如何使用PHP解析具有多个根元素的XML？

Question

I am trying to read this XML file using PHP and I have two root elements. The code that I wrote in PHP reads only one root element and when I add the other one ( <action> ) it gives me an error. I want to do something like this : if($xml->action=="register") then print all parameters.

This is my XML file:

<?xml version='1.0' encoding='ISO-8859-1'?>
<action>register</action>
<paramters>
    <name>Johnny B</name>
    <username>John</username>    
</paramters>

And this is my PHP script:

<?php
$xml = simplexml_load_file("test.xml");

echo $xml->getName() . "<br />";

foreach($xml->children() as $child)
{
    echo $child->getName() . ": " . $child . "<br />";
}
?>

I really don't know how to do all this...

Answer 1

Fix your XML, it's invalid. XML files can only have 1 root element.

Example valid XML:

<?xml version='1.0' encoding='ISO-8859-1'?>
<action>
    <type>register</type>
    <name>Johnny B</name>
    <username>John</username>
</actions>

Or if you want only parameters to have own elements:

<?xml version='1.0' encoding='ISO-8859-1'?>
<action type="register">
    <name>Johnny B</name>
    <username>John</username>
</actions>

or if you want multiple actions:

<?xml version='1.0' encoding='ISO-8859-1'?>
<actions>
    <action type="register">
        <name>Johnny B</name>
        <username>John</username>
    </action>
</actions>

EDIT :

As I've said in my comment, your teacher should fix his XML. It is invalid . Also he should put his XML through a validator .

If you're really desperate you can introduce an articificial root element, but this is really bad practice and should be avoided at all costs:

$xmlstring = str_replace(
    array('<action>','</paramters>'),
    array('<root><action>', '</paramters></root>'),
    $xmlstring
);

Answer 2

None of the previous answers is quite accurate. The XML specification defines several kinds of entity: document entities, external parsed entities, document type definitions for example. Your example is not a well-formed document entity, which is what XML parsers are normally asked to parse. However, it is a well-formed external parsed entity. The way to process a well-formed external parsed entity is to reference it from a skeletal document entity, like this:

<!DOCTYPE wrapper [
<!ENTITY e SYSTEM "my.xml">
]>
<wrapper>&e;</wrapper>

and then pass the document entity to the XML parser.

Answer 3

As it is an invalid xml file, you can do the following trick.

• Insert a dummy start tag at the second line as <dummy>
• In the end finish it with </dummy>

Happy parsing ;)