Sylvain Wallez wrote:
Daniel Fagerstrom wrote:
Sylvain Wallez wrote:
Leszek Gawron wrote:
other example that I posted some time ago: if every cocoon uses
error2html.xsl by default (along with some other default resources)
they should be also packed into jars.
Aha! This is something I wanted to talk about when working on Cocoon
stacktraces: standardizing the fact that some blocks provide
resources and include them in jars.
The first block to do this is CForms, which provides a lot of
runtime resources in org/apache/cocoon/forms/resources: XSLs, js,
css, etc. We also have a few items for the core block in
webapp/stylesheets/system and webapp/resources (js and css). What we
see here is that these are runtime resources targeted both at the
server side (XSLs) and the client side (js, css and also XSLs for
xsl-aware browsers).
What I propose is that we define a standard layout for resources
provided by blocks: they should be stored in
resource://org/apache/cocoon/{block-name}/resources/
The nice thing with this propsal is that it is back compatible and
follow current (emerging) conventions. OTH with the blocks
architecture, using the resource protocol is not such a good idea. In
OSGi resources have URLs like bundle://3/org.apache.cocoon.foo e.g.
where "3" is the number of the bundle and is deployment order
dependent and is therefore not usable in sitemaps. In OSGi one
typically puts the resources at the top level of the jar or in
directories at top level. There is normally not that much reason for
puting resources in the Java package structure, as the bundle poften
is an apropriate level of granularity anyway.
Hmm... as I understand it, the bundle: protocol is similar to what is
returned by ClassLoader.getResource(),
It will be returned by getResource() in Knopflerfish.
and is abstracted by the resource: protocol implementation (it can
actually be a jar: or a file: or something else that we never see).
Yes.
And BTW, unless I missed something I haven't seen an explicit
reference to the "bundle:" protocol in the OSGi specs, at least in R3.
Didn't found it either, maybe it is Knopflerfish specific. But even if
it is, the OSGi api have no direct ways for accessing a resource from
any bundle, you must specify from what bundle you want to read a
resource. Maybe there is a way to do it in some more indirect way.
We also have the block protocol that allows you to define what block
the resource is taken from: block:foo:/bar.xsl. Now the block
protocol assumes that everything is exported through the sitemap wich
might be appropriate (but maybe inconvenient) for the use cases you
have in mind. Maybe we could have an own bundle protocol (through the
source mechanism), that works like the OSGi bundle protocol but have
symbolic block names instead of bundle numbers.
Something like "block-resource://org.apache.cocoon.forms/..." ?
This can be implemented today in 2.1.x by having this protocol
delegating to "resource:"
That would be one possibility, question is if we want direct access to
blocks. Part of the idea with blocks is to have symbiolic names for the
blocks so that one can chnage implementation. OTH a package name could
be seen as a symbolic name as well, so it might be good enough.
Additionally, we should have a system-defined URI which allows
clients to fetch these resources, implemented in the root sitemap:
<map:match pattern="_cocoon_/*/**">
<map:read src="resource://org/apache/cocoon/{1}/resources/{2}"/>
</map:match>
By standardizing this URI pattern, we can easily solve
cross-referencing problems among resources, e.g. CForms XSLs having
to produce <script src="..."/> to load the JS files, etc.
This URI pattern could even be written **_cocoon_/*/** to be
location-independent so that we don't have to mess around with
{request:contextPath}.
All this is allready solved within the (sitemap) block architecture
and there is an implementation of it in trunk. block URIs are used
for accessing things and a special URL rewriting transformer
absolutizes the block URLs.
I'm proposing here a public URL pattern that can be accessed by
browsers. Block URIs are an internal thing and this pattern must be
implemented somewhere, no?
The idea for blocks is that blocks that contain public URLs are mounted
at deploy time at a some root URL, then the URL revriting transformer
translates internal use of symbolic block names to the public exported ones.
WDYT?
Your proposal makes sense and we should make something about the
issues you describe. What you describe will not be particulary future
proof though.
So how do we make it future proof yet possible in 2.1.x? Can we have a
single naming scheme (with a new protocol) implemented differently or
pointing to different locations (the 'resources' dir can be located at
the top-level of a bundle)?
Something like the block-resource: protocol could work. As said above
the question is if we want direct block references, the block
architecture only allow direct block refernces in the deploy descriptor
and use symbolic names everywhere else.
For where to put the resouces, we could put them in a "resources"
directory at top level and then let the build process put it at the
place appropriate for 2.1.x and OSGi based blocks repsectively.
Another question is of course if we really should back port everything
to 2.1.x.
/Daniel
