lcd4linux-devel

[Lcd4linux-devel] Question regarding evaluator and reuse of return values

[Dan F. <tem...@ya...>]

I've been pondering on this for a while now, maybe I'm daft and can't
see the obvious solution...

Ok, i got this plugin that communicates with a remote process, lets say
eMule as an example.
It is threaded and it returns a set of values every other minute.

How do i make use of these values in multiple widgets, i.e how to i use
them i one text only widget e.g "Upload 6KB, Download 10KB" and two bar
widgets at the same time without having to duplicate the "information 
retrieval" thread?

The only solution i can find is to let the widget that actually runs the
thread to be "named" and that other widgets can refer its data by that
name (or hash if you prefer) as a reference.

This is something i can easily implement since I've implemented the 
threading of python plugins in python :) 
This was much easier for me to implement and it makes the python plugin
development process much more convenient because python plugins can now
be developed, debugged and tested in pure python - threading and all.

Anyhow, this is how a config file could look like:

Widget EMULE {
    # This widget does not have to be visible
    class 'Text'
    # module = 'emule'
    # function = 'getStats'
    # hash/keyword/identifier/whatever = 'emule_hash'
    # periodicity = 1 minute (60000)
    expression  python::threaded_exec('emule', 'getStats', 'emule_hash',
60000)
    prefix 'eMule '
    width 22
    align 'M'
    update 30000
}

Widget EMULE_TXT {
    class 'Txt'
    expression  python::get_value('emule_hash', 'most_popular_upload')
    length 10
    direction 'E'
    update 30000
}

Widget EMULE_BAR {
    class 'Bar'
    expression  python::get_value('emule_hash',
'download_as_percentage')
    expression2 python::get_value('emule_hash', 'upload_as_percentage')
    length 10
    direction 'E'
    update 30000
}

i.e Widget EMULE_BAR and EMULE_TXT displays data retrieved by widget
EMULE.

Is this something you guys could live with (at least for the python
section of lcd4linux, since does not affect anything else than
plugin_python.c)? Or am i missing something?
Maybe something like this is already exists?

/dan 

Re: [Lcd4linux-devel] Question regarding evaluator and reuse of return values

[Michael R. <re...@eu...>]

Hi Dan,

> Ok, i got this plugin that communicates with a remote process, lets say
> eMule as an example.
> It is threaded and it returns a set of values every other minute.
> 
> How do i make use of these values in multiple widgets, i.e how to i use
> them i one text only widget e.g "Upload 6KB, Download 10KB" and two bar
> widgets at the same time without having to duplicate the "information 
> retrieval" thread?

Well, good point, I just didn't think of this until now :-)

> The only solution i can find is to let the widget that actually runs the
> thread to be "named" and that other widgets can refer its data by that
> name (or hash if you prefer) as a reference.
This would be a possible solution, especially when the python expression
returns a lot of values.

Another solution for the simpler issue "use a single value for text and
bar" would be the use of variables. This is possibel because all plugins
share a common namespace in the evaluator:

Widget Text {
   Expression my_var=python::exec('something')
}

Widget Bar {
   Expression my_var
}

Keep in mind that every widget can have its own update interval, which
won't make things easier... in the above example, if the text widget
will update every second, but the bar every 50 msec, the bar value will
change only every second, too.

Another drawback would be that if for any reason the text widget is not
displayed (because it's not visible at the moment, which may happen
sometime when scrolling is implemented), the variable will not be
updated :-(

Another solution may be a "data collection handler", which can be
implemented as a timer event (not implemented now). It will run every
second or so, and update one or more variables, which can be used in a
set of widgets.


bye, Michael

-- 
Michael Reinelt <re...@eu...>
http://home.pages.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781