Replacing WCF with AspNetCore Rest API as transport layer for XPO

Replacing WCF with AspNetCore Rest API as transport layer for XPO

by | Sep 12, 2019 | DevExpress, netcore, Nuget, XAF, Xamarin, XPO

I have been using XPO from DevExpress since day one. For me is the best O.R.M in the dot net world, so when I got the news that XPO was going to be free of charge I was really happy because that means I can use it in every project without adding cost for my customers.

Nowadays all my customer needs some type of mobile development, so I have decided to master the combination of XPO and Xamarin

Now there is a problem when using XPO and Xamarin and that is the network topology, database connections are no designed for WAN networks.

Let’s take MS SQL server as an example, here are the supported communication protocols

  • TCP/IP.
  • Named Pipes

To quote what Microsoft web site said about using the protocols above in a WAN network

https://docs.microsoft.com/en-us/sql/tools/configuration-manager/choosing-a-network-protocol?view=sql-server-2014

Named Pipes vs. TCP/IP Sockets

In a fast-local area network (LAN) environment, Transmission Control Protocol/Internet Protocol (TCP/IP) Sockets and Named Pipes clients are comparable with regard to performance. However, the performance difference between the TCP/IP Sockets and Named Pipes clients becomes apparent with slower networks, such as across wide area networks (WANs) or dial-up networks. This is because of the different ways the interprocess communication (IPC) mechanisms communicate between peers.”

So, what other options do we have? Well if you are using the full DotNet framework you can use WCF.

So, it looks like WCF is the solution here since is mature and robust communication framework but there is a problem, the implementation of WCF for mono touch (Xamarin iOS) and mono droid (Xamarin Android)

You can read about Xamarin limitations in the following links

Android: https://docs.microsoft.com/en-us/xamarin/android/internals/limitations

iOS: https://docs.microsoft.com/en-us/xamarin/ios/internals/limitations

I don’t want to go into details about how the limitation of each platform affects XPO and WCF but basically the main limitation is the ability to use reflection and emit new code which is needed to generate the WCF client, also in WCF there are problems in the serialization behaviors.

Well now that we know the problem is time to talk about the solution. As you know XPO has a layered architecture ( you can read about that here https://www.jocheojeda.com/2018/10/01/xpo-post-5-layered-architecture/)

So basically, what we need to do is to replace the WCF layer with some other technology to communicate to the database server

The technology I’ve selected for this AspNetCore which I would say is a really nice technology that is modern, multi-platform and easy to use. Here below you can see what is the architecture of the solution

AspNetCore

Rest API

So, what we need basically is to be able to communicate the data layer with the data store through a network architecture.

The network architecture that I have chosen is a rest API which is one of the strong fronts of AspNetCore. The rest API will work as the server that forward the communication from XPO to the Database and vice versa, you can find a project template of the server implementation here https://www.jocheojeda.com/download/560/ this implementation references one nuget where I have written the communication code, you can fine the nuget here https://nuget.bitframeworks.com/feeds/main/BIT.Xpo.AgnosticDataStore.Server/19.1.5.1

Also we need a client that is able to interpret the information from the rest API and feed XPO, for that I have created a special client you can find here https://nuget.bitframeworks.com/feeds/main/BIT.Xpo.AgnosticDataStore.Client/19.1.5.1

The client implementation has been tested in the following platforms

  • Xamarin Android
  • Xamarin iOS
  • Xamarin WPF
  • DotNetCore
  • DotNetFramework

The client implementation has been tested in the following operative systems

  • Android 5 to 9
  • iOS 9 to 11
  • MacOS: Sierra to Catalina
  • Windows 10

In this link, you can see a full implementation of the server and the clients (XAF and Xamarin)

What is next? Well here are a few topics for the upcoming posts

  • Understanding JWT tokens
  • How to secure your data store service with a JWT token
  • Hosting multiple data store with a single service
  • Implementing your own authentication method
  • Examples examples examples

 

How to fix Error MSB4044 The “FilterAssemblies” task was not given a value for the required parameter “DesignTimeBuild”

How to fix Error MSB4044 The “FilterAssemblies” task was not given a value for the required parameter “DesignTimeBuild”

by | Jul 31, 2019 | Uncategorized

If you updated your visual studio to version 16.2.0 and you are using MSBuildSdkExtras your project won’t compile.

so to fix this problem (this is a temporary fix). You need to add the following lines to your csproj

<PropertyGroup Label="Android DesignTimeBuild error workaround"> 
  <DesignTimeBuild>false</DesignTimeBuild>
</PropertyGroup>

 

 

How to automatically show a read me file after installing a NuGet

How to automatically show a read me file after installing a NuGet

by | Jul 24, 2019 | Nuget

There are times when you have been working on your new exciting project and it looks so good that you just want to release it as soon as possible so the world can be blessed with your new NuGet package but wait your new library is a complex library and require special setup instructions after it has been installed.

Well, we can solve that problem by adding a readme file with all the setup instructions, to do that add the following XML snippet to your csproj file, then you can just add a ReadMe.txt to your project. Now when the end-user install your NuGet package the read me file will automatically open

<ItemGroup>
<None Include="ReadMe.txt" pack="true" PackagePath="." />
</ItemGroup>
How to exclude package dependencies in a NuGet package

How to exclude package dependencies in a NuGet package

by | Jul 22, 2019 | Nuget

Sometimes during the development stage, you need to add package references to your project that are only needed either during the development or compilation stage but they are not actually required by the emitted assembly.

So how do we avoid to flood the end project with package dependencies that are actually not needed? Well the answer is super simple but is not obvious, so let’s see the following example

Now we can use the package explorer to open the package produced by the csproj above.

 

 

as you can see the package Newtonsoft.Json is included as a dependency since we include it on the csproj as package reference. So how can we fix that? the answer depend on how now you create your NuGet package, in this case, I’m going to focus my answer on excluding the dependency in a package created by the info in the csproj file (there is a different approach if you use the nuspec file).

To exclude a package reference you have to add the private asset attribute as shown in the image below.

 

<PackageReference Include="Newtonsoft.Json" Version="12.0.2">
  <PrivateAssets>all</PrivateAssets>
</PackageReference>

 

You can learn more about this attribute on the following link

Now if we open the package produced by the csproj above we will see that now there are not dependencies listed

So that is how we get rid of development dependencies, to learn more about how to package a NuGet I recommend the following link

https://docs.microsoft.com/en-us/nuget/reference/nuspec

 

 

Brevitas Application Framework (Alpha Release )

Brevitas Application Framework (Alpha Release )

by | Jun 24, 2019 | Brevitas

First, let’s start with that is Brevitas, if someone asks me (the creator) I will say that Brevitas is an application framework for Xamarin Forms that you can use to develop L.O.B (Line of Business) Applications. Creating mobile apps using MVVM pattern is fun, but it requires an incredible amount of time, I have been a long time user of the application framework XAF and I love its productivity-oriented approach. So when I created Brevitas that was my main goal, to save time for me and other developers, if you save development time and make money at the same time you can dedicate more time to yourself and your loved ones.

 

 

For Oscar & Юлия

Because everything that is good in my life was born this day

 

 

Download Brevitas Application Framework Installer

[download id=”516″]

 

Brevitas NuGet Repository

http://nuget.bitframeworks.com/nuget/brevitas/