My Sep 29 2011 talk at RejectJS.

1. Building an alarm clock
with node.js
or
Hacking vs. Engineering
Felix Geisendörfer 29.09.2011 (v1)
Donnerstag, 29. September 2011

2. Text
Welcome to the Siesta
right-after-lunch Session!
Donnerstag, 29. September 2011

3. Building an alarm clock
with node.js
or
Hacking vs. Engineering
Felix Geisendörfer 29.09.2011 (v1)
Donnerstag, 29. September 2011

4. @felixge
Twitter / GitHub / IRC
Donnerstag, 29. September 2011

5. My Problem
• Getting up early in the morning
• That means before 12:00 (noon)
Donnerstag, 29. September 2011

6. This talk
• How I solved this problem
• Hacking vs. Engineering the solution
Donnerstag, 29. September 2011

7. Patient History
• 23 years
• Working from home
• Can work any hours
Donnerstag, 29. September 2011

8. So why get up early?
• To get more stuff done ...
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9. Previous attempts
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10. Text
Behavioral Conditioning
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11. Text
Flying alarm clock
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12. Text
Circadian rhythm app (Sleep Cycle)
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13. Text
Many alarms
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14. Nothing was working
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15. Text
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16. Donnerstag, 29. September 2011

17. Donnerstag, 29. September 2011

18. Donnerstag, 29. September 2011

19. Donnerstag, 29. September 2011

20. VLC
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21. pmset
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22. The Script
https://gist.github.com/1a40a207cf6132f77efa
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23. sudo ./alarm.js 7 30
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24. Donnerstag, 29. September 2011

25. Result
• Reliably waking up at any time
• Get to choose different music every night
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26. Hacking vs. Engineering
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27. (Software) Engineering
“Rigorous application of science”
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28. Hacking
“Playful cleverness”
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29. Hacking vs. Engineering
this project
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30. Tests?
Engineering: Yes
Hacking: Maybe
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31. Airtunes?
Engineering:
Implement protocol
Hacking:
Piggyback on iTunes or VLC
Donnerstag, 29. September 2011

32. Code
var file = '/my/music/file.mp3';
var vlcPath = '/Applications/VLC.app/Contents/MacOS/VLC';
var vlc = spawn(vlcPath, [
'-R',
'--sout=#transcode {acodec = alac channels = 2, samplerate =
44100}: raop{host=10.0.1.13,volume=255}',
file
]);
vlc.stdout.setEncoding('utf8');
vlc.stderr.setEncoding('utf8');
vlc.stdout.on('data', process.stdout.write);
vlc.stderr.on('data', process.stderr.write);
vlc.on('exit', function(code, signal) {
console.log('vlc exit: %i %s', code, signal);
});
Donnerstag, 29. September 2011

33. Wakeup from Sleep?
Engineering:
pmset schedule wakeorpoweron <datetime>
Hacking:
pmset schedule wakeorpoweron MTWRFSU
<time>
Donnerstag, 29. September 2011

34. Code
var powerCmd = sprintf(
'pmset repeat wakeorpoweron MTWRFSU %02d:%02d:00',
powerHour,
powerMinute
);
exec(powerCmd, function(err) {
if (err) throw err;
process.setuid('felix');
});
Donnerstag, 29. September 2011

35. Turn off speakers?
Engineering:
Install speakers in unreachable place.
Hacking: ?
Donnerstag, 29. September 2011

36. Text
Duct Tape
Donnerstag, 29. September 2011

37. Duct Tape of Concurrent I/O
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38. Engineering Solution for Concurrency
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39. Why am I talking about this?
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40. JS has a very hacker-driven
culture
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41. Text
Duct tape of the web
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42. Text
Duct tape of the DOM
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43. • Hacking is lots of fun, go do it!
• Hacking can be a good solution!
• But be aware that many problems call for
an engineering approach.
Donnerstag, 29. September 2011

44. Where we need more
engineering:
• Libraries
• Domain logic
• Performance
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45. TL;DL
• Hack when in doubt
• Engineer when clear
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46. Hacking Engineering
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47. Questions?
@felixge
Donnerstag, 29. September 2011