Magento API, Return Orders with NULL values - api

Question

Using the magento api version 1 and soap.
Need to return all orders with 'coupon_code'=> NULL
The call I'm attempting:
$order_listAR = $proxy->call($sessionId, 'sales_order.list', array(array('coupon_code'=>array('null'=>'null'))));
The ouput I want returned is this:
array(237) {
["state"]=>
string(8) "complete"
["status"]=>
string(8) "complete"
["coupon_code"]=> NULL
So far this seems to work properly, but I'm not sure if ('null'=>'null') is the proper way to find NULL values in the array. Can someone explain why this works, and, or if this is the correct syntax? I don't have any margin for error on this.

Answer 1

Yes, the syntax you use is correct to filter against null.
array(
'coupon_code' => array(
'null' => 'this_value_doesnt_matter'
)
)
Magento maps* the API method sales_order.list to Mage_Sales_Model_Order_Api::items().
public function items($filters = null)
{
:
$collection = Mage::getModel("sales/order")->getCollection()
:
if (is_array($filters)) {
try {
foreach ($filters as $field => $value) {
if (isset($this->_attributesMap['order'][$field])) {
$field = $this->_attributesMap['order'][$field];
}
$collection->addFieldToFilter($field, $value);
}
} catch (Mage_Core_Exception $e) {
$this->_fault('filters_invalid', $e->getMessage());
}
}
:
}
The items() method uses a Mage_Sales_Model_Resource_Order_Collection to fetch the orders for the API call. That collection is based on Varien_Data_Collection_Db, so
$collection->addFieldToFilter($field, $value)
from above essentially does call
Varien_Data_Collection_Db::addFieldToFilter()
If you follow the latter, you'll hit Varien_Db_Adapter_Pdo_Mysql::prepareSqlCondition() in the end, params being
$fieldName = 'coupon_code'
$condition = array('null' => 'null')
Excerpt of that method:
public function prepareSqlCondition($fieldName, $condition)
{
$conditionKeyMap = array(
'eq' => "{{fieldName}} = ?",
:
'notnull' => "{{fieldName}} IS NOT NULL",
'null' => "{{fieldName}} IS NULL",
:
'sneq' => null
);
:
$query = '';
if (is_array($condition)) {
:
$key = key(array_intersect_key($condition, $conditionKeyMap));
if (isset($condition['from']) || isset($condition['to'])) {
:
} elseif (array_key_exists($key, $conditionKeyMap)) {
$value = $condition[$key];
if (($key == 'seq') || ($key == 'sneq')) {
:
}
$query = $this->_prepareQuotedSqlCondition($conditionKeyMap[$key], $value, $fieldName);
} else {
:
}
}
:
}
In your case _prepareQuotedSqlCondition() will be called with
$text = '{{fieldName}} IS NULL'
$value = 'null'
$fieldName = 'coupon_code'
which will result in $query = 'coupon_code IS NULL'.
If you take a closer look at the conversion method
protected function _prepareQuotedSqlCondition($text, $value, $fieldName)
{
$sql = $this->quoteInto($text, $value);
$sql = str_replace('{{fieldName}}', $fieldName, $sql);
return $sql;
}
you'll also see, why the value of the 'null' => 'null' key/value pair does not matter at all. That's because $text will be '{{fieldName}} IS NULL', i.e. not containing any binding ?.
Hence, there's nothing to replace for _quoteInto()^^
* see app/code/core/Mage/Sales/etc/api.xml