upstream-rocketchat/apps/meteor/server/lib/messaging/validateCustomMessageFields.ts

import { ajv } from '@rocket.chat/rest-typings';
import mem from 'mem';

const customFieldsValidate = mem(
	(customFieldsSetting: string) => {
		const schema = JSON.parse(customFieldsSetting);

		if (schema.type && schema.type !== 'object') {
			throw new Error('Invalid custom fields config');
		}

		return ajv.compile({
			...schema,
			type: 'object',
			additionalProperties: false,
		});
	},
	{ maxAge: 1000 * 60 },
);

export const validateCustomMessageFields = ({
	customFields,
	messageCustomFieldsEnabled,
	messageCustomFields,
}: {
	customFields: Record<string, any>;
	messageCustomFieldsEnabled: boolean;
	messageCustomFields: string;
}) => {
	// get the json schema for the custom fields of the message and validate it using ajv
	// if the validation fails, throw an error
	// if there are no custom fields, the message object remains unchanged

	if (messageCustomFieldsEnabled !== true) {
		throw new Error('Custom fields not enabled');
	}

	const validate = customFieldsValidate(messageCustomFields);
	if (!validate(customFields)) {
		throw new Error('Invalid custom fields');
	}
};