the
     * supplied context. If the supplied context does not resolve to a known
     * Command, this method throws an {@link IllegalArgumentException}.
     * @param context the request context
     * @return the resolved context
     */
    public static Command findCommand( String context )
    {
        Command command = CONTEXTS.get( context );
        if ( command == null )
        {
            throw new IllegalArgumentException( "Unsupported wiki context: " + context + "." );
        }
        return command;
    }

    /**
     * <p>
     * Attempts to locate a Command for a supplied wiki context and HTTP
     * request, incorporating the correct WikiPage into the command if reqiured.
     * This method will first determine what page the user requested by
     * delegating to {@link #extractPageFromParameter(String, HttpServletRequest)}. If
     * this page equates to a special page, we return the Command
     * corresponding to that page. Otherwise, this method simply returns the
     * Command for the supplied request context.
     * </p>
     * <p>
     * The reason this method attempts to resolve against special pages is
     * because some of them resolve to contexts that may be different from the
     * one supplied. For example, a VIEW request context for the special page
     * "UserPreferences" should return a PREFS context instead.
     * </p>
     * <p>
     * When the caller supplies a request context and HTTP request that
     * specifies an actual wiki page (rather than a special page), this method
     * will return a "targeted" Command that includes the resolved WikiPage
     * as the target. (See {@link #resolvePage(HttpServletRequest, String)}
     * for the resolution algorithm). Specifically, the Command will
     * return a non-<code>null</code> value for its {@link AbstractCommand#getTarget()} method.
     * </p>
     * <p><em>Note: if this method determines that the Command is the VIEW PageCommand,
     * then the Command returned will always be targeted to the front page.</em></p>
     * @param request the HTTP request; if <code>null</code>, delegates
     * to {@link #findCommand(String)}
     * @param defaultContext the request context to use by default
     * @return the resolved wiki command
     */
    public final Command findCommand( HttpServletRequest request, String defaultContext )
    {
        // Corner case if request is null
        if ( request == null )
        {
            return findCommand( defaultContext );
        }

        Command command = null;

        // Determine the name of the page (which may be null)
        String pageName = extractPageFromParameter( defaultContext, request );

        // Can we find a special-page command matching the extracted page?
        if ( pageName != null )
        {
            command = m_specialPages.get( pageName );
        }

        // If we haven't found a matching command yet, extract the JSP path
        // and compare to our list of special pages
        if ( command == null )
        {
            command = extractCommandFromPath( request );

            // Otherwise: use the default context
            if ( command == null )
            {
                command = CONTEXTS.get( defaultContext );
                if ( command == null )
                {
                    throw new IllegalArgumentException( "Wiki context " + defaultContext + " is illegal." );
                }
            }
        }

        // For PageCommand.VIEW, default to front page if a page wasn't supplied
        if( PageCommand.VIEW.equals( command ) && pageName == null )
        {
            pageName = m_engine.getFrontPage();
        }

        // These next blocks handle targeting requirements

        // If we were passed a page parameter, try to resolve it
        if ( command instanceof PageCommand && pageName != null )
        {
            // If there's a matching WikiPage, "wrap" the command
            WikiPage page = resolvePage( request, pageName );
            if ( page != null )
            {
                return command.targetedCommand( page );
            }
        }

        // If "create group" command, target this wiki
        String wiki = m_engine.getApplicationName();
        if ( WikiCommand.CREATE_GROUP.equals( command ) )
        {
            return WikiCommand.CREATE_GROUP.targetedCommand( wiki );
        }

        // If group command, see if we were passed a group name
        if ( command instanceof GroupCommand )
        {
            String groupName = request.getParameter( "group" );
            groupName = TextUtil.replaceEntities( groupName );