YangJian A-limon

Falsehoods programmers believe about time

This is a compiled list of falsehoods programmers tend to believe about working with time.

Don't re-invent a date time library yourself. If you think you understand everything about time, you're probably doing it wrong.

Falsehoods

There are always 24 hours in a day.
February is always 28 days long.
Any 24-hour period will always begin and end in the same day (or week, or month).

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

朴素VPN：一个纯内核级静态隧道

由于路由管控系统的建立，实时动态黑洞路由已成为最有效的封锁手段，TCP连接重置和DNS污染成为次要手段，利用漏洞的穿墙方法已不再具有普遍意义。对此应对方法是多样化协议的VPN来抵抗识别。这里介绍一种太简单、有时很朴素的“穷人VPN”。

朴素VPN只需要一次内核配置（Linux内核），即可永久稳定运行，不需要任何用户态守护进程。所有流量转换和加密全部由内核完成，原生性能，开销几乎没有。静态配置，避免动态握手和参数协商产生指纹特征导致被识别。并且支持NAT，移动的内网用户可以使用此方法。支持广泛，基于L2TPv3标准，Linux内核3.2+都有支持，其他操作系统原则上也能支持。但有两个局限：需要root权限；一个隧道只支持一个用户。

朴素VPN利用UDP封装的静态L2TP隧道实现VPN，内核XFRM实现静态IPsec。实际上IP-in-IP隧道即可实现VPN，但是这种协议无法穿越NAT，因此必须利用UDP封装。内核3.18将支持Foo-over-UDP，在UDP里面直接封装IP，与静态的L2TP-over-UDP很类似。

创建一个朴素VPN

Jake Archibald (@jaffathecake): The ServiceWorker is coming; look busy
https://speakerdeck.com/jaffathecake/the-serviceworker-is-coming-look-busy https://github.com/jakearchibald/trained-to-thrill/
https://www.youtube.com/watch?v=SmZ9XcTpMS4

Hunter Loftis (@hunterloftis): We Will All Be Game Progmrammers
http://wwabgp.herokuapp.com/s
http://youtu.be/QX0eauXBKwc

CarterRabasa (@carterrabasa): A Community of People; Not Projects

Commit Message Conventions

These rules are adopted from the AngularJS commit conventions.

Goals
Generating CHANGELOG.md
- Recognizing unimportant commits
- Provide more information when browsing the history
Format of the commit message
Subject line

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

Prolog

Google Chrome Developers says:

The new WOFF 2.0 Web Font compression format offers a 30% average gain over WOFF 1.0 (up to 50%+ in some cases). WOFF 2.0 is available since Chrome 36 and Opera 23.

Some examples of file size differences: WOFF vs. WOFF2

TTF to WOFF2 converting

http://www.fontsquirrel.com/tools/webfont-generator

	var render = hexo.render;
	/**
	* alert tag
	*
	* Syntax:
	* {% alert caption [style] %}
	* Alert string
	* {% endalert %}
	*/

	//Chrome上能用的
	["Image", "Audio", "MediaController", "TrackEvent", "Option", "PopStateEvent", "HashChangeEvent", "PageTransitionEvent", "Event", "CustomEvent", "MutationObserver", "Document", "FormData", "XMLHttpRequest", "FormData", "IDBVersionChangeEvent", "StorageEvent", "RTCSessionDescription", "RTCIceCandidate", "MediaStreamEvent", "Notification", "Blob", "FileReader", "ErrorEvent", "Worker", "SharedWorker", "TransitionEvent"]

	//标准里有但是还不能用的
	["RelatedEvent", "DragEvent", "AnonXMLHttpRequest", "RTCPeerConnection", "RTCPeerConnectionIceEvent", "DataChannelEvent", "ClipboardEvent", "FileReaderSync", "BlobBuilder", "FileSaver", "ParGroup", "SeqGroup", "Animation", "PseudoElementReference", "KeyframeAnimationEffect", "PathAnimationEffect", "TimingEvent", "AnimationEvent"]