XmlExtractor

The XmlExtractor is a class that will parse XML very efficiently with the XMLReader object and produce an object (or array) for every item desired. This class can be used to read very large (read GB) XML files

How to Use

Given the XML file below:

<root>
	<item>
		<tag1>Value 1</tag1>
		<tag2>
			<subtag1>Sub Value 2</subtag1>
		</tag2>
	</item>
</root>

this is the pattern you would use to parse XML with XmlExtractor:

$source = new XmlExtractor("root/item", "/path/to/file.xml");
foreach ($source as $item) {
  echo $item->tag1;
  echo $item->tag2->subtag1;
}

Options

There are four parameters you can pass the constructor

XmlExtractor($rootTags, $filename, $returnArray, $mergeAttributes)

• $rootTags Specify how deep to go into the structure before extracting objects. Examples are below
• $filename Path to the XML file you want to parse. This is optional as you can pass an XML string with loadXml() method
• $returnArray If true, every iteration will return items as an associative array. Default is false
• $mergeAttributes If true, any attributes on extracted tags will be included in the returned record as additional tags. Examples below

Methods

XmlExtractor.loadXml($xml)

Loads XML structure from a php string

XmlExtractor.getRootTags()

This will return the skipped root tags as objects as soon as they are available

XmlItem.export($mergeAttributes = false)

Convert this XML record into an array. If $mergeAttributes is true, any attributes are merged into the array returned

XmlItem.getAttribute($name)

Returns the record's named attribute

XmlItem.getAttributes()

Returns this record's attributes if any

XmlItem.mergeAttributes($unsetAttributes = false)

Merges the record's attributes with the rest of the tags so they are accessible as regular tags. If unsetAttributes is true, the internal attribute object will be removed

Examples

Iterating over XML items

Simple XML structure and straight forward php.

<earth>
	<people>
		<person>
			<name>
				<first>Paul</first>
				<last>Warelis</last>
			</name>
			<gender>Male</gender>
			<skill>Javascript</skill>
			<skill>PHP</skill>
			<skill>Beer</skill>
		</person>
	</people>
</earth>

$source = new XmlExtractor("earth/people/person", "/path/to/above.xml");
foreach ($source as $person) {
  echo $person->name->first; // Paul
  echo $person->gender; // Male
  foreach ($person->skill as $skill) {
    echo $skill;
  }
  $record = $person->export();
}

The first constructor argument is a slash separated tag list that communicates to XmlExtractor that you want to extract "person" records (last tag entry) from earth -> people structure. The export method on the $person object returns it in array form, which will look like this:

array(
  'name' => array(
    'first' => 'Paul',
    'last' => 'Warelis'
  ),
  'gender' => 'Male'
  'skill' => array(
    '0' => 'Javascript',
    '1' => 'PHP',
    '2' => 'Beer'
  )
)

It's important to note that the repeating tag "skill" turned into an array.

Loading XML from a string

First create the extractor and then use loadXml() method to get the data in.

$xml = <<<XML
<house>
	<room>
		<corner location="NW"/>
		<corner location="SW"/>
		<corner location="SE"/>
		<corner location="NE"/>
	</room>
</house>
XML;

$source = new XmlExtractor("house/room");
$source->loadXml($xml);
foreach ($source as $room) {
	var_dump($room->export());
	var_dump($room->export(true));
}

The first dump will show the "corner" field that contains four empty values:

array(
  'corner' => array(
    '0' => '',
    '1' => '',
    '2' => '',
    '3' => ''
  )
)

But when you merge the attributes with the tag data, the array changes to:

array(
  'corner' => array(
    '0' => array( "location" => "NW"),
    '1' => array( "location" => "SW"),
    '2' => array( "location" => "SE"),
    '3' => array( "location" => "NE")
  )
)

Dealing with attributes

This example demonstrates how to deal with attributes.

<office address="123 Main Street">
	<items total="2">
		<item name="desk">
			<size width="120" height="33" length="70">large</size>
			<image>desk.png</image>
		</item>
		<item image="cubicle.jpg">
			<name>cubicle</name>
			<size>
				<width>120</width>
				<height>33</height>
				<length>60</length>
				<size>large</size>
			</size>
		</item>
	</items>
</office>

There are a number of things going on with the above XML. The two root tags that we have to skip to get to our items have information attached. We can get at these with the getRootTags() method. The next issue is that both items are using attributes to define their data. This example is a bit contrived, but it will show the functionality behind the mergeAttributes feature. By the end of this example, we will have two items with identical structure.

$office = new XmlExtractor("office/items/item", "/path/to/above.xml");
foreach ($office as $item) {
  $compressed = $item->export(true); // true = merge attributes into the item
  var_dump($compressed);
}
foreach ($office->getRootTags() as $name => $tag) {
  echo "Tag name: {$name}";
  var_dump($tag->getAttributes());
}

Once "compressed" (exported with merged attributes) the structure of both items is the same. In the event of an attribute having the same name as the tag, the tag takes precedence and is never overwritten. The two items will end up looking like this:

array(
  'name' => 'desk',
  'size' => array(
    'width' => '120',
    'height' => '33',
    'length' => '70',
    'size' => 'large'
  ),
  'image' => 'desk.png'
)
array(
  'image' => 'cubicle.jpg'
  'name' => 'cubicle',
  'size' => array(
    'width' => '120',
    'height' => '33',
    'length' => '70',
    'size' => 'large'
  )
)

The root tags bit will come up with this:

Tag name: office
array(
  'address' => '123 Main Street'
)
Tag name: items
array(
  'total' => '2'
)

Using Wildcards (*)

If your XML file has markup like this:

<art>
	<painting>
		<name>Mona Lisa</name>
	</painting>
	<sculpture>
		<name>Dying Gaul</name>
	</sculpture>
	<photo>
		<name>Afghan Girl</name>
	</photo>
</art>

The art tag contains many different items. To parse them, do this (notice the path to the tag):

$art = new XmlExtractor("art/*", "/path/to/above.xml");
foreach ($art as $name => $piece) {
  echo "Piece : " . $piece->getName();
  var_dump($piece->export());
}

The output would be something like this:

Piece : painting
array('name' => 'Mona Lisa')
Piece : sculpture
array('name' => 'Dying Gaul')
Piece : photo
array('name' => 'Afghan Girl')

If you find bugs, post an issue. I will correct or educate.

Enjoy!

Contact

pwarelis at gmail dot com