如何在PHP中包含外部XML文件？

Question

I need a way to include an external XML file in PHP which does not use simplexml tags. Furthermore, I'd also need it to integrate with other imported XMLs, hence removing file headers as <?XML version...>

Basically have a PHP class which includes methods to dynamically create XML elements based on user-input. For example, I could create a node called "test", set "id=1" as attribute and add child nodes to it. What I basically need, is a way to extract further XML content from other files and have my PHP script recognize it, hence being able to call methods on this imported code. I tried using php's fopen() function but, although it would print the imported XML to the screen, it would not validate and signal an error as soon as the imported code began. I cannot use simpleXML extension for two main reasons. Firstly, the entire class is written using Pre-PHP5 XML handling, and I cannot re-write the whole thing from scratch as it is part of a team-project, secondly, such class features methods which could not be replicated with simpleXML extension.

This is the XML I generate: <?xml version="1.0"?> <ga><dsa>hea</dsa><sda>eh</sda></ga> <gg><ds>he</ds><sd>eh</sd></gg> And it returns: Illegal Content, Line 3 Column 1, highliting the "<" of the "gg" tag... (Which, by the way, is the part imported from the external file.)

This is a snippet of the code used to print imported XML:

$file = simplexml_load_file($url);
     foreach($file as $key => $value) {
         echo "<" . $key . ">" .  $value . "</" . $key . ">
";
      }

How can this be done?

Additional note: Yes, the server suppors PHP 5 (5.2.6), but the code was written in pre-php5.

Answer 1

Judging from your comments I'd say you get an error because a valid XML document needs a root element. You XML has two: <ga> and <gg>, which means the XML is invalid and cannot be parsed.

You should fix your XML by adding a root element. Then the parsing errors will go away.

Another option would be to load the snippet as a document fragment with DOM:

$brokenXML = <<< XML
<?xml version="1.0"?>
<ga><dsa>hea</dsa><sda>eh</sda></ga>
<gg><ds>he</ds><sd>eh</sd></gg>
XML;

$dom = new DOMDocument;
$fragment = $dom->createDocumentFragment();
$fragment->appendXML(trim(str_replace('<?xml version="1.0"?>', '', $brokenXML)));
echo $dom->saveXml($fragment);

Output:

<ga><dsa>hea</dsa><sda>eh</sda></ga>
<gg><ds>he</ds><sd>eh</sd></gg>

But note that this is still not a complete XML document because it misses a root element.

If you want to import a DOM Tree into another, you can use DOMDocument::importNode. To use that with the fragment above, you would do

$dom2 = new DOMDocument('1.0', 'utf-8');
$dom2->appendChild($dom2->createElement('foo'))
        ->appendChild($dom2->importNode($fragment, true));

echo $dom2->saveXml();

That would result in

<?xml version="1.0" encoding="utf-8"?>
<foo><ga><dsa>hea</dsa><sda>eh</sda></ga>
<gg><ds>he</ds><sd>eh</sd></gg></foo>

If you have an existing document you want to import to, you would simply do

$dom2 = new DOMDocument;
$dom2->load('existingFile.xml');
$dom2->documentElement->appendChild($dom2->importNode($fragment, true));

This would append the fragment as the last child of the root node. If you want to have it somewhere else on the DOM tree, you would have to traverse the DOM tree with Xpath or getElementsByTagName or getElementsById or the childNodes property on the various nodes and then append to that node instead.