Using OAuth2.0 (Google API) on a kiosk - json

I'm trying to set up a PC in kiosk mode that will display a list of events from a Google Calendar. I initially wanted to use the Google API for this (be it the JS client, Python client or other), but it seems that all of these require the user to consent via a page in the browser. This is not acceptable because it's a standalone system--there is no user to click on anything. The system will be on a daily power cycle so a 'consent once run forever' is also not possible.
Is there a way to use the authenticated (OAuth2.0) Google API to access calendar data without any user intervention whatsoever (except just a one-time initial setup)?
Thanks!

That's exactly what OAuth should be able to do. You should do a onetime setup (start he flow, authorize the request and get the tokens) and then store the tokens. Once the tokens are stored, you do NOT need any more user action as long as you have the tokens. The tokens would then be used to retrieve the data from the Google Calendar.

Related

Need refresh token without using consent screen in G Suite

We are using G Suite API with our Micro service for document editing, and we have a different data center and also different db. now once user comes to my application and trying to open document first time then google give consent screen based on that i can get refresh token and access token and i store into one data center.
But problem is that if user comes from another instance which use different data center with different db and user trying to open document with old credentials then google doesn't give any consent screen so i am not getting user's refresh token.
1) So is there any way to get refresh token without using consent screen?
2) Is there any way to identify if user comes from different sub domain then i need to provide consent screen for that?
It might be possible to use the prompt=consent option to force a re-prompt for auth, even though the user has already authorized your app.
See https://developers.google.com/identity/protocols/OAuth2WebServer#creatingclient
You can identify the user's domain using the hd parameter [1] and you can request a refresh token without the consent screen after the domain admin has configured domain wide delegation by installing your application from the GSuite Marketplace [2].
[1] https://developers.google.com/identity/protocols/OpenIDConnect#hd-param
[2] https://support.google.com/a/answer/172482?hl=en
When you request an OAuth Flow (access_type=offline`), a Refresh Token is returned to your application. This only happens once (obtaining a Refresh Token). Your application is expected to save the Refresh Token for future needs.
In your use case, one of your systems completed the authentication and the user has moved to a different system. You will need to reauthenticate with prompt=consent, access_type=offline. You will not get another Refresh Token without reauthenticating.
I spent a lot of time on this issue last November. Here is a link which has lots of details on this problem.
Any application can only have one valid refresh token for a user. You can request for a new refresh token using the prompt=true&access_type=offline on the request as said by #John. But every time the previous one will become invalid.
Based on you comments on the other answers, I'm assuming creating a new micro service that returns the token to the one being used is not a possibility (that would be my recommendation)
You asked "to identify if user comes from different sub domain"...
If those applications are for end users of gmail.com accounts, you can treat them as different applications and configure different projects on the developer console.
It will be a bit of a pain when enabling new APIs, I would recommend doing that from a script that replicates to all application needed.
If your end users are from companies using GSuite, you can have your app installed as domain-wide application (either manually or from GSuite Marketplace). In that case you can use just client side authentication to get an id_token, send the token to the server and use a service account to impersonate the user in any given service without worrying about any token from them.

How to fetch Google OAuth access tokens from Chrome extensions - tradeoffs between options

EDIT: In case it helps others who find this, the fact that Gaia clears cookies after Chrome restart is known behavior. They recommend the use of Chrome login. See more here.
The core question: how do I fetch Google OAuth access tokens in the background from a Chrome extension without using the getAuthToken method in the chrome.identity API? This method forces users to login to Chrome, which isn't ideal for our app. There's also no way I can find to retrieve OpenID Connect ID tokens using the native methods exposed in the identity API.
Currently, I'm fetching tokens using the launchWebAuthFlow method from the chrome.identity API. This method launches an "Identity API Scope Approval UI" window in which the user makes the initial OAuth grant. This window (referred to as "gaia") has its own session / cookie data, separate from a browser session.
After the initial OAuth grant, the extension periodically retrieves access tokens in the background, and subsequently fetches data from Google APIs (e.g. Drive). This works well. When a user quits and re-opens Chrome, however, fetching access tokens fails - gaia loses its session cookies when Chrome restarts, so running the launchWebFlowAuth method doesn't complete because Google can't authenticate the user (unless we prompt the user to login in the Identity API Scope Approval UI again). Others seem to have had the same issue.
Google Sign-In would be ideal, but it doesn't work in Chrome extensions (I'm getting the same "Invalid cookiePolicy" error as the author of that issue).
Any advice on how to best handle this use case would be very much appreciated!

How to use OAuth 2.0 with a Google Apps Script library, with a static redirect URL?

I can't figure out how to make a shared Google Apps Script library, that uses OAuth 2.0.
The problem is that the usercallback redirect URL changes, every time I use the library in a different script. However, that means I'd need to add a new app and whitelisted redirect URL to Asana for each spreadsheet I use the script in. I'm using https://github.com/googlesamples/apps-script-oauth2.
Is there a way to always authenticate with the same redirect URL, so that the library I make can be used from any script, without registering a new redirect URL in Asana?
I'm a Developer Advocate here at Asana. If I understand your question correctly, then yes, you'll have to handle the callback separately for each script. For security reasons, we validate that the OAuth app registration registers the same url as an integration actually requests when authenticating. If this weren't true, for instance, it'd be possible to create a malicious script that uses the client_id from a legitimate script but asks for the redirect to go to its own credential-grabbing endpoint. This is fixed if the app that got the client_id on app registration also specifies precisely which endpoint should be the legal endpoint to redirect to. That means each OAuth app needs to have its own unique and consistent redirect URL :(
I suppose you could possibly create a single "router" Google Apps script which would set the state parameter with some user/script pair when hitting Asana's oauth_authorize endpoint and forward the user credentials on to the script that exists behind the router script based on that user/script pair when the response comes back, but it's not super trivial.
One final option would be to use a Personal Access Token to access Asana's API. This one token can be used by an unlimited number of scripts for access. The downside is that this token "looks like you", that is, it takes action on behalf of not a third party user but you yourself - your scripts would be an automated version of the user whose Personal Access Token they use. This can be mitigated to some extent by creating a "bot account" to access our API and giving it access inside of Asana to the projects or teams you want to gather data on. The other downside to this approach is that every script that uses the personal access token will break if you ever revoke the one token, so if that ever happens by either intent or accident, you'll have to update the Personal Access Token information in every script that uses it.
Hopefully this helps you to evaluate the options and choose which one of these options works best for your script.

How to select account in Google App Scripts for users with multiple accounts?

For users that are logged into multiple accounts, how can a script let the user pick an account? For example, Gmail, Google Drive, etc. provide a way for the user to select which account to use with a selectable option on the top-right of the page:
How can developers implement a similar mechanism?
There seems to be no way to do that with Google Apps Script libraries - GAS just uses the current primary account. Also, unfortunately, the API Client Library and thus Google Sign-In for websites don't work inside GAS web apps because of the sandbox frame. You could write your own or use some existing OAuth implementation to authenticate with Google but I found a much much simpler solution using Auth0 Lock with only a Google Connection (using the popup method because the redirect method doesn't work within the sandbox frame).
With Chrome Version 70.0.3538.102. You may resolve your issue (at least i did)
Now i make sure i ONLY signed in ONE account at a time. Then use "manage people"
if i have 3 google accounts, i will create 3 people and each time you only have 1 active google account session. With this setup, i ensured everytime my script only execute with my G Suite user instead of #gmail accounts
You can try using the Directory API to work with Apps Script. Retrieve the user using:
GET https://www.googleapis.com/admin/directory/v1/users/userKey.
You can then make an interface that displays the user accounts details(Name, email,etc).

Google Script OAuth for multiple users

I've created a Google App Script that handle 2 different OAuth connections.
1- Google itself to send mail on behalf of the user and access google docs (google api console used to get keys, secret)
2- gtraxapp wich is a timesheet cloud-based app. (Script is registered, got a key/secret, etc.)
The script is published as a web app. It works perfectly for my user.
When logged on a different user name, I can authorize Google OAuth without providing different key/secret, and emails will be sent from the actual user.
Problem happens with the 2nd app (gTrax).
Authorization seems to work. Running the function inside the script to authorize lead to a screen asking for permission, gtrax then appears in the account as a registered app (could revoke access if needed).
But, when running the app, I get a message saying I need permission to do this action (UrlFetchApp / simple get)
My question is :
Is this possible that I need to register each user to get a key/secret for everyone (and dealing with that in the script)...
Or do OAuth can be registered with 1 key/secret ?
In other word, are (should) key/secret linked to a single user or are they only a kind of RSA-like key pairs that, when verified, can be used to authorize any user.
My understanding is this. When you use built-in Apps Script functions, like MailApp.sendEmail, the Google Apps Script "environment" takes care for you to ask authorization for the user (1st time he access your app) and save and manage the oAuth tokens for you, so it all runs smoothly.
When you call an external service using UrlFetchApp, Apps Script oAuth authorization process works differently. The authorization is just a strange popup you get on the script editor, when you actually make the fetch call. It is not processed at "compile time" and asked before you run anything like the other services. But you also do this step only once.
The "gotcha" is that this different authorization process does not work when a user is running the app as a webapp. AFAIK it only works from the script editor itself or running directly from a spreadsheet.
If your users are just a known few, you could advise everybody to open the script editor (or a spreadsheet that contains it) and run an specific function that will just attempt the UrlFetchApp.fetch call so the popup shows up and they authorize it. Once this step is done, they can use the webapp normally. Apps Script will do the magic for you after that.
But if you plan to share this broadly, say at the Chrome Web Store, and don't want to ask every user to do this somewhat strange step, then you'll need to manage all the authorization process yourself. It means, you'll have to register your app with the third party service (if it's Google's, it's at the API Console), where you will receive a client id and a client secret. With those you'll have to place a "Authorize" submit button on your app html that will redirect the users to the 3rd party authorization url, providing the correct scope, etc. When they authorize it, the 3rd party will redirect the user back to your app providing a code token as URL parameter. You'll use this code to call the 3rd party oAuth service to get the real access and possibly refresh tokens that you'll have to use on your UrlFetch calls. You'll be responsible to save these tokens, refresh them when they expire and so on. Not a very simple procedure :-/
Oh, and although your app have only one id and secret, the tokens are per user. Which makes sense, since each call you do must be on behalf of a specific user and he *must* have authorized it.
I hope this helps.