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From Thorsten Scherler <scher...@gmail.com>
Subject Re: blockcontext protocol (part 2) (was Re: [jira] [Created] (COCOON3-107) ...)
Date Fri, 28 Sep 2012 12:59:44 GMT
On 09/28/2012 02:41 PM, Jos Snellings wrote:
> Thanks, Thorsten, that makes it a lot clearer.
> I will give it a second thought and get back.
> Just another question: are there other use cases than:
> - within xslt : document() construct
> - sitemap
> - controller->modelAndView
> ?

Actually since you brought up cocoon:// protocol I think one possible 
solution is DROP the blockcontext protocol and force to expose all 
static matches via the sitemap. This way the calling instance would need 
to use the servlet protocol and there should no problem any more.

Not sure whether you remember the context:/ in c2.1.x which simply 
pointed to the underlying serlvet context path. The blockcontext is 
based on the same idea. You can reach the path where the actually block 
is deployed (within the calling servlet is to say). However as I see it 
the only real need to know that path is when we deploy the blocks (where 
francesco path works), meaning if we do not use it otherwise the issue 
is fixed.

> Now that we reanimated the thread, has anyone else ideas? I feel it is 
> an important issue and I would love to see it solved,
> as I have myself two cocoon apps that I would like to deploy to one 
> server.
>

Well if they are both c3 based that is ATM broken and I agree that this 
is an important issue since it renders c3 useless if we not fix it.

salu2

> Kind regards,
> Jos
>
> On Fri, Sep 28, 2012 at 2:29 PM, Thorsten Scherler <scherler@gmail.com 
> <mailto:scherler@gmail.com>> wrote:
>
>     On 09/28/2012 07:24 AM, Jos Snellings wrote:
>>     Dear all,
>>
>>     Noticing that is very interesting discussion is getting silent,
>>     I'd like to ask a question.
>>     First of all, pardon me my ignorance. (blonde, can't help it).
>>     So from just a high-level understanding, can I rephrase the problem?
>>     What we seek to accomplish is:
>>     * in a sitemap, being able to load resources from another sitemap,
>>       according to the scheme:
>>       <map:generate src="cocoon://{relative-url}"/>
>>     * within an xslt calling
>>         <xsl:variable name="var" select="'cocoon://{relative-url}'" />
>>     * within controller logic:  redirect, or send the reference of a
>>     ModelAndView
>
>     Well the cocoon:/ is/was never a java.net <http://java.net>
>     handler but resolved via avalon/excalibur. Further the c3
>     correspond  would be more servlet:/
>
>
>>
>>     So now, in C3, we want to address resources cross-block to
>>     accomplish modularity, right?
>>
>>         <map:generate src="{someBlock}://{relative-url}"/>
>
>     well yes and no. blockcontext:/ refers to static (resources) and
>     not matches in the blockcontext sitemap. If you would want to call
>     the block sitemap you would request servlet:${blockId}:/...
>
>
>>
>>     This should be restricted to the instance of the cocoon servlet
>>     itself, so it can peacefully coexist with another cocoon servlet
>>     in the same JVM.
>
>     The blockcontext protocol once installed only will work for the
>     first called servlet. With the change of Fran. we do what you
>     describe but on a specific point in the app. BUT we never install
>     the protocol which makes it unusable outside the java route where
>     you can pass a URLHandler to the context.
>
>>     So you would like to avoid tweaking "URL" for the servlet without
>>     interfering with the rest.
>>
>>     - something less invasive than URL.setURLStreamHandlerFactory ?
>>     - mechanism that keeps track of wich cocoon servlet deployed wich
>>     blocks?
>>
>>     Is that a correct way of stating it? Not even my 10 cents, just a
>>     question.
>
>     If we want to keep using blockcontext protocol, the handler needs
>     a central place where the different paths are resolved. However
>     due to the nature of the problem we can have the same name for a
>     block in 2 different servlet but if we resolve the url in the
>     connection we will have the problem deciding which path to return
>     to the caller, since it can happen that the underlying request has
>     no servlet context associated meaning it is impossible to
>     determine which block to use.
>
>     Thanks for keeping the thread alive.
>
>     salu2
>
>
>>
>>     Cheers,
>>     Jos
>>
>>
>>     On Wed, Sep 26, 2012 at 3:05 PM, Thorsten Scherler
>>     <scherler@gmail.com <mailto:scherler@gmail.com>> wrote:
>>
>>         On 09/26/2012 10:10 AM, Francesco Chicchiriccò (JIRA) wrote:
>>
>>             Francesco Chicchiriccò created COCOON3-107:
>>             ----------------------------------------------
>>
>>                           Summary: With latest
>>             cocoon-block-deployment and cocoon-service-impl
>>             SNAPSHOTs, integration tests fail
>>                               Key: COCOON3-107
>>                               URL:
>>             https://issues.apache.org/jira/browse/COCOON3-107
>>                           Project: Cocoon 3
>>                        Issue Type: Bug
>>                        Components: cocoon-sample-webapp,
>>             cocoon-servlet, cocoon-sitemap
>>                  Affects Versions: 3.0.0-beta-1
>>                          Reporter: Francesco Chicchiriccò
>>                          Priority: Critical
>>                           Fix For: 3.0.0-beta-1
>>
>>
>>             This is happening as a consequence of COCOON3-105.
>>
>>             Basically, since there is no more an installed
>>             URLStreamHandlerFactory, every "new URL()" should include
>>             an instance of BlockContextURLStreamHandler.
>>
>>             This makes every other URL loading (including XSLT sheets
>>             in a separate block, like happening for
>>             cocoon-sample-webapp) unaware of "blockcontext://" URLs.
>>
>>
>>         Meaning we are back to square one.
>>
>>         Andreas Hartman is ATM in our office and we had a small chat
>>         about the underlying problem.
>>         We think that blockcontext cannot work as protocol as it is
>>         for now.
>>
>>         The above report shows that we need to use a
>>         URLStreamHandlerFactory to be able to resolve this protocol.
>>
>>         {myblock2=file:/home/thorsten/src/apache/apache-tomcat-6.0.20/work/Catalina/localhost/mywebapp2-1.0-SNAPSHOT/blocks/myblock2/}
>>
>>         Now if we look on the above and how we defined it, we have:
>>
>>         in block-servlet-service.xml
>>
>>         <servlet:context mount-path="/${blockId}"
>>         context-path="blockcontext:/${blockId}/"/>
>>
>>         will then produce the following blockcontext object:
>>         ${blockId}=${tomcat.work}/${servlet_which uses the
>>         block}/blocks/${blockId}/
>>
>>         Meaning that blockcontext:/ will be resolved to
>>         "${tomcat.work}/${servlet_which uses the block}/blocks/"
>>
>>         There are various problematic parts:
>>
>>         As of the looks of it a block is treated as "servlet" mounted
>>         to a context.  Problematic is that the mount-path in some
>>         cases needs to become ="" to catch all incoming request,
>>         which means root context.
>>         Blocks are treated as servlets meaning you can only mount
>>         once a block (in a specific version of that block). If
>>         another block use this blockId it is not possible to use the
>>         same mount point. However that has the ultimate consequence
>>         that you need to manage the name of your block manually or
>>         ideally the ${blockId} is unique and contains the version of
>>         the block!
>>         However blocks are more servlets within a servlet, since
>>         without a servlet that has deps on them they would be not
>>         reachable.
>>
>>         This leads to to the "real" mount point "${servlet_which uses
>>         the block}/{@mount-path_as defined in the block}" in the
>>         servlet context and the path as above. For example
>>         "blockcontext:/test" could refer to
>>          "${tomcat.work}/${servlet1}/blocks/test" or
>>         "${tomcat.work}/${servlet2}/blocks/test", depending from
>>         which servlet the request is issued. Meaning the blockcontext
>>         protocol does not resolve url (Uniform (or universal)
>>         resource locator) since the resources it describes are not
>>         universal (due to the fixed connection to the underlying
>>         servlet).
>>
>>         With all the above said the logical consequence is that the
>>         pattern of blockcontext would need the ${servlet_which uses
>>         the block} in it somewhere, but that would render the whole
>>         block concept useless if used within the block. That however
>>         would force a url rewritting on the fly where the
>>         ${servlet_which uses the block} prefixed would be injected
>>         prior of resolving.
>>
>>         We tested to push the resolving logic into the handler but
>>         that failed since some calls have no resolvable servlet
>>         context while they issue the call. We succeed to inject the
>>         handler in the servlet context but never declared an
>>         UrlFactory so xsl imports e.g. are failing now since they do
>>         not know about our handler.
>>
>>         In the old days (2.1.x) we had our avalon/exaclibur source
>>         resolver for creating custom protocols within a specific
>>         context - with them above would not have been a prob.
>>
>>         Anyway, how can we refactor the blockcontext so we can deploy
>>         more then one c3 webapp? Any ideas?
>>
>>         salu2
>>
>>         -- 
>>         Thorsten Scherler <scherler.at.gmail.com
>>         <http://scherler.at.gmail.com>>
>>         codeBusters S.L. - web based systems
>>         <consulting, training and solutions>
>>
>>         http://www.codebusters.es/
>>
>>
>>
>>
>>     -- 
>>     The doctrine of human equality reposes on this: that there is no man
>>     really clever who has not found that he is stupid.
>>             -- Gilbert K. Chesterson
>>
>>
>
>
>     -- 
>     Thorsten Scherler <scherler.at.gmail.com  <http://scherler.at.gmail.com>>
>     codeBusters S.L. - web based systems
>     <consulting, training and solutions>
>
>     http://www.codebusters.es/
>
>
>
>
> -- 
> The doctrine of human equality reposes on this: that there is no man
> really clever who has not found that he is stupid.
>         -- Gilbert K. Chesterson
>
>


-- 
Thorsten Scherler <scherler.at.gmail.com>
codeBusters S.L. - web based systems
<consulting, training and solutions>

http://www.codebusters.es/


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