There is a bug in the code. That’s why relToAbs isn’t working.
In the following:
if (in_array("content",$this->fields["display"]["db"]) && $this->format != "html") {
$resource['content'] = $this->relToAbs($resource['content'], $modx->config['site_url']);
}
if (in_array("introtext",$this->fields["display"]["db"]) && $this->format != "html") {
$resource['introtext'] = $this->relToAbs($resource['introtext'], $modx->config['site_url']);
}
You should replace it with
if (in_array("content",$this->fields["display"]["db"]) && $this->format != "html") {
$placeholders['content'] = $this->relToAbs($resource['content'], $modx->config['site_url']);
}
if (in_array("introtext",$this->fields["display"]["db"]) && $this->format != "html") {
$placeholders['introtext'] = $this->relToAbs($resource['introtext'], $modx->config['site_url']);
}
After that, relative to absolute URLs are working perfectly.