Release notes for Optimizely CMS and Customized Commerce updates

Currently, when AB testing is installed, we listen for LoadedContent and LoadedChildren, so we can swap views out for running tests. This hook exists even if there are no active tests. This activity affects performance.

It’s caused by the IsInSystemFolder method of the TestingContextHelper class.

public bool IsInSystemFolder()
    {
bool flag = true;
if (this._contextHelper.HasCurrentContext())
        flag = this._contextHelper.RequestedUrl().ToLower().Contains(this._episerverHelper.GetRootPath().ToLower());
return flag;
    }

If you notice the blue underlines above, you’ll see that this method is called within a RaiseContentEvent repeatedly within an individual request. The number of calls to this method is dependent on the volume of content being loaded, consequently.

This method calls RequestedUrl() and performs a ToLower() method on the resulting string. It does the same for GetRootPath().
You can see on the right side of perf view that these result in a large amount of memory being allocated because the multiplier is called per piece of content being loaded.
Overall, this one method is allocating 146MB of memory to Gen 0 within a 130 second timeframe. Based on an average of 3 pieces of content being loaded, we could reduce this one method’s allocations by 2/3 (or 97MB in 130 seconds) by simply storing the lowered string value within the _contextHelper and episerver helper. If there were 100 pieces of content being loaded, the reduction would be 99/100ths, and so on.

Steps to reproduce

1. Create an AB test for a content item.
2. Disable the AB test in admin mode.
3. Go to Edit mode and view the disabled label.

Expect:
When the test is disabled, labels are consistent.

Actual:
When you open a running test page, its label is different from the "pick a winner" test page.
But if you close the pick a winner test page, and re-open a running test page, the labels of these pages are the same.

Steps to reproduce:
1. On an alloy site, make a change to a page and create an AB test.
2. Create a new tab in incognito mode.
3. Go to www.yoursite.com/api/episerver/Testing.

Expected:
Should not be able to see the tests if not authenticated.

Actual:
Can see tests even if not authenticated.

Customers and support have asked for a way to disable AB test processing without uninstalling the NuGet package and re-deploying the application.

Solution
A check box is added to the configuration page. It enables or disables all AB testing processing.
When enabled:

• All normal A/B testing resumes.

When disabled:

• On the Publish Menu, "AB Test changes" option should not be displayed.
• All A/B testing processing (creating views and conversions) is disabled.
• Users can still stop a test or pick a winner.
• Scheduled tests are marked as running at the scheduled time. However, no processing will occur.
• There should be no impact on page load performance.
• On details and pick a winner views, a message indicates that A/B feature is disabled.

The Enabled/Disabled configuration value is preserved and respected after updates and restarts of the web application.
The default state is enabled (that is, AB testing will be enabled by default), including upon upgrade.

Currently, in a load balanced environment, when the AB testing is disabled, other machines are not informed of this change and continue to run the tests.

In a load balanced environment, toggling the enabled state of A/B in one node is reflected in the other nodes. So, views and conversions will not be logged.

Problem

When enabling AB Testing for a home page, images everywhere on the site become broken - with some probability related to "Participation percentage" parameter in home page test.

Affected images are any image - static ones from disk, or static ones from packages (like, background image on login screen from /util path), or images from blobs (media). They are being returned like a binary stream sent with UTF-8 encoding or something similar.
Even the images in the default CMS login screen get broken.

Only images are served through path /episerver/ (in CMS editor) have no problems. Another exception are SVG images, because they're actually XML documents.

Step to Reproduce

We were able to reproduce issue with AB Test package on Alloy Demo sample site (with all episerver.* packages updated to latest versions)

1. In code, add following code into Global.asax.cs:
protected void Application_BeginRequest()

{
    var repository = ServiceLocator.Current.GetInstance<IContentRepository>();
    repository.Get<PageData>(ContentReference.StartPage);
}

2. Start AB Testing on Home page.
3. Flush cache, do a hard refresh on the browser. Images are unable to load.

On Chrome, it won't throw any error, just simply display blank 1x1 images. On Firefox, there'll be errors in browser console.