Question

Say I have an html file that I have loaded, I run this query:

$url = 'http://www.fangraphs.com/players.aspx';
$html = file_get_contents($url);    
$myDom = new DOMDocument;
$myDom->formatOutput = true;
@$myDom->loadHTML($html);
$anchor = $xpath->query('//a[contains(@href,"letter")]');

That gives me a list of these anchors that look like the following:

<a href="players.aspx?letter=Aa">Aa</a>

But I need a way to only get “players.aspx?letter=Aa”.

I thought I could try:

$anchor = $xpath->query('//a[contains(@href,"letter")]/@href');

But that gives me a php error saying I couldn’t append node when I try the following:

$xpath = new DOMXPath($myDom);
$newDom = new DOMDocument;
$j = 0;
while( $myAnchor = $anchor->item($j++) ){
   $node = $newDom->importNode( $myAnchor, true );    // import node
   $newDom->appendChild($node);
}

Any idea how to obtain just the value of the href tags that the first query selects?? Thanks!

Answer 1

Your XPath query is returning attributes themselves (i.e., DOMAttr objects) rather than elements (i.e., DOMElement objects). That’s fine, and that seems to be what you want, but appending them to the document is the problem. A DOMAttr is not a standalone node in the document tree; it’s associated with a DOMElement but is not a child in the usual sense. Thus, directly appending a DOMAttr to the document is invalid.

From the W3C specs:

Attr objects inherit the Node interface, but since they are not actually child nodes of the element they describe, the DOM does not consider them part of the document tree. . . . The DOM takes the view that attributes are properties of elements rather than having a separate identity from the elements they are associated with

Either associate the DOMAttr with a DOMElement and append that element, or pull out the DOMAttr‘s value and use that as you wish.

To just append its plain text value, use its value in a DOMText node and append that. For example, change this line:

    $newDom->appendChild($node);

to this:

    $newDom->appendChild(new DOMText($node->value));