Enhancement: Using markdown and moodle filters for the flagmessage

[fhkevin]

Proposal

Instead of using a plain text element for the flagmessage, which doesn't even allow line breaks inside the message:

echo $OUTPUT->box($msg, 'generalbox', 'notice');

we could allow markdown:

$context = $PAGE->context ?? context_system::instance();
$markdown = format_text($msg, FORMAT_MARKDOWN, [
    'context' => $context,
    'filter'  => true,
]);
echo $OUTPUT->box($markdown, 'generalbox', 'notice');

This allows formatting and also the use of the {mlang} modifier directly inside the flagmessage field in the Settings GUI:

{mlang en}
## Test-heading english
info-text english
{mlang}

{mlang en}
## Test-heading german
info-text german
{mlang}

Environment

• Moodle: 4.5.7
• Auth SAML2 Plugin: latest MOODLE_405_STABLE release

[danmarsden]

feels weird to use markdown to me - maybe we should just pass through format_text and allow FORMAT_HTML

[fhkevin]

@danmarsden HTML formatting would also work, but I'd argue that markdown would be easier to use in this context on the user-side.

1. we would need to replace the PARAM_TEXT argument from the settings page to PARAM_RAW in order to allow HTML tags in the first place:

    // Set the displayed message for flagged accounts.
    $settings->add(new admin_setting_configtextarea(
        'auth_saml2/flagmessage',
        get_string('flagmessage', 'auth_saml2'),
        get_string('flagmessage_help', 'auth_saml2'),
        get_string('flagmessage_default', 'auth_saml2'),
        PARAM_RAW, // <---- was: PARAM_TEXT
        50,
        3
    ));

2. FORMAT_MARKDOWN would allow HTML formatting anyway
3. Again regarding that the user only has a simple text field, I'd argue that markdown would be easier to apply formatting:

MARKDOWN Example:

{mlang en}
## Very Basic Heading (English)
a example **flagmessage** with some basic *formatting* done. 
List of instructions for the user
- [Instruction 1 with a URL](https://github.com/)
- Instruction 2
{mlang}

{mlang de}
## Very Basic Heading (German)
a example **flagmessage** with some basic *formatting* done. 
List of instructions for the user
- [Instruction 1 with a URL](https://github.com/)
- Instruction 2
{mlang}

HTML Example:

{mlang en}
<h2>Very Basic Heading (English)</h2>
<p>a example <strong>flagmessage</strong> with some basic <em>formatting</em> done.</p>
<p>List of instructions for the user</p>
<ul>
    <li><a href="https://github.com/">Instruction 1 with a URL</a></li>
    <li>Instruction 2</li>
</ul>
{mlang}

{mlang en}
<h2>Very Basic Heading (German)</h2>
<p>a example <strong>flagmessage</strong> with some basic <em>formatting</em> done.</p>
<p>List of instructions for the user</p>
<ul>
    <li><a href="https://github.com/">Instruction 1 with a URL</a></li>
    <li>Instruction 2</li>
</ul>
{mlang}

Depending on how much formatting the user needs, it might get a little messy to maintain.

[danmarsden]

it feels non-standard to me... I've had a quick look and I can't find any user editable settings in core moodle that do it in the way you've suggested here, but I can find a bunch that support full html editing in plain text settings fields that don't embed the full editor.