Friday, 13 December 2013

NuGet and WebMatrix: How to install a specific version of a package

I've recently been experimenting with WebMatrix. If you haven't heard of it, WebMatrix is Microsoft's "free, lightweight, cloud-connected web development tool". All marketing aside, it's pretty cool. You can whip up a site in next to no time, it has source control, publishing abilities, intellisense. Much good stuff. And one thing it has, that I genuinely hadn't expected is NuGet. Brilliant!

But like any free product there are disadvantages. As a long time Visual Studio user I've become very used to the power of the NuGet command line. I've been spoiled. You don't have this in WebMatrix. You have a nice UI that looks like this:

Looks great right? However, if you want to install a specific version of a NuGet package... well let's see what happens...

As you're probably aware jQuery currently exists in 2 branches; the 1.10.x branch which supports IE 6-8 and the 2.0.x branch which doesn't. However there is only 1 jQuery inside NuGet. Let's click on install and see if we can select a specific version:

Hmmm.... As you can see it's 2.0.3 or bust. We can't select a specific version; we're forced to go with the latest and greatest which is a problem if you need to support IE 6-8. So the obvious strategy if you're in this particular camp is to forego NuGet entirely. Go old school. And we could. But let's say we want to keep using NuGet, mindful that a little while down the road we'll be ready to do that upgrade. Can it be done? Let's find out.

NuGet, by hook or by crook

I've created a new site in WebMatrix using the Empty Site template. Looks like this:

Lovely.

Now to get me some jQuery 1.10.2 goodness. To the console Batman! We've already got the NuGet command line installed (if you haven't you could get it from here) and so we follow these steps:

  • At the C:\ prompt we enter nuget install jQuery -Version 1.10.2 and down comes jQuery 1.10.2.
  • We move C:\jQuery.1.10.2 to C:\Users\me\Documents\My Web Sites\Empty Site\App_Data\packages\jQuery.1.10.2.
  • Then we delete the C:\Users\me\Documents\My Web Sites\Empty Site\App_Data\packages\jQuery.1.10.2\Tools subfolder.
  • We move C:\Users\me\Documents\My Web Sites\Empty Site\App_Data\packages\jQuery.1.10.2\Content\Scripts to C:\Users\me\Documents\My Web Sites\Empty Site\Scripts.
  • And finally we delete the C:\Users\me\Documents\My Web Sites\Empty Site\App_Data\packages\jQuery.1.10.2\Content folder.

We hit refresh back in WebMatrix and now we get this:

If we go to NuGet and select updates you'll see that jQuery is now considered "installed" and an update is available. So, in short, our plan worked - yay!

Now for bonus points

Just to prove that you can upgrade using the WebMatrix tooling following our manual install let's do it. Click "Update", then "Yes" and finally "I Accept" to the EULA. You'll now see we're now on jQuery 2.0.3:

Rounding off

In my example I'm only looking at a simple JavaScript library. But the same principal should be able to be applied to any NuGet package as far as I'm aware. Hope that helps!

Wednesday, 4 December 2013

Simple fading in and out using CSS transitions and classes

Caveat emptor folks... Let me start off by putting my hands up and saying I am no expert on CSS. And furthermore let me say that this blog post is essentially the distillation of a heady session of googling on the topic of CSS transitions. The credit for the technique detailed here belongs to many others, I'm just documenting it for my own benefit (and for anyone who stumbles upon this).

What do we want to do?

Most web developers have likely reached at some point for jQuery's fadeIn and fadeOut awesomeness. What could be cooler than fading in or out your UI, right?

Behind the scenes of fadeIn and fadeOut JavaScript is doing an awful lot of work to create that animation. And in our modern world we simply don't need to do that work anymore; it's gone native and is covered by CSS transitions.

Added to the "because it's there" reason for using CSS transitions to do fading there is a more important reason; let me quote HTML5 rocks:

"CSS Transitions make style animation trivial for everyone, but they also are a smart performance feature. Because a CSS transition is managed by the browser, the fidelity of its animation can be greatly improved, and in many cases hardware accelerated. Currently WebKit (Chrome, Safari, iOS) have hardware accelerated CSS transforms, but it's coming quickly to other browsers and platforms."

Added to this, if you have mobile users then the usage of native functionality (as opposed to doing it manually in JavaScript) actually saves battery life.

I'm sold - let's do it!

This is the CSS we'll need:


.fader {
    -moz-transition: opacity 0.7s linear;
    -o-transition: opacity 0.7s linear;
    -webkit-transition: opacity 0.7s linear;
    transition: opacity 0.7s linear;
}

.fader.fadedOut {
    opacity: 0;
}

Note we have 2 CSS classes:

  • fader - if this class is applied to an element then when the opacity of that element is changed it will be an animated change. The duration of the transition and the timing function used are customisable - in this case it takes 0.7 seconds and is linear.
  • fadedOut - when used in conjunction with fader this class creates a fading in or fading out effect as it is removed or applied respectively. (This relies upon the default value of opacity being 1.)

Let's see it in action:

It goes without saying that one day in the not too distant future (I hope) we'll be able to leave behind the horrible world of vendor prefixes. Then we'll be down to just the single transition statement. One day...

Now, a warning...

Unfortunately the technique detailed above differs from fadeIn and fadeOut in one important way. When the fadeOut animation completes it sets removes the element from the flow of the DOM using display: none. However, display is not a property that can be animated and so you can't include this in your CSS transition. If removing the element from the flow of the DOM is something you need then you'll need to bear this in mind. If anyone has any suggestions for an nice way to approach this I'd love to hear from you.

A halfway there solution to the display: none

Andrew Davey tweeted me the suggestion below:

So I thought I'd give it a go. However, whilst we've a transitionend event to play with we don't have a corresponding transitionstart or transitionbegin. So I tried this:

$("#showHideButton").click(function(){
    var $alertDiv = $("#alertDiv");
    if ($alertDiv.hasClass("fadedOut")) {
        $alertDiv.removeClass("fadedOut").css("display", "");
    }
    else {
        $("#alertDiv").addClass("fadedOut");
    }
})

$(document).on('webkitTransitionEnd transitionend oTransitionEnd', ".fader", 
    function (evnt) {
        var $faded = $(evnt.target);
        if ($faded.hasClass("fadedOut")) {
            $faded.css("display", "none");
        }
});

Essentially, on the transitionend event display: none is applied to the element in question. Groovy. In the absence of a transitionstart or transitionbegin, when removing the fadeOut class I'm first manually clearing out the display: none. Whilst this works in terms of adding it back into the flow of the DOM it takes away all the fadeIn gorgeousness. So it's not quite the fully featured solution you might hope for. But it's a start.