wsrp-comment message

Subject: JSR286's MULTI-PHASE render not supported in WSRP 2.0

From: Nathan E Lipke <nlipke@bea.com>
To: wsrp-comment@lists.oasis-open.org
Date: Fri, 14 Sep 2007 10:22:17 -0600

Recent drafts of JSR-286 have included the concept of multi-phase
render. This allows a portlet to populate headers (including cookies)
and add elements to the <head> (such as script, style and meta elements)
section of the surrounding page.

WSRP 2.0 currently does not support this. There are a number of ways we
can support this:

1. Like JSR-286 defines
1. Portlet Descriptsion [O] boolean isMultPhaseRenderSupported
2. MimeRequest [O] QName renderPhase
* wsrp:head
* wsrp:body
* Requires structural changes to spec late in the spec
* Allows full independent caching of head an body separately
2. As discussed on the call: make the producer call the 286 portlet
twice and make the consumer cache head info
1. Consumer calls getMarkup on the portlet before rendering its
headers and <head> section
2. The producer calls the 286 portlet twice
1. for HEAD
2. for BODY
3. The getMarkupResponse contains both the <head> and <body>
sections as well as any headers
4. The consumer sets the headers, renders the head and caches
the body
5. The consumer later renders the body
* Requires no WSRP spec changes (although some notes would be
helpful)
* Need to bend the no <head>/<body> tag rule
* Requires the consumer to cache markup
* Does not allow independent caching of head and body
3. As discussed with Stefan: Send a WSRP defined event
1. The consumer sends a wsrp:getHead event
2. The response MUST contain a updateResponse with
markupContext populated
3. The consumer MUST interpret this as the head content and NOT
the normal content
* Requires little spec change
* Requiring markup as a response to an event seems odd (as
compared to the rest of the spec), same for special
interpretation on the consumer
* Allows full independent caching of head an body separately
4. Add a well known resource name (e.g. wsrp:head)
1. The consumer calls getResource() during head render phase
which returns head and headers
* This would require advertisement of the head section
(similar to solution #1)
* Allows full independent caching of head an body separately
5. Do nothing/use vendor dependent extensions

For what its worth: BEA Weblogic Portal already supports multi-phase
render as an extension called getRenderDependencies(). This has worked
fairly well for us so far. However we would prefer to interoperate with
3rd party consumers and producers.

Thanks,

Nate

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