Can I query a MediaWiki semantic value (SMW) directly in PHP?

Question

I am using Semantic MediaWiki and am also developing another custom extension. I would like to query semantic values directly in PHP; ie, something like:

SemanticMediaWiki::ask('PAGE_NAME', 'FIELD_NAME')

However, I cannot seem to find any documentation of this being possible. I know there is an Ask API , but this documents only querying using a URL, not a direct PHP query. I also know that I can include "ask" references inside pages via inline queries . However, what I want to do is query semantic values directly inside the PHP of my custom extension.

Does anyone know whether I can directly query a semantic value from PHP?

Answer 1

You can also use https://github.com/vedmaka/SemanticQueryInterface - it is a wrapper around SMW internal API which allows you to do things like that:

$results = $sqi->condition("My property", "My value")->toArray();

See more at https://www.mediawiki.org/wiki/User:Vedmaka/Semantic_Query_Interface

Answer 2

By looking at the way the Semantic Title extension does it, I was able to write a function to do what I needed:

/**
 * Given a wiki page DB key and a Semantic MediaWiki property name, get 
 * the value for that page.
 * 
 * Remarks: Assumes that the property is of type "string" or "blob", and that
 * there is only one value for that page/property combination.
 * 
 * @param string $dbKey The MediaWiki DB key for the page (i.e., "Test_Page")
 * @param string $propertyLabel The property label used to set the Semantic MediaWiki property
 * @return string The property value, or NULL if none exists
 */
static function getSemanticProperty($dbKey, $propertyLabel) {
    // Use Semantic MediaWiki code to properly retrieve the value
    $page       = SMWDIWikiPage::newFromTitle( Title::newFromDBkey($dbKey) );
    $store      = \SMW\StoreFactory::getStore();
    $data       = $store->getSemanticData( $page );
    $property   = SMWDIProperty::newFromUserLabel( $propertyLabel );
    $values = $data->getPropertyValues( $property );

    if (count($values) > 0) {
        $value = array_shift( $values );
        if ( $value->getDIType() == SMWDataItem::TYPE_STRING ||
            $value->getDIType() == SMWDataItem::TYPE_BLOB ) {
            return $value->getString();
        }
    } else {
        return null;
    }
}