I have not updated the MessageWire library for about a year now. But it still works just fine. Mostly. New Year's resolution #1: Update MessageWire.
Dependency Hell
I'm cleverly using MessageWire to create a customized shared session service for a hybrid set of web applications that include old ASP.NET Web Forms running in .NET Framework 4.6.1 and newer, upcoming, web sites built on ASP.NET Core 2.0. So first it had to work with the older Web Forms site. And it did work. Very well. I'll share some of that fun code on another day in another post.
What did not go well is that my Web Forms site using a library that uses HttpClient in System.Net.Http to call an internal web service suddenly failed.
Here's the HTTP request before pulling MessageWire into the project.
POST http://localhost:53739/api/ProfileDetail HTTP/1.1
Accept: application/json
Content-Type: application/json; charset=utf-8
Host: localhost:53739
Content-Length: 592
{"Id": "…removed actual data…"}
And here's the same request after pulling MessageWire into the project with no other code changes.
POST http://localhost:53739/api/ProfileDetail HTTP/1.1
Connection: Keep-Alive
Transfer-Encoding: chunked
Content-Type: application/json; charset=utf-8
Accept: application/json
Accept-Encoding: gzip, deflate
Host: localhost:53739
250
{"Id": "…removed actual data…"}
0
See the problem? Yikes, my web service was unable to deserialize the second request created with HttpClient v4.3.0, so of course, that led to a huge failure.
Everyone's Worst Nightmare
What's worst about this is that I did not know about this side effect and this code made it into production causing a nightmare during a critical moment of the day and the month. Of course we rolled it back to stop the bleeding, but damage was done and folks were not happy with me in the least. It took me the rest of the day to find the symptoms of the cause which precipitated the failure.
The fact that it took me so long felt like another failure. Even with the final discovery that the HTTP request was borked, I was clueless as to its exact cause. I even engaged several team members to pour through my code to find the problem with the code I had committed. They could not find it.
So today, with less pressure on, I began methodically thinking of it and tracing back the code that generates the HTTP request. Ultimately it came down to HttpClient in System.Net.Http. This led me to discover that pulling in MessageWire into my ASP.NET Web Forms application on .NET Framework 4.6.1 also pulled in the flawed System.Net.Http version 4.3.0 package.
Light bulb moment! Check for updates. Sure enough, there was a System.Net.Http 4.3.3 available. And boom goes the dynamite! The request was back to looking normal and working just fine with the service being called.
MS OSS Buyer Beware!
When you pull in any new NuGet package which brings with it some dependencies, be sure you check out any updates to those dependencies. Shocking as it may seem, even Microsoft's packages can contain nasty little bugs. And test your assumptions.