I'm just writing a few notes on the changes Shawn and I made to the Weather Ion
API due to a bug where a dropped network connection would lead to uninitialised
junk being sent to plasmoids. It was reported in the context of KDE 4.2, and
though it can't be fixed there so easily, by hooking into Solid, in 4.3 the
necessary information can be obtained. I'm sending this to the list as there a
few ions in playground, and at least one more of not in playground that I've
heard is being developed.
The executive summary is that you need to add one slot to your ion, and emit a
signal when it's done its job. The slot is called reset() - as the name
suggests, it resets the ion. When it's done, emit resetCompleted(this,bool)
where the bool is true if the reset was successful, or false otherwise. In
practice, the code for resetCompleted will need to do one of two things:
i) For ions which don't fetch a complete list of places, and only use the
network to get a forecast or query with a suggested location string, clear all
the existing data, and emit resetCompleted(this,true).
ii) For ions which fetch a list of place names off the 'net when the ion is
first called (e.g. environment canada), clear all the existing data, grab the
list of places again, then emit resetCompleted(this,true) if the download was
successful; or resetCompleted(this,false) otherwise.
That's it. The way it's written means the ions don't need to know /anything/
about whether the network is up. The weather engine will hold onto requests
until such a time as the network is available. The bool of resetCompleted
allows it to cope with the connection being dropped during list download - if
this is false, it will still hold onto the request before passing it on. Both
forecast request and location checks are queued. So, for instance, if it's
asked whether there's any forecast data for London, it will hold off answering
until it can find out - libplasmaweather will just sit there patiently. Shawn
tested it in ridiculous situations - three weather plasmoids going at once,
kill the 'net, search, bring it back up, click okay, take it down, click okay,
bring it back up....
Andrew
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