Step by Step Guide for Single Sign On into Wordpress with Google Apps

STEP 1: Configuring Google Apps as IdP

Go to https://admin.google.com and login to your Google Apps Administrator account.
On the Admin Home, select More Controls Apps.

In the App Settings, select SAML apps.
Click on the "+" button at the bottom right corner to create a new SAML app.
Now select SETUP MY OWN CUSTOM APP from the popup.
On the next screen, note down the SSO URL, Entity ID URLs and download the certificate. These will be required while configuring the Plugin.
Once you have noted the URLs and downloaded the certificate, click on Next.
Enter the Application Name and Description. Click on Next.

Configure the following things on the next screen:

ACS URL	ACS (Assertion Consumer Service) URL from Step1 of the plugin under Identity Provider Tab.
Entity ID	SP-EntityID / Issuer from Step1 of the plugin under Identity Provider Tab.
Signed Response	Checked
Name ID	Select Basic Information from the first dropdown. Then Primary Email from the second dropdown.

Click on Next. Then click on Finish.
Now go to SAML Apps again. Click on the menu link corresponding to your app (See the screenshot). Then select ON for everyone.
From the popup, Click on TURN ON FOR EVERYONE.

STEP 2: Configuring Wordpress as SP

In miniOrange SAML plugin, go to Service Provider Tab. Enter the following values:

Identity Provider Name:	GoogleApps
SAML Login URL:	The SSO URL that you noted while configuring the Wordpress site in Google Apps.
IdP Entity ID or Issuer:	The Entity ID that you noted while configuring the Wordpress site in Google Apps.
X.509 Certificate:	Open the downloaded certificate in the Notepad. Copy/paste the entire content of the file here.
Response Signed:	Checked
Assertion Signed:	Unchecked

In miniOrange SAML plugin, go to Attribute/RoleMapping tab. Enter the following values:

Username:	Name of the username attribute from IdP (Keep NameID by default)
Email:	Name of the email attribute from IdP (Keep NameID by default)
FirstName:	Name of the firstname attribute from IdP
LastName:	Name of the lastname attribute from IdP
Group/Role:	Name of the Role attribute from IdP

You can check the Test Configuration Results to get a better idea of which values to map here.

Under the Role Mapping section, configure which GROUP value coming in the SAML response needs to be mapped to which role in WordPress. The Group value coming in the SAML response will be mapped to the Role assigned here and the user will be assigned that role in WordPress.
Go to SSO Login Settings tab. Enable auto-redirect to IDP using Redirect to IdP if user not logged in option.