At work, AMQP looks to be the message queueing protocol that will be targeted in the future. One team there implemented some simple clients in C, that would send messages, and also listen for messages and launch a program on receipt, passing in the routing key and pointing to a temporary file containing the message. I didn't get to see their code, but was given RPMs with unnecessary dependencies that I couldn't be bothered to get running on my Ubuntu box, but I thought that low resource shell-scriptable AMQP send and receive programs would be a good idea for the world at large, so over the course of a couple of weekends I extended RabbitMQ-C's examples to have the same functionality. I compile librabbitmq statically into the binary, and the resident memory footprint when running is 500kb.
Let me present rmt's AMQP Tools: http://github.com/rmt/amqptools
For security, you could cryptographically sign the messages, or just rely on AMQP's security. libRabbitMQ-C only supports the plaintext SASL authentication method at the moment, and SSL isn't supported (try stunnel).
— by Robert Thomson, created 24th Oct, 2010, last modified 24th Oct, 2010 | Tags: Tech
It's a rather disorganised trip, and I know I've lost touch with many old friends, so send me an email (rob _at_ corporatism.org) or SMS me on +61434247158 and we'll see if we can meet up at some point. I'll be in Sydney for a little while at the start of the trip, and in Newcastle for a bit, but I'll probably travel up north for a couple of weeks. I'll be accompanied by Sophia.
— by Robert Thomson, created 14th Aug, 2010, last modified 20th Aug, 2010 | Tags: World
A command line interface to XBMC's Navi-X plugin's browser: http://github.com/rmt/navix_cli
XBMC not required.
It's still a little buggy (patches welcome), but I use it on a daily basis already.
— by Robert Thomson, created 24th Jun, 2010, last modified 24th Jun, 2010 | Tags: Tech
The Awesome window manager has me slightly impressed.. who knows whether I will continue to be impressed in a few days, but for now, I am. I found myself somewhat frustrated with the standard GNOME desktop when using multiple monitors in a Xinerama layout (the default if you just plug a screen in). Awesome is a tiling window manager.. in the past, I haven't been inclined to use one, because I work mostly on a single screen, or I have enough screen space for all my current work to be focused. My current work environment, however, involves a bit of task switching, and having a big monitor on my desk as well as the small laptop screen means I want better control of my windows.
The key feature for me is the ability to have independent virtual screens on each monitor, despite it being Xinerama. Most of the time I want the Windows VM showing on the laptop screen, but not always. In my current work environment, having tiling windows is actually proving quite nice, and it's helping me to be a little more organised. I split my tasks between virtual screens, and keep an eye on the Windows VM & outlook on the laptop, so context switching is easy.
Of course, some windows should be floating, and Awesome supports that just fine, as well as allowing each virtual screen to have its own layout style, and easily switch between them.
— by Robert Thomson, created 20th Apr, 2010, last modified 20th Apr, 2010 | 1 comment | Tags: Tech
A little while back I bought an ASRock 330HT as a media PC. Aside from the fan being a little noisier than I hoped, the remote control had no Linux driver so I bought a Hama MCE remote control after reading that it works well under Linux. Unfortunately, while it works fine under Linux, it's got hardcoded key values and not every key is unique. As an example the "i" info button is actually a prolonged right click, a couple of the keys send *exactly* the same keycodes as others (Play and Pause), and there are a bunch of buttons which generate Control-Shift-foo and Alt-bar and so on. I guess under Windows Media Center these all serve a specific purpose. Under Linux and its media center programs (such as XBMC) they don't (and XBMC's input layer is a bit restrictive).
I had my toys, but things weren't working exactly as I wanted. What's a guy to do? I got hacking, of course.
The Linux Input Subsystem is pretty clean nowadays and detecting the correct device and reading a few bytes from /dev/input/eventXX isn't all that hard. Within a couple of hours I was reading the bytes from the remote and pretty printing them as I received them. Unfortunately, this lead to the realisation (as shown above) that the remote's a little screwy and that a few hacks would be necessary to make things work as I wanted. But I was having fun and I was learning something.
The next step was deciding how to use these key events. XBMC has an interface to LIRC and another chap had written a python script making the HAMA MCE remote produce LIRC events. I tried it, fixed some bugs, and it worked.. but it was unsatisfying.. the MCE remote also has a mouse cursor (there are two input devices generated - a mouse and a keyboard - but the mouse device also sends a few key events that I care about as well as the all-important info button).. I started to explore the uinput device which lets you create a fake input device and write to it. Figuring out how to initialise it was a little tricky but I found some similar code and worked it out.. after that it's just writing input events to the device.
My initial idea of just reading all input, munging a few things, and passing the remaining events directly through proved somewhat problematic. If you leave a stranded Control or Alt key pressed down then you have a serious problem and in my tests I had to kill my X session a few times. A better way is to read all the input and have a virtual keyboard that handles the MOD keys, does the processing of normal keystrokes, does the translations, and then converts the translated events back into input events for uinput, ensuring there're no dangling modkeys.
The final step was to create a versatile translated step. I decided that I wanted a configuration file, instead of coding the translations all in python.
Here's some snippets from my config file:
# simple 1-1 translation
KEY_HOMEPAGE-down = send KEY_ESC-down
KEY_HOMEPAGE-up = send KEY_ESC-up
# the info button/right click magic
BTN_RIGHT-down = set rightclick time.time()
BTN_RIGHT-up = if (time.time()-rightclick) > 0.3; send KEY_I; else; send BTN_RIGHT
# compound key sequence example
Alt-KEY_F4-down = wait
Alt-KEY_F4-down KEY_F4-up = send KEY_ESC; clear
The wait action means to add the current key event to the match criteria for the next keystroke. clear then clear's the list.
Code will be online soon at http://github.com/rmt/pyinputevent/
— by Robert Thomson, created 3rd Feb, 2010, last modified 4th Feb, 2010 | 1 comment | Tags: Tech
