XML parsing in PHP with simpleXML

Civilian_Target

I'm trying to parse some XML with the new PHP SimpleXML libraries, but am running into difficulties. The XML is almost a soap mesage, and looks something like this

<?xml version="1.0" encoding="UTF-8"?>
<scenario xmlns="scenario.xsd">
 <global>
   <filter tag="startdate">MONTH+WEEK</filter>
   <filter tag="enddate">MONTH+WEEK+WEEK</filter>
  <input>
    <replace type="code">ABCD</replace>
    <replace type="language">en</replace>
  </input>
...
 </global>
...
</scenario>

I want to take the values of the filter tags and map them with the tag attribute as key. And I want to take the replace values and map them with the type attribute as key.

So...
map1: {startdate->MONTH+WEEK, enddate->MONTH+WEEK+WEEK}
map2: {code->ABCD, language->en}

So, this should be relatively simple, the documentation would suggest:

$parser = simplexml_load_file($xml);
$filters = array();
foreach($parser->global->filter as $filter_node){
    $key = $filter_node['tag'];
    $filters[$key] = $filter_node;
}
$replaces = array();
foreach($parser->global->input->replace as $replace_node{
    $key = $replace_node['type'];
    $replaces[$key] = $replace_node;
}

The catch is, it doesn't work.
In fact, the foreach-es never seem to enter the loop at all.

Rendering $parser as xml works fine, but attempting to print any sub nodes just fails. There are no warnings saying that the parser has failed.

Of course, I could just use an xpath, but I can't stand being mocked by a class called simple XML :rolleyes:

seamus

I suspect there's something missing in the initialisation of the parser. I had a bit of trouble when I started using simplexml, but flying along now. I have the code in work, and if you've no response by tomorrow morning, I'll take a look.

seamus

This isn't actually as simple as you're tearing your hair out about
This caught me out when I first started using it too:

When you take any node from the SimpleXML tree, it returns a SimpleXMLElement object. Then when you perform functions on this object, such as "echo $node", it casts the object to the relevant data type, in the case of echo, it casts to a string.

In your above example, if you take the first foreach loop, each $filter_node is a SimpleXMLElement, as is each $filter_node

So you're trying to use a SimpleXMLElement object as the key in an array, which obviously won't work. So you need to cast it to a string before it can be used as the key in an array, i.e.
[php]$key = (string) $filter_node;[/php]
If you wish, you can also cast $filter_node itself to a string before adding it as an element in the array. This would cut down on the amount of memory used by the array, but if $filter_node has further attributes or subnodes, you will lose them.

Civilian_Target

OK, that's great advice for later on - but the problem is more fundamental: we're not even getting into the foreach loop at

foreach($parser->global->filter as $filter_node)

seamus

I tested this, and indeed you are getting into these loops.

Stick in some debugging such as
[php]
foreach($parser->global->filter as $filter_node){
$key = (string) $filter_node;

echo "$key => ".((string) $filter_node)."<br>";

$filters[$key] = $filter_node;
}[/php]

seamus

Oh, and I'm assuming that's a code snippet, but you're aware that you're missing a closing parenthesis on line 8?

Civilian_Target

Yeah, the original code is sample I just composed for the original on the spot - don't worry, the IDE prevents syntax mistakes.

And I have tried such debugging - thats how I know it never makes it into the foreach, a die statement in there won't kill the script. Yet when you do

echo $parser.toXML()

, it outputs the xml that was input, with the correct names.

*scratches head*

Civilian_Target

woah - just Java-fied my PHP there, I do of course mean $parser->asXML()

Civilian_Target

Aha - got it.
Really simple - just compared my xpath and my SimpleXML and realised... it is of course case sensitive, but my code is not.

Always the simple bugs :rolleyes:

Thanks for your help