Re-sorting a CActiveDataProvider - php

Question

I am looking for a way in Yii to re-sort a CActiveDataProvider.
Currently I am using the the data provider to fetch sorted and paginated data.
I am then looping through it with a foreach loop adjusting data for specific fields, and now I need to re-sort it based upon the new adjusted data.
I can't sort the data in the model using afterFind because I need to query another DB (MySQL) to work out a calculated value and it doesn't seem to like the switching during the processing.
I don't want to use an CArrayDataProvider because there is no obvious way to paginate the data which comes back unless I put controls into a loop while adjusting the data, however I don't know how much data could come back, say 200 records, but the only adjusting 20 for the display seems counterintuitive.
This all is then pushed to a CGridView widget.
so now I need to readjust on the array below in ascending order for example.
$dataProvider = new CActiveDataProvider( blah );
foreach ( $dataProvider->getData() as $data ) {
$data->Score += SomeModel::model()->findByPk(1)->NewScore;
}
array(
'Score' => 7
),
array(
'Score' => 6
)
$this->render('blah', array('data' => $dataProvider);

Answer 1

It sounds like you should simply implement a new CDataProvider of your own that wraps an existing CDataProvider. You will need to override several methods, but for most of them you can simply forward to the wrapped data provider. The code might end up looking something like this:
$dataProvider = new CActiveDataProvider(...);
$myProvider = new CustomDataProvider($dataProvider);
// you could make CustomDataProvider work like this:
$myProvider->dataMutator = function(&$row, $key) {
$row->Score = SomeModel::model()->findByPk(1)->NewScore;
};
$this->render('blah', array('data' => $myProvider);
CustomDataProvider::fetchData might look like this:
protected function fetchData()
{
$data = $this->wrappedProvider->fetchData();
array_walk(&$data, $this->dataMutator);
uasort($data, function($a, $b) { return $a->Score - $b->Score; });
return $data;
}
I 've hardwired the sort here -- this works for prototyping, but to specify the post-processing sort cleanly is not trivial because:
CDataProvider exposes a sort property which is ignored. Integrating that property fully would either be non-trivial work (you have to write code that respects multiple sort criteria etc) or change the semantics of CustomDataProvider.sort compared to sort on its base class. CDataProvider is married to CSort, so if you wanted to go for the cleanest solution from an OO perspective it would be best to implement IDataProvider from scratch.
It's not intuitive to the user of CustomDataProvider how sorting works if a single 'sortproperty is used, becausesort` cannot reflect both what the wrapped data provider will do and what the "post-processing" sort will do at the same time; however, both of the above will affect the end result.
I suggest that you get a prototype working and then have a good think about what the object model should be.