Programming Assignment 3 – Authenticating Administrative Pages

The purpose of this assignment is to introduce you to authentication in website. In particular you will learn about:

  • Spring Security Core plugin for Grails
  • Spring Security UI plugin for Grails
  • How to control access to views
  • Bunus: Learn how to make AJAX calls

Step 1: Install Spring Security Plugins

We will use the Spring Security Core plugin with an additional plugin, the Spring Security UI plugin. The Spring Security Core authenticates users and control access to pages.  The Spring Security UI provides convenient UI  for controlling access and users. It also uses the mail plugin during the registration and reset forgotten passwords. The plugin pages are at:

http://plugins.grails.org/plugin/grails/spring-security-core

http://plugins.grails.org/plugin/grails/spring-security-ui

http://plugins.grails.org/plugin/grails/mail

The documentation for the plugins are at

https://grails-plugins.github.io/grails-spring-security-core/3.2.x/index.html

https://grails-plugins.github.io/grails-spring-security-ui/latest/

http://gpc.github.io/grails-mail/

To install plugins, all you need to do is to list them in build.gradle file. Near the bottom of the build.gradle file, you should see a long list of dependencies. Cut and paste into this dependencies list the declarations below:

dependencies {
    ...
    // Add for Spring Security
    compile 'org.grails.plugins:spring-security-core:3.2.3'
    compile 'org.grails.plugins:spring-security-ui:3.1.2'
    compile 'org.grails.plugins:mail:2.0.0'
}

If you stop and start your app now, you will get an error (500 Internal Server Error) because the app is try to access the database. We need to setup Spring Security Core.

Step 2: Setup Spring Security Core.

1. Run S2 Quick Start script.

Open the Grails command prompt by clicking the “Tools” in the menu bar then select “Grails” followed by “Grails Command”. In the widow that pops up enter:

s2-quickstart cs4760progassign User Role

The script creates 3 domain classes, User.groovy, Role.groovy and UserRole.groovy. It also creates a application.groovy file in grails-app/conf/ directory. Read the tutorial in the Spring Security documentation to learn more:

http://grails-plugins.github.io/grails-spring-security-core/3.2.x/index.html#tutorials

If you read the first part of the tutorial, you notice that you should add

grails.plugin.springsecurity.logout.postOnly = false

to the bottom of the conf/application.groovy file. This makes logout easy. During debugging your web app you can logout by clicking the logout controller in the control list page.

2. Make Role and Users in Bootstrap.groovy

We can add some users and roles to the Bootstrap.groovy file. Cut and paste the code below into init/Bootstrap.groovy init closure.

...

class BootStrap {
   
   def init = {servletContext ->

       ...

       // Add for creating Roles and Users
      def adminRole = new Role(authority: 'ROLE_ADMIN').save(flush: true)
      def userRole = new Role(authority: 'ROLE_USER').save(flush: true)
 
      def testAdmin = new User(username: 'admin', password: 'password')
      testAdmin.save(flush: true)
 
      def testUser = new User(username: 'user', password: 'password')
      testUser.save(flush: true)
 
      UserRole.create testAdmin, adminRole, true
      UserRole.create testUser, userRole, true

      UserRole.withSession {
         it.flush()
         it.clear()
      }
      ....
   }

If you do not have the package specification, you may have to import the User, Role and UserRole, click on the offending class name, then hit alt-enter, finally select import.

The code makes two roles and two users, one a regular user and the other an admin user.

Rerun your web app and you’ll be prompted with a log in screen. You can log in and see the home page, but you cannot navigate to any other pages. But nether Admin or User roles are authorize to see any pages yet. Spring Security set pessimistic locking by default:

https://grails-plugins.github.io/grails-spring-security-core/3.2.x/index.html#pessimistic-lockdown

Step 3: Setup Access to Views

There are basically two methods for setting up access, either using the Request Mapping or annotating the controller or action. Read the Spring Security documentation about Request Mappings

http://grails-plugins.github.io/grails-spring-security-core/3.2.x/index.html#requestMappings

1. Add Static Rules

We use static mapping for the public views.

http://grails-plugins.github.io/grails-spring-security-core/3.2.x/index.html#configGroovyMap

Add these two static rules to the grails.plugin.springsecurity.controllerAnnotations.staticRules map at the bottom of the conf/application.groovy file.

grails.plugin.springsecurity.controllerAnnotations.staticRules = [
    ...
    [pattern: '/books/**',       access: ['permitAll']],
    [pattern: '/authors/**',     access: ['permitAll']],

    [pattern: '/controllerList/**', access: ['ROLE_ADMIN']],
    [pattern: '/author/**',         access: ['ROLE_ADMIN']],
]

Do not forget to add a comma to the end of prior list. But I have noticed that groovy parser does not mind if the last item in a list has a comma, so I leave it with a comma at the end, making it easy to add more rules.

The first two rules grants public to access to all of the books and authors views. The last two rule restrict access to the controllerList and author views to admin users.

Rerun the grails app. Now you can view the home and book index views. To view the controller list you’ll need to login as admin. You still can not access the book views.

2. Add Annotation to BookController

Read about annotating controller actions at

http://grails-plugins.github.io/grails-spring-security-core/3.2.x/index.html#securedAnnotations

Now, you will try annotating the Book controller methods. Add the annotation just above the class definition.

@Secured(['ROLE_ADMIN'])
class BookController {
...
}

You also need to add the import to the top of the class.

import grails.plugin.springsecurity.annotation.Secured

Stop and start your web app. Notice that you can view the the home page, Books and Authors  index actions without logging in, but you cannot access the author or book actions without encountering the login screen.

Generally, you do not want to mix the two techniques. I prefer to use the static rules instead of the annotation for two reasons. First, you can see all the rules at once in application.groovy. Second, you can control access to code you did not write, for example plug in, without modify the plugin code.

Step 4: Spring Security UI

The Spring Security UI plugin provides admin user and role controllers and views, so that the admin can perform common tasks such as adding users and roles. Also Spring Security UI provides views for displaying security information.

1. Accessing User-Role Backend

At the start page you’ll notice that Spring Security UI plugin has added many controllers. At the bottom of the list is the grails.plugin.springsecurity.ui.UserControler. If you click on the link you will be confronted with the login screen. You can login as admin, but that will not give you access to the view.

In the conf/applictaion.groovy, add to the bottom of the staticRules the entries:

[pattern: '/user/**',             access: ['ROLE_ADMIN']],
[pattern: '/role/**',             access: ['ROLE_ADMIN']],
[pattern: '/registrationCode/**', access: ['ROLE_ADMIN']],
[pattern: '/securityInfo/**',     access: ['ROLE_ADMIN']],
[pattern: '/logout/**',           access: ['permitAll']],

We also add the finally rule to let anyone logout.

Restart the grails app. Login as admin, you should see the User Management Search page.

2. Explore User-Role Backend

Read about the Spring Security UI controllers and views in the documentation:

http://grails-plugins.github.io/grails-spring-security-ui/v3/index.html

Explore all the features of the backend. You can access them from the menu bar at the top of the page.

Step 5: Add login/logout to Navbar

In this step you will add login and out links to the navbar. You can also have the navbar identifiy the person logged in.

Read the chapter on Helper Classes in the Spring Security Core plugin documentation. In particular read about the Security Tag Library:

http://grails-plugins.github.io/grails-spring-security-core/3.2.x/index.html#securityTagLib

You will use the <sec:ifLoggedIn>, <sec:ifNotLoggedIn> and <sec:username> tags in the navbar.

Add the following code to _navbar.gsp below the other links for the menu:

<sec:ifLoggedIn><li><a href="#"><sec:username/></a></li></sec:ifLoggedIn>
<li> 
    <sec:ifLoggedIn><g:link controller="Logout">log out</g:link></sec:ifLoggedIn>
    <sec:ifNotLoggedIn><g:link controller="login" action="auth">Login</g:link></sec:ifNotLoggedIn> 
</li>

Restart the app, and try out the new menu items.

Notice that after logging in the user name appears in the navbar. The link could be used to send the user to their profile page.

The <sec:ifLoggedIn>, <sec:ifNotLoggedIn> and < sec:username/> tags are probably accessing session parameters. I’ll speak more about session parameters in a lecture.

Step 6: Study AJAX

AJAX is a technique to create dynamic effects in a view without loading a new page. The basic idea is that a request is sent to the server but the response is returned to the same page instead of loading a new page. In this way, only a portion of the page needs to load rather than the complete page.

1. Study Javascript

AJAX uses javascript, so you’ll want to study javascript. Good resource is W3 Schools.

http://www.w3schools.com/js/default.asp

Most of the language should be familiar to you. But there are some aspects that you should study.

For the most part, you will be writing functions for event handlers. You should read about javascript functions:

http://www.w3schools.com/js/js_function_definition.asp
http://www.w3schools.com/js/js_function_parameters.asp
http://www.w3schools.com/js/js_function_invocation.asp
http://www.w3schools.com/js/js_function_closures.asp

A major purpose of javascript is to manipulate the web page. Javascript’s models the web page as a Document Object Model (DOM). Read the chapters about the DOM.

http://www.w3schools.com/js/js_htmldom.asp
http://www.w3schools.com/js/js_htmldom_methods.asp
http://www.w3schools.com/js/js_htmldom_document.asp
http://www.w3schools.com/js/js_htmldom_elements.asp
http://www.w3schools.com/js/js_htmldom_html.asp
http://www.w3schools.com/js/js_htmldom_css.asp
http://www.w3schools.com/js/js_htmldom_events.asp
http://www.w3schools.com/js/js_htmldom_eventlistener.asp

These tutorials are very short, so they will not take long to read. Be sure to try the examples so that you understand each concept.

2. Study JQuery

JQuery is a javascript library that simplifies using javascript. We will be using JQuery, so you will want to study it. A good resource for JQuery is W3 Schools.

http://www.w3schools.com/jquery/default.asp

Be sure to study the introductory chapters about jQuery:

http://www.w3schools.com/jquery/default.asp
http://www.w3schools.com/jquery/jquery_intro.asp
http://www.w3schools.com/jquery/jquery_install.asp – JQuery is installed by default in Grails using the asset plugin, so this tutorial is only good for working with jQuery in isolation.
http://www.w3schools.com/jquery/jquery_syntax.asp
http://www.w3schools.com/jquery/jquery_selectors.asp
http://www.w3schools.com/jquery/jquery_events.asp

Also be sure to study the use of AJAX in jQuery:

http://www.w3schools.com/jquery/jquery_ajax_intro.asp
http://www.w3schools.com/jquery/jquery_ajax_load.asp
http://www.w3schools.com/jquery/jquery_ajax_get_post.asp

After reading the above, you should be prepared to understand the code addition that we’ll make to your web app.

Step 7: Make a Simple AJAX Call

Now, we’ll make a very simple ajax code in the home view. We’ll add a link to the home view to show the current date and time.

1. Edit index.gsp

In the views/index.gsp file, add the link and result div to the home/index.gsp by adding the code below in the body of the view just below the jumbotron div.

<!-- Simple Ajax link to show time -->
<g:link controller="home" action="showTime" elementId="timeLink">Show the time!</g:link>
<div id="time"> time </div>

You should notice that the “Show the time!” link will call the showTime action in the Home controller, so we should make that controller and action.

2. Add the Server Code

We need place to run the server code. Typically, we would use the controller for the view, but currently the home page does not have a controller associated with it. Note that the g:link already specifies a Home controller. Make a new controller call it Home. After grails has generated the controller add a showTime method to the home controller by cutting and pasting the code below.

private static final boolean debugTime = true //flag for debug printing 

def showTime() {
 if(debugTime)println "In showTime"
 render "The time is ${new Date()}"
}

You also need to grant the public access to home controller. In application.groovy add the following static rules:

[pattern: '/home/**',              access: ['permitAll']],

Rerun grails and try the link in the browser. It should take you to a new page showing the time.

But, that is not what we want. We would like for the date and time to show on this same page. We need to add some javascript.

4. Add JavaScript

In grails-app/assets/javascrips/ directory, make showTime.js file. Then cut and paste the code below into the file.

console.log("Hello showtime");
$(document).ready( function(){
      $('#timeLink').click(function(){
         console.log("showtime click function");
         $('#time').load(this.href); return false;
      });
});

You might wonder how the showTime.js file is added to the page

In the /views/layout/site.gsp, the other asset tag at the bottom of the page tells asset-pipline to source the application.js.

<asset:javascript src="application.js"/>

If you inspect the grails-app/asset/javascript/application.js file, you’ll notice that it has the directive:

//= require tree .

which includes all the JavaScript files in the directory.

The asset pipeline does much more especially for the production environment. The link below has a very good video introducing the asset-pipeline plugin.

http://www.bobbywarner.com/2014/02/26/grails-asset-pipeline-plugin/

It is worth watching because you will need to control your assets.

6. Test the Code

I want you to learn about Chrome and FireFox developer tools. They both have developer tools for debugging web pages and javascript. In Chrome, click on the menu icon (three vertical dots icon at the upper right) and select developer tools. In FireFox, click on the “hamburger” menu icon (three horizontal bar icon at the upper right) and select developer.

After exposing the developer tools click on the console. You should see the message “Hello showtime.” If not refresh the page and click the “show time” link again. The message is form the console.log method.

There is a lot more features in both of these developer tools that you will use to debug your apps. The “Inspector” or “Inspect Element” tools are good for debugging layout and css. Both Chrome and FireFox allow editing the css in the tool so that you can see the effects in real time.

The “Network” tool will show you request timing. Clicking on a request in the “Network” tool will show you the details of the request.

Step 8: Change AJAX call to trigger on Document Ready Event

Sometimes we want the results of a AJAX to load just after the page has loaded in the browser. The event that the document has loaded is the ready event on the document. Change the javascript in the showtime.js file to:

// Show time - Simple Ajax
 console.log("Hello showtime");
 $(document).ready( function(){
     console.log("In document ready");
     $('#time').load("/cs4760progassign/home/showTime");
     $('#timeLink').click(function(){
     $('#time').load(this.href); return false;
     });
 });

Refresh the page and you’ll see the time div is load with the date and time. You can navigate away from the home page and navigate back, and see that the date and time loads has the page load. You can also use the “Show the time!” link to update the time.

Step 9: Make AJAX Recent Book

On the Book Store home page we want the most recently published book to appear below the time. The home page should look something like

Book Store
Show the time!
The time is …..

Most Recent Book
The Stand by Stephen King

You are on your own coding this AJAX call, but I can give you some hints. Use the Domain class “last” method.

Note that the AJAX calls in this assignment are only for example. You would generally not use AJAX calls like these to generate simple dynamic content. Rather you would have the controller send the view a model as we did in the prior assignment.

One example of when you might want to use an AJAX call is when the user updates data in the view. Rather than redrawing the entire page, you would have the AJAX call update the effected portion of the view.

There another case when you have to use AJAX calls for dynamic content in the view. That is when the view should work both online and offline (meaning with or without an internet connection). In that case, the view must identify if there is an internet connect or not. If there is not an internet connection then generally the view should get the dynamic content from local storage, and if there is an internet connection then the view should get the dynamic content from an AJAX call similar to the ones in this assignment.

Step 10: Make the Screen Shot and Email Me

After creating the AJAX call for the most recent book, make two screen shows, one of your index.gsp and the other of the javascript file.

Email me the screen shots. The subject of the email should be

“cs4760 Programming Assignment 3 Proof”

Congratulations, you authorized your website and made your own AJAX call.