Refreshing question

[Mark Waddingham]

On 2017-07-12 18:23, jbv via use-livecode wrote:
> On Wed, July 12, 2017 5:34 pm, jonathandlynch at gmail.com wrote:
>> If the data is always the same, then I would update a page and have 
>> the
>> browser read it.
>> 
>> Are you looking to reload the whole page or just update a few data
>> points?
>> 
> 
> I really need to reload the xml data only, as the user will have the
> possibility to make some choices and changes on the page, and according
> to those changes, only some parts of the data will be displayed, or
> will be displayed in a different way...

I can see two main options:

1) If the data is expensive to recompute each time, or if you are 
expecting the number of fetches (for all users) of the data to vastly 
exceed the number of recomputations then you are probably better off 
recomputing at a fixed interval in a cron job, and serving the computed 
data statically.

2) If, however, the data is very cheap to recompute each time, or if you 
aren't expecting the number of fetches (for all users) of the data to be 
that much more frequent than the number of recomputations then you are 
probably better off computing it on demand for a request.

There is a third option, which is essentially a combination of the 2 - 
recompute lazily. If a request comes in and the data needs recomputed, 
recompute it and ensure all other requests block and wait for it. Then 
serve it statically to all requests.

Option (3) is probably the easiest (it has less 'moving parts'), 
followed by (2) and then (3).

Note: If you need to selectively return data, based on the request, then 
(2) is probably the best option.

Warmest Regards,

Mark.

-- 
Mark Waddingham ~ mark at livecode.com ~ http://www.livecode.com/
LiveCode: Everyone can create apps