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 install all the nuget references to run XPO with SQLite on Xamarin Android, iOS and Forms with a single package

by | Sep 18, 2018 | Nuget, Xamarin, XPO

When I got the news that XPO will run on DotNetCore, NetStandard and Xamarin I was super excited about all the new possibilities and to be able to port all the years of experience with XPO to the Xamarin platform.

A few days after the announcement of XPO being able to run on DotNetCore and NetStandard developer express publish a video tutorial and the source on GitHub.

As always like in any video tutorial most of the setup steps are not shown, so you need to do a little research to make your personal project work and I would say most of the time these steps are not that obvious.

I decided to test XPO on Xamarin forms and save data on an SQLite database, so as with every Xamarin project the first step is to install all the necessary nuggets for your project. So, to make it easier for myself I check the source code that DevExpres publish and I was surprised about how many references you need to run SQLite on both Android and iOS platforms. If you want to check the complete list of nuget references needed, click on the following links

To set up all the nuggets reference on both platforms took me around 15 minutes which I think it’s a lot, but then I said, “it does not matter, you only have to do this once right”… well no, since I was so excited that XPO is now able to run on Xamarin I started to create a lot of test projects and migrate some old projects too and every time I have to run to the process of install all the nuggets references.

So, to make my life easier I decided to create a NuGet package with all the references for each platform so here they are

On iOS you will need to add the following lines to your application class inside of the main method

//Initialize SQLite with the sqlite3 provider

SQLitePCL.Batteries_V2.Init();

I hope both Nugets will save you time when you start using XPO on Xamarin