Setting up Google Drive API on NodeJS using a service account

April 5, 2022

I’m trying to connect to the Google Drive API with a NodeJS server using a service account. The goal is for the server to be able to authenticate as the service account, retrieve relevant files from a drive, and send them back to the user, without the user needing to log in to Google directly. This would allow me to control file access through my web app instead of having to manually share and unshare files through Drive. From my understanding of the Google Drive API, this should all be possible. The problem is that I can’t even figure out how to authenticate my server. The server runs on an AWS EC2 instance. To clarify, I do not want the user to have to authenticate using the frontend interface.

I’ve followed the quickstart guide and set up a service account & key as instructed here, but upon creating the key as instructed in the second link, it doesn’t look like I have the correct credentials.json file. The JSON file I get after generating a key on the Google Developer Console has the following object keys (values intentionally removed):

type, project_id, private_key_id, private_key, client_email, client_id, auth_uri, token_uri, auth_provider_x509_cert_url, client_x509_cert_url

The quickstart guide suggests that this file should contain client_secret and redirect_uris within some installed object (const {client_secret, client_id, redirect_uris} = credentials.installed;):

Attempting to run this index.js quickstart file causes an error to be thrown, since installed does not exist within credentials.json. Where can I generate the necessary credentials file? Or am I on the wrong track completely?

Posts like this reference a similar issue on an older version of the quickstart documentation, but the solutions here don’t help since there isn’t a client_secret key in my credentials file.

>Solution :

When I saw the showing keys of your credentials.json file, I understood that the file is the credential file of the service account. If my understanding is correct, when I saw your showing script, it seems that the script is for OAuth2. In this case, this script cannot be used for the service account. I thought that this is the reason for your current issue.

In order to use Drive API using the service account, how about the following sample script?

Sample script:

Before you use this script, please set credentialFilename of the service account. In this case, please include the path.

const { google } = require("googleapis");

const credentialFilename = "credentials.json";
const creds = require(credentialFilename);
const scopes = ["https://www.googleapis.com/auth/drive.metadata.readonly"];

const auth = new google.auth.GoogleAuth({keyFile: credentialFilename, scopes: scopes});
const drive = google.drive({ version: "v3", auth });

// This is a simple sample script for retrieving the file list.
drive.files.list(
  {
    pageSize: 10,
    fields: "nextPageToken, files(id, name)",
  },
  (err, res) => {
    if (err) return console.log("The API returned an error: " + err);
    const files = res.data.files;
    console.log(files);
  }
);

When this script is run, as a sample script, the file list is retrieved from the Google Drive of the service account. So, please modify this for your actual situation.
This sample script uses https://www.googleapis.com/auth/drive.metadata.readonly as the scope. Please modify this for your actual situation.