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ASP.NET und mehr ...

Mehr oder weniger regelmäßig werden Artikel auf meinem Blog auf ASP.NET Zone veröffentlicht: ASP.NET und mehr...

Live streaming ideas

Friday, July 20, 2018 12:00 AM

With this post, I'd like to share some ideas about two live streaming shows with you. It would be cool to get some feedback from you, especially from the German speaking readers as well. The first idea is about an German speaking .NET Developer Community Standup and the second one is about a live coding stream (English or German), both hosted on Google Hangouts.

A German speaking .NET Developer Community Standup

Since the beginning of the ASP.NET Community Standup, I watch this show more or less regularly. I think I missed only two or three shows. Because of the different time zone it is almost not possible to watch the live stream. Anyway. I really like the format of that show.

Also since a few years the number of user group attendees decreases. In my user group sometimes only two or three attendees show up, even if we have a lot more registrations via meetup. We (Olivier Giss and me) have kinda fun hosting the user group, but it is also hard to push much effort in it for just a handful of loyal attendees. Since a while we record the sessions using skype for business or google hangouts and push them to YouTube. This gives some more folks the chance to see the talks. We thought a lot about the reasons and tried to change some things to get more attendees, but that didn't really work.

This is the reason why I'm thinking laud about a .NET Developer Community Standup for the German speaking region (Germany, Austria and Switzerland) since months.

I'd like to find two more people to join the team to host the show. Would be cool to have a person from Austria as well as from Switzerland. Since I'm a swiss MVP, I could also take over the swiss part in behalf ;-) In that case I would like to have another person from Germany. One host per country would be cool.

Three host is a nice number and it wouldn't be necessary for the hosts to be available every time we do a live stream. Anyone interested in joining the team?

To keep it simple I'd also use google hangouts to stream the show, and it is not necessary to have an high end steaming equipment. A good headset and a good internet connection should be enough.

In the show I would like to go threw some interesting community and technology news. Talking about some random stuff and I'd also like to invite special guests, who can show us things they did or who would like to talk about special things. This should be a lazy show about interesting stuff about technology and community. I'd also like to give community leads the chance to talk about their work and their events.

What are you thinking about that? Are you interested in?

If yes, I would set up a GitHub repo to collect ideas and topics to talk about.

Live Coding via Live Stream on Google Hangouts

Another idea is inspired by Jeff Fritz live stream on Twitch called "Fritz and Friends". The recorded streams are published to YouTube afterwards. I really like this live stream, even if it's a completely different kind of video to watch. Jeff is permanently in discussion with the users in the chat, while working on his projects. This is kinda wired and makes the show a little nervous, but it is also really interesting. The really cool thing is that he accepts pull request from his audience and he discuss their changes with the audience while working an his project.

I I would do such a live stream as well, there were a few projects I would like to work on:

Maybe it makes also sense to invite a special guest to talk about specific topics while working on the project. e.g. inviting Dominick Baier to implement authentication to the developer community platform.

What if I do the same thing? Are you interested in? What would be the best Language for that kind of life stream?

If you are interested, I would also set up a GitHub repo to collect ideas and topics to talk about and I would setup additional repos per project.

What do you think?

Do you like these ideas? Do you have any other idea? Please drop me a comment and share your thoughts :-)

Configuring HTTPS in ASP.NET Core 2.1

Monday, July 9, 2018 12:00 AM

Finally HTTPS gets into ASP.NET Core. It was there before back in 1.1, but was kinda tricky to configure. It was available in 2.0 bit not configured by default. Now it is part of the default configuration and pretty much visible and present to the developers who will create a new ASP.NET Core 2.1 project.

So the title of that blog post is pretty much misleading, because you don't need to configure HTTPS. because it already is. So let's have a look how it is configured and how it can be customized. First create a new ASP.NET Core 2.1 web application.

Did you already install the latest .NET Core SDK? If not, go to to download and install the latest version for your platform.

Open a console and CD to your favorite location to play around with new projects. It is C:\git\aspnet\ in my case.

mkdir HttpsSecureWeb && cd HttpSecureWeb
dotnet new mvc -n HttpSecureWeb -o HttpSecureWeb
dotnet run

This commands will create and run a new application called HttpSecureWeb. And you will see HTTPS the first time in the console output by running an newly created ASP.NET Core 2.1 application:

There are two different URLs where Kestrel is listening on: https://localhost:5001 and http://localhost:5000

If you go to the Configure method in the Startup.cs there are some new middlewares used to prepare this web to use HTTPS:

In the Production and Staging environment mode there is this middleware:


This enables HSTS (HTTP Strinct Transport Protocol), which is a HTTP/2 feature to avoid man-in-the-middle attacks. It tells the browser to cache the certificate for the specific host-headers and for a specific time range. If the certificate changes before the time range ends, something is wrong with the page. (More about HSTS)

The next new middleware redirects all requests without HTTPS to use the HTTPS version:


If you call http://localhost:5000, you get redirected immediately to https://localhost:5001. This makes sense if you want to enforce HTTPS.

So from the ASP.NET Core perspective all is done to run the web using HTTPS. Unfortunately the Certificate is missing. For the production mode you need to buy a valid trusted certificate and to install it in the windows certificate store. For the Development mode, you are able to create a development certificate using Visual Studio 2017 or the .NET CLI. VS 2017 is creating a certificate for you automatically.

Using the .NET CLI tool "dev-certs" you are able to manage your development certificates, like exporting them, cleaning all development certificates, trusting the current one and so on. Just time the following command to get more detailed information:

dotnet dev-certs https --help

On my machine I trusted the development certificate to not get the ugly error screen in the browser about an untrusted certificate and an unsecure connection every time I want to debug a ASP.NET Core application. This works quite well:

dotnet dev-cert https --trust

This command trusts the development certificate, by adding it to the certificate store or to the keychain on Mac.

On Windows you should use the certificate store to register HTTPS certificated. This is the most secured way on Windows machines. But I also like the idea to store the password protected certificate directly in the web folder or somewhere on the web server. This makes it pretty easy to deploy the application to different platforms, because Linux and Mac use different ways to store the certificated. Fortunately there is a way in ASP.NET Core to create a HTTPS connection using a file certificate which is stored on the hard drive. ASP.NET Core is completely customizable. If you want to replace the default certification handling, feel free to do it.

To change the default handling, open the Program.cs and take a quick look at the code, especially to the method CreateWebHostBuilder:

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>

This method creates the default WebHostBuilder. This has a lot of stuff preconfigured, which is working great in the most scenarios. But it is possible to override all of the default settings here and to replace it with some custom configurations. We need to tell the Kestrel webserver which host and port he need to listen on and we are able to configure the ListenOptions for specific ports. In this ListenOptions we can use HTTPS and pass in the certificate file and a password for that file:

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        .UseKestrel(options =>
            options.Listen(IPAddress.Loopback, 5000);
            options.Listen(IPAddress.Loopback, 5001, listenOptions =>
                listenOptions.UseHttps("certificate.pfx", "topsecret");

Usually we would use the hardcoded values from a configuration file or environment variables, instead of hardcoding it.

Be sure the certificate is password protected using a long password or even better a pass-phrase. Be sure to not store the password or the pass-phrase into a configuration file. In development mode you should use the user secrets to store such secret date and in production mode the Azure Key Vault could be an option.


I hope this helps to get you a rough overview over the the usage of HTTPS in ASP.NET Core. This is not really a deep dive, but tries to explain what are the new middlewares good for and how to configure HTTPS for different platforms.

BTW: I just saw in the blog post about HTTPS improvements, about HSTS in ASP.NET Core, there is a way to store the HTTPS configuration in the launchSettings.json. This is an easy way to pass in environment variables on startup to the application. The samples also shows to add the certificate password to this settings file. Please never ever do this! Because a file is easily shared to a source code repository or any other way, so the password inside is shared as well. Please use different mechanisms to set passwords in an application, like the already mentioned user secrets or the Azure Key Vault.

Four times in a row

Monday, July 2, 2018 12:00 AM

One year later, it is the July 1st and I got the email from the Global MVP Administrator. I got the MVP award the fourth time in a row :)

I'm pretty proud and honored about that and I'm really happy to be part of the great MVP community one year more. I'm also looking forward to the Global MVP Summit next year to meet all the other MVPs from around the world.

Still not really a fan-boy...!?

I'm also proud of being a MVP, because I never called myself a Microsoft fan-boy. And sometimes, I also criticize some tools and platforms built by Microsoft (I feel like a bad boy). But I like most of the development tools built by Microsoft and I like to use the tools, and frameworks and I really like the new and open Microsoft. The way how Microsoft now supports more than its own technologies and platforms. I like using VSCode, Typescript and Webpack to create NodeJS applications. I like VSCode and .NET Core on Linux to build Applications on a different platform than Windows. I also like to play around with UWP Apps on Windows for IoT on a Raspberry PI.

There are much more possibilities, much more platforms, much more customers to reach, using the current Microsoft development stack. And it is really fun to play with it, to use it in real project, to write about it in .NET magazines, in this blog and to talk about it in the user groups and on conferences.

In the last year being an MVP, I also learned that it is kinda fun to contribute to Microsoft's open source projects, being a part of that project and to see my own work in that projects. If you like open source as well, contribute to the the open source projects. Make the projects better, make the documentations better.

I also need to say Thanks

But I wouldn't get honored again without such a great development community. I wouldn't continue to contribute to the community without that positive feedback and without that great people. This is why the biggest "Thank You" goes to the development community :)

And like last year, I also need to say "Thank You" to my great family (my lovely wife and my three kids) which supports me in spending so much time to contribute to the community. I also need to say Thanks to the YooApplications AG, my colleagues and my boss for supporting me and allowing me to use parts of my working time to contribute the the community.

Creating a signature pad using Canvas and ASP.​NET Core Razor Pages

Tuesday, June 5, 2018 12:00 AM

In one of our projects, we needed to add a possibility to add signatures to PDF documents. A technician fills out a checklist online and a responsible person and the technician need to sign the checklist afterwards. The signatures then gets embedded into a generated pdf document together with the results of the checklist. The signatures must be created on a web UI, running on an iPad Pro.

It was pretty clear that we need to use the HTML5 canvas element and to capture the pointer movements. Fortunately we stumbled upon a pretty cool library on GitHub, created by Szymon Nowak from Poland. It is the super awesome Signature Pad written in TypeScript and available as NPM and Yarn package. It is also possible to use a CDN to use the Signature Pad.

Use Signature Pad

Using Signature Pad is really easy and works well without any configuration. Let me show you in a quick way how it works:

To play around with it, I created a new ASP.NET Core Razor Pages web using the dotnet CLI:

dotnet new razor -n SignaturePad -o SignaturePad

I added a new razor page called Signature and added it to the menu in the _Layout.cshtml. I created a simple form and placed some elements in it:

The form posts the content to the current URL, which is the same Razor page, but the different HTTP method handler. We will have a look later on.

The canvas is the most important thing. This is the area where the signature gets drawn. I added a border to make the pad boundaries visible on the screen. I add a button to accept the signature. This means we lock the canvas and write the image data to the input field added as last element. I also added a second button to submit the form. The image is just to validate the signature and is not really needed, but I was curious about, how it looks in an image tag.

This is not the nicest HTML code but works for a quick test.

Right after the form I added a script area to render the JavaScript to the end of the page. To get it running quickly, I use jQuery to access the HTML elements. I also copied the signature_pad.min.js into the project, instead of using the CDN version

@section Scripts{

As you can see, creating the Signature Pad is simply done by creating a new instance of SignaturePad and passing the canvas as an argument. On click at the accept button, I start working with the pad. The function toDataURL() generates an image data URL that can be directly used as image source, like I do in the next line. After that I store the result as value in the input field to send it to the server. In Production this should be a hidden field. at the end I switch the Signature Pad off to lock the canvas and the user cannot manipulate the signature anymore.

Handling the Image Date URL with C##

The image data URL looks like this:


So after the comma the image is a base 64 encoded string. The data before the comma describes the image type and the encoding. I now send the complete data URL to the server and we need to decode the string.

public void OnPost()
    if (String.IsNullOrWhiteSpace(SignatureDataUrl)) return;

    var base64Signature = SignatureDataUrl.Split(",")[1];            
    var binarySignature = Convert.FromBase64String(base64Signature);

    System.IO.File.WriteAllBytes("Signature.png", binarySignature);

On the page model we need to create a new method OnPost() to handle the HTTP POST method. Inside we first check whether the bound property has a value or not. Then we split the string by comma and convert the base 64 string to an byte array.

With this byte array we can do whatever we need to do. In the current project I store the image directly in the PDF and in this demo I just store the data in an image on the hard drive.


As mentioned this is just a quick demo with some ugly code. But the rough idea could be used to make it better in Angular or React. To learn more about the Signature Pad visit the repository:

This example also shows what is possible with HTML5 this times. I really like the possibilities of HTML5 and the HTML5 APIs used with JavaScript.

Hope this helps :-)

A generic logger factory facade for classic ASP.NET

Friday, April 13, 2018 12:00 AM

ASP.NET Core already has this feature. There is a ILoggerFactory to create a logger. You are able to inject the ILoggerFactory to your component (Controller, Service, etc.) and to create a named logger out of it. During testing you are able to replace this factory with a mock, to not test the logger as well and to not have an additional dependency to setup.

Recently we had the same requirement in a classic ASP.NET project, where we use Ninject to enable dependency injection and log4net to log all the stuff we do and all exceptions. One important requirement is a named logger per component.

Creating named loggers

Usually log4net gets created inside the components as a private static instance:

private static readonly ILog _logger = LogManager.GetLogger(typeof(HomeController));

There already is a static factory method to create a named logger. Unfortunately this isn't really testable anymore and we need a different solution.

We could create a bunch of named logger in advance and register them to Ninject, which obviously is not the right solution. We need to have a more generic solution. We figured out two different solutions:

// would work well
public MyComponent(ILoggerFactory loggerFactory)
    _loggerA = loggerFactory.GetLogger(typeof(MyComponent));
    _loggerB = loggerFactory.GetLogger("MyComponent");
    _loggerC = loggerFactory.GetLogger();
// even more elegant
public MyComponent(
    ILoggerFactory loggerFactoryA
    ILoggerFactory loggerFactoryB)
    _loggerA = loggerFactoryA.GetLogger();
    _loggerB = loggerFactoryB.GetLogger();

We decided to go with the second approach, which is a a simpler solution. This needs a dependency injection container that supports open generics like Ninject, Autofac and LightCore.

Implementing the LoggerFactory

Using Ninject the binding of open generics looks like this:


This binding creates an instance of LoggerFactory using the requested generic argument. If I request for an ILoggerFactory, Ninject creates an instance of LoggerFactory.

We register this as an singleton to reuse the ILog instances as we would do using the usual way to create the ILog instance in a private static variable.

The implementation of the LoggerFactory is pretty easy. We use the generic argument to create the log4net ILog instance:

public interface ILoggerFactory
	ILog GetLogger();

public class LoggerFactory : ILoggerFactory
    private ILog _logger;
    public ILog GetLogger()
        if (_logger == null)
            var type = typeof(T);
            _logger = LogManager.GetLogger(typeof(T));
        return _logger;

We need to ensure the logger is created before creating a new one. Because Ninject creates a new instance of the LoggerFactory per generic argument, the LoggerFactory don't need to care about the different loggers. It just stores a single specific logger.


Now we are able to create one or more named loggers per component.

What we cannot do, using this approach is to create individual named loggers, using a specific string as a name. There is a type needed that gets passed as generic argument. So every time we need an individual named logger we need to create a specific type. In our case this is not a big problem.

If you don't like to create types just to create individual named loggers, feel free to implement a non generic LoggerFactory and make a generic GetLogger method as well as a GetLogger method that accepts strings as logger names.

Creating Dummy Data Using GenFu

Wednesday, April 11, 2018 12:00 AM

Two years ago I already wrote about playing around with GenFu and I still use it now, as mentioned in that post. When I do a demo, or when I write blog posts and articles, I often need dummy data and I use GenFu to create it. But every time I use it in a talk or a demo, somebody still asks me a question about it,

Actually I really forgot about that blog post and decided to write about it again this morning because of the questions I got. Almost accidently I stumbled upon this "old" post.

I wont create a new one. Now worries ;-) Because of the questions I just want to push this topic a little bit to the top:

Playing around with GenFu

GenFu on GitHub

PM> Install-Package GenFu

Read about it, grab it and use it!

It is one of the most time saving tools ever :)

Running and Coding

Friday, March 30, 2018 12:00 AM

I wasn't really sporty before two years, but anyway active. I was also forced to be active with three little kids and a sporty and lovely women. But anyway, a job where I mostly sit in a comfortable chair, even great food and good southern German beers also did its work. When I first met my wife, I had around 80 Kg, what is good for my size of 178cm. But my weight increased up to 105Kg until Christmas 2015. This was way too much I thought. Until then I always tried to reduce it by doing some more cycling, more hiking and some gym, but it didn't really worked out well.

Anyway, there is not a more effective way to loose weight than running. It is btw. tree times more effective than cycling. I tried it a lot in the past, but it pretty much hurts in the lower legs and I stopped it more than once.

Running the agile way

I tried it again in Easter 2016 in a little different way, and it worked. I tried to do it the same way as in a perfect software project:

I did it in an agile way, using pretty small goals to get as much success as possible.

Also I bought me fitness watch to count steps, calories, levels and to measure the hart rate while running, to get some more challenges to do. At the same time I changed food a lot.

It sounds weird and funny, but it worked really well. I lost 20Kg since then!

I think it was important to not set to huge goals. I just wanted to loose 20Kg. I didn't set a time limit, or something like this.

I knew it hurts in the lower legs while running. I started to learn a lot of running and the different stiles of running. I chose the way of easy running which worked pretty well with natural running shoes and barefoot shoes. This also worked well for me.

Finding time to run

Finding time was the hardest thing. In the past I always thought that I'm too busy to run. I discussed it a lot with the family and we figured out the best time to run was during lunch time, because I need to walk the dog anyway and this also was an option to run with the dog. This was also a good thing for our huge dog.

Running at lunch time had another good advantage: I get the brain cleaned a little bit after four to five hours of work. (Yes, I usually start between 7 to 8 in the morning.) Running is great when you are working on software projects with a huge level of complexity. Unfortunately when I'm working in Basel, I cannot go run, because there is now shower available. But I'm still able to run three to four times a week.

Starting to run

The first runs were a real pain. I just chose a small lap of 2,5km, because I needed to learn running as the first step. Also because of the pain in the lower legs, I chose to run shorter tracks up-hill. Why up-hill? Because this is more exhausting than running leveled-up. So I had short up-hill running phases and longer quick walking phases. Just a few runs later the running phases start to be a little bit longer and longer.

This was the first success just a few runs later. That was great. it was even greater when I finished my first kilometer after 1,5 months running every second day. That was amazing.

On every run there was a success and that really pushed me. But I not only succeeded on running, I also started to loose weight, which pushed me even more. So the pain wasn't too hard and I continued running.

Some weeks later I ran the entire lap of 2.5km. I was running the whole lap not really fast but without a walking pause. Some more motivation.

I continued running just this 2.5km for a few more weeks to get some success on personal records on this lap.

Low carb

I mentioned the change with food. I changed to low-carb diet. Which is in general a way to reduce the consumption of sugar. Every kind of sugar, which means bread, potatoes, pasta, rice and corn as well. In the first phase of three months I almost completely stopped eating carbs. After that phase, started to eat a little of them. I also had one cheating-day per week when I was able to eat the normal way.

After 6 Months of eating less carbs and running, I lost around 10Kg, which was amazing and I was absolutely happy with this progress.

Cycling as a compensation

As already mentioned I run every second day. The days between I used my new mountain bike to climb the hills around the city where I live. Actually, it really was a kind of compensation because cycling uses other parts of the legs. (Except when I run up-hill).

Using my smart watch, I was able to measure that running burns three times more calories per hour in average than cycling in the same time. This is a measurement done on my person only and cannot adopt to any other person, but actually it makes sense to me.

Unfortunately cycling during the winter was a different kind of pain. It hurts the face, the feet and the hands. It was too cold. so I stopped it, if the temperature was lower than 5 degrees.

Extending the lap

After a few weeks running the entire 2.5Km, I increased the length to 4.5. This was more exhausting than expected. Two kilometers more needs a completely new kind of training. I needed to enforce myself to not run too fast at the beginning. I needed to start to manage my power. Again I started slowly and used some walking pauses to get the whole lap done. During the next months the walking pauses had decrease more and more until I didn't need a walking pause anymore on this lap.

The first official run

Nine months later I wanted to challenge myself a little bit and attended the first public run. It was a new years eve run. Pretty cold than, but unexpectedly a lot of fun. I was running with my brother which was a good idea. The atmosphere before and during the run was pretty special and I still like it a lot. I got three challenges done during this run. I reached the finish (1) and I wasn't the last one who passed the finish line (2). That was great. I also got a new personal record on the 5km (3).

This was done one year and three months ago. I did exactly the same run again last new years eve and got a new personal record, was faster than my brother and reached the finish. Amazing. More success to push myself.

The first 10km

During the last year I increased the number of kilometers, attended some more public runs. In September 2015 I finished my first public 10km run. Even more success to push me foreword.

I didn't increase the number of kilometer fast. Just one by one kilometer. Trained one to three months on this range and added some more kilometer. Last spring I started to do a longer run during the weekends, just because I had time to do this. On workdays it doesn't make sense to run more than 7 km because this would also increase the time used for the lunch break. I tried to just use one hour for the lunch run, including the shower and changing the cloths.

Got it done

Last November I got it done: I actually did loose 20kg since I started to run. This was really great. It was a great thing to see a weight less than 85kg.


How did running changed my life? it changed it a lot. I cannot really live without running for more than two days. I get really nervous than.

Do I feel better since I started running? Because of the sports I am more tired than before, I have muscle ache, I also had two sport accidents. But I'm pretty much more relaxed I think. Physically the most time it feels bad but in a wired positive way because I feel I've done something.

Also some annoying work was done more easily. I really looking foreword to the next lunch break to run the six or seven kilometer with the dog, or to ride the bike up and down the hills and to get the brain cleaned up.

I'm running on almost every weather except it is too slippery because of ice or snow. Fresh snow is fine, mud is fun, rain I don't feel anymore, sunny is even better and heat is challenging. Only the dog doesn't love warm weather.

Crazy? Yes, but I love it.

Yo you want to follow me on Strava?

Why I use paket now

Thursday, March 29, 2018 12:00 AM

I never really had any major problem using the NuGet client. By reading the Twitter timeline, it seems I am the only one without problems. But depending on what dev process you like to use, there could be a problem. This is not really a NuGet fault, but this process makes the usage of NuGet a little bit more complex than it should be.

As mentioned in previous posts, I really like to use Git Flow and the clear branching structure. I always have a production branch, which is the master. It contains the sources of the version which is currently in production.

In my projects I don't need to care about multiple version installed on multiple customer machines. Usually as a web developer, you only have one production version installed somewhere on a webserver.

I also have a next version branch, which is the develop branch. This contains the version we are currently working on. Besides of this, we can have feature branches, hotfix branches, release branches and so on. Read more about Git Flow in this pretty nice cheat sheet.

The master branch get's compiled in release mode and uses a semantic version like this. (breaking).(feature).(patch). The develop branch, get's compiled in debug mode and has an version number that tells NuGet that it is a preview version: (breaking).(feature).(patch)-preview(build). Where build is the build number generated by the build server.

The actual problem

We use this versioning, build and release process for web projects and shared libraries. And with those shared libraries it starts to get complicated using NuGet.

Some of the shared libraries are used in multiple solutions and shared via a private NuGet feed, which is a common way, I think.

Within the next version of a web project we also use the next versions of the shared libraries to test them. In the current versions of the web projects we use the current versions of the shared libraries. Makes kinda sense, right? If we do a new production release of a web project, we need to switch back to the production version of the shared libraries.

Because in the solutions packages folder, NuGet creates package sub-folders containing the version number. And the project references the binaries from those folder. Changing the library versions, needs to use the UI or to change the packages.config AND the project files, because the reference path contains the version information.

Maybe switching the versions back and forth doesn't really makes sense in the most cases, but this is the way how I also try new versions of the libraries. In this special case, we have to maintain multiple ASP.NET applications, which uses multiple shared libraries, which are also dependent to different versions of external data sources. So a preview release of an application also goes to a preview environment with a preview version of a database, so it needs to use the preview versions of the needed libraries. While releasing new features, or hotfixes, it might happen that we need to do an release without updating the production environments and the production databases. So we need to switch the dependencies back to the latest production version of the libraries .

Paket solves it

Paket instead only supports one package version per solution, which makes a lot more sense. This means Paket doesn't store the packages in a sub-folder with a version number in its name. Changing the package versions is easily done in the paket.dependencies file. The reference paths don't change in the project files and the projects immediately use the other versions, after I changed the version and restored the packages.

Paket is an alternative NuGet client, developed by the amazing F# community.

Paket works well

Fortunately Paket works well with MSBuild and CAKE. Paket provides MSBuild targets to automatically restore packages before the build starts. Also in CAKE there is an add-in to restore Paket dependencies. Because I don't commit Paket to the repository I use the command line interface of Paket directly in CAKE:

	.Does(() =>

	.Does(() => {
		var exitCode = StartProcess(".paket/paket.bootstrapper.exe");
		Information("LoadPaket: Exit code: {0}", exitCode);

	.Does(() =>
		var file = "./SolutionInfo.cs";		
		var settings = new AssemblyInfoSettings {
			Company = " YooApplications AG",
			Copyright = string.Format("Copyright (c) YooApplications AG {0}", DateTime.Now.Year),
			ComVisible = false,
			Version = version,
			FileVersion = version,
			InformationalVersion = version + build
		CreateAssemblyInfo(file, settings);

	.Does(() => 
		var exitCode = StartProcess(".paket/paket.exe", "install");
		Information("PaketRestore: Exit code: {0}", exitCode);

// ... and so on


No process is 100% perfect, even this process is not. But it works pretty well in this case. We are able to do releases and hotfix very fast. The setup of a new project using this process is fast and easy as well.

The whole process of releasing a new version, starting with the command git flow release start ... to the deployed application on the web server doesn't take more than 15 minutes. Depending on the size of the application and the amount of tests to run on the build server.

I just recognized, this post is not about .NET Core or ASP.NET Core. The problem I described only happens to classic projects and solutions that store the NuGet packages in the solutions packages folder.

Any Questions about that? Do you wanna learn more about Git Flow, CAKE and Continuous Deployment? Just drop me a comment.

Recap the MVP Global Summit 2018

Wednesday, March 28, 2018 12:00 AM

Being a MVP has a lot of benefits. Getting free tools, software and Azure credits are just a few of them. The direct connection to the product group has a lot more value than all software. Even more valuable is the is the fact of being a part of an expert community with more than 3700 MVPs from around the world.

In fact there are a lot more experts outside the MVP community which are also contributing to the communities of the Microsoft related technologies and tools. Being an MVP also means to find those experts and to nominate them to also get the MVP award.

The most biggest benefit of being an MVP is the yearly MVP Global Summit in Redmond. Also this year Microsoft invites the MVPs to attend the MVP Global Summit. More than 2000 MVPs and Regional Directors were registered to attend the summit.

I also attended the summit this year. It was my third summit and the third chance to directly interact with the product group and with other MVPs from all over the world.

The first days in Seattle

My journey to the summit starts at Frankfurt airport where a lot of German, Austrian and Swiss MVPs start their journey and where many more MVPs from Europe change the plain. The LH490 and LH491 flights around the summits are called the "MVP plains" because of this. This always feels like a yearly huge school trip.

The flight was great, sunny the most time and I had an impressive view over Greenland and Canada:


After we arrived at SEATEC, some German MVP friends and me took the train to Seattle downtown. We checked in at the hotels and went for a beer and a burger. This year I decided to arrive one day earlier than the last years and to stay in Seattle downtown for the first two nights and the last two nights. This was a great decision.

Pike Place Seattle

I spent the nights just a few steps away from the pike place. I really love the special atmosphere at this place and this area. There are a lot of small stores, small restaurants, the farmers market and the breweries. Also the very first Starbucks restaurant is at this place. It's really a special place. This also allows me to use the public transportation, which works great in Seattle.

There is a direct train from the airport to Seattle downtown and an express bus from Seattle downtown to the center of Bellevue where the conference hotels are located. For those of you, who don't want to spent 40USD or more for Uber, Taxy or a Shuttle, the train to Seattle costs 3USD and the express bus 2,70USD. Both need around 30 minutes, maybe you need some time to wait a few minutes in the underground station in Seattle.

The Summit days

After checking-in into the my conference hotel on Sunday morning, I went to the registration, but it seemed I was pretty early:

Summit Registration

But it wasn't really right. The most of the MVPs where in the queue to register for the conference and to get their swag.

Like the last years, the summit days where amazing, even if we don't really learn a lot of really new things in my contribution area. The most stuff in the my MVP category is open source and openly discussed on GitHub and Twitter and in the blog posts written by Microsoft. Anyway we learned about some cool ideas, which I unfortunately cannot write down here, because it is almost all NDA content.

So the most amazing things during the summit are the events and parties around the conference and to meet all the famous MVPs and Microsoft employees. I'm not really a selfie guy, but this time I really needed to take a picture with the amazing Phil "Mister ASP.NET MVC" Haack.

Phil Haak

I'm also glad to met Steve Gorden, Andrew Lock, David Pine, Damien Bowden, Jon Galloway, Damien Edwards, David Fowler, Immo Landwerth, Glen Condron, and many, many more. And of course the German speaking MVP Family from Germany (D), Austria (A) and Switzerland (CH) (aka DACH)

Special Thanks to Alice, who manages all the MVPs in the DACH area.

I'm also pretty glad to meet the owner of millions of hats, Mr. Jeff Fritz in person who ask me to do a lightning talk in front of many program managers during the summit. Five MVPs should tell the developer division program managers stories about the worst or the best things about the development tools. I was quite nervous, but it worked out well, mostly because Jeff was super cool. I told a worse story about the usage of Visual Studio 2015 and TFS by a customer with a huge amount of solutions and a lot more VS projects in it. It was pretty wired to also tell Julia Liuson (Corporate Vice President of Visual Studio) about that problems. But she was really nice, asked the right questions.

BTW: The power bank (battery pack) we got from Jeff, after the lightning talk, is the best power bank I ever had. Thanks Jeff.

On Thursday, the last Summit day for the VS and dev tools MVPs, there was a hackathon. They provided different topics to work on. There was a table for working with Blazor, another one for some IoT things, F#, C# and even VB.NET still seems to be a thing ;-)

My idea was to play around with Blazor, but I wanted to finalize a contribution to the ASP.NET documentation first. Unfortunately this took longer than expected, this is why I left the table and took a place on another table. I fixed a over-localization issue in the German ASP.NET documentation and took care about an issue on LightCore. On LightCore we currently have an open issue regarding some special registrations done by ASP.NET Core. We thought it was because of special registrations after the IServiceProvider were created, but David Fowler told me the provider is immutable and he points me to the registrations of open generics. LightCore already provides open generics, but implemented the resolution in a wrong way. In case a registrations of a list of generics is not found, LightCore should return an empty list instead of null.

It was amazing how fast David Fowler points me to the right problem. Those guys are crazy smart. Just a few seconds after I showed him the missing registration, I got the right answer. Glen Condron told me right after, how to isolate this issue and test it. Problem found and I just need to fix it.

Thanks guys :-)

The last days in Seattle

I also spent the last two nights at the same location near the Pike Place. Right after the hackathon, I grabbed my luggage at the conference hotel and used the express bus to go to Seattle again. I had a nice dinner together with André Krämer at the Pike Brewery. On the next Morning I had a amazingly yummy breakfast in a small restaurant at the Pike Place market, with a pretty cool morning view to the water front. Together with Kostja Klein, we had a cool chat about this and that, the INETA Germany and JustCommunity.

The last day usually is also the time to buy some souvenirs for the Kids, my lovely wife and the Mexican exchange student, who lives in hour house. I also finished the blog series about React and ASP.NET Core.

At the last morning in Seattle, I stumbled over the Pike Street into the Starbucks to take a small breakfast. It was pretty early at the Pike Place:

Pike Place Seattle

Leaving the Seattle area and the Summit feels a little bit of leaving a second home.

I'm really looking forward to the next summit :-)

BTW: Seattle isn't about rainy and cloudy weather

Have I already told you, that every time I visited Seattle, it was sunny and warm?

It's because of me, I think.

During the last summits it was Sunny when I visit Seattle downtown. In summer 2012, I was in a pretty warm and sunny Seattle, together with my family.

This time it was quite warm during the first days. It started to rain, when I left Seattle to go to the summit locations in Bellevue and Redmond and it was sunny and warm again when I moved back to Seattle downtown.

It's definitely because of me, I'm sure. ;-)

Or maybe the rainy cloudy Seattle is a different one ;-)

Topics I'll write about

Some of the topics I'm allowed to write about and I definitely will write about in the next posts are the following:

Creating a chat application using React and ASP.NET Core - Part 5

Tuesday, March 6, 2018 12:00 AM

In this blog series, I'm going to create a small chat application using React and ASP.NET Core, to learn more about React and to learn how React behaves in an ASP.NET Core project during development and deployment. This Series is divided into 5 parts, which should cover all relevant topics:

  1. React Chat Part 1: Requirements & Setup
  2. React Chat Part 2: Creating the UI & React Components
  3. React Chat Part 3: Adding Websockets using SignalR
  4. React Chat Part 4: Authentication & Storage
  5. React Chat Part 5: Deployment to Azure

I also set-up a GitHub repository where you can follow the project: Feel free to share your ideas about that topic in the comments below or in issues on GitHub. Because I'm still learning React, please tell me about significant and conceptual errors, by dropping a comment or by creating an Issue on GitHub. Thanks.


In this post I will write about the deployment of the app to Azure App Services. I will use CAKE to build pack and deploy the apps, both the identity server and the actual app. I will run the build an AppVeyor, which is a free build server for open source projects and works great for projects hosted on GitHub.

I'll not go deep into the AppVeyor configuration, the important topics are cake and azure and the app itself.

BTW: SignalR was going into the next version the last weeks. It is not longer alpha. The current version is 1.0.0-preview1-final. I updated the version in the package.json and in the ReactChatDemo.csproj. Also the NPM package name changed from "@aspnet/signalr-client" to "@aspnet/signalr". I needed to update the import statement in the WebsocketService.ts file as well. After updating SignalR I got some small breaking changes, which are easily fixed. (Please see the GitHub repo, to learn about the changes.)

Setup CAKE

CAKE is a build DSL, that is built on top of Roslyn to use C#. CAKE is open source and has a huge community, who creates a ton of add-ins for it. It also has a lot of built-in features.

Setting up CAKE is easily done. Just open the PowerShell and cd to the solution folder. Now you need to load a PowerShell script that bootstraps the CAKE build and loads more dependencies if needed.

Invoke-WebRequest -OutFile build.ps1

Later on, you need to run the build.ps1 to start your build script. Now the Setup is complete and I can start to create the actual build script.

I created a new file called build.cake. To edit the file it makes sense to use Visual Studio Code, because @code also has IntelliSense. In Visual Studio 2017 you only have syntax highlighting. Currently I don't know an add-in for VS to enable IntelliSense.

My starting point for every new build script is, the simple example from the quick start demo:

var target = Argument("target", "Default");

  .Does(() =>
    Information("Hello World!");


The script then gets started by calling the build.ps1 in a PowerShell


If this is working I'm able to start hacking the CAKE script in. Usually the build steps I use looks like this.

To deploy the App I use the CAKE Kudu client add-in and I need to pass in some Azure App Service credentials. You get this credentials, by downloading the publish profile from the Azure App Service. You can just copy the credentials out of the file. Be careful and don't save the secrets in the file. I usually store them in environment variables and read them from there. Because I have two apps (the actual chat app and the identity server) I need to do it twice:

#addin nuget:?package=Cake.Kudu.Client

string  baseUriApp     = EnvironmentVariable("KUDU_CLIENT_BASEURI_APP"),
        userNameApp    = EnvironmentVariable("KUDU_CLIENT_USERNAME_APP"),
        passwordApp    = EnvironmentVariable("KUDU_CLIENT_PASSWORD_APP"),
        baseUriIdent   = EnvironmentVariable("KUDU_CLIENT_BASEURI_IDENT"),
        userNameIdent  = EnvironmentVariable("KUDU_CLIENT_USERNAME_IDENT"),
        passwordIdent  = EnvironmentVariable("KUDU_CLIENT_PASSWORD_IDENT");;

var target = Argument("target", "Default");

    .Does(() =>

	.Does(() => 

	.Does(() => 
              var settings = new DotNetCoreBuildSettings
                  NoRestore = true,
                  Configuration = "Release"
              DotNetCoreBuild("./react-chat-demo.sln", settings);

	.Does(() =>
              var settings = new DotNetCoreTestSettings
                  NoBuild = true,
                  Configuration = "Release",
                  NoRestore = true
              var testProjects = GetFiles("./**/*.Tests.csproj");
              foreach(var project in testProjects)
                  DotNetCoreTest(project.FullPath, settings);

	.Does(() => 
              var settings = new DotNetCorePublishSettings
                  Configuration = "Release",
                  OutputDirectory = "./publish/ReactChatDemo/",
                  NoRestore = true
              DotNetCorePublish("./ReactChatDemo/ReactChatDemo.csproj", settings);
              settings.OutputDirectory = "./publish/ReactChatDemoIdentities/";
              DotNetCorePublish("./ReactChatDemoIdentities/ReactChatDemoIdentities.csproj", settings);

	.Does(() => 
              var kuduClient = KuduClient(
              var sourceDirectoryPath = "./publish/ReactChatDemo/";
              var remoteDirectoryPath = "/site/wwwroot/";


              kuduClient = KuduClient(
              sourceDirectoryPath = "./publish/ReactChatDemoIdentities/";
              remoteDirectoryPath = "/site/wwwroot/";


    .Does(() =>
              Information("Your build is done :-)");


To get this script running locally, you need to set each of the environment variables in the current PowerShell session:

$env:KUDU_CLIENT_PASSWORD_APP = "super secret password"
# and so on...

If you only want to test the compile and publish stuff, just set the dependency of the default target to "Publish" instead of "Deploy". Doing this the deploy part will not run, you don't deploy in accident and you save some time while trying this.

Use CAKE in AppVeyor

On AppVeyor the environment variables are set in the UI. Don't set them in the YAML configuration, because they are not properly save and everybody can see them.

The most simplest appveyor.yml file looks like this.

version: 1.0.0-preview1-{build}
  do_not_increment_build_number: true
  - master
skip_tags: true
image: Visual Studio 2017 Preview
- ps: .\build.ps1
test: off
deploy: off
# this is needed to install the latest node version
  nodejs_version: "8.9.4"
  - ps: Install-Product node $env:nodejs_version
  # write out version
  - node --version
  - npm --version

This configuration only builds the master and the develop branch, which makes sense if you use git flow, as I used to do. Otherwise change it to just use the master branch or whatever branch you want to build. I skip tags to build and any other branches.

The image is Visual Studio 2017 (preview only if you want to try the latest features)

I can switch off tests, because this is done in the CAKE script. The good thing is, that the XUnit test output, built by the test runs in CAKE , gets anyway published to the AppVeyor reports. Deploy is also switched off, because it's done in CAKE too.

The last thing that needs to be done is to install the latest Node.JS version. Otherwise the already installed pretty much outdated version is is used. This is needed to download the React dependencies and to run Webpack to compile and bundle the React app.

You could also configure the CAKE script in a way that test, deploy and build calls different targets inside CAKE. But this is not really needed and makes the build a little less readable.

If you now push the entire repository to your repository on GitHub, you need to go to AppVeyor and to setup a new build project by selecting your GitHub repository. An new AppVeyor account is easily set up using an existing GitHub account. When the build project is created, you don't need to setup more. Just start a new build and see what happens. Hopefully you'll also get a green build like this:

Closing words

This post was finished one day after the Global MVP Summit 2018 on a pretty sunny day in Seattle

I spent two nights before the summit starts in Seattle downtown and the two nights after. Both times it was unexpectedly sunny.

I finish this series with this fifth blog post and learned a little bit about React and how it behaves in an ASP.NET Core project. And I really like it. I wouldn't really do a single page application using React, this seems to be much easier and faster using Angular, but I will definitely use react in future to create rich HTML UIs.

It works great using the React ASP.NET Core project in Visual Studio. It is great that Webpack is used here, because it saves a lot of time and avoids hacking around the VS environment.