"Yahoo! Weather" ion dataengine review

[Amos Kariuki]

Aaron J. Seigo wrote:

> On January 11, 2010, Amos Kariuki wrote:
>> Marco Martin wrote:
>> > On Monday 11 January 2010, Aaron J. Seigo wrote:
>> >> On January 10, 2010, Amos Kariuki wrote:
>> >> > Is there a need to use both kdereview (svn) and reviewboard or should
>> >> > I just submit a patch for review in reviewboard and ignonre
>> >> > kdereview?
>> >> 
>> >> no, if it is in playground, move it to kdereview when it's ready.
>> >> 
>> >> my biggest question before even looking at the code is licensing. what
>> >> are the license requirements that Yahoo! puts on this data?
>> > 
>> > don't know if it's changed since some time ago.
>> > it was free for non profit entities, that would be ok for us...
>> > but could have potential problems for distributions
>> > (another point for making things scripted and downloadable via get hot
>> > new stuff)
>> 
>> The terms of use for the weather feeds are listed at
>> <http://developer.yahoo.com/weather/#terms>, although Marco brings up a
>> good point.  In this case assume there's no need to move this to kdereview
>> until this is resolved.
> 
> i think it's a very grey area, but at least we are ok. it would be a possible
> land mine for our downstreams and i don't know if we should be creating such
> problems for them :)
> 
>> I'd actually considered scripting the 'ion' (as Shawn had also suggested in
>> the past) but I didn't see any examples of writing a DataEngine (in
>> javascript-- which I wanted to use) so I assumed it wasn't possible at the
>> time.
> 
> it is possible in trunk (probably not in 4.4 given the lack of network support
> then). if you are using svn trunk (even just kdebase/runtime/plasma/ and
> kdelibs/plasma from trunk) we could use this as a real world test case to make
> sure that it does indeed work.
> 
> since this can't go into 4.4 anyways, this should work out well. so ... what
> do we need in the JS to make this feasible?
> 
> * DataEngine -> check
> * network access -> check
> * xml parsing -> negatory
> * but .... reg exp -> yes!
> 
> we do have the rss engine, but i just tested and it won't be of use to us
> here. i think we could get away with reg exp usage, however. which means that
> this should work right now in svn as-is without too much trouble. actual XML
> parsing would be nicer, but i don't think is strictly necessary.
> 
> we probably need some additional JS glue in the weather DataEngine Ion
> interface, however, to inject the Ion API. and that looks like it requires two
> methods:
> 
> * void reset()
> * bool updateIonSource(const QString &source)
> 
> the trouble _there_ is that we don't have access to the QScriptEngine since
> that's encapsulated behind the Plasma::ScriptEngine implementation. soo ....
> to get the API into the runtime, we could create a QScript extension plugin
> that has those bits of API and have the DataEngine request it in its .desktop
> file.
> 
> then the question would be how to trigger those calls, since they are meant to
> be called from the outside of the Ion (from the WeatherEngine). a possible
> hack would be to create a method in ScriptEngine that allows an arbitrary
> method call to be made (QString methodName, QVariantList args?) that could be
> optionally implemented by the ScriptEngine implementation to trigger calls
> internally.  not sure how i feel about that yet, but it would (in combination
> with the QScriptExtension plugin) allow this to Work(tm)
> 
> if you're into that plan, then i can write an example DataEngine in JavaScript
> for you tomorrow and put it into kdeexamples. what do you say?
> 

FYI: I've checked in some preliminary javascript code (initial port of the 
current C++ code) that currently just fetches a random data feed from Yahoo! 
Weather, parses it and prints some debugging output.  We can build on it as we 
go along.  It's located at [trunk/playground/base/plasma/ions/yahooweather-
javascript]

I found a simple JS XML parser, XML for <SCRIPT> (http://xmljs.sourceforge.net), 
that seems to have a nice clean API, and works well--that part of the problem is 
at least taken care of--it was the reason for recent the "plasmoid.include()" 
discussion thread :)

On a somewhat related note: Is it possible to display a "terms of use" 
disclaimer that a user has to agree to before installing a script via GHNS; I'm 
assuming this would be a nice addition to eventually notify the end-user of the 
Yahoo! Weather feed usage guidelines

Thanks,
Amos Kariuki