Convert HTML to eZ Platform Rich Text DocBook XML format

preparerichtext.php

<?php

// This is the namespace you want to use
use EzSystems\EzPlatformRichText\eZ\FieldType\RichText\Type as RichTextFieldType;

// this would be a method in your class (you'll need to inject RichTextFieldType)
// It has some extra wrangling of input not required, but makes it moarrr robust
private function prepareRichText($inputText){
    
    if($inputText === ''){
        $inputText = '<p>&nbsp;</p>';
    }

    $tidyConfig = array(
        'show-body-only' => true,
        'output-xhtml'   => true,
        'wrap'           => -1);
    
    $inputText = tidy_parse_string($inputText, $tidyConfig);

    $inputText = str_replace(array("\r\n", "\r", "\n"), "", $inputText);

    $content = ['xml' => '<?xml version="1.0" encoding="UTF-8"?><section xmlns="http://ez.no/namespaces/ezpublish5/xhtml5/edit">'. $inputText . '</section>'];

    return $this->richTextFieldType->fromHash($content);

}

// HTML content. To see full range of options (embeds, links, etc.) it's best to see the RichTextFieldType xhtml5 input test
// fixtures here: https://github.com/ezsystems/ezplatform-richtext/tree/master/tests/lib/eZ/RichText/Converter/Xslt/_fixtures/xhtml5/edit
$htmlContent = '<p>Foo <b>Bar</b>.</p><blockquote>Bar Foo</blockquote><p>Baz Bay</p>';

// This is how you would use the helpere to populare a field in a content create struct
$contentCreateStruct->setField('body', $this->prepareRichText($htmlContent));

Nice to hear you found it helpful :)