How to use DocumentApp in custom functions?

Question

Google Sheets

Good afternoon. We needed a function that gets the text of a document by its id . There were no problems with getting the data. But when I try to wrap it all in a custom function, I get this error:

Вам не разрешено вызывать пользователя DocumentApp.openById.
Необходимые разрешения: https://www.googleapis.com/auth/documents.

Similarly, I could not get a list of files by folder id through a custom function.
I read somewhere that working with the disk from user functions was disabled for security reasons. It's true?

Answer 1

No way. Because user-defined functions are a different type from other scripts.
Custom Functions in Google Sheets | Apps Script...

Unlike most other types of Apps Scripts, custom functions never ask users to authorize access to personal data. consequent, they can only call services that do not have access to personal data, specifically the following:

Supported services	notes
Cache	Works, but not particularly useful in custom functions
HTML	Can generate HTML, but cannot display it (rarely useful)
JDBC
language
lock	Works, but not particularly useful in custom functions
Maps	Can calculate directions, but not display maps
Properties
Spreadsheet	Read only (can use most get*()methods, but not set*()). Cannot open other spreadsheets ( SpreadsheetApp.openById() or SpreadsheetApp.openByUrl()).
URL Fetch
Utilities
XML