Code Example – User Authentication with Google App Engine Java Applications

• Web.xml configuration to restrict access to pages
• Use Google User service

Web.xml configuration to restrict access to pages

With following code in web.xml, one could restrict access to one or more pages in matter of no time. You could try on how below configuration works by accessing the page, http://agilesqm.appspot.com/createreport and you would be sent to Google login if not yet logged in on the browser.

<security-constraint>
    <web-resource-collection>
        <web-resource-name>createreport</web-resource-name>
        <url-pattern>/createreport</url-pattern>
    </web-resource-collection>
    <auth-constraint>
        <role-name>*</role-name>
    </auth-constraint>
    <user-data-constraint>
        <transport-guarantee>CONFIDENTIAL</transport-guarantee>
    </user-data-constraint>
</security-constraint>

Use Google User service

With following code in java code, one could get an access to userId which could be used to store in the datastore as a creator of one or more data objects.

UserService userService = UserServiceFactory.getUserService();
User user = userService.getCurrentUser();
String userId = user.getUserId();

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