miércoles, 28 de mayo de 2014

How to identify in IRC

Sometimes I need to identify myself on irc chats, mostly freenode.org for programming questions and I often not remember how to. Well this is it:
/nick cancerbero_sgx
/msg NickServ identify my_secret

sábado, 24 de mayo de 2014

Calculate average in javascript

Currently I'm doing a lot of performance improvements in one of our pages in often I need to calculate the average of the numbers in an array. For this I simply write something like the following in a javascript terminal:
(function(a){var c = 0; for(var i in a){c+=a[i]}; return c/a.length})([11.368,  10.065, 4.403])

viernes, 23 de mayo de 2014

How to measure web page load visually using window.performance API

Navigation Timing API, http://www.w3.org/TR/navigation-timing/ provides detailed  measurements about of current web page performance in terms of load time. It support server, requests and browser loading and rendering information. This standar is supported at least by chrome, firefox and IE>=9

The project https://github.com/kaaes/timing provides a visual report for seeing this information. For make it work, in your web page just add the following lines:

var profiler_js = 'https://raw.githubusercontent.com/kaaes/timing/gh-pages/profiler.js'; 
var d = document;
var h = d.getElementsByTagName('head')[0];
var s = d.createElement('script');
var t = new Date();  
s.type='text/javascript';
s.src=profiler_js+'?'+t.getTime();  
s.onload = c;
s.onreadystatechange = function(){
 if(this.readyState == 'loaded'){
  c();
 }
};  
h.appendChild(s);
function c() {
 window.__profiler = window.__profiler || function() {
  var p = new __Profiler();
  p.init();
 }  
 window.__profiler();
 __profiler.scriptLoaded = true;
}

IMHO this is the best way of measure some browser internal stuff like DNS fetching, rendering, html markup parsing, etc.

Also another way of running this profile tools but less intrusive, this is not downloading any extra file is the following:
Include the minified inline version of profile.js:
function __Profiler(){this.totalTime=0;this.barHeight=18;this.timeLabelWidth=50;this.nameLabelWidth=160;this.textSpace=this.timeLabelWidth+this.nameLabelWidth;this.spacing=1.2;this.unit=1;this.fontStyle="11.5px Arial";this.containerPadding=20;this.container=null;this.customElement=false;this.timingData=[];this.sections=[]}__Profiler.prototype.eventsOrder=["navigationStart","redirectStart","redirectStart","redirectEnd","fetchStart","domainLookupStart","domainLookupEnd","connectStart","secureConnectionStart","connectEnd","requestStart","responseStart","responseEnd","unloadEventStart","unloadEventEnd","domLoading","domInteractive","msFirstPaint","domContentLoadedEventStart","domContentLoadedEventEnd","domContentLoaded","domComplete","loadEventStart","loadEventEnd"];__Profiler.prototype.cssReset="font-size:12px;line-height:1em;z-index:99999;text-align:left;font-family:Calibri,'Lucida Grande',Arial,sans-serif;text-shadow:none;box-shadow:none;display:inline-block;color:#444;font-weight:normal;border:none;margin:0;padding:0;background:none;";__Profiler.prototype.elementCss="position:fixed;margin:0 auto;top:0;left:0;right:0;border-bottom:solid 1px #EFCEA1;box-shadow:0 2px 5px rgba(0,0,0,.1);";__Profiler.prototype.containerCss="background:#FFFDF2;background:rgba(255,253,242,.99);padding:20px;display:block;";__Profiler.prototype.headerCss="font-size:16px;font-weight:normal;margin:0 0 1em 0;width:auto";__Profiler.prototype.buttonCss="float:right;background:none;border-radius:5px;padding:3px 10px;font-size:12px;line-height:130%;width:auto;margin:-7px -10px 0 0;cursor:pointer";__Profiler.prototype.infoLinkCss="color:#1D85B8;margin:1em 0 0 0;";__Profiler.prototype._getPerfObjKeys=function(obj){var keys=Object.keys(obj);return keys.length?keys:Object.keys(Object.getPrototypeOf(obj))};__Profiler.prototype._setUnit=function(canvas){this.unit=(canvas.width-this.textSpace)/this.totalTime};__Profiler.prototype._getSections=function(){return Array.prototype.indexOf?[{name:"network",color:[224,84,63],firstEventIndex:this.eventsOrder.indexOf("navigationStart"),lastEventIndex:this.eventsOrder.indexOf("connectEnd"),startTime:0,endTime:0},{name:"server",color:[255,188,0],firstEventIndex:this.eventsOrder.indexOf("requestStart"),lastEventIndex:this.eventsOrder.indexOf("responseEnd"),startTime:0,endTime:0},{name:"browser",color:[16,173,171],firstEventIndex:this.eventsOrder.indexOf("unloadEventStart"),lastEventIndex:this.eventsOrder.indexOf("loadEventEnd"),startTime:0,endTime:0}]:[]};__Profiler.prototype._createContainer=function(){var container=document.createElement("div");var header=this._createHeader();var button=this._createCloseButton();button.onclick=function(e){button.onclick=null;container.parentNode.removeChild(container)};container.style.cssText=this.cssReset+this.containerCss;if(!this.customElement){container.style.cssText+=this.elementCss}header.appendChild(button);container.appendChild(header);return container};__Profiler.prototype._createHeader=function(){var c=document.createElement("div");var h=document.createElement("h1");var sectionStr="/ ";for(var i=0,l=this.sections.length;i<l;i++){sectionStr+='<span style="color:rgb('+this.sections[i].color.join(",")+')">'+this.sections[i].name+"</span> / "}h.innerHTML="Page Load Time Breakdown "+sectionStr;h.style.cssText=this.cssReset+this.headerCss;c.appendChild(h);return c};__Profiler.prototype._createCloseButton=function(){var b=document.createElement("button");b.innerHTML="close this box ×";b.style.cssText=this.cssReset+this.buttonCss;return b};__Profiler.prototype._createInfoLink=function(){var a=document.createElement("a");a.href="http://kaaes.github.com/timing/info.html";a.target="_blank";a.innerHTML="What does that mean?";a.style.cssText=this.cssReset+this.infoLinkCss;return a};__Profiler.prototype._createNotSupportedInfo=function(){var p=document.createElement("p");p.innerHTML="Navigation Timing API is not supported by your browser";return p};__Profiler.prototype._createChart=function(){var chartContainer=document.createElement("div");var canvas=document.createElement("canvas");canvas.width=this.container.clientWidth-this.containerPadding*2;var infoLink=this._createInfoLink();this._drawChart(canvas);chartContainer.appendChild(canvas);chartContainer.appendChild(infoLink);return chartContainer};__Profiler.prototype._prepareDraw=function(canvas,mode,eventData){var sectionData=this.sections[eventData.sectionIndex];var barOptions={color:sectionData.color,sectionTimeBounds:[sectionData.startTime,sectionData.endTime],eventTimeBounds:[eventData.time,eventData.timeEnd],label:eventData.label};return this._drawBar(mode,canvas,canvas.width,barOptions)};__Profiler.prototype._drawBar=function(mode,canvas,barWidth,options){var start;var stop;var width;var timeLabel;var metrics;var color=options.color;var sectionStart=options.sectionTimeBounds[0];var sectionStop=options.sectionTimeBounds[1];var nameLabel=options.label;var context=canvas.getContext("2d");if(mode==="block"){start=options.eventTimeBounds[0];stop=options.eventTimeBounds[1];timeLabel=start+"-"+stop}else{start=options.eventTimeBounds[0];timeLabel=start}timeLabel+="ms";metrics=context.measureText(timeLabel);if(metrics.width>this.timeLabelWidth){this.timeLabelWidth=metrics.width+10;this.textSpace=this.timeLabelWidth+this.nameLabelWidth;this._setUnit(canvas)}return function(context){if(mode==="block"){width=Math.round((stop-start)*this.unit);width=width===0?1:width}else{width=1}context.strokeStyle="rgba("+color[0]+","+color[1]+","+color[2]+",.3)";context.lineWidth=1;context.fillStyle="rgba(255,255,255,0)";context.fillRect(0,0,barWidth-this.textSpace,this.barHeight);context.fillStyle="rgba("+color[0]+","+color[1]+","+color[2]+",.05)";context.fillRect(0,0,barWidth-this.textSpace,this.barHeight);context.shadowColor="white";context.fillStyle="rgba("+color[0]+","+color[1]+","+color[2]+",.2)";context.fillRect(Math.round(this.unit*sectionStart),2,Math.round(this.unit*(sectionStop-sectionStart)),this.barHeight-4);context.fillStyle="rgb("+color[0]+","+color[1]+","+color[2]+")";context.fillRect(Math.round(this.unit*start),2,width,this.barHeight-4);context.fillText(timeLabel,barWidth-this.textSpace+10,2*this.barHeight/3);context.fillText(nameLabel,barWidth-this.textSpace+this.timeLabelWidth+15,2*this.barHeight/3)}};__Profiler.prototype._drawChart=function(canvas){var time;var eventName;var options;var skipEvents=[];var drawFns=[];var context=canvas.getContext("2d");context.font=this.fontStyle;this._setUnit(canvas);for(var i=0,l=this.eventsOrder.length;i<l;i++){var evt=this.eventsOrder[i];if(!this.timingData.hasOwnProperty(evt)){continue}var item=this.timingData[evt];var startIndex=evt.indexOf("Start");var isBlockStart=startIndex>-1;var hasBlockEnd=false;if(isBlockStart){eventName=evt.substr(0,startIndex);hasBlockEnd=this.eventsOrder.indexOf(eventName+"End")>-1}if(isBlockStart&&hasBlockEnd){item.label=eventName;item.timeEnd=this.timingData[eventName+"End"].time;drawFns.push(this._prepareDraw(canvas,"block",item));skipEvents.push(eventName+"End")}else{if(skipEvents.indexOf(evt)<0){item.label=evt;drawFns.push(this._prepareDraw(canvas,"point",item))}}}canvas.height=this.spacing*this.barHeight*drawFns.length;context.font=this.fontStyle;var step=Math.round(this.barHeight*this.spacing);drawFns.forEach(function(draw){draw.call(this,context);context.translate(0,step)},this)};__Profiler.prototype._matchEventsWithSections=function(){var data=this.timingData;var sections=this.sections;for(var i=0,len=sections.length;i<len;i++){var firstEventIndex=sections[i].firstEventIndex;var lastEventIndex=sections[i].lastEventIndex;var sectionOrder=this.eventsOrder.slice(firstEventIndex,lastEventIndex+1);var sectionEvents=sectionOrder.filter(function(el){return data.hasOwnProperty(el)});sectionEvents.sort(function(a,b){return data[a].time-data[b].time});firstEventIndex=sectionEvents[0];lastEventIndex=sectionEvents[sectionEvents.length-1];sections[i].startTime=data[firstEventIndex].time;sections[i].endTime=data[lastEventIndex].time;for(var j=0,flen=sectionEvents.length;j<flen;j++){var item=sectionEvents[j];if(data[item]){data[item].sectionIndex=i}}}};__Profiler.prototype._getData=function(){if(!window.performance){return}var data=window.performance;var timingData=data.timing;var eventNames=this._getPerfObjKeys(timingData);var events={};var startTime=timingData.navigationStart||0;var eventTime=0;var totalTime=0;for(var i=0,l=eventNames.length;i<l;i++){var evt=timingData[eventNames[i]];if(evt&&evt>0){eventTime=evt-startTime;events[eventNames[i]]={time:eventTime};if(eventTime>totalTime){totalTime=eventTime}}}this.totalTime=totalTime;return events};__Profiler.prototype._init=function(){this.timingData=this._getData();this.sections=this._getSections();this.container=this._createContainer();if(this.customElement){this.customElement.appendChild(this.container)}else{document.body.appendChild(this.container)}var content;if(this.timingData&&this.sections.length){this._matchEventsWithSections();content=this._createChart()}else{content=this._createNotSupportedInfo()}this.container.appendChild(content)};__Profiler.prototype.init=function(element,timeout){if(element instanceof HTMLElement){this.customElement=element}if(timeout&&parseInt(timeout,10)>0){var self=this;setTimeout(function(){self._init()},timeout)}else{this._init()}};


And now just run it:
 window.__profiler = window.__profiler || function() {
  var p = new __Profiler();
  p.init();
 }  
 window.__profiler();


Enjoy!