MySQL server to receive an SQL query and convert to LDAP to query LDAP backend

Question

The requirement is to receive an SQL query(over tcp) from a client(which is using a mysql client library - libmysqlclient.so.16.0.0) and then convert it to an LDAP request and send out to an LDAP server.

The reason is that the client cannot be changed to use the LDAP interface, so I am looking to include a component that can reside between the MySQL client and the LDAP server.

I have tried looking at the MySQL server plug-ins but I could not get something that matches my requirement. Do you have any recommendations?

Edit: The SQL query in this case is a "SELECT" statement. So in this case the LDAP results received(usually one row and just one column), needs to be sent back as an SQL response.

Answer 1

Very tricky requirement, I doubt a ready-to-use solution is available.

Here is something you can try:

1. Use a normal MySQL database with tables defined for your needs mimicking LDAP nouns and verbs.
2. Write MySQL triggers for each table.
3. In the MySQL triggers, call sys_exec() then do some housekeeping (for instance after an INSERT remove the inserted MySQL row).
4. In the external program you just called using sys_exec(), perform the actual LDAP calls via your favorite LDAP client library.

That's still very hacky.

Reference: https://dev.mysql.com/doc/refman/8.0/en/faqs-triggers.html#faq-mysql-can-triggers-udf

Edit: To use that technique with SELECT, use a BEFORE trigger.