HTML tags in column_formatters_detail

[wnowicki]

It would be nice to being able to add some HTML to column_formatters_detail. Example below:

def formatter_json(m: Any, a: str) -> str:
    """Format JSON to string"""
    return f"<pre>{json.dumps(getattr(m, a), indent=2)}</pre>" if getattr(m, a) else "NULL"

is returning on screen:

[baljir0901]

Hey! 👋 I really like this idea — supporting safe HTML rendering in column_formatters_detail would unlock much more expressive detail views.

Your example with <pre> is especially useful for nicely formatting JSON blobs or structured data. Right now, escaping behavior or sanitization often causes it to display as raw HTML instead of rendering.

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✅ Suggestion

Maybe this could be solved by adding an optional flag like:

column_formatters_detail_html_safe = {
  "your_column_name": True
}

Or simply allow returning a Markup object (from markupsafe) so developers can explicitly opt-in to render HTML safely:

from markupsafe import Markup

def formatter_json(m, a):
    value = getattr(m, a)
    return Markup(f"<pre>{json.dumps(value, indent=2)}</pre>") if value else "NULL"

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🛡️ Of course, this should be opt-in to prevent XSS risks.

Would love to see this added — especially for dashboards that display nested data, code blocks, or logs.

Thanks for proposing this! 🚀

[wnowicki]

Thank you for your comment.

Personally I don't think another flag is necessary. If the value that gets in the formatter is already safe then I don't suspect developer for any malicious HTML. So for safety key is that what we process is already safe. This gives freedom, flexibility and no additional boilerplate. And of course you can still use Markup if you like.