21. September 2015

Feature Flags

(Image: bytearrays.com)
In one of my projects I just stumbled across the topic "Feature Flags".

Feature flags (aka Feature Toggle, aka Feature Switch) let you enable program/web site features selectively. This is especially important in continuous delivery environments where code is always committed and deployed even if a feature is not ready for prime time. It can be useful if you have a large user base and want to introduce the feature incrementally by enabling the feature for sub-sets of users. Feature flags are useful in anything beyond toy apps.

Feature flags are not new. They are widely known since Martin Fowler blogged about the pattern. He did not invent them. Many good developers have been using feature flags or alike for a long time. But Martin Fowler recognized feature flags as a remarkable pattern. Writing about feature flags was a good idea, because other developers who are not aware of the pattern can learn from it. That was 2010.

Guess what, in 2006 a lonely Weblin programmer added feature flags to the Weblin portal. Weblin has been using feature flags from the start.


15. September 2015

ZEIT online Relaunch - Undo

ZEIT online hat gerelauncht. Jetzt irgendwie dunkel und schmaler als vorher. Gefällt nicht. Kann man aber fixen. 

Links: ZEIT nach Relaunch, 
Rechts: gefixt: wieder weiß, ohne Rand 


Mit Tampermonkey, eine Chrome Erweiterung. Tampermonkey führt auf jeder Webseite Javascript aus.

Bei ZEIT online muss man nur ein paar CSS Anweisungen verändern: den Hintergrund vom <body>-Tag wieder in weiß und der Rahmen vom Content-<div> weg:

body { background-color: #ffffff !important; } 
.page__content { box-shadow: none; }

Man braucht noch etwas Javascript, um das CSS einzufügen. Hier das ganze Tampermonkey-Script für ZEIT online:

// ==UserScript==
// @name        ZEIT
// @namespace   http://wolfspelz.de/
// @version     0.1
// @description Restore white background
// @match       http://www.zeit.de/*
// @copyright   2015+, wolfspelz
// ==/UserScript==

function addGlobalStyle(css) {
    var head, style;
    head = document.getElementsByTagName('head')[0];
    if (!head) { return; }
    style = document.createElement('style');
    style.type = 'text/css';
    style.innerHTML = css;

addGlobalStyle('body { background-color: #ffffff !important; } .page__content { box-shadow: none; }');


Für Firefox: Greasemonkey