Premise

On the weekend i wanted to perform the task of drawing a yellow rectangle programmatically onto the screen of a Personal Computer:

• The program would feature a viewport that occupies the entirety of the primary display of the PC.
• On the viewport, 640 pixels could be adressed in width, 480 in height.
• The viewport would be drawn in black color by default.
• A yellow, filled rectangle would be drawn from an upper left corner at pixel coordinates 10 from the left, 20 from the top to a lower right corner at 100 from the left, 75 from the top.

• When having drawn the yellow rectangle, the program would indefinately await any keypress and then shut down.

I solved this task using several different programming languages and toolkits, having the following goals for the implementation:

• The program does a simple thing, so it should require little processing and memory resources.
• The program should still work in 24 months from now.

1. NodeJS und npm installieren.

Wie das geht, hängt vom Betriebssystem ab.

Auf jeden Fall sollte man ein möglichst aktuelles NodeJS verwenden. Ich habe das folgende Verfahren mit v7.8.0 durchgeführt.

2. grunt-cli installieren.

~$ npm install -g grunt-cli

3. Aktuellen (stabilen) Source von bootstrap holen.

~$ git clone https://github.com/twbs/bootstrap.git
~$ cd bootstrap
bootstrap$ git checkout v3.3.7

4. Abhängigkeiten installieren.

bootstrap$ npm install

5. Bootstrap übersetzen.

bootstrap$ grunt dist

6. Verzeichnis für eigene Anpassungen erstellen.

bootstrap$ mkdir ../boostrap-custom
bootstrap$ cd ../bootstrap-custom

7. Dateien für eigene CSS-Anpassungen erstellen:

bootstrap-custom$ touch custom-variables.less custom-other.less
bootstrap-custom$ echo '
@import "../bootstrap/less/bootstrap.less";
@import "custom-variables.less";
@import "custom-other.less";
@import "../bootstrap/less/utilities.less";
' > custom-bootstrap.css

8. LESS CSS-compiler installieren:

bootstrap-custom$ npm install -g less

und schließlich:

9. Angepasstes bootstrap-CSS erstellen:

bootstrap-custom$ lessc -x custom-bootstrap.css > custom-bootstrap.min.css

Damit steht ein angepasstes Bootstrap-CSS als custom-bootstrap.min.css zur Verfügung. Diese kann anstelle von bootstrap.min.css verwendet werden.

Quellen:

• https://www.smashingmagazine.com/2013/03/customizing-bootstrap/

As an exercise in password storage i implemented a PHP function that takes a UTF-8 encoded Unicode cleartext, generates a random salt and produces a password hash using the MD5 algorithm.

Please note that this is just an exercise and should not be used in production.

• This code has not been properly tested and has never been reviewed. I think it’s OK for educational purposes (otherwise i would not have published it), but it is very likely to have bugs.
• There are computational attacks on MD5 that break the algorithms fundamental promises, they can be performed without extraordinary effort. That makes MD5 unusable for security-related purposes in the general case.
• For PHP version 5.5 and later, you can use the password hashing API instead.

At any rate, it can be helpful to understand what the use case is and what “password hashing” actually can accomplish. Read on for further observations.

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