Using web.config transforms on assembly binding redirects

2021-12-10 Andy BurnsIIS, web transformsLeave a comment

Right, I keep having to do this, and keep having to look this up, so here it is.

If you want to do a web transform for an assembly binding redirect it can be a bit tricky. The assembly details are in an <assemblyIdentity /> element, and the <bindingRedirect /> is its sibling. Yeah, I don’t know why it was designed this way; I’m assuming alcohol was involved. Yes, having the oldVersion and newVersion attributes in the same element at the assembly’s identity would be much simpler.

Anyway, it is what it is. An alternative is to replace the entire <dependentAssembly /> element, but the locator becomes a bit more fiddly. Still, it works. See this example – the locator on the parent element is checking the name of the child assemblyIdentity.

<dependentAssembly xdt:Transform="Replace" xdt:Locator="Condition(./_defaultNamespace:assemblyIdentity/@name='System.Runtime')">
    <assemblyIdentity name="System.Runtime" publicKeyToken="b03f5f7f11d50a3a" />
    <bindingRedirect oldVersion="0.0.0.0-4.1.2.0" newVersion="4.1.2.0" />
</dependentAssembly>

Carousels are killing our Core Web Vitals scores

2021-09-092021-09-09 Andy BurnsCore Web Vitals, LCP, SpeedLeave a comment

So, we’re all familiar with the Core Web Vitals scores, right? Just in case we’re not, lets recap. These are scores that Google uses to just the speed of your page. It’s more than just “How much data” does the page use, or “When is the DOM ready”, but also includes things like “When is the content painted on the page” and “How much does stuff shift as the page is loaded”.

This is actually really good, as these are much better metrics; people want your page to read, and these metrics focus on that.

So, one of the things I’ve noticed is that a number of our customers are not getting great scores for the Largest Contentful Paint (LCP) – and this seems to be due to a particular bugbear of mine – carousels.

Continue reading →

Email Regular Expression

2021-03-192021-11-08 Andy BurnsregexLeave a comment

One of my colleagues asked a question that I’ve heard dozens of times over my career…

What’s a good regular expression for validating email addresses.

Sadly, due to poor standards, poor implementation choices, and just the sheer age of Email, this is a surprisingly tough problem.

The best way to validate an email address is to email it, and get the user to do something. That’s not really feasible if it’s someone just filling in a form.

Failing that, I came up with:

^[^@\s]+@[^@\s]+\.[^@\s]+$

This is the same as suggested by Microsoft, which is gratifying. You can see the logic of it here.

Logging client actions near page Unload

2020-09-152020-09-15 Andy BurnsLeave a comment

I had an interesting problem; we wanted to log stuff that was happening on a client’s browser. Fair enough, we can use AJAX to do that. However, this had a twist – we wanted to log events that were happening immediately before the page might be redirected to a new location. In other words, the page might unload, and a new page load. What I found was the messages from just before the page unloaded might not be sent to the server; as the page was unloading, the AJAX requests were not being performed. I wondered what I could do about this. Continue reading “Logging client actions near page Unload” →

Don’t be Lax about your SameSite cookies

2020-08-05 Andy Burnssage, samesiteLeave a comment

We have a customer who is using Sitecore and the SagePay Pi service to take credit card payments. They were using a multi-page Sitecore Forms form, and weirdly their confirmation emails couldn’t use field values from the first pages of the form. Eventually, we found that the problem was due to the the user’s session being lost, but only if the user was using 3D-secure, and a recent browser. Here’s why…

Continue reading “Don’t be Lax about your SameSite cookies” →

Random discovery: Why the 13th Hex character of Guids is ‘4’

2019-11-12 Andy BurnsGUIDs1 Comment

I noticed something strange in Sitecore; for most of my nodes (not the Sitecore node!), the 13th Hex character of the identifying GUID is ‘4’.

I had a list of about 50 of these, and my eye was drawn to the pattern. Now, I thought Guids were entirely random, except that the chance of 50 page template IDs all having a 4 at that character was infinitesimal.

Weird. Except it turns out that they’re not random. I had no idea that there are different versions of guids, or than that character defined the version of the GUID.

This requires a test, so I wrote a program to print Guid.NewGuid() a lot:

All of them are 4s.

So:

GUIDs aren’t entirely random.
They might not be very random at all, looking at some of the other GUID versions.
Which is why they shouldn’t be used as a source of entropy for encryption.
I still have things to learn.

Keeping the size of of Sitecore Azure Backups under control

2019-11-04 Andy Burnsazure, backupsLeave a comment

I’ve written before about Azure Backup fails due to Content Testing Screenshots not clearing and the resulting problems with backup size.

That’s not the whole problem though.

Sitecore made some effort to configure some directories to be outside the home folder of the app services, and therefore not subject to backup – but there’s still a lot that shouldn’t be in the backup. Continue reading “Keeping the size of of Sitecore Azure Backups under control” →

Sitecore App Center Login Fails

2019-09-022019-09-02 Andy BurnsChrome, cookiesLeave a comment

I tried logging into Sitecore’s App Center, and got the following error:

The credentials used to log in to the Sitecore App Center cannot access the license used on this server

Weird.

This was in Chrome. Strangely, I discovered that I could log in through Chrome Canary. What’s different?

Continue reading “Sitecore App Center Login Fails” →

Application Initialization for Azure Service Apps (and Sitecore)

2019-08-30 Andy BurnsAppInitialization, azureLeave a comment

We have been having a problem with Sitecore in Azure PAAS – it appears that when auto-scaling scales out, App Services are being put into rotation before they have started up. This is causing all sorts of weirdness.

Sitecore support recommended making sure that we had Application Initialization configured. That seems a good idea. I’m not sure why the guys who set up this instance didn’t; perhaps they were unaware of it (and to be fair, it’s something I’ve not looked at before).

Continue reading “Application Initialization for Azure Service Apps (and Sitecore)” →

My problems with Sitecore FXM

2019-07-232019-07-23 Andy BurnsfxmLeave a comment

Sitecore’s Federated Experience Manager (FXM) allows non-Sitecore sites to record analytics data into Sitecore. It’s both quite neat, and has a number of problems. I’m going to assume you’ve done a little reading about FXM already, but here’s how it works (in Sitecore 9.0.x).

FXM works by having you adding a JavaScript reference to your pages:

This JavaScript, when run, instantiates a JavaScript Object (a Beacon) which makes a request of Sitecore:

And the response to that sets up a Sitecore Session ID, Contact ID, and returns element matches, which are stored in Cookies:

The element matches use HTML Element IDs to identify content to a) attach click handlers too, or b) elements to insert content around or in place of.

This is where we hit the first of my problems with FXM… Continue reading “My problems with Sitecore FXM” →

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