a NO thank-you to Cocoon-developers

Sascha Kulawik Sun, 28 Jul 2002 02:47:09 -0700

Title: Nachricht

Thank you very much, but it didn't work out.

I've now taken the DatabaseReaser.java and changed it in a little way for my needs - now it works.

I think, te DatabaseReader that comes with Cocoon will never work in that case. I haven't found the solution, to give the reader the informations which "id" or something else I'm searching for.

It was REALLY messy to get this working - I'm a Java Developer of course, also I'm a Cocoon User - but not a Cocoon Developer. So I've tried to get this reader working, without any good documentation. Hey Cocoon guys, it's really hard to understand components with a Javadoc Information, that doesn't fit to the sourcecode of this component !

A little example for the DatabaseReader:

At first I have to give the reader the Information, which Datasouce from my Sitemap I want to use.

Nothing found in Javadoc, in the Source I've found, that there must be an Parameter "use-connection" for giving the Name of the Database Connection.

But - as I said, I'm not a Cocoon-Dev or Avalon Expert, so: is this a Value of a XML Parameter ? Is this a Attribute ? Where do I have to use the Attribute ?

After 2 hours trial & error I've found, that this is a Element (not map:parameter) in the map:reader section. Also I've found, that this component doesn't like my Entrys in the cocoon.xconf like:

(like any other components), so that there MUST be also a given class like:
<jdbc name="MyConnectionName" class="org.apache.avalon.util.datasource.JdbcDataSource">
But: how should I know that ? Why does all the other components work without this class ? (Thats an Avalon Issue, I don't know how the selektors work...)

Afer all that work and a lot of Time there was the last two issues for getting this Reader working:

How can I give the component the part of the SQL, where I'm looking for ?

(Like: SELECT * FROM table WHERE id = ?, the "?" Part was never filled.)

After that and a new Parameter for that in the Sorce (there was a varaible, that was never been initialized and used for that (also in the parent-class), don't know hw this should work) I've got NullPointerExceptions that I can't resolve.

(Hey, I'm not a Cocoon Expert ! :-)

So I've found, that I also need to give the reader the mime-type like any redirect to an Image, so that there will be a correct output.

This Issue was fast to resolve, because in the procedure getMimeType() was an entry like super.getMimeType() and the super.getMimeType() will ever give NULL.

So I've taken the Mimetsype from the Database for supporting DOc/PDF/GIF/JPG ... and so on.

My Sitemap looks like this right now:

<map:match pattern="BLOB">
    <map:act type="request">
     <map:parameter name="parameters" value="true"/>
     <map:read type="db">
      <parameter name="table" value="teasermessage_blob"/>
      <parameter name="image" value="data"/>
      <parameter name="key" value="id"/>
      <parameter name="find" value="{id}"/>
      <parameter name="filename" value="filename"/>
      <parameter name="mime" value="mimetype"/>
     </map:read>
    </map:act>
   </map:match>

So, If anybody is interested in my source, I can give it to you, but what I want to say is, that this was REALLY messy to get a reader working, and a lot of the soruce in Cocoon isn't right documented - so If you aren't a cocoon-source-expert you have to look and invest a lot of time to get thinks working.

Especially all of the Actions / Readers / Generators that aren't in any HowTo are not easy to understand and there is a documentation, that won't give any correct answer to that question.

Also there was been saved with examples and so on. Sometimes it isn't clear, if there will be a Sitemap entry at the component or where do you use this component.

Ok,

thats enough for today,

greetings,

Sascha

-----Original Message-----
From: Jeroen ter Voorde [mailto:[EMAIL PROTECTED]]
Sent: Saturday, July 27, 2002 3:25 PM
To: [EMAIL PROTECTED]
Subject: Re: Return BLOB Value
Importance: High

You can use a Reader to implement this (That's what i did).

(Stripped) Example:

public class Reader extends AbstractReader implements Poolable, Composable {

Request request = null;
Response response = null;
Context context = null;
ComponentManager manager = null;

public void setup(SourceResolver resolver, Map objectModel, String src, Parameters par) throws ProcessingException, SAXException, IOException {
  super.setup(resolver, objectModel, src, par);
  context = ObjectModelHelper.getContext(objectModel);
  request = ObjectModelHelper.getRequest(objectModel);
  response = ObjectModelHelper.getResponse(objectModel);
}

  public void generate() throws IOException, SAXException, ProcessingException {

  try {
    response.setHeader("Cache-Control", "no-cache");
    response.setHeader("Pragma", "no-cache");
    response.setDateHeader("Expires", 0);

   // out is the outputstream to write your blob data to.

    ((OutputStream)out).write('The blob data');

   }
  } catch (Exception e) {
   throw new ProcessingException("Error in reader: "+e);
  }
}

public String getMimeType() {
  return context.getMimeType(source.substring(source.lastIndexOf("/") + 1));
}

}

----- Original Message -----

From: Sascha Kulawik

To: [EMAIL PROTECTED]

Sent: Friday, July 26, 2002 10:07 PM

Subject: Return BLOB Value

Hello,

I'm trying to implement a File-Upload / Download for a small Forum written in Cocoon XSP.
Currently Ive no idea how to implement the FileDownload. The easiest way for that would be to write the data to a mySQL Ressouce and read the data because of Userpermissions and so on.

Is it possible, to returm plain BLOB Data from a Database to the User for a Download ?
Is there a better way to implement that in Cocoon ?

Thank you very much,

Greetings,
Sascha

RE: Return BLOB Value / redesigned DatabaseReader / a NO thank-you to Cocoon-developers

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