Load file from DB

[Kaspar Fischer <fi...@inf.ethz.ch>]

Hi there,

I am struggling in implementing a (Web)Resource to load a file (not an
image) from an external source. Does anybody have/know of an example
that illustrates

* where/when to open the connection to the DB and start a transaction,
* fetch the file, and
* close the transaction?

I am trying to output to the browser a file from the Alfresco content
repository and need to perform similar steps.

Thanks,
Kaspar

P.S. Here's what I have, which results in ERROR - RequestCycle - Unable
to write the response.

public final class RepositoryFileResource extends WebResource
{
   private static final long serialVersionUID = 8406533594955148061L;

   private FileResourceStream stream;

   public RepositoryFileResource()
   {
     setCacheable(true);
     stream = new FileResourceStream();
   }

   @Override
   protected void setHeaders(WebResponse response)
   {
     super.setHeaders(response);
   }

   @Override
   public IResourceStream getResourceStream()
   {
     return this.stream;
   }

   @Override
   protected int getCacheDuration()
   {
     return 48 * 3600; // 2 days
   }

   private final class FileResourceStream implements IResourceStream
   {
     private static final long serialVersionUID = 390065327841658269L;

     private NodeRef nodeRef;

     private transient RepositoryContext context;
     private transient UserTransaction transaction;
     private transient ContentReader reader;
     private transient InputStream contentStream;

     void prepare()
     {
       if (transaction != null)
         return;

       // Determine node to deliver
       ValueMap params = getParameters();
       String nid = params.getString("nid");
       nodeRef = new NodeRef(KnowledgeCenterModel.STORE, nid);

       // Get request cycle
       context = RepositoryContext.get();
       try
       {
         transaction =  
context.transactionService.getNonPropagatingUserTransaction();
         transaction.begin();
         context.authenticationService.authenticate(Website.LOGIN,  
Website.PASSWORD.toCharArray());
         reader =  
context.serviceRegistry.getContentService().getReader(nodeRef,  
ContentModel.PROP_CONTENT);
       }
       catch (Exception e)
       {
         throw new RuntimeException("Error...", e);
       }
     }

     public void close() throws IOException
     {
       if (contentStream != null)
         contentStream.close();
       try
       {
         if (transaction != null)
           transaction.commit();
       }
       catch (Exception e)
       {
       }
       finally
       {
         transaction = null;
       }
     }

     public String getContentType()
     {
       prepare();
       return reader.getMimetype();
     }

     public InputStream getInputStream() throws  
ResourceStreamNotFoundException
     {
       prepare();
       return contentStream = reader.getContentInputStream();
     }

     public Locale getLocale()
     {
       // TODO
       return null;
     }

     public long length()
     {
       prepare();
       return reader.getSize();
     }

     public void setLocale(Locale locale)
     {
     }

     public Time lastModifiedTime()
     {
       // TODO
       return null;
     }
   }

}

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
For additional commands, e-mail: users-help@wicket.apache.org