If you use your IBM i as an LDAP server, you'll love this tip that provides a simple command to keep that server synchronized.

I love learning new ways to use my i. I've been programming the midrange for over 30 years now, and I'm still learning new capabilities of the platform. For me, the most recent was the capability of the IBM i to act as a Lightweight Directory Access Protocol (LDAP) server.

LDAP is one of the primary forms of authentication in the computer world and I needed to learn how to use it for securing rich Web applications (written in EGL, of course!). A large part of that work is done by Windows machines running Active Directory, but the built-in LDAP capabilities of the IBM i can be sufficient for many environments. One of the issues is keeping the directory synchronized, and this tip shows you a simple command that can help you do just that.

If you've never heard of LDAP, start here or you could refer to my recent article on accessing LDAP servers via RPG. If you're LDAP-aware but never got around to configuring the LDAP server on the i (also known as the IBM Tivoli Directory Server, or ITDS), the Infocenter has excellent configuration instructions.

On to the Tip

For those who have implemented the LDAP server on the i, you already know that it provides a very simple way to let you use your IBM i user profiles as LDAP entries. For example, you can set up your Web application in such a way that when users attempt to access secured resources, your Web browser will challenge them for their user ID and password and then pass those to the ITDS server on the i, which will in turn validate those credentials against your IBM i user profile and password. I think of it as a poor man's Single Sign-On (SSO); users still have to sign on to the Web application, but they don't have to worry about another password or keeping them synced.

However, user profiles are not automatically available to ITDS. The user profiles must be enrolled in the system directory (WRKDIRE). But adding a directory entry doesn't make it available to ITDS. You have to go through one additional step: call the API Synchronize System Distribution Directory to LDAP (QGLDSSDD). This API will publish either all the directory entries or the ones added since the last time the API was called, depending on the parameters.

This tip focuses on those parameters. QGLDSSDD is documented in the Infocenter, but if you read the documentation, you'll see that the official calling technique is to call the API directly from the command line, passing manually entered parameters, many of them hardcoded literals. Not exactly my preferred method. Instead, I'm giving you a short CL program and an associated command that will allow you to either completely rebuild the LDAP directory or synchronize the most recent entries.

The code is very, very simple. First, the command:

PUBLDAP:    CMD        PROMPT('Publish LDAP Entries')              

            PARM       KWD(TYPE) TYPE(*CHAR) LEN(4) RSTD(*YES) +   

                         DFT(*CHG) VALUES(*ALL *CHG) PROMPT('Users +

                         to Synchronize')                           

Nothing to it. A single parameter with two values, *ALL and *CHG. I chose those values because they match the parameter values on the API itself, so I can just call the API with the value passed to me. Speaking of which…

PUBLDAP:    PGM        PARM(&TYPE)                             

            DCL        VAR(&TYPE) TYPE(*CHAR) LEN(4)           

            CALL       PGM(QGLDSSDD) PARM(&TYPE *CFG *CFG 0 0 0)

            ENDPGM                                             

This isn't much more difficult. Basically, I just call the QGLDSSDD API with the type that was selected from the command and the rest of the parameters hardcoded. If you read the documentation, you'll find that the second and third parameters can be *CFG as shown or you can actually specify your LDAP user ID and password. I prefer not to do that and instead configure those values using IBM i Navigator (right-click on your machine and select Properties; then click on the Directory Services tab).

Was this necessary? I suppose not; you could always call the API directly. But for me, it just seems a little nicer to have a command. Now, instead of trying to remember the parameters, I simply type PUBLDAP and hit F4 to get this screen, which is a bit more user friendly:

                        Publish LDAP Entries (PUBLDAP)     

Type choices, press Enter.                               

Users to Synchronize . . . . . . *CHG          *ALL, *CHG

That's it for this tip. I hope that you're able to use it and that it inspires you to start looking for more capabilities in your i!

as/400, os/400, iseries, system i, i5/os, ibm i, power systems, 6.1, 7.1, V7, V6R1