Problems with CDN

Hello, there,

Thank you very much for trying out our plugin and reporting these issues! I am really sorry to hear that our plugin broke down your website and I would like to try to get to the bottom of this.

First of all, I must say that CDN support is inherently “tricky” in what we are trying to accomplish. Actually, what a CDN does comes to some kind of conflict with our plugin. (Well, not exactly a conflict but…) The thing is that, in order to serve resized images, our plugin needs to serve the images itself! When the CDN comes in the middle, then our plugin has to instruct the CDN to serve the resized versions of images itself. This little bit is not easy to accomplish in an unobtrusive and transparent. (And being unobtrusive and transparent is a major principle of our plugin!)

Anyhoo, this sort of sums up why CDN support is indeed tricky in our case and why this feature is still experimental.

If I may ask, did your htaccess get updated automatically by the plugin or did you have to do this manually? Also, could you send me the part of the htaccess file that our plugin inserted, so I can check it out?

You see, the worst thing that is supposed to happen when our plugin works with a CDN is to simply not accomplish much -or even accomplish nothing at all- but it should not break anything, unless something really weird is going on.

Cheers,
Takis

Hello,

Thank you for you kind support. I can’t even imagine the challenges you face in order to make the plugin work in an unobtrusive and transparent way.

In my case, I have two plugins inserting codes in the htaccess file: BPS Security anb W3 total cache. I don’t know if Adaptive Image conflicted with one of them. We know for sure that files delivered via CDN were blocked all of a sudden, but files delivered via the main server were ok.

My htaccess is blocked by default. All I had to do was unblock the htaccess and the plugin was able to insert the code by itself. That’s was the moment my site broke down.

I got a little desperate at the moment and I did not save a copy of my htaccess, since I did not suspect it was the problem at that very instant.

I plan to try the plugin again with minification turned off, but test it in late hours, when there is less visitors online. Then, I will save the htaccess file and inform you guys.

Best Regards

Hello, again,

If you could actually do the experiment once again, then perhaps we could trace the problem! As I said before, the worst that is supposed to happen is images not being resized and be served in their actual sizes. Which is at least not catastrophic!

Other that, what our plugin does usually does not mix with what other plugins do in the htaccess file.

I will be waiting for your tests.

Cheers,
Takis

Hi there,

I have just given it another try. I was able to activate the plugin along with all my other plugins, but it didn’t work. But it worked for a brief moment and I have no idea why.

So, I can give you my feedback.

1. Image Sizes

My Adaptive Images setup was: 75% quality and Retina display checked.

I use an app called JPEGmini in order to optimize image sizes before uploading them to my WordPress post. With that, I get smaller images without compromising quality.

The problem was that the images created by Adpative Images plugin, even with 75% quality, ended up being larger or almost the same size as the orginial image.

I upload images with 800px width by default. For the brief moment it worked, adaptive images only created 640px images. I do not know if the 480px would have been smaller.

2. CDN

The plugin was able to add a string at the end of some image files. Please, see an example here.

However, the image source was wrong. I guess we may instruct W3 Total Cache to deliver the files in the “cache/adaptive-images” folder via CDN, but it would require some aditional configuration.

Best Regards

Hello, again,

Thank you for the comprehensive feedback!

1. Image sizes

We are using the GD PHP library which is inherent in most LAMP setups and web hosting environments. It will never produce such optimized compression results compared to tools like JPEGmini, but it usually does it fairly well.

Are you sure that even the resized versions, which our plugin produced, were bigger in file size than the original images from JPEGMini? That would be so strange indeed! I would really appreciate it if you could send me one of these images to test myself.

2. CDN

What you point out most correctly in your screenshot, is the exact reason why our plugin support is mentioned as “still experimental”. We used a Javascript technique where -in your example- the first image was handled by our plugin before actually loading, but the second one did manage to load in its original size, so the plugin decided to just leave it be.

Now, what we could troubleshoot here is why the CDN did not deliver the image with the ?resolution=360,3 part in its src attribute.

One culprit might be the CDN itself! Does it have an issue with adding url parameters to image sources? This should be escalated to the support people of the CDN.

The other culprit could of course be the Adaptive Images plugin. There is a way to test this though, by simply making a direct request for that image with the url parameters, via your actual domain and not the CDN’s subdomain. If the image is actually delivered correctly, then the plugin works fine and the problem is with the CDN. And vice versa!

—

I am sorry for putting you through all this trouble and I would totally understand it if you are fed up with it already, but it really helps me investigate edge cases and I do appreciate it!

Also, I am preparing a next version where the CDN support will be handled totally differently. It is still in beta, but if you have the spare time, I could send it to you for debugging.

Cheers,
Takis