support a connection callback for proxies

lib/net/ldap.rb

@@ -441,6 +441,10 @@ def self.result2string(code) #:nodoc:
   # described below. The following arguments are supported:
   # * :host => the LDAP server's IP-address (default 127.0.0.1)
   # * :port => the LDAP server's TCP port (default 389)
+  # * :connect_cb => a Proc that will be called when a new connection is
+  #   needed. This should return an actual Ruby IO object. Useful for
+  #   manually handling connecting, like if you want to go through a proxy
+  #   server. It will receive :host: and :port: as arguments.
   # * :auth => a Hash containing authorization parameters. Currently
   #   supported values include: {:method => :anonymous} and {:method =>
   #   :simple, :username => your_user_name, :password => your_password }
@@ -469,6 +473,7 @@ def self.result2string(code) #:nodoc:
   def initialize(args = {})
     @host = args[:host] || DefaultHost
     @port = args[:port] || DefaultPort
+    @connect_cb = args[:connect_cb]
     @verbose = false # Make this configurable with a switch on the class.
     @auth = args[:auth] || DefaultAuth
     @base = args[:base] || DefaultTreebase
@@ -1215,7 +1220,9 @@ def use_connection(auth)
   end
 
   def new_connection
+    socket = @connect_cb.call(@host, @port) if @connect_cb
     Net::LDAP::Connection.new \
+      :socket                  => socket,
       :host                    => @host,
       :port                    => @port,
       :encryption              => @encryption,

test/test_ldap.rb

@@ -57,4 +57,22 @@ def test_instrument_search_with_size
     assert_equal "(uid=user1)", payload[:filter]
     assert_equal result.size, payload[:size]
   end
+
+  def test_connect_cb
+    flexmock(Net::LDAP::Connection).should_receive(:new).with(
+        :socket => 42,
+        :host => "test.mocked.com",
+        :port => 636,
+        :encryption => nil,
+        :instrumentation_service => @service).and_return(@connection)
+    flexmock(@connection).should_receive(:bind).and_return(flexmock(:bind_result, :result_code => Net::LDAP::ResultCodeSuccess))
+
+    @subject = Net::LDAP.new \
+      :connect_cb => lambda { |host, port| 42 },
+      :host => "test.mocked.com", :port => 636,
+      :force_no_page => true, # so server capabilities are not queried
+      :instrumentation_service => @service
+
+    @subject.open {}
+  end
 end