Wednesday Oct 03, 2007

Mort Learns JDBC Realm Authentication for GlassFish

Here is another good blog on this subject.

In my last blog I showed you how to make a jdbc-resource that you can use for accessing a database.

Now I'll explain how to use that jdbc-resource to setup JDBC Realm Authentication and Authorization.

Realm Background

The job of a realm is to maintain a repository of user information.  Each user has one password and 0 or more groups that he belongs to.

At runtime a Realm is initially given a username and password and the realm then figures out if the user is authentic by checking the password.  It checks for authorization by seeing if the user's list of groups is authorized to use a resource (more on this later).

How to Create The Realm for userauth 

Using Admin GUI navigate to Configuration/Security/Realms.  Press the "new" button

Pick the classname that ends in JDBCRealm.  Use the jndi name of your jdbc-resource -- if it isn't userauth.

I'm assuming that you are starting from scratch with no user database.  If you already have such a database, you need to make sure your database table and column names are entered correctly and that your tables correspond to what JDBCRealm needs.  Such details are coming up...

Tip: Use the names in the screen-shot for the 2 table names and 3 column names.  These names are as good as the next.  If you standardize on these names you can use some tools I've developed for help administering and testing the realm.

Database user and password -- I'm not so sure about this.  The connection you get from the jndi name already has the username and password for that database.  I put the username and password from my database here and everything worked fine...

Digest Algorithm

You have to decide whether to save passwords as clear-text or encrypted.  If you want clear-text, leave the edit field blank.  If you want your passwords encrypted set this field to MD5.

My recommendation is to use MD5 for the passwords.  I have some tools with the code you need to convert a plain text password to an encrypted string in the right format for JDBCRealm.

On the other hand you can set it to no encryption -- and it will be much easier to seed the tables with test user info.   You can always change it to MD5 later when you have everything working.

All of the GlassFish administration work is now done.

Now you need to add some tables to your database.  You can run this sql script and it will do all the work for you.  The script also adds one user with username=admin and password=admin. 

The easy way to do this is to run "ij" -- a javaDB  sql console -- there is a copy here: <gf>/javadb/bin

ij> connect 'jdbc:derby://localhost:1527/userauth;user=APP;password=APP;create=true';

ij> run 'createdb.sql';


Now it's time to try out a protected web module.   What we want here is the World's Simplest Web Module.
In NetBeans, create a new web module.  The web module consists of one hello world jsp file.  Perfect.  If you don't use NetBeans then create some sort of ultra simple web module.

We have to add quite a bit of stuff to web.xml.  Netbeans makes fast work of it:


Here are the additions to web.xml (generated by NetBeans)



I have 2 roles named "ADMINISTRATORS" and "USERS".  I use these same names as the groupid values in the database table.  This makes the role-mapping a bit easier because you use the exact same name on both ends.

You must setup the roll-mapping in sun-web.xml  The easiest way to do it so directly edit the file and add these lines:


 Build and deploy this web module and then run it.  It will ask you for authentication info.  If you enter "admin" "admin" you should be allowed in to see the jsp page.

If you enter the name and password for someone that does not belong to the group "ADMINISTRATORS" then you will get an access violation error.

If there is interest, I'll follow up with some tools you can use to add users dynamically and to manage the database itself.



Monday Jun 11, 2007

Let's Get This Glassfish Party Going!

This is the first chapter in a n-chapter tutorial on how to exploit Glassfish capabilities. I learned long ago that the only way I can really cement into my head a hunk of technology is to just do it. I came up with a useful application for web technology. In this series we will be building an application that will slowly but surely use these areas of javaee. They are in the approximate order that we will tackle in the project.
  • HTTP File downloading (HyperText Transfer Protocol)
  • Servlets
  • JSPs (Java Server Pages)
  • User Authentication - Basic, then File Realms, then JDBC Realms
  • Derby Database
  • JNI (Java Naming Interface)
  • EJB 3.0 (Enterprise Java Beans)
  • JPA (Java Persistence API)
  • EJB Timer Service
  • Struts
  • JSP Tag Libraries
  • MDB (Message Driven Beans)

Chapter 0: The Application Description

Dr. Dean Edell has an interesting radio talk show on KGO radio in San Francisco. His show is from 1 to 2 PM Monday through Friday. KGO posts an mp3 file for the show once a day. KGO takes it down, forever, after 24 hours. KGO does not maintain an archive of old shows. I like to burn the shows onto CDs and listen to them in my car. What this application will do is:
  • Automatically download the mp3 at 11:38 PM every night, Monday through Friday and save them to a subdirectory of docroot on my Glassfish Application Server.
  • Maintain user accounts for people that wish to download the files. New accounts will be accepted and added to the list on demand.
  • The application will persist which files have been downloaded for each user. When a user is authenticated he will see his own custom list of programs he has yet to download.
  • A list of all available programs will also be available in case of trouble (like the dog eating the Dean Edell CDs)

This sounds like a lot of overkill for such modest sounding requirements. But making it 100% automatic is a bit challenging. Besides, the whole point of this is to create an application - any application -- in order to learn how to do all this stuff. We will start simple but thorough and correct. We will constantly change and modify it to use the cutting edge Java EE technology as the tutorial progresses.

Stay Tuned for the next installment, Chapter 1:

Write a stand alone Java application that will download the mp3 file. The OS will be in charge of running this application via a chron/at job.




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