All posts tagged Development

SharePoint Custom Solution Crashes IIS Worker Process (w3wp.exe) – Part 2

In Part 1 of this series, I discussed an issue we were having in one of our SharePoint 2013 farms and how I determined the issue was occurring because of a set of event receivers acting on the library.  In this post, I will discuss the code being used and what the final result was determined to be.  Stick around, it’s not what you think.

To be terribly honest nothing jumped out at me while looking over the code.  The initial review of the code indicated the issue could be around where the event receiver was trying to determine if the user adding the file was a member of the site owner group.  The original code was:

This seems pretty straight forward, but when “CheckIfUserInSPGroup” is called things aren’t quite as kosher.

Again, normally not a huge issue, except that best practices state that you shouldn’t instantiate SPSite, SPWeb or SPList objects within an Event Receiver.  The reason for this is it causes extra database calls (more information here: https://msdn.microsoft.com/en-us/library/office/ee724407(v=office.14).aspx).  I thought this could be the culprit, but wasn’t convinced.  If this was the issue, why does it work fine for years and then suddenly stop working?  The reason the code is instantiating the SPSite and SPWeb object is it is used elsewhere in the solution and could be called by users who do not have the required access.  The same goes for the event receiver.  If I do not have access to control security groups in the site, I get an UnauthorizedAccessException.

So I thought, why not just use that.  We can safely assume that if the UnauthorizedAccessException error is thrown, the user is not in the Owners group.  So I updated the code with a try\catch (why one wasn’t already being used I don’t know) and added some logic into the catch.  Not generally the best method, but when used for targeted exceptions I believe acceptable IMHO.

I also created a new method for the event receiver to call.  I couldn’t modify the existing one, as it contained valid logic to handle users without access and was being used elsewhere.

So I moved the code into Pre-Prod and tried it out.  No change.  Still hanging, throwing errors and crashing the app pool.

Next step was to install Visual Studio into Pre-Prod and attach to the IIS Worker process.  I followed the code until it got into the newly created CheckIfUserInSPGroupEvntRcvr method.  There it stayed.  It kept looping through the AD users and groups within the SharePoint group.  As it was looping I watched the worker process memory usage grow and grow until it finally crashed again.  This didn’t make any sense as there are NOT that many users in these groups.

The Cause of it All

I took a look at the ownership group for the site I was testing with.  Like most (not all) of our project sites, it contained an AD group that contains our project team.  Let’s call that group All-Project.  All-Project had about a dozen users within it, however, there was an anomaly.  It also contained the Owners group from another project site.  This was an oddity.  I took a look at the Owner group and it also contained the same All-Project group. There was the culprit.

As you can see in the code above, it is designed for nested groups, so if the code hits a group it digs down to see if the nested group contains the user.  Because this Owner group was added (in error I found out while trying to figure out why it was there) to the All-Projects group, the code would dig into All-Projects then to the Owners group, from there back into the All-Projects group and then back into the Owners group… see where I am going with this?  By adding that single group to the All-Projects group in error an infinite recursion loop was created in the code.

The Final Fix

So the final fix was not an environmental change or a code modification.  It was simply to remove the Owners group from the All-Projects group.  Once that was done, the original code functioned as designed.  If this becomes a regular occurrence I will have to update the code to handle such an event, but in this case, I didn’t.  The farm is in containment (no further development short of break\fix) and the issue has not occurred for two years before this.  I hope the steps I documented in this blog series helps others out.

 

Thanks for reading!

Customize SharePoint Forms with KendoUI Grid

Today I am going to shift gears a bit from ITPro\Admin topics to a dev based topic. I would like to show you how to customize SharePoint forms with KendoUI Grid. Everything I cover in this post can be done in either SharePoint On-Premise or SharePoint Online (O365).

I recently had a need to add a field to a SharePoint form that contained multiple columns of its own data. For example a table or grid within the form itself. A couple of OOTB ideas to handle this could be a lookup field that also brings in additional fields from the lookup list:

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Let’s Do Away with Best Practices

Wait! Before you call out the angry mob with the torches and pitch forks allow me to explain:

bring_all_the_pitchforks

I think the concept of best practices is absolutely fantastic.  It allows members of different communities (IT or other) to find out what is considered the best way to perform a task.  Whether that task is to create a form letter informing users of an opportunity or building a SharePoint environment (*ahem*, like this one), knowing the best methods to accomplish that need is extremely important, so no, I am not against best practices.  I am actually against the term\phrase “Best Practice”

Away With Best Practices

I hope the pitchforks have been put away and the torches doused.  Let me explain a bit further.  Bear with me as I freely admit that this is completely subjective.  The problem I have with the term best practice is in what it implies.  When you think of the word “best”, what comes to mind?  For me it is this is the highest level we can achieve.  This is the only way that we should do it and nothing else can replace it.  And there-in lies the problem.  If it is the only way something should be done ever, how can we improve?  In IT we know the best way to do something changes constantly.  Sometimes within days (a bit extreme I know, but it has been known to happen).

Let’s add a bit to this.  Another common thing heard is “current best practice”.  So if it is current, then that means it is expected to change. But if it is the best; how can it change?  See where I am going with this?

What Should We Use Instead?

I am not a word smith.  I spend most of my day writing code or configuring systems to make a user’s experience better.  However, since I have brought this up I should at least provide a suggestion of an alternative.  I personally prefer something like Leading Practice.  To me this implies, this is the way things should be done now, but there are also other great ways to do it or with time better ways could be found.  It encourages people to think, “this is good, but perhaps there is a better way”.  It doesn’t encourage people to think it shouldn’t be used.  To me it instills a sense of confidence in the method without causing people to believe it will always be the only way.

Let me know in the comments what you think?  Do you agree?  Am I out to lunch?  Do you have a suggestion for a descriptive phrase besides Leading Practices?

 

Thanks for reading!