php xml simplexml_load_string simplexml_load_file parse error: extra content at the end of the document
Having not worked with parsing xml in a VERY long time (and the last time i did it, it was much harder) I ran into a problem problem when trying to load in some dynamic XML snippets that are being created by an api I'm writing.
The scenario -
Long story short, I created XML modules that each represent different tasks. When the application picks and chooses which of the modules needs to be compiled together, it dynamically creates one final XML document and spits that back as the response to making a certain call into the API.
Example modules:
1) XML_HEADER:
<?xml version="1.0" encoding="utf-8"?>
2) XML_CAR:
<car>
<door></door>
<tires></tires>
<tires></tires>
</car>
3) XML_BIKE:
<bike>
<frame></frame>
<spokes></spokes>
<tires></tires>
<spokes></spokes>
<tires></tires>
</bike>
4) XML_APPLE:
<apple>
<color></color>
<type></type>
<type></type>
</apple>
Alright, so you get the point... Let's say the app, put together modules 1, 2, and 4 to create the following xml:
<?xml version="1.0" encoding="utf-8"?>
<car>
<door></door>
<tires></tires>
<tires></tires>
</car>
<apple>
<color></color>
<type></type>
<type></type>
</apple>
And I loaded this xml into a variable like so:
$xml = simplexml_load_string($the_xml_above);
The following error message would occur: Warning: simplexml_load_string() [function.simplexml-load-string]: Entity: line 3: parser error : Extra content at the end of the document in the_file_name on line 3
Hopefully you are smarter than I was and see the problem right away.
Unfortunately for me, I worked on each module separately (and they are much more complex than the examples above) and I got lost in each one, not thinking of what the final compiled XML would look like.
So I searched teh google machine and came up completely empty. It wasn't until 20 minutes after searching that I output the xml on screen, stared at it for another 5 minutes that I came up with the problem.
THE SOLUTION?... I never specified a root element (like HTML's open <body> and close</body> tags). The the example XML above worked just fine like so:
<?xml version="1.0" encoding="utf-8"?>
<document>
<document>
<car>
<door></door>
<tires></tires>
<tires></tires>
</car>
<apple>
<color><color>
<type><type>
<type><type>
</apple>
</document>
Be sure to always specify your root element in an XML file, there are a couple ways of doing this, those ways you can google. q确保在你的xml文件里有一股根元素root element.
enjoy