Odd Apache pitfall: ErrorDocument and POST

August 12th, 2007

I am writing a web app that hides much of its inner workings, as any good web app should. (Why? future-proofing, security, simplicity of user experience, etc.) I chose to route all requests that involve server-side scripting through a single file, capture.php. But somewhere along the way, form POSTs stopped working! Why?

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Firefox/Mozilla-firefox package conflict in Ubuntu

September 24th, 2005

This post contained incorrect information and has been modified.

Ubuntu (Hoary Hedgehog) wanted to upgrade Firefox from version 1.0.6 to version 1.0.7, but the upgrade barfed with errors like this: dpkg: error processing /var/cache/apt/archives/mozilla-firefox_1.0.6-0ubuntu0.1_i386.deb (--unpack): trying to overwrite `/var/lib/mozilla-firefox/extensions.d/00classic', which is also in package firefox dpkg-deb: subprocess paste killed by signal (Broken pipe) After that, firefox would no longer start. Apparantly, I somehow had both the "firefox" package and the "mozilla-firefox" package installed. Additionally, they seemed to have cross-dependencies, and simply uninstalling firefox would also affect the packages "yelp", "ubuntu-desktop", and "language-support-en".
  1. Remove all firefox packages. In System:Administration:Synaptic Package Manager, do a search for "firefox" and mark all packages there for removal. Click the "Apply" button, and make note of any other packages that will also be removed. On my system, they were "yelp", "ubuntu-desktop", and "language-support-en".
  2. Reinstall Firefox. In the package manager, mark "firefox" for installation, along with "firefox-dom-inspector" (optional, but I recommend it) and "firefox-gnome-support". If you use a non-US locale, reinstall that as well (it will be something like mozilla-firefox-locale-xx). Apply changes. You should now have the latest version of Firefox, and it should be functional.
  3. Reinstall the affected dependent packages. Search for and install those dependent packages you wrote down two steps ago. Your system should now be essentially unchanged, other than the Firefox upgrade. In the future, only the "firefox" will need upgrading -- this is a one-time bug.
When the Firefox project split off of Mozilla, there was some trickiness in the package naming. The result is a legacy package (mozilla-firefox) that interferes with upgrades -- they share files. Once you kill both and reinstall one, there's no conflict. Incidentally, as long as your settings are stored in the default location, they should carry over to the new install. Make sure to use "Mark for removal", not "Mark for complete removal"; the latter destroys your settings.
Original solution in an Ubuntu support thread.

Totem on Ubuntu – not starting up

August 28th, 2005
Totem on Ubuntu won't start up properly. Error message:
Totem could not startup
Resource busy or not available.
  • Run gstreamer-properties
  • Go to tab "Video"
  • Under "Default Sink", select "SDL" or "XWindows (no xv)"
I actually don't know why this works.
Original solution: Español