Trying to configure LDAP as JNDI Resource in Tomcat

Question

I have an ldap server that I'm using to authenticate users within a tomcat web application. I'm using the JNDIRealm and it's configured within a context file and this works great.

I'll also need to search the ldap for user information. I've figured out how to do this with the "jndi method" and I have it working fine outside of tomcat by creating my own jndi context using a hashtable. However, instead of configuring the jndi properties in code, I'd like to create a JNDI Rsource in my context file right next to the Realm configuration.

I'm thinking I would do something like this:

<Resource 
  name="ldap"
  auth="Container"
  type="com.sun.jndi.ldap.LdapCtxFactory"
  java.naming.factory.initial="com.sun.jndi.ldap.LdapCtxFactory"
  java.naming.provider.url="ldap://localhost:389"
  java.naming.security.authentication="simple"
  java.naming.security.principal="uid=rjcarr,dc=example"
  java.naming.security.credentials="abc123"
/>

But either tomcat tells me the resource can't be created or when I try to initialize it with something like this:

Context initctx = new InitialContext();
DirContext ctx = (DirContext) initctx.lookup("java:comp/env/ldap");

Tomcat tells me the "Cannot create resource instance". I've also added the correct resource-ref in my web.xml file, so I don't think that's the problem.

Since LDAP is being used with the JNDI method I'm assuming it should be able to be configured as a Resource, right? What am I missing?

Answer 1

This answer is a bit late, but probably it'll be useful for other users. It's based on EJP's answer .

The following solution was tested on Apache Tomcat 7 .
If you need, you can replace LdapContext with DirContext .

Create an ObjectFactory

Create a class which implements ObjectFactory to instantiate a LdapContext :

public class LdapContextFactory implements ObjectFactory {

    public Object getObjectInstance(Object obj, Name name, Context nameCtx, 
        Hashtable<?, ?> environment) throws Exception {

        Hashtable<Object, Object> env = new Hashtable<Object, Object>();
        Reference reference = (Reference) obj;
        Enumeration<RefAddr> references = reference.getAll();

        while (references.hasMoreElements()) {

            RefAddr address = references.nextElement();
            String type = address.getType();
            String content = (String) address.getContent();

            switch (type) {

            case Context.INITIAL_CONTEXT_FACTORY:
                env.put(Context.INITIAL_CONTEXT_FACTORY, content);
                break;

            case Context.PROVIDER_URL:
                env.put(Context.PROVIDER_URL, content);
                break;

            case Context.SECURITY_AUTHENTICATION:
                env.put(Context.SECURITY_AUTHENTICATION, content);
                break;

            case Context.SECURITY_PRINCIPAL:
                env.put(Context.SECURITY_PRINCIPAL, content);
                break;

            case Context.SECURITY_CREDENTIALS:
                env.put(Context.SECURITY_CREDENTIALS, content);
                break;

            default:
                break;
            }
        }

        LdapContext context = new InitialLdapContext(env, null);
        return context;
    }
}

Define your resource

Add the following to your context.xml , referencing the factory and defining the values to create a LdapContext instance:

<?xml version="1.0" encoding="UTF-8"?>
<Context>
    ...
    <Resource name="ldap/LdapResource" auth="Container"
        type="javax.naming.ldap.LdapContext"
        factory="com.company.LdapContextFactory"
        singleton="false" 
        java.naming.factory.initial="com.sun.jndi.ldap.LdapCtxFactory"
        java.naming.provider.url="ldap://127.0.0.1:389"
        java.naming.security.authentication="simple"
        java.naming.security.principal="username"
        java.naming.security.credentials="password" />
</Context>

If you need to add more attributes/values to your resource, consider updating your ObjectFactory created above to read these new attributes/values.

Use your resource

Inject your resource wherever you need:

@Resource(name = "ldap/LdapResource")
private LdapContext bean;

Or look it up:

Context initialContext = new InitialContext();
LdapContext ldapContext = (LdapContext)
    initialContext.lookup("java:comp/env/ldap/LdapResource");

See more

Apache Tomcat's documentation explains how to add custom resource factories .

Answer 2

You're making it up. The type of a Tomcat resource must be a class that implements javax.naming.spi.ObjectFactory. See the Tomcat documentation for custom resources.