Caching
and Prefetching in VoiceXML
(Continued
from Part 1)
Where
Does Caching Work?
The
following tags support the caching
and fetchhint attributes:
- audio
- choice
- dtmf
- goto
- grammar
- link
- object
- script
- subdialog
- submit
By
applying the two attributes to these VoiceXML elements,
the application author can exercise fine-grained control
over how and when things are fetched.
The
developer can also control caching and prefetch using
the following properties
- caching
- this property can be set to safe
or fast;
- audiofetchhint,
documentfetchhint,
grammarfetchhint,
objectfetchhint,
scriptfetchhint
- these properties can have the values safe or prefetch;
The
various fetchhint
properties apply to the related types of fetches (e.g.,
grammarfetchhint
applies to grammar file fetches only).
If
a tag has the attribute applied, then the caching is
applied to that element only. If no caching attribute
is present, then the tag inherits the value derived
from the innermost relevant caching property.
Caching
in VoiceXML 2.0
VoiceXML
2.0 isn't yet a public working draft, but should be
soon. Suffice it to say that the Voice Browser Working
group has made some improvements in the area of caching,
including giving it a better mapping to HTTP 1.1, and
giving the developer tighter control over when web fetches
occur (and, more importantly, when they don't!).
What's
Next?
Well,
we've finally gotten caching out of the way. Next month,
we're going to look the <transfer> tag, and, if
we have space, the <record> tag. In the meantime,
enjoy what's left of the summer!
Watch
future issues of VoiceXML Review for more articles about
getting started with VoiceXML.
back
to the top
Copyright
© 2001 VoiceXML Forum. All rights reserved.
The VoiceXML Forum is a program of the
IEEE
Industry Standards and Technology Organization (IEEE-ISTO).
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