Heads-up if you use ADAL.JS on a site added to the “Trusted Sites” zone

When working on a SharePoint Online solution that is using the ADAL.JS library for authentication, a customer reported strange problems. In our solution, our site sends the client to the authentication authority (Azure AD), which authenticates the client and forwards it to the reply URL which in turn returns the client to the original page in a logged in state.

The problems we saw were mainly that the clients tended to get stuck in an authentication loop, where the client seemed to correctly receive a token from the authority, but our ADAL-based solution did not see the authenticated user and thus sent the browser back to be authenticated, in a seemingly endless loop. The behavior was quite erratic though – sometimes the clients were actually able to log in, either directly or after several tries. Other times it eventually failed and stopped somewhere in the “loop”.

The oddest behavior was however that the browser tab (or whole browser if only one tab) could sometimes simply just close by itself!

I experienced this myself on IE11, but the customer reported that same happening in Chrome too. A clue was that it only happened on the customer’s computers when logged in through their VPN, and only against their own SharePoint Online tenant.

Eventually we cracked the problem. Turns out that the customer had put SharePoint Online (https://customer-tenant.sharepoint.com) in the Trusted Sites zone under Internet Options in Windows. But authentication with ADAL.JS relies on a hidden iFrame working against a different URL. Because the site and iFrame belonged to different security zones, they were no allowed to share cookies.

The solution was to simply put the authentication authority (https://*.microsoftonline.com) in the Trusted Sites zone as well.

This weakness and solution is actually stated in the ADAL.JS readme, but it is easy to miss or forget, and quite hard to figure out the cause if it happens. Hopefully this post will save someone from this agony.

PS: Need to view all trusted sites, but the list can not be scrolled due to being controlled by a group policy? Superuser has the answer!

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Downloading OneDrive documents as PDF

As part of automating a build process I needed a way to download the product documentation from OneDrive and save as PDF files for shipping with product. The result is this PowerShell script with two cmdlets, one that takes an array or OneDrive files to download, and one that converts the downloaded DocX files to PDF (using Word). Here is the script (also on my GitHub):


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A drag-and-drop GUI made with PowerShell

The script below shows how to create a simple WinForms GUI in PowerShell, where you can drag and drop files and folders and then process these with PowerShell commands when you click the button. I’ve pieced this together using various online source and my own trial and error, and figured it might be useful as a base for others who need to create an interface.


I probably won’t win any design prices with this one :-)

Tip: If you are unsure of control names or how to use properties on a control, remember that you can always launch Visual Studio with a WinForms project and then inspect the Properties window and Form1.Designer.cs file for “inspiration”.

Here is the script (or get it at GitHub).

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Think twice before uploading assets to Sharepoint Online

Here’s a heads up if you are uploading assets such as CSS files to SharePoint Online. In a solution I’m working on we have an “Alternate CSS” file that we upload to the master page gallery. It contains the following line:

Nothing special there. Everything was fine until one day when the icons stopped loading. Debugging led me to the CSS file, in which above line had been changed:

Notice that “//mytenant.sharepoint.com” has been added to the url. When I saw this I assumed I had made some error. I checked my original files and upload procedures, but could find nothing wrong. Provisioning the file again fixed the problem everyone was happy.

But a month or so later it happened again. Could SharePoint be modifying the file? We contacted Microsoft support and asked if they knew anything about it. They confirmed that they do indeed modify files in SharePoint Online through a time job that runs before site colection updates. Basically their response was: Deal with it.

So how *do* we deal with this? What we did was to replace “//” with “https://”. So far this seems to be working, but we are aware that it might break at any time. To be really sure you will want to skip @import statements (and other URL:s) in files you upload to SharePoint. But we don’t know what kind of files Microsoft takes the liberty to modify, nor if they process all locations or just the master page gallery. The only safe solution is probably to skip SharePoint altogether and move the files to a separate web server that you are in control of.

What we have to remember is that SharePoint Online is a cloud service, and as such, the operator is in complete control of changes. There are a lot of hidden rules and jobs going on behind the scenes in SharePoint Online that customers are not aware of. Microsoft does not necessarily tell us when changes happen or what the implications will be. And they might change the rules at any time. So we need to be cautious, even when dealing with with supported features such as Alternate CSS.

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Converting a CSV file to RegX with PowerShell

If you need to convert a CSV file with terms to a RegX file for use in your .Net project, you can use this simple PowerShell script:

The script assumes your CSV file contains two columns, “Name” and “Value”, such as this:

You can use Excel to export such files. You may need to change the -Delimiter parameter in the script to match your locale (Why? See my post on working with CSV files in Excel).

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Working with enterprise custom fields in Project Online

I was tasked with with writing a utility for setting Enterprise Custom Fields on User Resources in Microsoft Project Online. The fields got their values from Lookup Tables. Since is was Project Online, the client side object model, CSOM, had to be used. Without previous experience of MS Project, this proved to be tricky.

Here I present a C# class that should help anyone in the same situation to get started. It is a simple console application that show various ways to interact with MS Project, and in particular how to extract available custom field values and and set on user resources. Below are some interesting snippets of the code showing how to work with Project and CSOM. The complete class can do more and is available at the bottom as well as on GitHub.


Project Online is a (very) customized SharePoint site collection. We can use same techniques when working with it as with any SharePoint Online site. As always, we need to begin with getting a context. In this case we request a ProjectContext which is just a normal SharePoint context object with additional properties:


As always in CSOM, we need to explicitly load all resources we need to access:


Listing enterprise custom fields and lookup table entries is simply a matter of iterating over the respective properties:


A user resources is not the same as the user object. It seems that we can’t trust that all users emails are synced to Project Online. To get around this, I load user resource using the login name instead of just the email, by simply appending the claims prefix to the email:


Now we can get the custom fields from the user resource. Note that fieldValue is a string array, because it can be multi valued.


To set a custom field with the value of a lookup table we need to understand the internal structure:

  • Each value in both the custom fields and lookup tables have a GUID, an internal name and a display name (also called simply name or full value). (The internal name is actually a concatenation of the GUID and a word like “custom” or “entry”.)
  • A custom field may be bound to a lookup table. We use the internal name of the lookup table entries to set such custom fields.
  • Since these are custom fields, the compiler is not aware of them. In order to set such a field we need to access it using an [indexer] together with the internal name.
  • Since field values can be multi-valued, we need to set it using a string array.
  • Finally, to persist the changes we need to update the EnterpriseResources collection, because this is where the resources are stored.

Now that we know all this, it is actually quite easy to set the field! Assuming that we already have the internal names of the custom field and lookup table entry we wish to set it to:


Putting all of this together, I made a class that can be used to read and write custom fields, and also shows how to list a bunch of information from Project sites and its users. Use it as a template to make your own solution. You need to modify it to use your own login information and GUID:s before you can use it. Again, the full Visual Studio solution can be downloaded from GitHub.


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See what Boostrap screen mode you are currently viewing

Working with a responsive framework such as Bootstrap, you build websites to display differently depending on the screen size. Bootstrap defines four screen widths that determine what “mode” you are in (xs, sm, md and lg). But it’s not always obvious what mode you are viewing. For this I put together a small piece of CSS that can be dropped into any project during development. It will display a label in the top left corner that shows the mode you are currently viewing. Here is a demo. Resize the window to see the label change!

screen mode label

This is the CSS. The screen sizes are based on Bootstrap 3 but can easily be changes to any kind of framework.

Note: The screen widths above are hard coded pixel sizes, so this CSS does not depend on any framework. To the right of each @media I have written the corresponsing Bootstrap LESS variable (@screen-xx). Replace the ###px with the variable to make sure it is always correct.

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Why image renditions are slow in SharePoint Online

Image renditions are supposed to be a great way to speed up SharePoint. But if you’ve ever tried to use them in SharePoint Online you have probably noticed that the images load very slow. It’s usually even faster to get the original high resolution image instead. If you look at the network requests, you’ll see that most of the time the browser is just waiting for the server to respond. Actually downloading the image data takes no time at all. But why?

This is what I think is happening: Image renditions rely on front end caching. But SharePoint Online is a huge farm with lots and lots of front ends. When you request an image rendition it will be generated and cached. But the next time you make a request for the same image rendition, the probability that you get a cache hit is very small. You will probably be served by another front end server, and even if you are served by the same server, it handles so many requests that your image rendition has already been dropped from the cache.

Thanks to my friend Dan Andersson for helping me figure out this.

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Edit SharePoint property bags with SpPropertyBag.js bookmarklet

SpPropertyBag.js is a drop-in JavaScript for editing SharePoint web properties (the “property bag”). Simply paste the script into the JavaScript console and run it to open a dialog where you can view, edit, add, and remove properties:


Even easier is to use it as a bookmarklet in your web browser that you can click when you need access to the web properties! Simply paste this code into a new link in your browser’s toolbar:

Here is the full script. It is also available for forking at GitHub.


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