Ghost/core/server/services/themes/index.js

const debug = require('@tryghost/debug')('themes');
const logging = require('@tryghost/logging');
const errors = require('@tryghost/errors');
const tpl = require('@tryghost/tpl');
const themeLoader = require('./loader');
const validate = require('./validate');
const list = require('./list');
const activator = require('./activation-bridge');
const settingsCache = require('../../../shared/settings-cache');

const messages = {
    activeThemeIsMissing: 'The currently active theme "{theme}" is missing.',
    themeCannotBeActivated: '{themeName} cannot be activated because it was not found in the theme directory.'
};

module.exports = {
    // Init themes module
    // TODO: move this once we're clear what needs to happen here
    init: async () => {
        const activeThemeName = settingsCache.get('active_theme');

        debug('init themes', activeThemeName);
        try {
            // Just read the active theme for now
            const theme = await themeLoader.loadOneTheme(activeThemeName);
            // Validate
            // @NOTE: this is now the only usage of check, rather than checkSafe...
            const checkedTheme = await validate.check(theme);

            if (!validate.canActivate(checkedTheme)) {
                logging.error(validate.getThemeValidationError('activeThemeHasFatalErrors', activeThemeName, checkedTheme));
            } else if (checkedTheme.results.error.length) {
                // CASE: inform that the theme has errors, but not fatal (theme still works)
                logging.warn(validate.getThemeValidationError('activeThemeHasErrors', activeThemeName, checkedTheme));
            }

            activator.activateFromBoot(activeThemeName, theme, checkedTheme);
        } catch (err) {
            if (err instanceof errors.NotFoundError) {
                // CASE: active theme is missing, we don't want to exit because the admin panel will still work
                err.message = tpl(messages.activeThemeIsMissing, {theme: activeThemeName});
            }

            // CASE: theme threw an odd error, we don't want to exit because the admin panel will still work
            // This is the absolute catch-all, at this point, we do not know what went wrong!
            logging.error(err);
        }
    },
    getJSON: require('./to-json'),
    activate: async (themeName) => {
        const loadedTheme = list.get(themeName);

        if (!loadedTheme) {
            throw new errors.ValidationError({
                message: tpl(messages.themeCannotBeActivated, {themeName: themeName}),
                errorDetails: themeName
            });
        }

        const checkedTheme = await validate.checkSafe(themeName, loadedTheme);

        activator.activateFromAPI(themeName, loadedTheme, checkedTheme);

        return checkedTheme;
    },
    storage: require('./storage'),
    /**
     * Load all inactive themes
     */
    loadInactiveThemes: async () => {
        return await themeLoader.loadAllThemes();
    }
};