Added config option to build the ldap auth string

Made the auth string for LDAP auth the result of a builder (proc) when not connecting with an admin account

visibility fix

lib/devise_ldap_authenticatable.rb

@@ -31,6 +31,9 @@ module Devise
 
   mattr_accessor :ldap_use_admin_to_bind
   @@ldap_use_admin_to_bind = false
+
+  mattr_accessor :ldap_auth_username_builder
+  @@ldap_auth_username_builder = Proc.new() {|attribute, login, ldap| "#{attribute}=#{login},#{ldap.base}" }
 end
 
 # Add ldap_authenticatable strategy to defaults.

lib/devise_ldap_authenticatable/ldap_adapter.rb

@@ -5,8 +5,11 @@ module Devise
   module LdapAdapter
 
     def self.valid_credentials?(login, password_plaintext)
-      options = {:login => login, :password => password_plaintext}
-      options.merge!({ :admin => true }) if ::Devise.ldap_use_admin_to_bind
+      options = {:login => login, 
+                 :password => password_plaintext, 
+                 :ldap_auth_username_builder => ::Devise.ldap_auth_username_builder,
+                 :admin => ::Devise.ldap_use_admin_to_bind}
+
       resource = LdapConnect.new(options)
       resource.authorized?
     end
@@ -35,6 +38,7 @@ def initialize(params = {})
         @ldap.port = ldap_config["port"]
         @ldap.base = ldap_config["base"]
         @attribute = ldap_config["attribute"]
+        @ldap_auth_username_builder = params[:ldap_auth_username_builder]
 
         @group_base = ldap_config["group_base"]
         @required_groups = ldap_config["required_groups"]        
@@ -53,7 +57,7 @@ def dn
         ldap_entry = nil
         @ldap.search(:filter => filter) {|entry| ldap_entry = entry}
         if ldap_entry.nil?
-          "#{@attribute}=#{@login},#{@ldap.base}"
+          @ldap_auth_username_builder.call(@attribute,@login,@ldap)
         else
           ldap_entry.dn
         end