Authorizing requests with OAuth 2.0 in Google Spreadsheet API

Question

I am trying to create a PHP web page that requires reading some data from a google spreadsheet in my domain (I am using Google Apps Free Edition).

The spreadsheet to be read is a non-public one but is visible to some people in my domain. Since it's non-public, I know there will be some authentication and authorization stuff even I am using the API to read it.

I found this page but there is something that I don't understand: http://code.google.com/intl/zh-TW/apis/spreadsheets/data/3.0/developers_guide.html#Auth

It says we should use OAuth 2.0 protocol, this is ok. But it also says during the authorizing process, "Google displays an OAuth dialog to the user, asking them to authorize your application to request some of their data.".

My webpage will display some data read from the spreadsheet. So whenever somebody goes to my webpage, it will display a dialog to the spreadsheet owner asking for permission? Is this what it means?

Any advice will be very welcome.

Answer 1

What you're actually trying to accomplish is Server to Server authentication between your server and Google.

This way, when a visitor enters your page/s you'll grab data from your own spreadsheet, without any 3rd party involvement.

I'ts possible you'll find what you're looking for in Google Service Account, and here

Also, another solution (which is much easier to accomplish, but might have some set backs) is to use the oauth 2.0 protocol with your Google dev account (retrieved from Google Console API).

1. If you haven't already, create a Google Dev account (Google Console API)
2. Generate a access/refresh token for your application with "offline" grant - meaning you can make API requests with your dev account to your spreadsheet account even when you're not logged in with your spreadsheet account.
3. Save the refresh token you generated and use it to generate access token over and over again (access tokens last 1 hour).

Refresh token are not supposed to expire, but in case it would, you can always generate it again and replace the one you had with a new one, and keep generating access tokens with it.

The major set back is in case your refresh token gets invalidated, you'll have to manually replace it, as it will require you to re-grant access to your dev account to access your spreadsheet account.

I hope this helps a bit.

Meny

Answer 2

Google & OAuth tutorial: I searched for days to find this. It is far better then any other OAuth style tutorial I have used. It is for connecting to Google Docs/google drive.

Python example is here, also see other examples for java etc: https://developers.google.com/drive/examples/python

Note you need to add refresh token to it. But that works just as you would expect.

Also to connect to the spreadsheet use:

          SpreadsheetService service =
                  new SpreadsheetService("MySpreadsheetIntegration-v1");

          service.setHeader("Authorization", "Bearer " + accessToken);

Answer 3

yes, OAuth protocol means that when you will try to ask protected resources from other side (google), your site should redirect your user to other's side site, showing him google's login/password dialog, with a request for confirmation that user is agreed to allow your site to use user's resourses from the other site (google in your case). That is how OAuth is working

and google needs yours user's credentials because google is not sure that user is exactly this user (if he does not have any cookies for example)

Answer 4

You can use the new provided oauth2 flow

//flow use httpTransport, clientSecrets, json factory and datastore factory
val flow = new GoogleAuthorizationCodeFlow
  .Builder(httpTransport,JSON_FACTORY,clientSecrets,SCOPES)
  .setDataStoreFactory(datastoreFactory)
  .build()

// authorize
val credential=new AuthorizationCodeInstalledApp(flow, new LocalServerReceiver()).authorize("user")

and use it with your gdata service:

val service:SpreadsheetService=new SpreadsheetService("SpreadsheetIntegration") 
 service.setOAuth2Credentials(credential)

full example in scala: https://github.com/spaced/spreadsheet-oauth2-example