On December 28, 2006 9:34:36 AM +0100 Pierangelo Masarati ando@sys-net.it wrote:
fcusack@fcusack.com wrote:
I did find LDAP_OPT_NETWORK_TIMEOUT, which I didn't try, but which is close to the desired functionality. AFAICT it implements a *separate* timeout for the connect() (and maybe unbind/close()?) part of an ldap connection. Why someone would want to distinguish between connect() and bind I don't know, especially when they don't get feedback about how long connect() took.
It should be easy (?) to add something like LDAP_OPT_CONNECT_BIND_TIMEOUT which would be the total time for connect() and bind, given that non-blocking connect() is already implemented. That would probably solve a lot of folk's need for a working async bind.
I think you're missing a point: there's no bind timeout because there's no need for it. The delay (or the hang) you likely see when dong ldap_sasl_bind() is actually spent doing a connect() to establish a connection.
Oh, in that case I am definitely missing a lot. Since my understanding of the timeout value passed to ldap_sasl_bind() is that it is a *bind* timeout, which I assumed would be because some artibrary SASL mechanism might take some arbitrarily long amount of time. If there is no bind timeout, then why is LDAP_OPT_NETWORK_TIMEOUT implemented? The timeout passed to ldap_sasl_bind() should just be the connect() timeout then.
ldap_initialize() doesn't actually establish any connection, it just sets up the handler, and the connection is established by the first operation that requires it. the asynchronous bind, muck like any other asynchronous operation, simply returns after sending the packet(s) containing the request.
That much I do understand. (Although I thought the async bind() functions weren't actually implemented async.)
But, of course, the first of them requires the connection to be established, and that's where LDAP_OPT_NETWORK_TIMEOUT comes into play. Doing a really asynchronous connect() implies returning some sort of LDAP_X_INPROGRESS, keeping track of the status of the connection and polling it for response for each subsequent call until the connection is established before actually sending any request. In this sense the change should be intrusive: in this design, client code should be able to handle the LDAP_X_INPROGRESS return code and resubmit the request until the connection is ready. A "smarter" design would cache the request, poll for connect() response during calls to ldap_result(), and submit the actual request when the connection is established.
Sure, I understand that also (now).
What I'm saying is that most folks probably don't really need an async connect(), they just need a non-blocking one that returns in some known amount of time. LDAP_OPT_NETWORK_TIMEOUT doesn't do that, since it only controls the connect() part, and not the subsequent bind (important since you can only get to connect() via the ldap_bind() or other calls, ie there is no ldap_connect() and ldap_open() is deprecated). But a new LDAP_OPT_CONNECT_BIND_TIMEOUT option could do it.
-frank