Re: [wsrp] Caching of resources

[Subbu Allamaraju <subbu@bea.com>]

This is a bit more complicated, and it may not suffice to say that the 
Consumer SHOULD NOT supply the NavigationalContext. For example, what 
happens if the resource is relying on portletState to generate the 
resource? We should say that when a portlet wants the resource 
cacheable, the portlet MUST NOT rely on any consumer-managed or 
producer-managed state (or state that is different from its initial 
state and which could change during other markup operations). That would 
make getResource equivalent to the HTTP proxy.

Subbu


Rich Thompson wrote:
> 
> I did not include this as even the portlet's own navState would drop the 
> cacheability of the resource significantly. The flip side is that use of 
> gR for view fragments will increase as AJAX use grows, but this just 
> means those are somewhat less cacheable than they are natively (i.e. if 
> they depend on portlet navState, then they won't be very cacheable to 
> start with).
> 
> Rich
> 
> 
> *Stefan Hepper <sthepper@hursley.ibm.com>*
> 
> 02/27/2007 07:52 PM
> 
> 	
> To
> 	wsrp@lists.oasis-open.org
> cc
> 	
> Subject
> 	Re: [wsrp] Caching of resources
> 
> 
> 	
> 
> 
> 
> 
> 
> Hi Rich,
> good start, but I've some questions:
> - why don't we allow access to the nav state? I think encoding the
> current nav state of only this portlet in the URL does not hurt caching
> as the nav state cannot be changed by a gR call
> - why don't we allow to have other resource URLs in the response of
> cachable resource markup?
> 
> Stefan
> 
> Rich Thompson wrote:
>  >
>  > Here is the proposal I promised to draft:
>  >
>  >
>  >
>  > Rich
>  > ------------------------------------------------------------------------
>  >
>  > Next change
>  >
>  >
>  >       6.3.1 Caching of resources
>  >
>  > For performance reasons the Consumer might prefer to cache resources
>  > across a series of requests. The Producer passes information about the
>  > cacheability of the resource representation in the cacheControl
>  > structure returned in a MarkupContext structure. The Consumer can infer
>  > from this information when it may cache the resource and when the cached
>  > resource needs to be invalidated and updated by a new call to
>  > *getResource*. All of the cache semantics described in [Section 6.2.1]
>  > <#_MarkupCaching> applies to the caching of resources as well.
>  >
>  > In addition to Consumer caching, both browser and web-based caching may
>  > apply to the resource. Since resources can contain URLs which need to be
>  > written using either the template or Consumer URL rewriting techniques
>  > discussed in [Section 10.2] <#_URL_Considerations>, the URI used by the
>  > browser to fetch the resource will likely contain state information
>  > which virtually guarantees the resource will not be retrieved from the
>  > cache on subsequent accesses. [Section 10.2.1.1.3.6]
>  > <#_wsrp-cacheableResource> defines the wsrp-cacheableResource portlet
>  > URL parameter for the purpose of increasing the hit ratio for the
>  > browser and web caches of appropriate resources.
>  >
>  >
>  >             10.2.1.1.3.6 wsrp-cacheableResource
>  >
>  > This boolean (default value is false) provides an indication to the
>  > Consumer that it can limit the amount of state it places on the URI for
>  > the resource such that the likelihood of a subsequent browser access
>  > being served from a browser/web cache is increased. This portlet url
>  > parameter can only be set to true if the resource contains no URIs
>  > referring back to the portlet and if the resource, when served using the
>  > *getResource* operation, does not require the Consumer to supply the
>  > navigationalContext structure. When the wsrp-cacheableResource portlet
>  > url parameter has a value of true, the Consumer SHOULD NOT include any
>  > navigationalContext structure on a related invocation of the
>  > *getResource* operation.
>  >
>  > Note that this portlet url parameter only impacts Consumer URL rewriting
>  > as the templates related to resource URIs have to allow for resources to
>  > access the excluded state/functionality.
>  >
>  > If both the wsrp-cacheableResource and wsrp-requiresRewrite portlet URL
>  > parameters are set to true, the Consumer MUST parse the resource for the
>  > purpose of rewriting namespace prefixing as per [Section 10.3] 
> <#__Toc77>.
>  >
>  >
>  >       10.2.3 Extended BNF Description of URL formats
>  >
>  > These definitions utilize the syntax defined in ISO/IEC 14977 ^[21]
>  > <#_ftn21>
>  >
>  > ConsumerURL = BeginToken (RenderURL | ActionURL | ResourceURL |
>  > ExtensionURL) EndToken
>  >
>  > BeginToken = "wsrp_rewrite?"
>  >
>  > EndToken = "/wsrp_rewrite"
>  >
>  > RenderURL = "wsrp-urlType=render" {("&" | "&amp;") (CommonPair |
>  > RenderPair)}
>  >
>  > ActionURL = "wsrp-urlType=blockingAction" {("&" | "&amp;") (CommonPair |
>  > ActionPair)}
>  >
>  > ResourceURL = "wsrp-urlType=resource" {("&" | "&amp;") (CommonPair |
>  > ResourcePair)}
>  >
>  > WSRPURLTypes = "render" | "blockingAction" | "resource"
>  >
>  > ExtensionURL = "wsrp-urlType=" (Text - WSRPURLTypes) {("&" | "&amp;")
>  > (ExtensionPair)}
>  >
>  > CommonPair = CommonTextPair | CommonBooleanPair
>  >
>  > CommonTextPair = CommonTextName "=" Text
>  >
>  > CommonTextName = "wsrp-fragmentID" | "wsrp-extensions"
>  >
>  > CommonBooleanPair = CommonBooleanName "=" BooleanValue
>  >
>  > CommonBooleanName = "wsrp-secureURL"
>  >
>  > RenderPair = RenderTextName "=" Text
>  >
>  > RenderTextName = "wsrp-mode" | "wsrp-windowState" |
>  > "wsrp-navigationalState" | "wsrp-navigationalValues"
>  >
>  > ActionPair = ActionTextName "=" Text
>  >
>  > ActionTextName = "wsrp-interactionState" | RenderTextName
>  >
>  > ResourcePair = (ResourceTextName "=" Text) | (ResourceBooleanName "="
>  > BooleanValue)
>  >
>  > ResourceTextName = "wsrp-url" | "wsrp-resourceID" | "wsrp-resourceState"
>  >
>  > ResourceBooleanName = "wsrp-requiresRewrite" | "wsrp-preferOperation" |
>  > wsrp-cacheableResource"
>  >
>  > ExtensionPair = Text "=" Text
>  >
>  > Text = { "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" | "j" | "k"
>  > | "l" | "m" | "n" | "o" | "p" | "q" | "r" | "s" | "t" | "u" | "v" | "w"
>  > | "x" | "y" | "z" | "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I"
>  > | "J" | "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" | "S" | "T" | "U"
>  > | "V" | "W" | "X" | "Y" | "Z" | "0" | "1" | "2" | "3" | "4" | "5" | "6"
>  > | "7" | "8" | "9" | "-" | "_" | "." | "!" | "~" | "*" | "'" | "(" | ")"
>  > | "%" }
>  >
>  > BooleanValue = (("true" | "1") | ("false" | "0"))
>  >
>  >  
>  >
>  > ProducerURLTemplate = {{Text} {ReplacementToken}}
>  >
>  > ReplacementToken = "{" CommonTextName | RenderTextName | ActionTextName
>  > | ResourceTextName | CommonBooleanName | ResourceBooleanName |
>  > ParameterName "}"
>  >
>  > ParameterName = "wsrp-urlType" | "wsrp-portletHandle" |
>  > "wsrp-userContextKey" | "wsrp-portletInstanceKey" | "wsrp-sessionID"
>  >
> 
> 
> 
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