Convert a selected HTML Table to JSON

Question

Is it possible to convert just a selection of a HTML with multiple tables to JSON ?

I have this Table:

<div class="mon_title">2.11.2015 Montag</div>
    <table class="info" >
    <tr class="info"><th class="info" align="center" colspan="2">Nachrichten zum Tag</th></tr>
    <tr class='info'><td class='info' colspan="2"><b><u></u>   </b>
    ...
    </table>
    <p>
    <table class="mon_list" >

    ...
    </table>

And this PHP code to covert it into JSON:

function save_table_to_json ( $in_file, $out_file ) {
    $html = file_get_contents( $in_file );
    file_put_contents( $out_file, convert_table_to_json( $html ) );
}

function convert_table_to_json ( $html ) {
    $document = new DOMDocument();
    $document->loadHTML( $html );

    $obj = [];
    $jsonObj = [];
    $th = $document->getElementsByTagName('th');
    $td = $document->getElementsByTagName('td');
    $thNum = $th->length;
    $arrLength = $td->length;
    $rowIx = 0;

    for ( $i = 0 ; $i < $arrLength ; $i++){
        $head = $th->item( $i%$thNum )->textContent;
        $content = $td->item( $i )->textContent;
        $obj[ $head ] = $content;
        if( ($i+1) % $thNum === 0){ 
            $jsonObj[++$rowIx] = $obj;
            $obj = [];
        }
    }
    save_table_to_json( 'heute_S.htm', 'heute_S.json' );

What it does is takes the table class=info and the table class=mon_list and converts it to json.

Is there any way that it can just take the table class=mon_list ?

Answer 1

You can use XPath to search for the class, and then create a new DOM document that only contains the results of the XPath query. This is untested, but should get you on the right track.

It's also worth mentioning that you can use foreach to iterate over the node list.

$document = new DOMDocument();
$document->loadHTML( $html );

$xpath = new DomXPath($document);
$tables = $xpath->query("//*[contains(@class, 'mon_list')]");
$tableDom = new DomDocument();
$tableDom->appendChild($tableDom->importNode($tables->item(0), true));

$obj = [];
$jsonObj = [];
$th = $tableDom->getElementsByTagName('th');
$td = $tableDom->getElementsByTagName('td');
$thNum = $th->length;
$arrLength = $td->length;
$rowIx = 0;

for ( $i = 0 ; $i < $arrLength ; $i++){
    $head = $th->item( $i%$thNum )->textContent;
    $content = $td->item( $i )->textContent;
    $obj[ $head ] = $content;
    if( ($i+1) % $thNum === 0){ 
        $jsonObj[++$rowIx] = $obj;
        $obj = [];
    }
}

Answer 2

Another unrelated answer is to use getAttribute() to check the class name. Someone on a different answer has written a function for doing this:

function getElementsByClass(&$parentNode, $tagName, $className) {
    $nodes=array();

    $childNodeList = $parentNode->getElementsByTagName($tagName);
    for ($i = 0; $i < $childNodeList->length; $i++) {
        $temp = $childNodeList->item($i);
        if (stripos($temp->getAttribute('class'), $className) !== false) {
            $nodes[]=$temp;
        }
    }

    return $nodes;
}