Mike Meyer <mwm-keyword-googlegroups.620...@mired.org> writes:
> My simple web app
> (http://blog.mired.org/2010/11/x10-controller-in-clojure.html) has
> some stuff that needs to happen just once (in this case, opening the
> serial port). It's not clear how to get this to happen using ring. If
> I do it inside my ring handler, then it gets run on every request, and
> I have to check to make sure it's not run multiple times.
I would just open it lazily on the first request. That gives you a nice
place to gracefully retry on error as well, instead of being dead until
the entire servlet container is restarted. As a sysadmin I really hate
apps that can get stuck in a error state and need restarting. ;-)
For example you could be using a USB to Serial adapter, which somebody
might have temporarily removed and plugged in later. Similarly if
you're opening a database connection on startup and there's a network
dropout, or perhaps your app got started before the database server
did...
> If I run it outside the handler, then it gets run when I do "lein
> uberwar", which is simply wrong.
If you really want to do it at load time you can avoid executing
something at compile time by wrapping it in this:
(when-not *compile-files*
...)
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
