Possible to get the browser/request URL in a hook?

[TRiBotWillB]

I have a hook on 'render:html' because I want to pull in some theme data based on the subdomain and set some CSS variables (see script below). Locally, I am using getHeader to pull in host header, but when run inside Docker that is simply set to 'localhost:3000'. Is there a better way of getting the request URL?

export default defineNitroPlugin(async (nitroApp) => {
    nitroApp.hooks.hook('render:html', async (html, h3event) => {
        // Get HOST header
        const host = getHeader(h3event.event, 'host') ?? ''

        // Default org to fall back to if not found in the header
        const defaultOrg = "wm";

        console.log(host)
        
        const orgDomain = extractSubdomain(host) ?? defaultOrg;

        let theme = {
            notificationThemeColor: '#5701AD',
            themeColor: '#5701AD',
            themeColorDarken: '#5701AD',
            themeName: 'Light',
            themeFontFamilyName: 'Poppins, sans-serif',
        }

        const baseUrl = host ? `http://${host}` : '';

        try {
            const response = await axios.get(`${baseUrl}/api/organisations/theme?orgDomain=${orgDomain}`)

            theme = response.data;
        } catch (e) {
            console.error('Failed to load theme, reverting to default')
            console.error(e)
        }

        const darkMode = theme?.themeName === 'Dark'
        const bgColor = darkMode ? '#222222' : '#FFFFFF'
        const textColor = !darkMode ? '#222222' : '#FFFFFF'
        const themeColor = theme?.themeColor || '#5701AD'
        const themeColorDark = LightenDarkenColor(themeColor, -50)
        const themeColorLight = LightenDarkenColor(themeColor, 50)
        const style = `
        <style>
        :root {
            --themeColor: ${themeColor};
            --themeColorDark: ${themeColorDark};
            --themeColorLight: ${themeColorLight};
            --notificationColor: ${theme?.notificationThemeColor};
            --themeFontFamilyName: ${theme?.themeFontFamilyName || 'Roboto, sans-serif'};
            --color-bg-theme: ${bgColor};
            --color-text-theme: ${textColor};
        }
        </style>`;

        html.head.push(style);
        html.body.push(`<script>window.__MY_DATA__ = ${JSON.stringify(theme)}</script>`);

        if (darkMode) {
            html.htmlAttrs.push('class="dark"')
        }
    });
})