How to convert XML attributes to text nodes - php

Question

I have a PHP script that pulls an XML file from a remote server, and converts it to JSON using simplexml_load_string and json_encode. However, the simplexml_load_string seems to ignore inline attributes, like so:
<AxisFeedrate dataItemId="iid7" timestamp="2012-03-21T15:15:41-04:00" sequence="7" name="Yfrt" subType="ACTUAL" units="MILLIMETER/SECOND">UNAVAILABLE</AxisFeedrate>
In this case the JSON representation would be {AxisFeedrate: 'UNAVAILABLE'}
However, I need to have those attributes available. One idea I've been approaching is replacing strings to turn the attributes into text nodes like so:
<AxisFeedrate>
<dataItemId>iid7</dataItemId>
<timestamp>2012-03-21T15:15:41-04:00</timestamp>
<sequence>7</sequence>
<name>Yfrt</name>
<subType>ACTUAL</subType>
<units>MILLIMETER/SECOND"</units>
<value>UNAVAILABLE</value>
</AxisFeedrate>
I can turn the attributes into their own tag elements with regular find/replace, but I'm having trouble wrapping the original text value in a Value tag, at least with find/replace.
What are some good approaches for doing this? The above chunk of XML is in the middle of many similar chunks on different data items, so I couldn't just start by replacing the first closing > with >...

Answer 1

You could use SimpleXML itself to read the attributes.
Example:
<?php
$xml=simplexml_load_string('<AxisFeedrate dataItemId="iid7" timestamp="2012-03-21T15:15:41-04:00" sequence="7" name="Yfrt" subType="ACTUAL" units="MILLIMETER/SECOND">UNAVAILABLE</AxisFeedrate>');
foreach($xml->attributes() as $k=>$v) {
echo $k." -> ".(string)$v."\n";
}
?>
Output:
dataItemId -> iid7
timestamp -> 2012-03-21T15:15:41-04:00
sequence -> 7
name -> Yfrt
subType -> ACTUAL
units -> MILLIMETER/SECOND

Answer 2

Try this regex: ([\w]*?)="(.*?)" with this replace <$1>$2</$1>\n

Answer 3

You should use SimpleXML. Be aware though, that you have to cast values to string type explicitly, or you'll get objects.
$xml_string = <<<XML
<AxisFeedrate
dataItemId="iid7"
timestamp="2012-03-21T15:15:41-04:00"
sequence="7"
name="Yfrt"
subType="ACTUAL"
units="MILLIMETER/SECOND"
>UNAVAILABLE</AxisFeedrate>
XML;
$xml = simplexml_load_string($xml_string);
$axis_info = array('value' => (string)$xml);
foreach($xml -> attributes() as $attr => $val) {
$axis_info[$attr] = (string) $val;
}
echo json_encode(array("AxisFeedrate" => $axis_info));
Update:
This will give you a more generic version, but notice that the attributes are cast as an array and that this only works on a single element:
$xml_string = <<<XML
<AxisFeedrate dataItemId="iid7" timestamp="2012-03-21T15:15:41-04:00" sequence="7" name="Yfrt" subType="ACTUAL" units="MILLIMETER/SECOND">UNAVAILABLE</AxisFeedrate>
XML;
$xml = simplexml_load_string($xml_string);
$obj_name = $xml -> getName();
$attributes = (array) $xml->attributes();
$axis_info[$obj_name] = $attributes["#attributes"];
$axis_info[$obj_name]['value'] = (string) $xml;
echo json_encode($axis_info);