From: Luke Daley <ld@...>
Date: 2006-11-01T11:21:06+09:00
Subject: Net::LDAP connection semantics problem and nested blocks.

Hi,

I am working with the Net::LDAP library to communicate with active  
directory. The connection semantics of that library are causing me  
problems which I am trying to solve. The library was designed to  
connect and then disconnect from the LDAP server before and after  
each operation. I am running into a problem where the server is  
refusing connections because of too many successive connections.

Some background....

I have a Net::LDAP subclass that among other things, supplies  
credential and connection information to the parent on construction  
based on a single key string that is given.

class MyLDAP < Net::LDAP

   @cache = {}

   def self.get(key)
     if @cache.has_key? key
       @cache[key]
     else
       @cache[key] = CortecsLDAP.new(key)
     end
   end

   def initialize(key)
     super self.connect_details_for_key(key)
   end

   def self.connect_details_for_key(key)
     # Connect to DB and get details here relating to key
   end

The caching business is because this it is common for 1000+ ldap  
operations to happen in one execution so I thought I was being more  
efficient in holding the connections open like that.

The semantics of Net::LDAP however open and close underling tcp  
connection before and after each operation. Basically making my  
caching obsolete. However, Net::LDAP provides the method open() at  
the class and object level which takes a block and passes a Net::LDAP  
object to the block, keeping its connection open for the duration of  
the block. What I would like to do is be able to hold open all of the  
objects in the cache for the duration of a block. This is probably  
what I would want the interface to look like....

LDAPSession.open do | ldap_connection_cache |
   my_ldap_instance = ldap_connection_cache.get('some_key')
   my_other_ldap_instance = ldap_connection_cache.get('some_other_key')
end

The important thing here is that my_ldap_instance and  
my_other_ldap_instance remain open for the whole time they are in the  
block they are in. The only way to keep a Net::LDAP connection open  
is to use the open() method described above and pass it a block.

I hope that makes sense to someone who can help.

Cheers.

-----------------------------
Luke Daley
http://www.ldaley.com
-----------------------------