contextloader.java

这个weblogging 设计得比较精巧

package org.roller.presentation.velocity;

import java.net.MalformedURLException;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.TimeZone;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.util.RequestUtils;
import org.apache.velocity.context.Context;
import org.apache.velocity.tools.view.context.ChainedContext;
import org.apache.velocity.tools.view.context.ToolboxContext;
import org.apache.velocity.tools.view.servlet.ServletToolboxManager;
import org.roller.RollerException;
import org.roller.config.RollerConfig;
import org.roller.config.RollerRuntimeConfig;
import org.roller.model.Roller;
import org.roller.model.RollerFactory;
import org.roller.pojos.CommentData;
import org.roller.pojos.PageData;
import org.roller.pojos.RollerPropertyData;
import org.roller.pojos.UserData;
import org.roller.pojos.WeblogEntryData;
import org.roller.pojos.WebsiteData;
import org.roller.presentation.LanguageUtil;
import org.roller.presentation.RollerContext;
import org.roller.presentation.RollerRequest;
import org.roller.presentation.RollerSession;
import org.roller.presentation.newsfeeds.NewsfeedCache;
import org.roller.presentation.weblog.formbeans.CommentFormEx;
import org.roller.util.RegexUtil;
import org.roller.util.StringUtils;
import org.roller.util.Utilities;

/**
 * Load Velocity Context with Roller objects, values, and custom plugins.
 * 
 * @author llavandowska
 * @author David M Johnson
 */
public class ContextLoader
{   
    private RollerRequest mRollerReq = null;
    
    // List of PagePlugins for "transforming" WeblogEntries
    static List mPagePlugins = new ArrayList();
    
    private static Log mLogger = 
       LogFactory.getFactory().getInstance(ContextLoader.class);

    //------------------------------------------------------------------------
    
    /**
     * Setup the a Velocity context by loading it with objects, values, and
     * RollerPagePlugins needed for Roller page execution.
     */
    public static void setupContext( Context ctx, 
        RollerRequest rreq, HttpServletResponse response ) 
        throws RollerException
    {
        mLogger.debug("setupContext( ctx = "+ctx+")");
        
        HttpServletRequest request = rreq.getRequest();
        RollerContext rollerCtx = RollerContext.getRollerContext( request );
        
        try 
        {    
            // Add page model object to context 
            String pageModelClassName = 
                RollerConfig.getProperty("velocity.pagemodel.classname");
            Class pageModelClass = Class.forName(pageModelClassName);
            PageModel pageModel = (PageModel)pageModelClass.newInstance();
            pageModel.init(rreq);
            ctx.put("pageModel", pageModel );
            ctx.put("pages", pageModel.getPages());
        }
        catch (Exception e)
        {
            throw new RollerException("ERROR creating Page Model",e);
        }
        
        // Add Velocity page helper to context
        PageHelper pageHelper = new PageHelper(rreq, response, ctx);
        pageHelper.initializePlugins(mPagePlugins);
        ctx.put("pageHelper", pageHelper );

        // Add legacy macros too, so that old-school pages still work
        Macros macros= new Macros(rreq.getPageContext(), pageHelper);
        ctx.put("macros", macros);

        // Load standard Roller objects and values into the context 
        String userName = loadWebsiteValues(ctx, rreq, rollerCtx );
        loadWeblogValues( ctx, rreq, rollerCtx, userName );            
        loadPathValues( ctx, rreq, rollerCtx, userName );                                         
        loadRssValues( ctx, rreq, userName );                        
        loadUtilityObjects( ctx, rreq, rollerCtx, userName ); 
        loadRequestParamKeys(ctx);
        loadStatusMessage( ctx, rreq );
        
        // If single entry is specified, load comments too
        if ( rreq.getWeblogEntry() != null )
        {
            loadCommentValues( ctx, rreq, rollerCtx );
        }
        
        // add Velocity Toolbox tools to context
        loadToolboxContext(request, response, ctx);        
    }
    
    //------------------------------------------------------------------------
    
    /**
     * If there is an ERROR or STATUS message in the session,
     * place it into the Context for rendering later.
     * 
     * @param rreq
     */
    private static void loadStatusMessage(Context ctx, RollerRequest rreq)
    {
        HttpSession session = rreq.getRequest().getSession(false);
        String msg = null;
        if (session != null)
            msg = (String)session.getAttribute(RollerSession.ERROR_MESSAGE);
        if (msg != null)
        {
            ctx.put("errorMessage", msg);
            session.removeAttribute(RollerSession.ERROR_MESSAGE);
        }

        if (session != null)
            msg = (String)session.getAttribute(RollerSession.STATUS_MESSAGE);
        if (msg != null)
        {
            ctx.put("statusMessage", msg);
            session.removeAttribute(RollerSession.STATUS_MESSAGE);
        }
    }
    
    //------------------------------------------------------------------------

    /**
     * @param ctx
     * @param rreq
     * @param rollerCtx
     * @param userName
     */
    private static void loadWeblogValues(
       Context ctx, RollerRequest rreq, RollerContext rollerCtx, String userName)
       throws RollerException
    {
        // if there is an "_entry" page, only load it once
        WebsiteData website = rreq.getRoller().getUserManager().getWebsite(userName);
        PageModel pageModel = (PageModel)ctx.get("pageModel");
        if (website != null && pageModel != null) 
        {
            /* alternative display pages - customization */
            PageData entryPage = pageModel.getUsersPageByName(website, "_entry");
            if (entryPage != null)
            {
                ctx.put("entryPage", entryPage);
            }
            PageData descPage = pageModel.getUsersPageByName(website, "_desc");
            if (descPage != null)
            {
                ctx.put("descPage", descPage);
            }
        }
    }

    private static String figureResourcePath( RollerRequest rreq )
    {
        /*  old way -- Allen G
        HttpServletRequest request = rreq.getRequest();
        RollerContext rCtx = RollerContext.getRollerContext( request );
        RollerConfigData  rollerConfig = rCtx.getRollerConfig();
    
        StringBuffer sb = new StringBuffer();
        String uploadPath = rollerConfig.getUploadPath();
        if ( uploadPath != null && uploadPath.trim().length() > 0 )
        {
            sb.append( uploadPath );
        }
        else
        {
            sb.append( request.getContextPath() );
            sb.append( RollerContext.USER_RESOURCES );
        }
        return sb.toString();
        */
        
        String uploadurl = null;
        try {
            uploadurl = RollerFactory.getRoller().getFileManager().getUploadUrl();
        } catch(Exception e) {}
        
        return uploadurl;
    }

    //------------------------------------------------------------------------
    
    public boolean isUserAuthorizedToEdit()
    {
        try
        {
            return mRollerReq.isUserAuthorizedToEdit();
        }
        catch (Exception e)
        {
            mLogger.warn("PageHelper.isUserAuthorizedToEdit)", e);
        }
        return false;
    }
    
    //------------------------------------------------------------------------
    
    protected static void loadCommentValues(
       Context ctx, RollerRequest rreq, RollerContext rollerCtx ) 
       throws RollerException
    {
        HttpServletRequest request = rreq.getRequest();
        
        String escapeHtml = RollerRuntimeConfig.getProperty("users.comments.escapehtml");
        String autoFormat = RollerRuntimeConfig.getProperty("users.comments.autoformat");
        
        // Add comments related values to context
        ctx.put("isCommentPage", Boolean.TRUE);
        ctx.put("escapeHtml", new Boolean(escapeHtml) );
        ctx.put("autoformat", new Boolean(autoFormat) );
        
        // Make sure comment form object is available in context
        CommentFormEx commentForm = 
            (CommentFormEx)request.getAttribute("commentForm");
        if ( commentForm == null )
        {
            commentForm = new CommentFormEx();
        
            // Set fields to spaces to please Velocity
            commentForm.setName("");
            commentForm.setEmail("");
            commentForm.setUrl("");
            commentForm.setContent("");
        }        
        ctx.put("commentForm",commentForm); 
            
        // Either put a preview comment in to context          
        if ( request.getAttribute("previewComments")!=null )
        {
            ArrayList list = new ArrayList();
            CommentData cd = new CommentData();
            commentForm.copyTo(cd, request.getLocale());
            list.add(cd);
            ctx.put("previewComments",list);            
        }
        WeblogEntryData entry = rreq.getWeblogEntry();
        ctx.put("entry",entry);            
    }   

    //------------------------------------------------------------------------
    
    protected static void loadPathValues(
        Context ctx, RollerRequest rreq, RollerContext rollerCtx, String userName) 
        throws RollerException
    {
        HttpServletRequest request = rreq.getRequest();
        String url = null;
        if ( userName != null && !userName.equals("zzz_none_zzz"))
        {
            url = Utilities.escapeHTML( 
                rollerCtx.getAbsoluteContextUrl(request)+"/page/"+userName);
        }
        else
        {
            url= Utilities.escapeHTML(rollerCtx.getAbsoluteContextUrl(request));
        }
        ctx.put("websiteURL", url);
        ctx.put("baseURL",    rollerCtx.getContextUrl( request ) );
        ctx.put("absBaseURL", rollerCtx.getAbsoluteContextUrl( request ) );
        ctx.put("ctxPath",    request.getContextPath() );
        ctx.put("uploadPath", ContextLoader.figureResourcePath( rreq ) );
        
        try
        {
            URL absUrl = RequestUtils.absoluteURL(request, "/");
            ctx.put("host", absUrl.getHost());
        }
        catch (MalformedURLException e)
        {
            throw new RollerException(e);
        }