PHP-DOMelement select不返回选项值

Question

I've been trying to parse a website, through using DOMelements. Everything was working properly, except from this issue which doesn't make sense to me.

There is a select box, and I need the contents of all its possible option values:

<select name="super_attribute[141]" id="attribute141" class="required-entry super-attribute-select">
    <option value="">Choose size</option>
    <option value="36" price="0">36</option>
    <option value="38" price="0">38</option>
    <option value="41" price="0">40</option>
    <option value="43" price="0">42</option>
    <option value="45" price="0">44</option>
    <option value="47" price="0">46</option>
    <option value="49" price="0">48</option>
</select>

I want to retrieve an array containing the values (either of innerHTML or 'value' attribute). I use this code:

foreach ($dom->getElementsByTagName('option') as $option_tag) {
    $sizes_list[] = $option_tag->getAttribute('value');
}

However there is only always one 'option' tag returned, with an empty value. So I tried a different approach:

$item_options = $dom->getElementById('attribute141');
print(sizeof($item_options->childNodes)); // Prints "1"
foreach ($item_options->childNodes as $child) {
    $sizes_list[] = $child->getAttribute('value');
}
$cloth_item->setSizes($sizes_list);

And again it seems to find this single empty value ... Why cannot I access the rest of the options?

Answer 1

When you parse a HTML page from an URL, you must not ever refer to browser page inspector, because inspector shows source after DOM/js parsing. You need to refer to “View page source” browser command, or — better — to do this in php:

$html = file_get_contents( 'http://www.example.com/your/url.html' );
file_put_contents( '/Path/Local/Download/Page.html', $html );

Then, open downloaded file with a text editor to see the real HTML with which you are working.

In your specific case, you can retrieve only one <option> because... there is only one <option> in loaded page:

<div class="input-box">
    <select name="super_attribute[141]" id="attribute141" class="required-entry super-attribute-select">
        <option>בחר אפשרות...</option>
    </select>
</div>

Other options are loaded by JavaScript. Their values are stored in JSON format inside a script in the same page. There is not a clean way to retrieve it. You can use PhantomJS , but — as you can see here or on other Stack Overflow questions — this way is not easy using php.

A dirty way can be this: looking at HTML source, you can see that your data is in this format:

<script type="text/javascript">
    var spConfig = new Product.Config({ (...) });
</script>

So, you can retrieve all <script> nodes and search for new Product.Config value.

With pure DOM:

$nodes = $dom->getElementsByTagName('script');  // Result: 70 nodes

Using DOMXPath :

$xpath = new DOMXPath( $dom );
$nodes = $xpath->query('//script[@type="text/javascript"]');  // Result: 58 nodes

Then, loop through all nodes, find for a regular expression pattern and decode it:

foreach( $nodes as $node )
{
    if( preg_match( '~new Product\.Config\((.+?)\);~', $node->nodeValue, $matches ) )
    {
        $data = json_decode( $matches[1] );
        break;
    }
}

At this point, in $data you have this decoded JSON:

stdClass Object
(
    [attributes] => stdClass Object
        (
            [141] => stdClass Object
                (
                    [id] => 141
                    [code] => size
                    [label] => מידה
                    [options] => Array
                        (
                            [0] => stdClass Object
                                (
                                    [id] => 36
                                    [label] => 36
                                    [price] => 0
                                    [oldPrice] => 0
                                    [products] => Array
                                        (
                                            [0] => 93548
                                        )
                                )
                            (...)
                        )
                )
        )
)

So to access to first <option> id, you can use this:

echo $data->attributes->{141}->options[0]->id; // Output: 36
#                       ↑ note curly brackets to access to a not-valid property key

And so on:

echo $data->attributes->{141}->options[1]->id;    // Output: 38
echo $data->attributes->{141}->options[1]->label; // Output: 38
echo $data->attributes->{141}->options[1]->price; // Output: 0