SimpleXML and large files

I encountered an issue earlier today whilst trying to process a fairly large (~37MB) XML file through SimpleXML.

It worked just fine on mine and a colleague's development systems but failed with weird errors on the live server, for instance reporting there was "Extra content at the end of the document".

After about an hour of trying to figure it out we realised our dev systems were using libxml v2.6.x and the live server was using 2.7.6. We then read that somewhere between those versions some hard-coded limits were added in that can cause the problem we were seeing.

To get around it you need to specify the LIBXML_PARSEHUGE flag:

$simplexml = simplexml_load_file($file_path, 'SimpleXMLElement', LIBXML_PARSEHUGE);
//OR
$simplexml = new SimpleXMLElement($xml_string, LIBXML_PARSEHUGE);