Can I use DocumentApp.openById() with read only permission? - google-apps-script

Question

I am creating a Google Apps Script add-on that is for a Google Spreadsheet, but it needs to be able to access the content of a separate Google Doc, which I am doing using DocumentApp.openById(). I have given the script these scopes:
"oauthScopes": [
"https://www.googleapis.com/auth/documents.readonly",
"https://www.googleapis.com/auth/script.container.ui",
"https://www.googleapis.com/auth/spreadsheets.currentonly"
]
But apparently, that's not enough. The script is telling me it needs the https://www.googleapis.com/auth/documents permission to work properly. However, it seems excessive to give the add-on permission to edit ALL Google Docs files when it just needs to be able to view the content of one. Am I missing something? Is there a way to give it read-only access to a separate Google Docs file?
Here is the function I am using for testing, with most of the document ID censored out:
function getDoc() {
var id = '1NLH----------------------------------------'
var templateFile = DocumentApp.openById(id)
var templateText = templateFile.getBody().getText()
Logger.log(templateText)
}
Thanks!

Answer 1

I believe your goal as follows.
You want to retrieve the text data from Google Document using the following script.
function getDoc() {
var id = '1NLH----------------------------------------'
var templateFile = DocumentApp.openById(id)
var templateText = templateFile.getBody().getText()
Logger.log(templateText)
}
You want to achieve this using the scope of https://www.googleapis.com/auth/documents.readonly and Google Apps Script.
Issue and workaround:
In the current stage, DocumentApp.openById of Document service is used, it is required to use the scope of https://www.googleapis.com/auth/documents. It seems that this is the current specification. So, in this answer, as a workaround, I would like to propose to use Google Docs API instead of Document service. When Google Docs API is used, your script can be achieved using the scope of https://www.googleapis.com/auth/documents.readonly.
When your above script is modified using Google Docs API, it becomes as follows.
Sample script:
Before you use this script, please enable Google Docs API at Advanced Google services. This script can work with only the scope of https://www.googleapis.com/auth/documents.readonly.
function myFunction() {
const documentId = "###"; // Please set the Document ID.
const obj = Docs.Documents.get(documentId);
const text = obj.body.content.reduce((s, c) => {
if (c.paragraph && c.paragraph.elements) {
s += c.paragraph.elements.map(e => e.textRun.content).join("");
}
return s;
}, "");
console.log(text)
}
Reference:
Method: documents.get