Topic: interface
Class:
Technical
Title: Caching Mechanism
Document Section: Interfaces/6.1
Description:
I am
submitting the following proposition to the committee as a proposition for
dealing with caching of the markup. This proposition deals with
"Expires"-like methods of caching, along with "If-Modified-Since/ETags"
type of caching. I believe it is simple enough to be included in the v1.0
spec.
Caching Proposal
[The
proposal is described as edits to the spec]
6.1 Operations
[getMarkup]
[instead of expires in markupResponse, add the
following]
cacheControl: A data structure,
defined in Section 11, which includes information which CAN be used by the
Consumer to cache the markup. This
structure includes:
validUntil: The time at which the markup is valid. Until that time the Consumer
CAN use its cache entry instead of calling getMarkup. After this time passes, the
Consumer MAY continue to use this cache entry, but only after validating
it with a getMarkup operation, using the
validationTag below, if
given.
validationTag: The Consumer MUST store this tag along with the markup while the markup is
valid. This enables the Producer to use this tag to invalidate the cache
entry by sending an invalidationTagPrefix
in the performInteraction operation. After the markup expires, the Consumer CAN send the validationTag in the
markupResponse to indicate that it still has the
markup but would like to validate it. The Producer returns a fault
response [TBD] to indicate that the markup is still valid, otherwise if it
returns markup
, the Consumer MUST invalidate the old markup.
[add
to markupContext the following
field]
validationTag: This field CAN be sent to indicate that the Consumer has
cached markup (which was tagged by the Producer with this value) and
wishes to check whether it is still valid. See validationTag in markupResponse for more information.
6.1
Operations [performInteraction]
[add
the following field to interactionResponse]
invalidationTagPrefix: If the Producer returned
this value, the Consumer MUST expire all markup-s who's validationTag begins with this value.
The Consumer MUST not call getMarkup with these invalidationTag-s to validate these expired
markup-s.
[add
these fields to the relevant places in section 11]
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Discussion: