grima-xmlbag.php

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<?php

 

/******************************************************************************


 *  XML Bags!


 *


 *  Wish you could treat XML as an array? Now you can!


 *


 *  What does xml['item'] = ?


 * 


 *  Three plausible answers:


 *  (1) A single DOMNode, so you have to use innerXML and such to get its string value


 *  (2) A DOMNodeList, so you can have multiple nodes that match


 *  (3) A string, just the innerXML


 *  (4) An array of strings, just the innerXMLs


 */


 

 

function xml_debug( $obj ) {

    $retval = get_class($obj)."\n";

    switch(true) {

        case ($obj instanceof DOMDocument):

            $retval .= "XPath: {$obj->getNodePath()}\n".$obj->saveXML($obj);

            break;

        case ($obj instanceof DOMElement):

            $retval .= "XPath: {$obj->getNodePath()}\n".$obj->ownerDocument->saveXML($obj);

            break;

        case ($obj instanceof DOMAttr):

            $retval .= "XPath: {$obj->getNodePath()}\n".$obj->ownerDocument->saveXML($obj);

            break;

        case ($obj instanceof DOMNodeList):

            $retval .= "NodeList of length {$obj->length}\n";

            print $retval;

            for ($i = 0; $i < $obj->length; $i++) {

                $retval .= "Item #$i, " . xml_debug($obj->item($i));

            }

            break;

        default:

            return "Instance of unknown class";

    }

    return $retval;

}

        

abstract class XMLAsArrayOfWhateversSpecifiedByXPath implements ArrayAccess {

    public $xml;

    public $context_node;

    private $xpath = null;

    function __construct( $xml, $context_node ) {

        if( is_string($xml) ) {

            $this->xml = new DOMDocument();

            $this->xml->loadXML($xml);

        } elseif( $xml instanceof DOMDocument ) {

            $this->xml = $xml;

        } else {

            throw new Exception("<xml> must be of type DOMDocument in new XMLAsArrayOf...(xml,context)");

        }

        $this->xpath = new DOMXPath($this->xml);

        if( is_string($context_node) ) {

            $nodeList = $this->xpath->query($context_node);

            //print( "Context ($context_node) is: " . xml_debug($nodeList) . "\n" );


            if( $nodeList->length === 1 ) {

                $this->context_node = $nodeList->item(0);

            } else {

                $this->context_node = $this->xml->documentElement;

            }

        } elseif( $context_node instanceof DOMElement ) {

            $this->context_node = $context_node;

        } else {

            $this->context_node = $this->xml->documentElement;

        }

    }

    protected function query( string $offset ) {

        if( isset($this->context_node) ) {

            return $this->xpath->query($offset, $this->context_node);

        } else {

            return $this->xpath->query($offset);

        }

    }

    public function __toString() {

        return $this->xml->saveXML($this->context_node);

    }

    public function __get( string $name ) {

        $class = get_class($this);

        return new $class($this->xml, $this->query($name));

    }

    public function __set( string $name, $value ) {

        $this[$name] = $value;

    }

    public function __isset( string $name ) {

        return isset($this[$name]);

    }

    public function __unset( string $name ) {

        unset($this[$name]);

    }

}

 

class XMLAsArrayOfDOMNodesSpecifiedByXPath extends XMLAsArrayOfWhateversSpecifiedByXPath {

    public function offsetExists ( $offset ) {

        return $this->query($offset)->length === 1;

    }

    public function offsetGet ( $offset ) {

        $nodeList = $this->query($offset);

        if( $nodeList->length === 1 )

            return $nodeList->item(0);

    }

    public function offsetSet ( $offset, $value ) {

        $nodeList = $this->query($offset);

        if( $nodeList->length === 1 ) {

            $node = $nodeList->item(0);

            if($node->parentNode !== NULL) {

                $node->parentNode->replaceChild($value, $node);

            }

        } elseif( $nodeList->length === 0 ) {

            $nodeList->context_node->appendChild($value);

        }

    }

    public function offsetUnset ( $offset ) {

        $nodeList = $this->query($offset);

        if( $nodeList->length === 1 ) {

            $node = $nodeList->item(0);

            if($node->parentNode !== NULL) {

                $node->parentNode->removeChild($node);

            }

        }

    }

}

 

class XMLAsArrayOfDOMNodeListsSpecifiedByXPath extends XMLAsArrayOfWhateversSpecifiedByXPath {

    public function offsetExists ( $offset ) {

        return $this->query($offset)->length > 0; // technically it always exists, but...


    }

    public function offsetGet ( $offset ) {

        return $this->query($offset);

    }

    public function offsetSet ( $offset, $value ) {

        $nodeList = $this->query($offset);

        $cur_length = $nodeList->length;

        $new_length = $value->length;

        for( $i = 0 ; $i < min($cur_length, $new_length); $i++ ) {

            $cur_node = $nodeList->item($i);

            $new_node = $value->item($i);

            $cur_node->parentNode->replaceChild($new_node, $cur_node);

        }

        for( $i = min($cur_length, $new_length); $i < $cur_length ; $i++ ) {

            $cur_node = $nodeList->item($i);

            $cur_node->parentNode->removeChild($cur_node);

        }

        for( $i = min($cur_length, $new_length); $i < $new_length ; $i++ ) {

            $new_node = $value->item($i);

            $this->context_node->appendChild($new_node);

        }

    }

    public function offsetUnset ( $offset ) {

        $nodeList = $this->query($offset);

        $cur_length = $nodeList->length;

        for( $i = 0 ; $i < $cur_length ; $i++ ) {

            $cur_node = $nodeList->item($i);

            $cur_node->parentNode->removeChild($cur_node);

        }

    }

}

 

class XMLAsArrayOfStringsSpecifiedByXPath extends XMLAsArrayOfWhateversSpecifiedByXPath {

    public function offsetExists ( $offset ) {

        return $this->query($offset)->length === 1;

    }

    public function offsetGet ( $offset ) {

        $nodeList = $this->query($offset);

        if( $nodeList->length === 1 ) {

            return $nodeList->item(0)->nodeValue;

        }

    }

    public function offsetSet ( $offset, $value ) {

        $nodeList = $this->query($offset);

        if( $nodeList->length === 1 ) {

            print "Setting!\n";

            $nodeList->item(0)->nodeValue = $value;

        } else if( $nodeList->length === 0 ) {

            $node = $this->xml->createElement(basename($offset));

            $node->nodeValue = $value;

            $this->contextNode->appendChild($node);

        }

    }

    public function offsetUnset ( $offset ) {

        if( $nodeList->length === 1 ) {

            $node = $nodeList->item(0);

            $node->parentNode->removeChild($node);

        }

    }

}

 

function test() {

    $xml = file_get_contents("item-sample.xml");

    $item_item_data = new XMLAsArrayOfStringsSpecifiedByXPath($xml, "/item/item_data");

    print "EnumerationA: " . $item_item_data['enumeration_a'] . "\n\n";

    $item_item_data['enumeration_a'] = "NOOOOOOOOO";

    print $item_item_data->xml->saveXML();

}

 

//test();