Rails Page Caching + Mongrel

So you’ve got a great Rails app. You’re setting up page caching for those publicly accessible pages shared by everyone. One of your pages is the :index. It seems like the caching isn’t working when you’re testing it, but the output constantly says:

Cached page: /tag.html (0.00044)

What gives? Try seeing if “/tag” seems to use the cache, but “/tag/” doesn’t.

The mechanism behind the Rails page caching takes your action output and stuffs it all into an HTML file that can easily be found by the web server. Ah! So there’s no voodoo in Rails itself that tries to check for that page. In fact, it’s banking on not being called by pushing that burden off to the web server. In our case, this is Mongrel.

So how does Mongrel decide? Well, the mongrel_rails fires up a RailsHandler which uses the PATH_INFO to check for the existence of a cached file. When you’re requesting “/tag/” it’s looking for tag/.html, but not finding it.

I put together a patch here to address it. Seems to work in my limited testing, but I don’t know what I may have broken. Yeah, usually I make sure to write a test for my patches. This time I didn’t. Perhaps it won’t make it in until I do, but at least I’ve got it written down here to remind me when my cache doesn’t seem to work quite right.

Macports Erlang Install

So I ran into a funny error today while trying to install erlang on my Mac.

Zdot-MBP:~ tim$ sudo port install erlang
Error: Unable to execute port: invalid command name “configure.cppflags”

It turns out (after running port using the -d option), that macports was trying to upgrade my gettext version. The Portfile seemed to be trying to set the CPPFLAGS option for the configure tool. I opened up /opt/local/var/db/dports/sources/ rsync.rsync.darwinports.org_dpupdate_dports/devel/gettext/Portfile and replaced:

configure.cppflags \
    -no-cpp-precomp

with this:

configure.env   CPPFLAGS=-no-cpp-precomp

That seemed to have fixed things. I was able to continue my install and fire up erl. Since I couldn’t find the answer on the big Google-Net I cast, I figured I’d write it up here in case some poor soul had the same bad luck I did.

Now it’s time to try out some Amazon API stuff.

A Day Of Mourning And Resolve

CollegiateTimes Front Page 4/17/2007

My youngest cousin was in a building next to Norris Hall. She’s an engineering major at VT. Her mother works on campus. Her father has worked for the campus for years, and works for the campus from home. She wrote yesterday with a brief update that said, in part:

One guy I know was in a classroom in Norris (the building that the gunman barricaded) but they put a table up against the door and all pushed on the door when the gunman tried to enter. Two bullets came through the door at chest level but everyone was down low to the ground and later escaped safely.

As I read through the Wikipedia entry she sent, I was amazed at the story of Liviu Librescu. He was a survivor of the violence of the Holocaust.

He was killed in the Norris Hall Engineering Building. He was 77 years old.[5] Librescu held the door of his classroom shut while the gunman, Cho Seung-hui, was attempting to enter it, and was shot through the door, but was able to prevent the shooter from entering the classroom until his students had escaped through the windows[6][7], sacrificing his life to save several students from being harmed and is regarded as a hero during the aftermath of the Blacksburg massacre.

As a student of self-defense, I have great respect for those willing to put their lives at risk to help others. My uncle suggested that in addition to classes in self-defense, we should have classes on group defense. The heros of United 93 forever changed the way airplane passengers respond to threats. Tragedies like the Virginia Tech massacre and others may produce the same resolve for group defense in our collective culture when we’re faced with such situations.

Virginia Tech and Blacksburg, our hearts and prayers are with you.