admin/url/custom cause media directives to break

Question

If admin uses a custom domain, different from the default website, the WYSIWYG image-selector will return malformed media directives, causing broken links to images.

Expected directive: {{media url="wysiwyg/image.jpg"}}

Returned directive: {{media url="http://backend.dev/media/wysiwyg/image.jpg"}}

This is known Magento 2 bug https://github.com/magento/magento2/issues/16427, but maybe there are some workarounds until Magento 2.3 will be released?

Answer 1

I've done the following workaround that works for me.

vendor/magento/module-cms/Helper/Wysiwyg/Images.php

...
protected $scopeConfig;
...
public function __construct(
    ...
    \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig,
    ...
) {
    ...
    $this->scopeConfig = $scopeConfig;
}
...
public function getImageHtmlDeclaration($filename, $renderAsTag = false)
{
    $fileurl = $this->getCurrentUrl() . $filename;
/**** WORKAROUND START ****/
    $adminUrl = $this->scopeConfig->getValue('admin/url/custom');
    $baseUrl = $this->scopeConfig->getValue('web/secure/base_url');
    $fileurl = str_replace($adminUrl, $baseUrl, $fileurl);
/**** WORKAROUND END ****/
    $mediaUrl = $this->_storeManager->getStore()->getBaseUrl(\Magento\Framework\UrlInterface::URL_TYPE_MEDIA);
    $mediaPath = str_replace($mediaUrl, '', $fileurl);
    $directive = sprintf('{{media url="%s"}}', $mediaPath);
    if ($renderAsTag) {
        $html = sprintf('<img src="%s" alt="" />', $this->isUsingStaticUrlsAllowed() ? $fileurl : $directive);
    } else {
        if ($this->isUsingStaticUrlsAllowed()) {
            $html = $fileurl; // $mediaPath;
        } else {
            $directive = $this->urlEncoder->encode($directive);

            $html = $this->_backendData->getUrl(
                'cms/wysiwyg/directive',
                [
                    '___directive' => $directive,
                    '_escape_params' => false,
                ]
            );
        }
    }
    return $html;
}

It is not a good idea to modify vendor files, so I've added this into separate extension https://github.com/troublediehard/wysiwyg-custom-admin-workaround