Planning new ShoppingCart system

gistfile1.aw

<?php

/*
 * goal: build SQL filter, based on parameter array
 */

//a hypothetical filter(parameters) for a new order item.
    //This data would typically come from request parameters.
$filter = array(
    'Size' => 20,
    'Color' => 'blue',
    'Premium' => true,
    'Date' => '2-3-2014',
    'RelatedObject' => 35
);
//I could even introduce an extra callback to do more complex duplicate checks
   //eg: date falls within a particular week, or size is between x and y

//this might come from OrderItem::$allowed_fields;
    //this would prevent 
$allowed_fields = array(
    'Size',
    'Color',
    'Premium',
    'Date'
);

foreach($filter as $key => $value){
    if(!in_array($key,$allowed_fields)){
         unset($filter[$key]);    //remove non allowed fields
    }else{
        $filter[$key] = Convert::raw2sql($value);
    }
}

//TODO: automatically add in any other missing allowed fields as empty/null query
    //otherwise you might get a result that you shouldn't
    //eg a red sweater is not the same as a sweater


$filter['ProductID'] = $product->ID;
$filter['OrderID'] = $order->ID;

//add query to 
$result = DataObject::get_one('OrderItem',$filter);

I thought the same thing might be able to be accomplished with SearchContext. I'm not so sure after trying, as I think it relates too much to searching from a form, rather than a generic array.

interesting concept. Can you pass an array to DataObject::get_one - is that possible or is this just shorthand?

I believe you can. See SQLQuery ->where function, which is the code DataObject::get uses for filtering.

EDIT: after things failing for a bit, I found it isn't / shouldn't be possible. ie, don't bother trying.

I think I may need ensure data is correctly formatted by passing each through appropriate DBField ->setValue. However, I can't see this happening in SearchContext, which is performing a similar role.

I've posted my updated (mostly working) idea here: https://gist.github.com/2395385