Implementing Google federated login using Hybrid Protocol (OpenID+OAuth)

How it works ?

Just a few days ago, I was badly in need to implement Google federated login using Hybrid Protocol (OpenID+OAuth). After searching a while I found myself that I was not keen to read. So read the Federated Login for Google Account Users again and found the solution.
To use Google service all you need

OAuth Consumer Key
OAuth Consumer Secret

How to get OAuth Consumer Key and OAuth Consumer Secret

Step 1 : First you need to add your domain name in google. To add your domain click

Add a New Domain

Step 2 : In Add a New Domain put your domain (sign in if you don’t) and you will get Manage your.domain.name below.

Step 3 : Click on Manage your.domain.name will get Verify ownership page. You will have

Site URL
Verification status
Verification method

Verification Status obviously Not Verified . To verified your domain with Google service you can choose Meta Tag, Upload an HTML file or Add a DNS record from select box. Choose whatever you want. Here we take Meta Tag. Something like

<meta name="google-site-verification" content="OTInrbJb1bsZ4JODXahOcdA2Ab16zZEcOURtss2Fnws" />

Add this meta tag in your site root file (i.e: index.php or index.html) on your site and then click verify button.

Step 4 : After verification it’s time to get the OAuth Consumer Secret. Now create your certificate authority first. The easiest way to create X.509 certificates on Linux is the openssl command. In your LINUX box got to terminal and paste the following code.

$ sudo openssl req -x509 -nodes -days 365 -newkey rsa:1024 -sha1 -subj ‘/C=US/ST=CA/L=Mountain View/CN=www.example.com’ -keyout myr
sakey.pem -out /tmp/myrsacert.pem

Now, you have your .pem file in /tmp/myrsacert.pem and upload and save it to your google account management.
You will see something like:

OAuth Consumer Key: your.domain.name
OAuth Consumer Secret: mx4KGNaNdcqHt+BDuJusaUvc

Step 5 : You are all most done! Just download the Source Code and run. You will need Zend Gdata library. If you don’t have you can download it form here.

Source Code
Zend Frameword :: Zend Gdata

“The demo illustrates the simplicity of a combined user interface doing double duty: view a page requesting sign-on approval and access to your Google Docs and Spreadsheets services, click “Continue Sign-in”, and voila: you’re logged into the site and viewing a list of all your Google docs. All the authentication/authorization is happening behind the scenes, while the cost to the user is one page view and one click.”

Now you can play on Google as well. Visit Google Developer’s OauthPlayGround to discover OpenID+OAuth in action

Thanks for reading my blog.

References:
Google API
OpenID Federated Login Service for Google Apps
Federated Login for Google Account Users
Generating keys using OpenSSL