From: Jason Foster [mailto:[EMAIL PROTECTED]]
I am in the process of trying to create a Cocoon baby-block
that can be
used to generate output from a DocBook source file. I was
hoping that the
group could help me puzzle through the right way to
accomplish my goal.
The process that I am envisioning looks something like this...
1. The user visits a web page where they specify the DocBook
source file
they would like to upload and the various processing options
they would
like to use. These options are presented as pulldowns, text fields,
checkboxes, etc.
2. The uploaded file into a temporary directory somewhere
3. The DocBook stylesheets are applied to the file, using the
specified
processing options
4. (For now) a PDF document is returned to the user
My primary implementation goal is to use the minimum amount
of code as
possible. Right now the W3, and in my opinion the Cocoon
developers, are
pushing for a more declarative web development experience
I would not say for all the Cocoon developers.
(check out the
XForms spec for an example) so I would like my implementation
to adhere to
this vision.
Accomplishing part 1 is fairly straightforward, as it is a
simple XHTML
page, no bells or whistles. I could base it on a transform,
but for now
that seems like overkill.
Yes.
Part 2 looks to be be handled by the SourceUploadAction that
is currently
sitting in the scratchpad. The alternative that is most
often discussed in
this list is to use an XSP page to do the work, which I would
prefer not to
do for the reasons discussed earlier. Any other techniques would be
greatly appreciated.
IMO, SourceUploadAction is the right choice.
Part 3 looks to be the most complicated. I don't want the
user to have to
always select all of the processing options. I also don't
want to have to
keep track of the default values used by the DocBook
stylesheets, which
would be a maintenance nightmare. My plan is to provide a
use default
option for the pulldowns and to assume that empty text fields
mean use
default.
What's wrong with having defaults in stylesheets and assign new values from
request params?
xsl:param name=use.extensionsnoxsl:param
And then in the sitemap turn on
use-request-parametersfalse/use-request-parameters option for the XSL
transformer.
Another problem is that the DocBook stylesheets assume that
there will be
a driver stylesheet that looks like:
xsl:stylesheet
xmlns:xsl=http://www.w3.org/1999/XSL/Transform;
version='1.0'
xsl:import
href=file:///Users/jafoster/Development/docbook-xsl-1.50.0/fo
/docbook.
xsl/
xsl:param name=use.extensions/
xsl:param name=autotoc.label.separator/
/xsl:stylesheet
I would really like to do things properly and use the
driver stylesheet
approach. This means that I need to first use the submitted
form to create
the driver stylesheet and then use that new stylesheet to process the
uploaded file.
At a guess what I will have to do is use two different
pipelines. The
first will use some kind of FileWritingTransformer or
WriteableSource
or something similar to generate the driver stylesheet. That
pipeline will
then call the second pipeline which will actually do the
transformation and
generate the PDF. Hopefully someone can provide some advice
on this part
of the implementation. One issue that I have no idea how to
address is the
namespacing issues associated with having one XSLT generate
another XSLT.
You can do it this way:
- First pipeline generates the content transformations into PDF and
calls the second pipeline to obtain the needed stylesheet
- Second pipeline generates a stylesheet depending on request params
and using a stylesheet template
Look at the Slashedit sitemap
(xml-cocoon\2.1-dev\src\scratchpad\webapp\samples\editor\editor.xmap),
particularly, the lines 101-123. You'll see several map:transform
src=cocoon:/something.xsl /.
Assuming that I can get this to work, part 4 is automatic,
assuming that I
use Saxon. As of today Xalan can't handle DocBook, so I am using the
specify your own factory approach and forcing the use of Saxon.
I have every intention of documenting the full design process and
implementation of this project, assuming that I can ever
make it work. I
know that the DocBook community would love to have an
automated way for new
users to play with the DocBook stylesheets in a controlled manner.
And I'm sure that Cocoon community would like to have a use-case like this,
and more over if it will be documented in details.
Hope my comments help a little.
Konstantin.
Thanks for any help you can give. Once this is all documented, you
(hopefully) won't have to answer these kind of questions again!
Jason Foster
-
Please check
