Essential IT Admin Skills for .NET Developers

EssentialITAdminSkills

My article on “Essential IT Admin skills for .NET Developers” is published on DNC .NET Magazine May 2013 issue.

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7 hard earned lessons from a Single Page Application

7HardEarnedLessons

My talk at London AJAX User group on some performance optimization techniques that can give a javascript rich Single Page Application big boost in terms of page load performance.

MyPicAJAXTalk

See the lecture here:

http://skillsmatter.com/podcast/ajax-ria/7-real-life-lessons-learnt-from-a-single-page-application/mh-6922

Here are the slides.

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10 IT Admin skills every .NET developer should have before going live

ITAdminSkillTalk

My talk at London .NET User Group on couple of essential skills every .NET developer should have under their belt before going live. If you are a startup or a developer who has to code, deploy and maintain .NET apps on production, you will find these techniques very handy.

Omar Skillsmater

http://skillsmatter.com/podcast/design-architecture/10-it-admin-skills-every-dot-net-developer-should-have-before-going-live/mh-6871

Watch the video at Skills Matters website.

Here are the slides from the talk.

SlidePreview

Using custom font without slowing down page load

CustomFont

Custom fonts are widely used nowadays to give your websites trendy look, but at the great expense of page loading speed. Each custom font has to be downloaded, initialized and applied throughout the page before browser can render anything. If you have a custom font in any CSS, anywhere on the page, most browsers (like IE) will not render anything (remain white) until the custom font is downloaded, initialized and applied. Usually custom fonts are over 300KB. As a result, they significantly slow down page load speed. See this timeline of a website that uses custom font:

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The gray bar is the .eot font. The green vertical bar is when browser renders the page. Until that green bar, user is staring at a white page with absolutely nothing for 5.5 seconds. The .eot is the very last thing browser downloads before it can render anything on the page. Usually 5.5 second page load time is unacceptable for most websites because on an average 40% users abandon your site if it does not load in 3 seconds!

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The above graph shows you that nearly 80% change in bounce rate for pages that have over 4 second page load time!

It is absolutely key that you maintain less than 4 sec home page load time. Browser cannot remain blank for more than 4 sec. Ideally the page should be fully loaded within 4 sec if you want to encourage users to come back to your site.

Let’s learn a trick that you can use to download custom fonts behind the scene, without preventing browser from rendering anything and then apply the font as soon as the font is downloaded. Once you apply this trick, browser will render the page before the custom font is downloaded:

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As you see here, browser has rendered the page on 4th second before it has downloaded the custom font file. The font takes a long time to downloading. During this whole time, browser is free, content is rendered, user can scroll around. Once the font is downloaded, it is applied. It freezes from 8.5 sec till 9.5 second while it initializes the font and applies on the page.

Step 1: Create a CSS that loads the custom font

First create a css that will load the custom font and apply to the html elements. First create a IE version of the CSS:

@font-face{
  font-family:'Nikosh';
  src: url('nikosh2.eot'); /* here you go, IE */
}

p, li, input, select, div, span, em, i, b, u, strong {
    font-family: 'Nikosh', Arial, Helvetica, sans-serif;
}

IE only supports Embedded True Type font (.eot). It does not support TTF, OTF, WOFF.

Other browsers do not support .eot. So, for them, you need to use some other open format. Say you are using OTF:

@font-face{
  font-family:'Nikosh';
  src: url('nikosh2.otf') format('opentype');
}

p, li, input, select, div, span, em, i, b, u, strong {
    font-family: 'Nikosh', Arial, Helvetica, sans-serif;
}

This one IE won’t understand. So, you need two different CSS files. I understand there’s this bullet-proof font face hack which is claimed to work in all browsers. But I have tried it and it does not work in Chrome. Chrome does not understand the url(://) hack.

Step 2: Javascript to pre-cache the font file and download the CSS after font is loaded

Next step is to pre-cache the font file behind the scene so that browser is not frozen while the large custom font file downloads. You can use jQuery to download the font file.

var fontFile = jQuery.browser.msie ? '/wp-content/uploads/font/nikosh2.eot' 
    : '/wp-content/uploads/font/nikosh2.otf';
var cssFile = jQuery.browser.msie ? '/wp-content/uploads/font/nikosh2ie.css' 
    : '/wp-content/uploads/font/nikosh2nonie.css';

jQuery(document).ready(function(){
	jQuery.ajax({
	  url: fontFile,
	  beforeSend: function ( xhr ) {
		xhr.overrideMimeType("application/octet-stream");
	  }
	}).done(function (data) {
		jQuery("	")
		  .appendTo(jQuery('head'))
		  .attr({type : 'text/css', rel : 'stylesheet'})
		  .attr('href', cssFile);
	});
});

First it pre-caches the right font file based on browser version. Make sure you define the correct font file name here as you have defined in the browser specific css file. Once the file is downloaded, jQuery done will fire and then it will inject a link that tag will fetch the css. The css will refer the exact same font file, from the exact same location. So, browser will not download it again as it has just downloaded the file and cached in local cache. Thus the css will be applied immediately.

Remember, as soon as the <link> tag is added, browser will freeze and become white until the font is initialized and applied. So, you will some freezing here. As it is freezing after the page has loaded completely, user is at least looking at the page and thinks that the page has finished loading. So, the user experience is better.

Step 3: Enable static content expiration

For this to work, you must have static content expiration in the webserver. If you don’t have it then browser will not cache the font file and it will download the file again as soon as you add the <link> tag. In order to enable static content expiration, follow these steps:

  • Click on the website in IIS.
  • Click on “HTT Response Headers” icon.
  • Click on “Set Common headers” from the right side menu.
  • Turn on “Expire Web Content” and set a far future date.

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This will turn on browser caching for all static files, not just font file.

Step 4: Set MIME type for fonts

IIS 7 or 8 does not come with MIME settings for .otf, .ttf etc font extensions. Only .eot is there. So, you need to set the MIME type for these extensions, otherwise it won’t deliver the font and browser will get a 404.3.

  • Click on the website on IIS.
  • Select “MIME Types” icons.
  • Click Add…
  • Add the .otf and .ttf extensions.
  • Set Content Type as: application/octet-stream

That should now enable custom fonts on your webserver.

Talk on replicating Windows 8 modern UI on web using HTML, JS and CSS

DroptilesTalk

Here’s my talk on my Open Source project Droptiles, which replicates the Windows 8 Start UI on the web using HTML 4, JS, CSS 2. I have given an walkthrough on how to use Twitter Bootstrap to create modern looking UI. Then how to use KnockoutJS to build a web applicatoin following the Model-View-ViewModel pattern. And some handy use of UnderscoreJS. After the introduction of these frameworks, you will see a quick demo to build a sample dynamic modern UI page that mimics the Windows 8 Start screen look and feel – implementing Bootstrap, KnockoutJS, jQuery together. Then I have shown how to build a new Tile in Droptiles.

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http://skillsmatter.com/podcast/home/droptiles-windows-8-modern-ui-on-the-web-using-plain-html-css-and-javascript

Droptiles: Metro style Live Tiles enabled Web 2.0 Dashboard

DroptilesDashboard

Droptiles is an Open Source  Windows 8 Start like Metro style Web 2.0 Dashboard. It builds the experience using Tiles. Tiles are mini apps that can fetch data from external sources. Clicking on a tile launches the full app. Apps can be from any existing website to customized website specifically built to fit the Dashboard experience. Droptiles is built almost entirely of HTML, Javascript and CSS and thus highly portable to any platform. The sample project is built using ASP.NET to show some server side integration, like Signup, Login and getting dynamic data from server. But with very little change you can port it to PHP, Ruby, JSP or any other platform. Droptiles is the sequel of my Dropthings, which is the first Open Source Web 2.0 Dashboard.

See it live!, go to Droptiles.com

Features

  • Metro style user interface. CSS framework to build metro style websites, inspired by metroui.org.ua.
  • Drag & Drop tiles to personalize the experience.
  • Client side object model and data binding for easy MVVM implementation.
  • Server side platform neutral implementation. Can be ported to PHP, JSP easily.
  • Live tiles. Tiles are mini-apps, loading data from variety of sources.

How can you use Droptiles

  • Enterprise Dashboard aggregating data from various systems and offering a launch pad for intranet/internet applications.
  • Web 2.0 Portal offering portlets in the form of tiles. Aggregating data from various services and as a launch pad for different services.
  • Touch enabled Kiosk front-end.
  • Content aggregator for News and Research purpose.

License

Droptiles is Open Source. It is free for personal use as long as you keep the copyright notices intact. In order to buy license, go to theDroptiles production site and there’s a tile on the right side to place the order through Paypal.

Technologies

Screenshots

App Store

App Store

AppStore offers new applications

Tiles are mini apps, built using Javascript

Tiles

Tiles are mini apps that can have their own html, javascript and css. They are loaded by the Dashboard dynamically and executed dynamically. Each tile runs on its own delivering the in-tile experience. There’s no special Widget framework to follow. Just plain simple Javascript.

Tiles can be dynamic, loaded from server side pages

Dynamic Tile

Tiles can be dynamic pages delivered from the server. Here is a tile that captures the html output of an ASPX page. Tiles can be intercative as well. You can embed a form inside a tile.

Apps running inside Droptiles

Apps

External applications can run inside Droptiles offering a seamless integration experience.

You can get the code from the GitHub site: http://oazabir.github.com/Droptiles/

Codeuml–design UML diagrams as fast as you can code

CodeumlPicture

Codeuml.com is a web based UML designer where you code the diagram using a special language and it generates the diagram on the fly. It is faster than using any visual designer where you have to drag & drop diagram elements and use mouse to connect them. Codeuml uses the open source plantuml engine to produce diagram from text. You can produce UML diagrams as fast as you can code.

This web application shows some interesting design and coding challenges. First, it shows you how to build a web based IDE like environment that mimics Windows 8 Metro UI. Second it shows how you can periodically collect data from the website, send to the server in the background asynchronously and get the result generated on the fly. Third and the most important, it shows how you can maintain a server side pool of very expensive resource that you cannot just create on every hit to the server and must have a finite pool that is shared by all your web users.

Read details about this from this CodeProject article:

Codeuml – design UML diagrams as fast as you can code

Caching WCF javascript proxy on browser

CacheWCFProxy

When you use WCF services from Javascript, you have to generate the Javascript proxies by hitting the Service.svc/js. If you have five WCF services, then it means five javascripts to download. As browsers download javascripts synchronously, one after another, it adds latency to page load and slows down page rendering performance. Moreover, the same WCF service proxy is downloaded from every page, because the generated javascript file is not cached on browser. Here is a solution that will ensure the generated Javascript proxies are cached on browser and when there is a hit on the service, it will respond with HTTP 304 if the Service.svc file has not changed.

Here’s a Fiddler trace of a page that uses two WCF services.

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You can see there are two /js hits and they are sequential. Every visit to the same page, even with the same browser session results in making those two hits to /js. Second time when the same page is browsed:

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You can see everything else is cached, except the WCF javascript proxies. They are never cached because the WCF javascript proxy generator does not produce the necessary caching headers to cache the files on browser.

Here’s an HttpModule for IIS and IIS Express which will intercept calls to WCF service proxy. It first checks if the service is changed since the cached version on the browser. If it has not changed then it will return HTTP 304 and not go through the service proxy generation process. Thus it saves some CPU on server. But if the request is for the first time and there’s no cached copy on browser, it will deliver the proxy and also emit the proper cache headers to cache the response on browser.

http://www.codeproject.com/Articles/360437/Caching-WCF-javascript-proxy-on-browser

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Memory Stream Multiplexer–write and read from many threads simultaneously

MultiplexerImage

Here’s an implementation of MemoryStream like buffer manager where one thread can write and many threads can read simultaneously. Each reading thread gets its own reader and can read from the shared stream on its own without blocking write operation or other parallel read operations. It supports blocking Read call so that reader threads can call Read(…) and wait until some data is available, exactly the same way you would expect a Stream to behave. You can use this to read content from network or file in one thread and then get it read by one or more threads simultaneously. Readers do not block writing. As a result, both read and write happens concurrently. Handy for building http proxy where you are downloading a certain file and you have multiple clients asking for the same file at the same time. You can download it in one thread and let one or more client threads read from the same buffer exactly at the same time. You can also use this to read same file on disk from multiple clients at the same time. You can also use this to implement a server side cache where the same buffer is read by multiple clients at the same time.

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See the detail implementation here:

Memory Stream Multiplexer–write and read from many threads simultaneously

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