Opinions on CDN

[Markus Pope]

Do you fellers have any opinions on CDN-hosted javascript?  Good?  Bad?  Any personal experience?

 

Thanks,

Markus

[b...@benandsuz.com]

I think it’s a good idea overall for performance reasons, but I recommend providing a fallback for the script like the following:

 

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script>window.jQuery || document.write('<script src="js/vendor/jquery-1.9.1.min.js"><\/script>')</script>

 

CDNs have been known to have outages.  I’ve also ran into a problem once where a user on a corporate network had some IE-related issue that didn’t allow the external script.

 

I’ve only used CDNs for 3rd party libraries that are versioned.  If you are hosting your own libraries, you could run into some caching issues unless you use a good versioning strategy or some other strategy.

 

Hope that helps!

Ben

 

 

Sent from Windows Mail

 

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[J.P. Cummins]

It's great for libraries that are stable and never change (jQuery, et. al). However, if your code changes often or you're using HTTPS, it can be problematic. You have to have to have a good versioning system so the JS stays in sync with the CDN when you deploy a build. 

Unless your serving millions of requests a day, I'd avoid it. Instead look at other ways to optimize your JS.

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J.P.

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[Markus Pope]

Good feedback Ben and JP, thanks!

 

Markus

[Jeff Berry]

I assume you have a lot of javascript or you wouldn't be asking.

 

We have used the Telerik CDN which is hosted on Amazon with great success.  It obviously contains more than just javascript, but the potential benefits should be the same. 

 

I believe browsers will open only a limited # of connections at a time to a given domain.  So, separating javascript files to a CDN can be quite beneficial as the browser can pull the scripts AND your content simultaneously.  It obviously also unburdens your web server(s).  Same thing with image files, having them pull from a different domain can help performance.

 

The only downside we've experienced that it is possible that users may be able to get to your site but not to the CDN (due to firewall, DNS probs or whatever).  The solution is to use some type of beacon on your CDN and if it's missing, default to pulling the javascript from your server. 

 

If it's your content/javascript, then you obviously have to worry about versioning as your site evolves.  We don't have that concern w/Telerik since they handle that.

 

And as a general disclaimer: anything like this is relative to your specific situation (environment, size of files, amount of traffic, etc...). 

 

That's my .02

:)

 

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Springfield .NET Users Group - http://www.sgfdotnet.org/

[Chad Boschert]

Markus, if you're not already, I'd recommend using a tool like Google's PageSpeed (or Yahoo's YSlow) to identify and prioritize what you need to optimize. There may be other areas that could offer better performance improvements for your effort.

[Ray]

Unrelated to this specific issue, but quite relevant is to bundle and minify scripts to greatly increase performance.:

http://www.asp.net/mvc/tutorials/mvc-4/bundling-and-minification

[justin coon]

Was just going to recommend checking out bundling and minification... Sent from Yahoo! Mail on Android

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From: Ray <smda...@gmail.com>;

To: <sgfd...@googlegroups.com>;
Subject: Re: Opinions on CDN

Sent: Fri, May 10, 2013 10:29:22 PM

[Markus Pope]

Thanks everyone for your feedback!  Most helpful!

 

From: sgfd...@googlegroups.com [mailto:sgfd...@googlegroups.com] On Behalf Of Ray
Sent: Friday, May 10, 2013 5:29 PM
To: sgfd...@googlegroups.com
Subject: Re: Opinions on CDN

 

Unrelated to this specific issue, but quite relevant is to bundle and minify scripts to greatly increase performance.:

 

http://www.asp.net/mvc/tutorials/mvc-4/bundling-and-minification