Question

I have a function which uses simplexml to return the first level of nodes in an XML file and write it into an unordered list:

function printAssetMap() {
    $xml = simplexml_load_file(X_ASSETS);
    $assets = $xml->asset;
    $html = '<ul>'."\n";
    foreach ($assets as $asset) {
        $html .= '<li id="asset'.$asset->asset_assetid.'"><ins>&nbsp;</ins><a href="#">'.$asset->asset_name.' ['.$asset->asset_assetid.']</a></li>'."\n";
    }//end foreach
    $html .= '</ul>'."\n";
    return $html;
}// printAssetMap()

XML I am using, that has nested nodes:

<?xml version="1.0"?>
<assets>
  <asset>
    <asset_name>Home</asset_name>
    <asset_url>/home</asset_url>
    <asset_assetid>1</asset_assetid>
  </asset>
  <asset>
    <asset_name>Projects</asset_name>
    <asset_url>/projects</asset_url>
    <asset_assetid>2</asset_assetid>
    <asset>
      <asset_name>Portfolio</asset_name>
      <asset_url>/projects/portfolio</asset_url>
      <asset_assetid>3</asset_assetid>
    </asset>
    <asset>
      <asset_name>Current Jobs</asset_name>
      <asset_url>/projects/current-jobs</asset_url>
      <asset_assetid>4</asset_assetid>
    </asset>
  </asset>
</assets>

Now, I am starting to add child nodes of the nodes that I am currently returning. Is there a way to loop through ALL levels of child nodes in an xml file, even if I don’t know how many levels there are, and add those to my list?

Answer 1

So basically what you need to do is a function that takes each <asset/> child of current node, builds the HTML then checks if the current node has <asset/> children of its own and keeps recursing deeper down the tree.

Here’s how you can do it:

function printAssetMap()
{
    return printAssets(simplexml_load_file(X_ASSETS));
}

function printAssets(SimpleXMLElement $parent)
{
    $html = "<ul>\n";
    foreach ($parent->asset as $asset)
    {
        $html .= printAsset($asset);
    }
    $html .= "</ul>\n";

    return $html;
}

function printAsset(SimpleXMLElement $asset)
{
    $html = '<li id="asset'.$asset->asset_assetid.'"><ins>&nbsp;</ins><a href="#">'.$asset->asset_name.' ['.$asset->asset_assetid.']</a>';

    if (isset($asset->asset))
    {
        // has <asset/> children
        $html .= printAssets($asset);
    }

    $html .= "</li>\n";

    return $html;
}

By the way, I would expect a function named “printX” to actually print or echo something, rather than return it. Perhaps you should name those functions “buildX” ?