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Showing posts from November, 2009

Linux: Help, my Mouse is Possessed!

I have a MacBook running Ubuntu 9.04. Every once in a while, the mouse moves by itself. I always assumed it was my palm grazing the trackpad. If you have VertEdgeScroll turned on (which is the default), it's really easy for your right hand to touch the right side of the trackpad and cause your window to scroll. I figured OS X was just better at palm detection.

However, I recently bought a really nice external monitor, keyboard, and mouse. I was sitting reading some code. I was nowhere near my trackpad. In fact, I wasn't even typing or moving the mouse, although my hand was resting gently on my mouse. (If you're in the mood for a good conspiracy theory, keep in mind that it's a Microsoft mouse and an Apple keyboard.) All of a sudden, my mouse started moving. It's not a bluetooth mouse. None of my friends are around to be playing tricks on me (that I know of). It moved three inches right, and then down and to the left, and then all the way to the right. Wh…

Web: Redirecting the User Back After Some Workflow

Here's a common Web application workflow. A user gets to a page. He doesn't have access to the page because he isn't logged in. He gets redirected to the login page. He logs in. Perhaps he even has to create an account first. Afterwards, he gets redirected to the page he was trying to go to in the first place. Users find this sort of behavior helpful.

Here's another. The user is trying to buy something. He gets redirected to Google checkout (disclaimer: I've never used Google checkout). After he finishes checking out, he gets redirected back to the origin site. Perhaps he now has access to download the thing he just bought.

Thanks to the authlogic tutorial, I already had code to take care of the login workflow. However, I now find myself needing to do more workflows like it. The user tries to go to a page. However, he must do this other thing. Afterwards, he can go to the original page. What's the best way to handle the problem generically?

Here ar…

ActionScript: Dates

I had to parse an RFC 2822 date today in ActionScript. I couldn't find any equivalent of strptime in order to allow me to parse dates in a variety of formats. It turns out that ActionScript can do it automatically:new Date("Sat, 28 Nov 2009 10:15:02 +0000");The Date constructor will attempt to guess at the correct format, and it'll raise an exception if it can't.

The next problem I had was that I was using Date.getTime() to return the number of milliseconds since midnight January 1, 1970, universal time. Even though getUTCYear() said that my Date object was for 2009, I kept getting a value somewhere around January 12, 1970. The value returned by getTime() was just too small!

I finally figured out that getTime() returns a Number, not an int. If you store the value in an int, you'll be completely hosed, and there aren't even any warnings to help you out. It's obvious in retrospect--a 32-bit int can't possibly hold the number of milliseconds sinc…

ActionScript: Flowplayer vs. Open Source Media Framework

I've been playing around with Flowplayer, which is an "Open Source (GPL 3) video player for the Web". I decided to check out the Open Source Media Framework (formerly known as Strobe), which "enables developers to easily assemble pluggable components to create high-quality, full-featured playback experiences." In short, if you need a Flash video player today, stick with Flowplayer. The OSMF just isn't ready for prime time. It's a large framework written by a large company (Adobe). It's not a simple, hackable video player that you can throw on a production website in a couple of hours.

The website reeks of corporate speak. For instance, here is part of the page that talks about plugins:One the primary goals for OSMF is to provide a set of standard APIs for video ecosystem service integration so that player integration is no longer a barrier in the market. The framework will have a plugin API that allows for integration of client-side code for the…

Linux: Convert Mac to UNIX Line Endings

I'm working with a project that has a bunch of ActionScript (.as) files with old Mac line endings (i.e. CR instead of LF). For some reason, I see a bunch of references to mac2unix online, but I don't see anything readily available in Debian packages.

I want to convert to UNIX line endings, but without screwing up DOS files, etc. That is, I want it to be somewhat intelligent. This is what I came up with. It finds all the ActionScript files, determines if they're using just CRs, and then converts them to UNIX format:for i in $(find . -name '*.as' -exec file '{}' \; |
grep 'with CR line terminators' |
sed 's/:.*//g'); do
echo $i;
perl -pi -e 's/\r/\n/g;' "$i";
doneBy the way, yes, that'll fit on one line ;)

Linux: Making Your Desktop Calm

Have you ever noticed that the more you tweak your desktop theme, the more it drives you crazy? Maybe it's just me--I'm pretty compulsive obsessive. For most of my career, I've tried to create an interesting, exciting, cool-looking desktop. I know that a lot of you are probably saying, "Duh!" right about now, but I figured out I was actually more productive when I made my desktop more boring.

I've heard people say that if you paint a child's room bright yellow, it makes them more hyperactive. I've also heard people say that if you paint a prisoner's cell soft pink, he'll be more sedated. I'm not sure if those things are true, but they seem reasonable.

I've always sought after the perfect wallpaper. However, the cooler the wallpaper is, the more it drives me crazy. For some reason, I've always found the default wallpaper in OS X to be very calming (with the exception of OS 10.5).

Recently, while using Ubuntu, I switched to havin…

Linux: My xmonad Setup

Since I already blogged about why I think xmonad is interesting, I thought I would take the time to blog about my xmonad setup. I'd like to thank arjuna del toso for his instructions, because that's how I got started.

Start by installing all the software:apt-get install xmonad libghc6-xmonad-contrib-dev libghc6-xmonad-dev dwm-tools fehNow, edit /usr/share/xsessions/xmonad.desktop so that it executes "xmonad.start" instead of "xmonad".

Then create /usr/local/bin/xmonad.start:#!/bin/bash

xrdb -merge .Xresources

gnome-panel &
syndaemon -d -t

# feh --bg-scale /usr/share/backgrounds/warty-final-ubuntu.png &
# xsetroot -solid "#978989" # Lighter gray.
xsetroot -solid "#636161" # Darker gray.

# This must be started before seahorse-daemon.
eval $(gnome-keyring-daemon)

# This is all the stuff I foun…

What Makes a Good Operating System?

There are a lot of good operating systems these days. How do you pick one? If you're going to pick Linux, how do you pick which distribution to use? Here are the criteria that are important to me:It must support my hardware. It doesn't matter if it's the best operating system in the world, if I can't run it on my hardware, it does me no good. An operating system that doesn't support my wireless card just isn't a viable alternative.It must be painless to install the software I want and uninstall it when I don't want it anymore. I like keeping a clean, "repeatable" system, so building software by hand without being able to uninstall it is something I avoid whenever possible.It must be easy to update. I like to apply security patches as soon as they come out, and I like running modern versions of all my favorite software. Installing a new kernel in production under Ubuntu is trivial. Running "make world" in production isn't.It …

Linux: xmonad

xmonad is a tiling window manager. If you don't know what I'm talking about, take a peek at one of the screencasts. I've been using xmonad for the last couple weeks. It's been a couple years since I tried it last, and it's really improved:It's now a lot easier to install on Ubuntu.It's now a lot easier to integrate with panels such as gnome-panel or xmobar.It's now a lot easier to try out various layouts, and there are more layouts to choose from.Every time I try out a tiling window manager, I am reminded of the fact that I fundamentally disagree with the premise:They think that maximizing a window as much as possible whenever possible is useful. I think that's true with terminals and chat windows, but less so for many other windows. For instance, I always want GVim to be 80 columns wide.They think that minimizing windows to very small sizes is more acceptable than allowing windows to overlap. I disagree.They think that forcibly resizing windo…

Linux: Minimizing Memory Usage

It's still fashionable in certain Linux circles these days to pick a leaner distro in order to minimize resource utilization. Advocates of Arch Linux and Gentoo like to point out that Ubuntu is a bit heavy on RAM usage. As a Linux old timer, I'm sympathetic to the yearnings for a leaner, meaner past. Even Linus Torvalds admits that Linux is getting a bit bloated these days.

However, does switching to something like Arch Linux or Xubuntu really help? Consider the fact that I have a dual core MacBook with two gigs of RAM. It'd be one thing if I had an ancient machine, but I actually have relatively beefy hardware. Also, consider what top says when I sort by RAM usage:top - 03:32:53 up 10 days, 4:03, 3 users, load average: 0.37, 0.37, 0.41
Tasks: 154 total, 2 running, 149 sleeping, 0 stopped, 3 zombie
Cpu(s): 12.9%us, 5.4%sy, 0.0%ni, 81.5%id, 0.0%wa, 0.2%hi, 0.0%si, 0.0%st
Mem: 2026720k total, 1834468k used, 192252k free, 189524k buffers
Swap: 3559984k…

Python: Concurrency

With all the excitement surrounding Tornado Web Server, I'd like to mention that I wrote a great article last year on Python Concurrency, with an emphasis on the various approaches to writing Web servers.

By the way, has anyone played with gevent or Eventlet? Like the proprietary version of stackless Python we used at IronPort, they offer asynchronous networking without the need to use continuation passing style.

Happy Hacking!

My Friend Committed Suicide

He was a brilliant programmer, and he had everything going for him. He was very successful.

I'm crushed because I know I could have helped if only he had given me a chance. He never did.

We in the programming world aren't always the most emotionally balanced. I know of three others who took their lives in the programming world. I've hinted at this before on my Bipolar Lisp Programmer post. To compound matters, our society has been moving away from personal interaction and responsibility for decades, leading to a culture that is toxic.

Mother Theresa said that the greatest poverty that she ever saw was to see people who felt unloved. If your friends are feeling unloved, please reach out to them. We are each far more loved than we think. In the programming world, it's so easy to get caught up in petty struggles, like Pylons vs. Django, Ruby vs. Python, free software vs. open source, Linux vs. pretty much everything else ;) What we forget is that we're all peopl…