Naming Things is Hard: Spotlight Edition

Like most specialist industries, software is rife with mainstream English words that we’ve taken and misappropriated to mean something completely different. Show business is no different. The software team here at Spotlight sits smack-bang in the intersection between these two specialist fields, and so when we’re talking to our customers and product owners about the systems we build, it’s very important to understand the difference between typecasting and type casting, and exactly what sort of actor model we’re talking about. We therefore present this delightful “double glossary” of everyday terms that you’ll hear here at Spotlight Towers. Because as we all know, there’s only two hard problems in software: cache invalidation, naming things, and off-by-one errors.


Software: A mathematical model of concurrent computation that treats “actors” as the universal primitives of concurrent computation.

Showbiz: A person whose profession is acting on the stage, in films, or on television.


Software: A software agent is a computer program that acts for a user or other program in a relationship of agency

Showbiz: A person who finds jobs for actors, authors, film directors, musicians, models, professional athletes, writers, screenwriters, broadcast journalists, and other people in various entertainment or broadcast businesses.


Software: Any executable code that is passed as an argument to other code, which is expected to call back (execute) the argument at a given time.

Showbiz: A follow-up interview or audition


Software: Explicitly converting a variable from one type to another

Showbiz: Employing actors to play parts in a film, play or other production. Also the act of doing same.


Software: The opposite of a server

Showbiz: An actor, specifically in the context of the actor’s relationship with their agent or manager Internally at Spotlight we have both internal and external clients/customers

Client Profile

Software: A subset of the .NET framework intended to run on mobile and low-powered devices

Showbiz: An actor’s professional CV, as it appears on their agent’s’ website or in various kinds of casting software and directories


Software: Primitive data type representing a floating-point number

Showbiz: A performer who appears in place of another performer, i.e., as in a stunt.


Software: A copy of a system that updates from the original in near to real time, often a database or file storage system

Showbiz: An optical device that helps a performer check they’ve applied their makeup correctly


Software: Used in database mirroring to refer to the primary instance of the database

Showbiz: A performer with lines.


Software: The live infrastructure and code environment

Showbiz: A film, TV or stage show, such as a professional actor might list on their acting CV.


Software: Representational State Transfer – an architectural style used when building hypermedia APIs

Showbiz: What actors do between jobs.


Software: A computer program written in a scripting language

Showbiz: The written dialogue and directions for a play, film or show


Software: Standard pronunciation of SQL, referring to either the database query language. Also commonly refers to Microsoft’s SQL Server database product.

Showbiz: A published, broadcast, or recorded work that continues the story or develops the theme of an earlier one.


Software: The opposite of a client

Showbiz: Someone working as waiting staff in a restaurant. Who is quite possibly an actor moonlighting as a server to pay the bills between acting jobs.


Software: The native MacOS search application

Showbiz: Our company –,  “The Home of Casting” – and the directories and services we have created since 1927. Not to be confused with the 20-odd different ‘Spotlight’ companies around the world, many of whose customers blindly email whenever they have a problem. 🙂


Software: A replica of a production hosting environment used to test new features and deployments.

Showbiz: The method of presenting a play or dramatic performance; also used to refer to the stage structure itself in theatre and live performance.

Semantic Versioning with Powershell, TeamCity and GitHub

Here at Spotlight Towers, we’ve been using TeamCity as our main build server since version 6; it’s a fantastic tool and we love it dearly. It got even better a few years back when we paired it with the marvellous Octopus Deploy; TeamCity builds the code and creates a set of deployable packages known as Octopacks; Octopus deploys the packages, and everything works quite nicely. Well, almost everything. One of the few problems that TeamCity + Octopus doesn’t magically solve for us is versioning. In this post, we’re going to look at how we use Git and TeamCity to manage versioning for our individual packages.

If this sounds like your sort of thing, why not come and work for us? That’s right – Spotlight is hiring! We’re looking for developers, testers and a new UX/Web designer – check out and get in touch if you’re interested.

First, let’s establish some principles

  • We are going to respect the semantic versioning convention of MAJOR.MINOR.PATCH, as described at
  • Major and minor versions will be incremented manually. We trust developers to know whether their latest commit should be a new major or minor release according to semantic versioning principles.
  • Building the same codebase from the same branch twice should produce the same semantic version number.
  • Packages created from the master branch are release packages.
  • Packages created from a merge head of an open pull request are pre-release packages.
  • Pre-release packages will use the version number that would be assigned if that branch was accepted for release at build time.

Now, here’s the part where we’re going to deviate from the semantic versioning specification, because our packages actually use a four-part version number. We want to include a build number in our package versions, but the official semver extension for doing this – MAJOR.MINOR.PATCH+BUILD – won’t work with NuGet, so we’re going to use a four-part version number MAJOR.MINOR.PATCH.BUILD. Pre-release packages will be appended with a suffix describing which branch they were built from – MAJOR.MINOR.PATCH.BUILD-BRANCH.

OK, here’s an illustrated example that demonstrates what we’re trying to achieve. Master branch is green. Two developers are working on feature branches – blue and red in this example. To create our pre-release builds, we’re using a little-documented but incredibly useful feature of GitHub known as ‘merge heads’. The idea is that if you have an open pull request, the merge head will give you a snapshot of the codebase that would be created by merging the open pull request into master – so you’re not just testing your new feature in isolation, you’re actually building and testing your new feature plus the current state of the master branch. There is one caveat to this, which I’ll explain below.

So, we’ve got TeamCity set up to build and publish packages every time there’s a commit to master or to the merge head of an open pull request, and we’re also occasionally triggering manual builds just to make sure everything’s hanging together properly. Here’s what happens:

semantic merging 500px

That line there that’s highlighted in yellow is a gotcha. At this point in our workflow, we’ve merged PR1 into our master branch, but because we haven’t pushed anything to the blue branch since this happened, the blue merge head is out of date. PR2 does NOT reflect the latest changes to master, and if we trigger a build manually, we’ll end up with a package that doesn’t actually reflect the latest state of the codebase. The workaround is pretty simple; if you’re creating pre-release builds from merge heads, never run these builds manually; make sure you always trigger the build by pushing a change to the branch.

Now let’s look at how can we get TeamCity to automatically calculate those semantic version numbers whenever a build is triggered. We’ll start with the major and minor version. We’re going to track these by creating a version.txt file in the root of the project codebase, which just contains the major and minor version numbers. If a developer decides that their feature branch represents a new major or minor version, it’s their responsibility to edit version.txt as part of implementing the feature. This also means that prerelease packages built from that branch will reflect the new version number whilst master branches will continue to use the old version until the branch gets merged, which I think is rather elegant.

For the patch version, we’re going to assume that every commit or merge to the master branch represents a new patch version, according to the following algorithm

  • If the current version.txt represents a NEW major/minor version, the patch number is zero
  • Otherwise, the patch number is the patch number of the latest release, incremented by the number of commits to the master branch since that release.

So – how do we know how many commits there have been since the last release? First, each time we build a release branch, we’re going to use Git tags to tag the repository with the version number we’ve just built. TeamCity will do this for you automatically using a build feature called “VCS labeling”:


Assuming every release has a corresponding tag, now we need to find the most recent release number, which we can do from the Git command line.

git fetch –tags
git tag –sort=v:refname

Git tags aren’t retrieved by default, so we need to explicitly fetch them before listing them. Then we list all the tags, specifying sort=v:refname which causes tag names to be treated as semantic versions when sorting. (Remember that semver sorting isn’t alphanumeric – in alphanumerics, v9 is higher than v12). Once we’ve got the latest tag, we need to count the number of revisions since that tag was created, which we can do using this syntax:

git rev-list v1.2.3..HEAD –count

To use this in our TeamCity build, we’ll need to output the various different formats of that version so that TeamCity can use them. We want to do three things here:

  • Label the VCS root with the three-part semantic version number v1.2.3
  • Update the AssemblyInfo.cs files with the four-part version number – note that we can’t put any prerelease suffix in the AssemblyInfo version.
  • Pass the full version – – to Octopack when creating our deployable packages with Octopus.

I’ve wrapped the whole thing up in a Powershell script which runs as part of the TeamCity build process, which is on GitHub:

To use it in your project, add versions.ps1 to the root of your project repo; create a text file called version.txt which contains your major.minor version, and then add a TeamCity build step at the beginning of your build process that looks like this:


Finally, it’s worth mentioning that to use command-line git from Powershell, I had to set up TeamCity to use an SSH VCS root rather than HTTP, and install the appropriate SSH keys on the TeamCity build agent. I don’t know whether this is a genuine requirement or a quirk of our configuration; your mileage may vary. And I still find Powershell infuriatingly idiosyncratic, but hey – you probably knew that already. 🙂

Happy versioning! And like I said, if this sort of thing sounds like something you’d like to work on, awesome – we’re hiring! Check out for more details and get in touch if you’re interested.

IdentityServer, OpenID Connect and Microsoft CRM Portals

As readers of this blog will know, here at Spotlight we’re in the process of moving nine decades’ worth of legacy business process onto Microsoft Dynamics CRM, aka CRM Online, which I gather is now called Dynamics 365 (because hey, it’s not like naming things was hard enough already, right?)

We’re also investigating a couple of options for building customer-facing systems that integrate with Dynamics. Until last year, there were really three options for this – a product called Adxstudio, a free Microsoft component called the CRM Portal Accelerator, or rolling your own solution using the CRM SDK. Around this time last year, Microsoft quietly retired the Portal Accelerator component and acquired Adxstudio, and since then, they’ve been in the process of assimilating it into the Dynamics product family – which has meant it’s been something of a moving target, both in terms of the supported features and in terms of the quality of documentation and examples.

I’ve previously blogged about one way to integrate Adxstudio with your existing authentication system, but that approach relied completely on running Adxstudio on-premise so you could run your own code as part of the request lifecycle – and as you may have noticed, there’s a bit of a trend in IT at the moment away from running your own servers and towards using hosted managed services, so that patching and backups are somebody else’s problem. Since Microsoft acquired Adxstudio, there’s been a lot of churn around what’s supported and what’s not – I’m guessing that behind the scenes they’re going through the Adxstudio codebase feature-by-feature and making sure it lines up with their plans for the Dynamics 365 platform, but that’s just guesswork on my part.

One of the main integration points I’ve been waiting for is the ability for a Microsoft-hosted Portal solution to use a third-party OpenID Connect endpoint to authenticate users, and it appears in the latest update this is finally supported – albeit with a couple of bumps along the way. Here’s what I’ve had to do to get a proof-of-concept up and running.

Setting up Dynamics CRM Portals

First, you’ll need to set up a Dynamics Portal trial. You can get a 30-day hosted trial of Dynamics CRM Online by signing up here – this actually gives you a full Office 365 organization including things like hosted Active Directory, as well as the Dynamics CRM Online instance we’re using in this example. Next, you’ll need to ask nicely for a trial of the portal add-on – which you can do by filling out the form at

Setting up IdentityServer and configuring an ngrok tunnel

Whilst you’re waiting for the nice Microsoft people to send you your trial license, get up and running with IdentityServer. For this prototype, I’m using the MVC Authentication example from the IdentityServer3.Samples project – clone it to your workstation, open the MVC Authentication solution, hit F5, verify you can get up and running on localhost.

Next – in order for Dynamics CRM Online to talk to your IdentityServer instance, you’ll need to make your IdentityServer endpoints visible to the internet. You could do this by deploying your IdentityServer sample to Azure or AWS, but for experiments like this, I like to use a tool called ngrok, which will create temporary, secure tunnels from the internet to your workstation. Download ngrok, unzip it somewhere sensible.

Pick a tunnel name. I’m using authdemo in this example but any valid DNS host name will do. Next, create a local IIS application pointing to the EmbeddedMvc folder in your samples directory, and set the host name to <your tunnel name>


Now run ngrok.exe to create a tunnel from the internet to your new IIS application:

C:toolsngrok> ngrok.exe http –subdomain=authdemo 80

ngrok by @inconshreveable


Session Status        online
Version               2.1.18
Region                United States (us)
Web Interface
Forwarding   -> localhost:80
Forwarding   -> localhost:80

Connections           ttl     opn     rt1     rt5     p50     p90
0       0       0.00    0.00    0.00    0.00

All being

If that’s worked, you should be able to fire up a browser, go to – replacing ‘authdemo’ with your own tunnel name – and see the IdentityServer3 sample landing page:


Configuring IdentityServer

Right. Next thing we need to do is to make a couple of changes to the IdentityServer configuration, so that it’ll run happily on instead of on localhost

First, enable logging. Just do it. Use the package manager console to install the Serilog.Sinks.Trace package. Then add this to the top of your Configuration() method inside Startup:

Log.Logger = new LoggerConfiguration()

and add this to your web.config, specifying a path that’s writable by the application pool:

  <trace autoflush="true"
      <add name="myListener"
           initializeData="C:logfilesidentityserver.log" />
      <remove name="Default" />

Next, do a global search and replace, replacing any occurrence of localhost:44319 with – again, substituting your own tunnel name as required.

Next, add a new client to the static EmbeddedMvc.IdentityServer.Clients class the IdentityServer sample project – changing the highlighted values to your own client ID, client secret, and portal instance URL:

new Client {
    ClientName = "Dynamics CRM Online",
    ClientId = "crm",
    Flow = Flows.Hybrid,
    ClientSecrets = new List() { new Secret("secret01".Sha256()) },
    RedirectUris = new List { 
    PostLogoutRedirectUris = new List { 
    AllowedScopes = new List { "openid" }

Adding IdentityServer as an endpoint in CRM Portals

Finally, you need to add your new IdentityServer as an identity provider. CRM Portals uses the Dynamics CRM platform for all its configuration and data storage, so to add new settings you’ll need to log into your Dynamics CRM Online instance, go into Portals > Site Settings, and add the following values:

Name Value Website
Authentication/OpenIdConnect/AuthDemo/Authority Customer Self-Service
Authentication/OpenIdConnect/AuthDemo/Caption IdentityServer OpenID Connect Demo Customer Self-Service
Authentication/OpenIdConnect/AuthDemo/ClientId crm Customer Self-Service
Authentication/OpenIdConnect/AuthDemo/ClientSecret secret01 Customer Self-Service
Authentication/OpenIdConnect/AuthDemo/MetadataAddress Customer Self-Service

Finally, it looks like you’ll need to restart the portal instance to get it to pick up the updated values – which you can do by logging into the Office 365 Admin Center, Admin Centers, CRM, Applications, Portal Add-On, clicking ‘MANAGE’, and pressing the nice big RESTART button on the Portal Actions page:


And – assuming everything lines up exactly right – you should now see an additional login button on your CRM Portals instance:


Clicking on it will bounce you across to your ngrok-tunnelled IdentityServer MVC app running on localhost:

imageLog in as bob / secret, and you’ll get the OpenID permissions check:


…and when you hit ‘Yes, Allow’, you’ll be redirected back to the CRM Portals instance, which will create a new CRM Contact linked to your OpenID Connect identity, and log you in to the portal.


Of course, in the real world there’s a lot more to it than this – there is a huge difference between a proof of concept like this and a production system. These sorts of user journeys form such a key part of delivering great user experience, and integrating multiple systems into your login and authentication/authorization journeys only makes this harder. But it did work, and it wasn’t actually all that complicated to get it up and running. It’s also interesting to see how something like OpenID Connect can be used to integrate a powerful open-source solution like IdentityServer with a heavyweight hosted platform service like CRM Portals.

Whether we end up adopting a hosted solution like CRM Portals – as opposed to just building our own apps that connect to CRM via the SDK or the new OData API – remains to be seen, but it’s nice to see solutions from two radically different sources playing nicely together thanks to the joy of open protocols like OpenID Connect. Long may it continue.

The Mystery of the Chinese Junk

You know it’s going to be one of those days when, just as you’re about to put on your headphones and get into ‘the zone’, you overhear somebody saying the fateful words ‘ok, then maybe we’ll need to get Dylan to look at it.’

See, amongst the many hats I wear in the course of a given week, there’s one that’s probably labelled ‘dungeon master’ I’m the one who remembers where all the bodies are buried, because – for all sorts of reasons that made very good sense at the time – I probably helped bury most of them. And on this particular day, the source of so much excitement was our venerable Microsoft Dynamics CRM v4 server. It started out with a sort of general grumbling on the support channel about CRM4 being slow… but by the time it was handed over to me to look into, it was beautifully summarised as ‘dude… there’s Chinese in the Windows event log’

And, sure enough, there is – complete with the lovely Courier typeface that Windows Event Viewer kicks into when you get errors so weird that good old Microsoft Sans Serif can’t even display them:


Now, whilst it’s been a while since I’ve done any serious work on our old CRM system, I’m pretty sure it’s not supposed to do that – so we start investigating. Working theory #1: some sort of vulnerability has resulted in attackers injecting Chinese characters into our database – whilst CRM4 is generally pretty well insulated from any public-facing code, there’s one or two places where signup forms would generate CRM Leads, that sort of thing. So we start grepping the entire database for one of the Chinese strings we’ve found in the event log.

Whilst this is going on – and trust me, it takes a while – I decide to share my excitement via the wonder of social media. This turns out to be a Really Good idea, because… well, here’s what happened…

“The incoming tabular data stream TDS RPC protocol stream is incorrect. Parameter (“䐀攀氀攀琀椀漀渀匀琀愀琀攀…” Oh. It’s gonna be one of THOSE days.

— Dylan Beattie (@dylanbeattie) October 18, 2016//

@dwm @dylanbeattie The low bits are all null, so this probably UTF-16LE being mistaken for UTF-16BE (or vice versa…?).

— Fake Unicode ⁰ ⁧ (@FakeUnicode) October 18, 2016//

You see in @FakeUnicode’s screenshot there, the words ‘DeletionState’ appear quite clearly at the bottom of the message?

Whilst this is going on, our database search comes back reporting that there’s no mysterious Chinese characters in any of our CRM database tables. Which is good, since it means we probably haven’t been compromised. So, next step is to work through that Unicode lead, see if that gets us anywhere. Because .NET has a built-in encoding for big-endian Unicode, this is pretty simple:

var source = “䐀攀氀攀琀椀漀渀匀琀愀琀攀”;
var bytes = Encoding.BigEndianUnicode.GetBytes(source);
var result = Encoding.Unicode.GetString(bytes);

Turns out – just as in FakeUnicode’s screenshot – that’s the text “DeletionState” with the byte order flipped. We grabbed a few examples of the ‘Chinese’ text from the event log, ran it through this – sure enough, in every single case it’s a valid CRM database query that’s somehow been flipped into wrong-endian Unicode. At this point we start suspecting some sort of latent bug – this is old software, running on an old operating system,talking to an old database server, and sure enough, a bit of googling turns up a couple of  likely-looking issues, most of which are addressed in various updates to SQL Server 2008. We take a VM snapshot in case everything goes horribly wrong, and one of the Ops gang volunteers to work late to get the server patched.

Next morning, turns out the server hasn’t been patched – because every single download of the relevant service pack has been corrupted. At which point all bets are off, because chances are the problem is actually network-related – which also explains where the ‘Chinese’ is coming from.

OK, let’s capture a stream of bytes from somewhere. Like, say, from the TDS data stream used by the MSCRMAsyncService


What does that say? If you think you know the answer, you’re wrong. Pop off and read The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!) – done? Awesome. NOW what do you think it says?

See, we have no idea. It’s a stream of bytes. Without some indication of how we’re supposed to interpret those bytes, it’s meaningless. OK, I’ll give you a clue – it’s UTF-16. Now can you tell what it says? No, you can’t – because (1) you don’t know whether it’s big-endian or little-endian, and (2) you don’t know where it started.

If we assume it’s big-endian, then the first byte pair – 00 48 – would encode the character ‘H’, the second byte pair – 00 65 – would encode ‘e’, and so on. If we assume it’s little-endian, then the first byte pair – 00 48 – encodes the character 䠀 – and suddenly the mysterious Chinese characters in the event log start to make sense.


Of course, the data stream between the MSCRMAsyncService and the SQL server hasn’t actually flipped from little-endian UTF-16 to big-endian – what’s happened is that the network connection between them is dropping bytes. And if you drop a single byte – or any odd number of bytes – from a little-endian Unicode stream, you get a sort of off-by-one error right along the rest of the data stream, resulting in all sorts of weirdness – including Chinese in the event logs.

Turns out there was a problem with the virtual network interface on the SQL Server box – which was causing poor performance, timeouts, bizarre query syntax errors, Chinese in the event logs, and corrupted service pack downloads. Fortunately the databases themselves were intact, so we offlined them, cloned the virtual disk they were sitting on, attached that to a different server and brought them back online.

Every once in a while, you get a weird problem like this. I’ve seen maybe half-a-dozen problems in my entire career that made absolutely no sense until they turned out to be a faulty network connection, at which point generally you not only solve the problem, but explain a whole load of other weirdness that you hadn’t got round to investigating yet. The only thing more fun than dodgy networks is dodgy memory – but that’s a post for another day.

Oh, and if you’re wondering about the title of this post, you clearly haven’t studied the classics.

The Next Big(int) Thing

One of our systems here uses a bigint identity column as a database primary key – because we knew when we built it, back in 2010, that we were going to end up with more than 2,147,483,647 records.

Well, that happened at 12:02 today, and a couple of systems promptly failed – because, despite the underlying database being designed to handle 2^63 records, the POCOs that were being mapped to those classes were using a regular C# int to store the record ID, and so as soon as they got an ID from the database that’s bigger than Int32.MaxValue, they blew up. Thanks to the underlying DB schema already supporting 64-bit IDs, the fix was pretty simple – just change int to long in a few carefully-selected places and redeploy the applications – but it’s still annoying that something we knew about, and planned for, still came back to bite us. So I started thinking – how could we stop this happening?

The problem is that, despite being a bigint column, we just accepted SQL Server’s default identity setting of (1,1) – i.e. start counting at 1, and increment by 1 each time. Which means that until you hit 2-billion-and-something records, it doesn’t actually make any difference – and that takes a while. In our case, it took 5 years, 8 months and 26 days. During that time we’ve made hundreds of changes to our code, and in a handful of those cases, we’ve mapped that bigint ID onto a regular C# Int32 – and so inadvertently planted a little time-bomb in our production code. Tick, tick, tick…

So here’s a nice neat solution, that I wish I’d thought of five years ago. Anytime you create a bigint identity, seed it with (2147483648, 1) – so that right from day one, it’s already too big to fit in an Int32. Any system that tries to store an ID in a regular int variable will fail immediately, not in five years when someone creates that magic 2.14-billion-and-somethingth record. Even though you’ve effectively thrown away 2^32 possible values, you have another (2^64 – 2^32) values to play with, so you’ve lost a tiny, tiny fraction of the available keyspace in exchange for immediate feedback if any of your client apps can’t cope with 64-bit ID values.

ASP.NET Authentication with Adxstudio

I’m looking into options for integrating our shiny new CRM system with our website, so we can provide all sorts of neat self-service capabilities and features. One of the applications I’m investigating is a thing called Adxstudio – now owned by Microsoft – which claims to “transform Dynamics CRM into powerful application platform with dozens of apps and starter portals.”


This is one of those situations where we really are dealing with ‘solved problems.’ Email campaigns. Customers updating their own contact details, potentially things like forums, helpdesk/ticketing systems – lots of things which are nice-to-have but really aren’t strategic differentiators, and so there’s a compelling argument to find an off-the-shelf solution and just plug it in. We already have a federated authentication system here at Spotlight – something we built a few years ago that provides basic identity and authentication capabilities on top of OAuth2. At the time we built it, OpenID Connect didn’t exist yet, so we’ve got a system that does basically the same thing but isn’t actually compatible with OpenID Connect – and consequently doesn’t work out-of-the-box with Adxstudio. So I’ve been poking around, trying to work out the best way to plug Adxstudio into our infrastructure so we can evaluate it as a solution.

One of the options on the table was to replace our existing authentication system with IdentityServer; another was to implement OpenID Connect support on top of our existing authentication system – both quite elegant solutions, but both of which involve quite a lot more work than is actually required for what we’re trying to do.

The core requirement here is:

  • We already have a CRM Contact record for every user of our system
  • We can look up a user’s CRM Contact GUID during authentication
  • We want to set up the Adxstudio MasterPortal demo so that our customers are seamlessly authenticated and can use Adxstudio features as though they had registered via the Adxstudio registration facility.

Now, one of the nice things about Adxstudio is that it’s built as OWIN middleware, and uses the ASP.NET Identity framework to handle authentication – so what we need to do is work out how to translate the CRM Contact GUID into an IPrincipal/IIdentity instance that we can assign to the HttpContext.Current.User property, and hope that Adxstudio then does the right thing once the HttpContext User is set correctly.

Adxstudio provides an implementation of ApplicationUserManager that’s already registered with the OWIN model, which accepts a CRM Contact GUID (as a string) and returns an instance of ApplicationUser that we can use to spin up a new ClaimsIdentity. So the simplest possible approach here is this snippet of code:

protected void Application_AuthenticateRequest(object sender, EventArgs e) {
Guid userGuid;
var cookie = Request.Cookies[“crm_contact_guid”];
if (cookie != null && Guid.TryParse(cookie.Value, out crmContactGuid)) {
var http = HttpContext.Current;
var owin = http.GetOwinContext();
var userManager = owin.Get<ApplicationUserManager>();
var user = userManager.FindById(crmContactGuid.ToString());
var identity = user.GenerateUserIdentityAsync(userManager).Result;
HttpContext.Current.User = new RolePrincipal(identity);

Doing this with a Contact that’s been created via the Adxstudio registration thing works just fine – but trying to do it with a ‘vanilla’ contact blows up:

imageAs you can see from that stack trace, deep down buried under several layers of Adxstudio and ASP.NET Identity code, something is trying to construct a System.Security.Claims.Claim() instance and it’s blowing up because we’re passing in a null value for something that’s not allowed to be null. Unfortunately for us, because we don’t have the source for the thing that’s actually blowing up, we can’t see what the actual parameter values are that are causing the exception… so it’s time for a bit of hunch-driven development. 🙂

I’d already noticed that when you install Adxstudio into your CRM system, it adds a bunch of custom attributes to the Contact entity in Dynamics CRM; here’s a dump of those attributes for a working contact:

Attribute Key Value
adx_changepasswordatnextlogon False
adx_identity_emailaddress1confirmed False
adx_identity_lockoutenabled True
adx_identity_logonenabled True
adx_identity_mobilephoneconfirmed False
adx_identity_passwordhash (omitted for security reasons)
adx_identity_securitystamp ca49a664-0385-4eb4-90c0-6283c9e704ea
adx_identity_twofactorenabled False
adx_identity_username ali_baba
adx_lockedout False
adx_logonenabled False
adx_profilealert False
adx_profileisanonymous False
adx_profilemodifiedon 2016-07-20 09:18:43

The ASP.NET Identity model is generally pretty flexible, but I have a hunch that the username and the security stamp are both required fields because they’re fundamental to the way authentication works. So, let’s try inserting some code into the AuthenticateRequest handler that will check these fields exist, and update them directly in CRM if they don’t:

protected void Application_AuthenticateRequest(object sender, EventArgs e) {
Guid userGuid;
var cookie = Request.Cookies[“crm_contact_guid”];
if (cookie != null && Guid.TryParse(cookie.Value, out userGuid)) {
var http = HttpContext.Current;
var owin = http.GetOwinContext();
var userManager = owin.Get<ApplicationUserManager>();
    var user = userManager.FindById(userGuid.ToString());
    if (String.IsNullOrEmpty(user.UserName)
) {
// “Xrm” is the connection string name from web.config
using (var crm = new OrganizationService(“Xrm”)) {
var entity = crm.Retrieve(“contact”, userGuid, new ColumnSet(true));
entity.Attributes[“adx_identity_securitystamp”] =
entity.Attributes[“adx_identity_username”] =
Guid.NewGuid().ToString().Substring(0, 8);

var identity = user.GenerateUserIdentityAsync(userManager).Result;
HttpContext.Current.User = new RolePrincipal(identity);

(For the sake of this demo, all we care about is making sure those values are no longer null. In reality, make sure you understand the significance of the username and security stamp fields in the identity model, and populate them with suitable values.)

OK, this now works sometimes – but only following an IISRESET. Turns out that Adxstudio is actually caching data from CRM locally, so although that new chunk of code is updating the Contact entity into a valid identity, the Adxstudio local cache doesn’t see those changes because it’s looking at an out-of-date copy of the Contact entity. So… time to configure some cache invalidation.

You can read about Adxstudio’s web notifications feature here. Adxstudio includes some code that will call a cache invalidation handler on your own site every time an entity is updated. Which works just fine IF CRM Online can see your Adxstudio portal site. And right now I’m running CRM Online as a 30-day trial and I’m running Adxstudio on localhost, and my workstation isn’t on the internet, so CRM Online can’t see it.

Time to fire up my favourite toolchain – Runscope and Ngrok. First, I’ve set up ngrok so that any requests to will be forwarded to my local machine – you’ll need a paid ngrok license to use custom tunnel names, but if you’re using the free version try this:

D:toolsngrok>ngrok http –host-header=adx.local 80


Now, as long as that NGrok process is running, you can hit that URL – – from anywhere on the internet, and it’ll be tunneled to localhost on port 80 and have the host-header rewritten to be adx.local. This neatly solves the problem of CRM Online not being able to connect to my local Adxstudio instance.

Next, just to give us a bit of insight into what’s going on, I’m going to set up a Runscope bucket for that. Remember – we need to route requests to /cache.axd on our local Adxstudio portal instance, via ngrok, so here’s how to get the Runscope URL you’ll need:


So, last step – you see that big URL in the middle?  We need to tell the Adxstudio Web Notifications plugin to notify that URL every time something changes. The option is under CRM > Settings > Web Notification URLs.

Note that the Adxstudio documentation refers to a Configuration screen accessible from the Solutions > Adxstudio Portals Base. It appears this screen doesn’t exist any more – I certainly couldn’t find any trace of it in my CRM Online instance – but it also appears it isn’t necessary, because as soon as I’d created and active Web Notification URL things started happening.

So, now we have something that works – but it still fails on the first Portal request for a particular Contact, probably because the Adxstudio cache isn’t picking up those two new fields fast enough for the login to succeed. To work around this, I’ve put in a thread sleep and then an HTTP redirect, so the first time a user lands on the portal they’ll get a slight delay whilst we populate their Adxstudio attributes, and then they’ll get their personalised screen:

protected void Application_AuthenticateRequest(object sender, EventArgs e) {
Guid userGuid;
var cookie = Request.Cookies[“crm_contact_guid”];
if (cookie != null && Guid.TryParse(cookie.Value, out userGuid)) {
var http = HttpContext.Current;
var owin = http.GetOwinContext();
var userManager = owin.Get<ApplicationUserManager>();
    var user = userManager.FindById(userGuid.ToString());
   if (String.IsNullOrEmpty(user.UserName)
) {
using (var crm = new OrganizationService(“Xrm”)) {
var entity = crm.Retrieve(“contact”, userGuid, new ColumnSet(true));
entity.Attributes[“adx_identity_securitystamp”] =
entity.Attributes[“adx_identity_username”] =
Guid.NewGuid().ToString().Substring(0, 8);
// Redirect back to the same page, so that Adxstudio will
// retrieve a fresh copy of the cached data.

var identity = user.GenerateUserIdentityAsync(userManager).Result;
HttpContext.Current.User = new RolePrincipal(identity);

And it works. The final step for me was to spin up a separate web app that lists all the Contacts in the CRM system, with a login handler that puts the CRM Contact GUID into a cookie and redirects the browser to http://adx.local/ – and it works. No registration, no login, and any user with a valid CRM Contact GUID can now log directly into the Adxstudio MasterPortal example.

Affordances, Signifiers, and Cartographobia

One of the teams here is putting the finishing touches on a new online version of Spotlight Contacts, our venerable and much-loved industry guide that started life as a printed handbook way back in 1947. Along the way, we’ve learned some very interesting things about data, and how people perceive that their data is being used.


One of the features of the new online version is that every listing includes a location map – a little embedded Google Map showing the business’ location. When we rolled this feature out as part of a recent beta, we got some very unhappy advertisers asking us to please remove the map from their listing immediately. Now, most of these were freelancers who work from home – so you can understand their concerns. But what’s really interesting is that in most cases, they were quite happy for their full street address to stay on the page – it was just the map that they were worried about.

Of course, this immediately resulted in a quite a lot of “what? they want to keep the address and remove the map? ha ha! that’s daft!” from developers – who, as you well know, are prone to occasional outbursts of apoplectic indignation when they have to let go of their abstractions and engage with reality for any length of time – but when you think about it, it actually makes quite a lot of sense.

See, street addresses are used for lots of things. They’re used on contracts and invoices, they’re used to post letters and deliver packages. Yes, you can also use somebody’s address to go and pay them a visit, but there are many, many reasons why you might need to know somebody’s address that have nothing to do with you turning up on their doorstep. In UX parlance, we’d say that the address affords all of these interactions – the presence of a street address enables us to post a letter, write a contract or plan a trip.

A map, on the other hand, only affords one kind of interaction; it tells you how to actually visit somewhere. But because of this, a map is also a signifier. It sends a message saying “come and visit us” – because if you weren’t actually planning to visit us, why would you need to know that Spotlight’s office at 7 Leicester Place is actually in between the cinema and the church, down one of the little alleys that run between Leicester Square and Chinatown? For posting a letter or writing a contract, you don’t care – the street address is enough. But by including a map, you’re sending a message that says “hey – stop round next time you’re in the neighbourhood”, and it’s easy to see why that’s not really something you want if you’re a freelancer working from your home.

It’s important to consider this distinction between affordances and signifiers when you’re designing your user interactions. Don’t just think about what your system can do – think about all the subtle and not-so-subtle messages that your UI is sending.

Here’s the classic Far Side cartoon “Midvale School for the Gifted”, which provides us with some great examples of affordances and signifiers. The fact you can pull the door is an affordance. The sign saying PULL is a signifier – but the handle is both. Looking at it gives you a clue “hey – I could probably pull that!” – and when you do, voila, the door swings open. If you’ve ever found a door where you have to grasp the handle and push,, then you’ve found a false affordance – a handle that’s sat there saying ‘pull me…’ and when you do, nothing happens. And, in software as in the Far Side, there’s going to be times when all the affordances and signifiers in the world are no match for your users’ astonishing capacity to ignore them all and persist in doing it wrong.

(Far Side © Gary Larson)

ASP.NET Core 1.0 High Performance

Former Spotlighter James Singleton – who worked on our web team for several years and built some of our most popular applications, including our video/voice upload and playback platform – has just published his first book, ASP.NET Core 1.0 High Performance. Since the book includes one or two things that James learnt during his time here at Spotlight, he was gracious enough to invite me to contribute the foreword – and since the whole point of a foreword is to tell you all why the book is worth buying, I figured I’d just post the whole thing. Read the foreword, then read the book (or better still, buy it then read it.)

TL;DR: it’s a really good book aimed at .NET developers who want to improve application performance, it’s out now, and you can buy your copy direct from

And that foreword in full, in case you’re not convinced:


“The most amazing achievement of the computer software industry is its continuing cancellation of the steady and staggering gains made by the computer hardware industry.”
– Henry Petroski

We live in the age of distributed systems. Computers have shrunk from room-sized industrial mainframes to embedded devices smaller than a thumbnail. However, at the same time, the software applications that we build, maintain and use every day have grown beyond measure. We create distributed applications that run on clusters of virtual machines scattered all over the world, and billions of people rely on these systems, such as email, chat, social networks, productivity applications and banking, every day. We’re online 24 hours a day, 7 days a week,  and we’re hooked on instant gratification. A generation ago we’d happily wait until after the weekend for a cheque to clear, or allow 28 days for delivery; today, we expect instant feedback, and why shouldn’t we? The modern web is real-time, immediate, on-demand, built on packets of data flashing round the world at the speed of light, and when it isn’t, we notice. We’ve all had that sinking feeling… you know, when you’ve just put your credit card number into a page to buy some expensive concert tickets, and the site takes just a little too long to respond. Performance and responsiveness are a fundamental part of delivering great user experience in the distributed age. However, for a working developer trying to ship your next feature on time, performance is often one of the most challenging requirements. How do you find the bottlenecks in your application performance? How do you measure the impact of those problems? How do you analyse them, design and test solutions and workarounds, and monitor them in production so you can be confident they won’t happen again?

This book has the answers. Inside, James Singleton presents a pragmatic, in-depth and balanced discussion of modern performance optimization techniques, and how to apply them to your .NET and web applications. Starting from the premise that we should treat performance as a core feature of our systems, James shows how you can use profiling tools like Glimpse, MiniProfiler, Fiddler and Wireshark to track down the bottlenecks and bugs that are causing your performance problems. He addresses the scientific principles behind effective performance tuning – monitoring, instrumentation, and the importance of using accurate and repeatable measurements when you’re making changes to a running system to try and improve performance.

The book goes on to discuss almost every aspect of modern application development – database tuning, hardware optimisations, compression algorithms, network protocols, object-relational mappers. For each topic, James describes the symptoms of common performance problems, identifies the underlying causes of those symptoms, and then describes the patterns and tools you can use to measure and fix those underlying causes in your own applications. There’s in-depth discussion of high-performance software patterns like asynchronous methods and message queues, accompanied by real-world examples showing how to implement these patterns in the latest versions of the .NET framework. Finally, James shows how you can not only load test your applications as part of your release pipeline, but can continuously monitor and measure your systems in production, letting you find and fix potential problems long before they start upsetting your end users.

When I worked with James here at Spotlight, he consistently demonstrated a remarkable breadth of knowledge, from ASP.NET to Arduinos, from Resharper to resistors. One day he’d be building reactive front-end interfaces in ASP.NET and JavaScript, the next he’d be creating build monitors by wiring microcontrollers into Star Wars toys, or working out how to connect the bathroom door lock to the intranet so that our bicycling employees could see from their desks when the office shower was free. Since James moved on from Spotlight, I’ve been following his work with Cleanweb and Computing 4 Kids Education. He’s one of those rare developers who really understands the social and environmental implications of technology – that whether it’s delivering great user interactions or just saving electricity, improving your systems’ performance is a great way to delight your users. With this book, James has distilled years of hands-on lessons and experience into a truly excellent all-round reference for .NET developers who want to understand how to build responsive, scalable applications. It’s a great resource for new developers who want to develop a holistic understanding of application performance, but the coverage of cutting-edge techniques and patterns means it’s also ideal for more experienced developers who want to make sure they’re not getting left behind. Buy it, read it, share it with your team, and let’s make the web a better place.

Check it out. The chapter on caching & message queueing is particularly good 🙂

Quality of Life with Git and Pivotal

At Spotlight we are currently using Pivotal Tracker as our planning tool and git for version control. One of the obvious things to do is to connect code changes to stories by including the story id in the branch and commit messages. This allows you to cross reference between the two and track why you did what code changes.

But developers are lazy beasts, the pivotal numbers are long, and life is too short to write [#123456789] a gazillion times a day. Let’s see how we can improve it!

Automated branch creation

If you follow the standard git workflow, the first thing to do when starting some work is to create a branch. The branch should have a story number, as well as a meaningful title. Luckily, pivotal has a very nice REST api we can use directly from curl to free us from burden of typing the branch name:

STORY_ID=`grep -o '[0-9]*' <<< $1} `
NAME=`curl -X GET -H "X-TrackerToken: $TOKEN" "$PROJECT_ID/stories/$STORY_ID" | grep -o '"name":"[^"]*"'| head -1 | sed "s/'//" | sed s/'"name":"'// | sed s/'"'//g | sed s/' '/'_'/g | sed s/'#'//g | sed s~/~_~g | sed s/,//g`

git checkout -b $branchName
git push origin -u $branchName

Yes, my bash is horrendous, so if your eyes are melting from reading it here is what it does: you pass the pivotal story id, the script curls the story as json, extracts the name and replaces characters that would upset git. Then it creates a branch and pushes it to the origin upstream repo.

Stick it into a file (eg., put this in your PATH and set chmod 755. For added automation, set it as your git alias and hey presto! Guaranteed to work 99% of the time.


This gets the job done, the only downside being that the branch names sometimes end up being too long. But that’s just an added incentive to keep the story titles short.

Add [#story id] if you are committing to a story branch

We can (hopefully) assume that people will not start their branch with a number, so we can try to filter them on commit:

BranchName=`git rev-parse --abbrev-ref HEAD`
TicketNo=`grep -o '^[0-9]*' <<< $BranchName`
if [ -n "$TicketNo" ] 
 git commit -m "[#$TicketNo] $1"
 git commit -m "$1"

Now you can just type your commit message, and git will add the story number if you are on a story branch. That saves us 11 keystrokes per commit! How cool is that?


And just for completion, the git aliases I am using that go into .gitconfig

 cm = !
 grab = !

Enjoy one line git-pivotal experience!

Exupérianism: Improving Things by Removing Things

Last night this popped up on Twitter:

Last year, as part of migrating our main web stack to AWS, we created a set of conventions for things like connection strings and API endpoint addresses across our various environments, and then updated all of our legacy systems to use these conventions instead of fragile per-environment configuration. This meant deleting quite a lot of code, and reviewing pull requests with a lot more red lines than green lines in them – I once reviewed a PR which removed 600 lines of code across fifteen different files, and added nothing. No new files, no new lines – no green at all – and yet that change made one of our most complicated applications completely environment-agnostic. It was absolutely delightful.

When I saw John’s tweet, what instantly came to mind was a quote from Antoine de Saint-Exupéry:

“Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.”

So how about we adopt the term “Exupérian” for any change which improves something by making it smaller or simpler? The commit that removes 600 lines of unnecessary configuration. The copy-edit that turns fifteen thousand words of unstructured waffle into ten thousand words of focused, elegant writing. Maybe even that one weekend you spent going through all the clutter in your garage and finally getting rid of your unwanted lamps and old VHS tapes.

Saint-Exupéry was talking about designing aircraft, but I think the principle is equally applicable to software, to writing, to music, to architecture – in fact, to just about any creative process. I was submitting papers to a couple of conferences last week, and discovered that Øredev has a 1,000-character limit for session descriptions. Turns out my session descriptions all end up around 2,000-3,000 characters, and editing those down to 1,000 characters is really hard. But – it made them better. You look at every single word, you think ‘does it still work if I remove this?’, and it’s surprising how often the answer is ‘yes’.

Go on, give it a try. Do something #exuperian today. Edit that email before you send it. Remove those two classes that you’re sure aren’t used any more but you’re scared to delete in case they break something. Throw out the dead batteries and expired coupons from your desk drawer. Remove a pointless feature nobody really wants.

Maybe you even have an EU cookie banner you can get rid of? 🙂