Windows Core IoT – ASP DotNet Core Razor Pages & SQLite & Web Service on a Raspberry PI3

May 28, 2018

Building a Web Server App using ASP .Net Core using a SQLite Database and a Web Service starts here using this example.

https://docs.microsoft.com/en-us/aspnet/core/data/ef-rp/intro?view=aspnetcore-2.1

I gave it a little twist in order to get it to use SQLite and add a Web Service to it.

This means you need to follow page 1 of 8 from this Tutorial.

But make the necessary change mentioned below.

Requirements are that you have Dotnet Core installed.

And have the DB using EF Tools installed from NuGet

Creating the  .Net Razor App

1. Create a new blank RAZOR project

Create a new folder in your PC and run the command to create a new RAZOR project

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Command : dotnet New Razor

This will create a new blank Razor project

2. Install the DB using EF Tools

Go to Nuget and look for this package

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I used the version 2.1.0-rc1-final

Run this command :

dotnet add package Microsoft.EntityFrameworkCore.Tools –version 2.1.0-rc1-final

3. Add more packages needed

dotnet add package Microsoft.EntityFrameworkCore.Tools.DotNet –version 2.1.0-preview1-final

dotnet add package Microsoft.VisualStudio.Web.CodeGeneration.Design –Version 2.0.0

dotnet add package Microsoft.VisualStudio.Web.CodeGeneration.Utils –Version 2.0.0

3. Add missing other packages

correct the project .Json package references

4. Add the missing code like to generate the DB

Or generate the code based on an existing DB using Scaffolding

Example : Create a Models folder. In the Models folder, create a class file named Student.cs

5. Create the xxxxContext DB context

In the Data folder create SchoolContext.cs

In Startup.cs add the missing references (Using xxx)

add the DB Context refence : services.AddEntityFrameworkSqlite().AddDbContext<SchoolContext>(); // Added

In the Data folder, create a new class file named DbInitializer.cs

6. Generate the View pages based on the model

Courses :

dotnet aspnet-codegenerator razorpage -m Course -dc SchoolContext -udl -outDir Pages\Courses –referenceScriptLibraries

Instructor :

dotnet aspnet-codegenerator razorpage -m Instructor -dc SchoolContext -udl -outDir Pages\Instructors –referenceScriptLibraries

7. Correct the ERRORS

When running the command in step 6 you will get ERRORS.

Globally change _context.Student to _context.Students (add an “s” to Student)

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There are 7 occurrences found and updated. This is a bug and the hope to fix this bug in the next release.


=> TEST THE APP

8. BEFORE publishing add the following string in the program.cs and republish again.

UseURLs(“http://*:5000)

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9. Publish for RPI3 – ARM

Run this command :

dotnet publish -r win8-arm

10. Copy from Publish to your RPI3

Copy the Files from the PUBLISH folder to your RPI3.

ASPRazor -> C:\CoreIoT\ASPRazor\bin\Debug\netcoreapp2.0\win8-arm\ASPRazor.dll

ASPRazor -> C:\CoreIoT\ASPRazor\bin\Debug\netcoreapp2.0\win8-arm\publish\

Next MAKE SURE your FOLDER STRUCTURE on the RPI3, is exactly the same as it was on your PC before Publishing.

Next COPY the SQLite Database to your RPI3. Because this is NOT included when publishing using DotNet Core to win8Arm

11. Test the .Net Razor App on your RPI3

Connect to PowerShell Remote to your RPI3 and start the app.

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Let access the database ?

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Let’s add some data ?

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Haleluja, this is fully functional and cross platform !!

Since you now have an SQLite DB running your can feed it with your RPI3 SENSOR data and read it out using the Web J

Adding a Web Service to the .Net Razor App

Next I will add it to the site to see we can access the data using a web service API.

Again instead of using the full blown Visual Studio we will only use the command line options.

Because we don’t want to install an elephant weight of software !

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Actually Visual Studio uses all these commands in the background too … Winking smile

Run this command :

dotnet aspnet-codegenerator controller -api -name StudentAPIController -m Student -dc SchoolContext -udl -outDir Models\API –referenceScriptLibraries -f

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see the result

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You also have the option to generate XML instead of JSON

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Check the result !!

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This is how you you select ID 5

ID = 5

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It contains GET / POST / PUT / DELETE methods !

Accessing the Web Service using PowerShell

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CLS

$URL = "http://localhost:5000/api/StudentAPI"

$APIService = Invoke-RestMethod -Uri $URL

$APIService | select ID, lastName, firstMidName 

Enjoy !

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Powershell Error connecting to SharePoint Online using CSOM Assemblies

April 27, 2018

When using a Powershell Script to connect to SharePoint Online I got this error…

msoidcliL.dll : System.IO.FileNotFoundException – SharePointOnlineCredentials

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Solution :

Update your SP client side Assemblies, which does not rely anymore on Msoidclil.dll

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Once updated the error was gone Smile

Enjoy !


Windows Core IoT – ASP DotNet Core Razor Pages on a Raspberry PI3

April 20, 2018

Continuing on based on my prior posts

.Net Core on RPI3

SQLite on RPI3

I am going to explain how to use Windows IoT and ASP .Net Core on a RPI3.

As of version 2.0 we now can create ASP Razor webpages in .NET Core.

Remember that in the past I made some post about Web Matrix

That is in fact the predecessor of ASP .Net Core. Read more here

How to use Razor Pages in ASP.NET Core 2.0

Start with installing the DotNet Core Template to begin with

Run command :

dotnet new Razor -n ASPnetCoreRazor -o C:\CoreIoT\ASPnetCoreRazor

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Next Run the Template Application on your Windows PC.

Use command :

cd C:\CoreIoT\ASPnetCoreRazor

dotnet Run

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Voila as simple as that Smile

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Next Publish it for Windows IoT on a RPI3 Architecture

Run command :

dotnet publish -r win8-arm


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Copy the files to your RPI3 from C:\CoreIoT\ASPnetCoreRazor\bin\Debug\netcoreapp2.0\win8-arm\publish

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Connect to RPI3 using PowerShell remote session and start the ASPNetCoreRazor.exe Application

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No connection … ? Sad smile

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SOLUTION :

1. You need to open the Firewall Port 5000 on your RPI3 first.

Run command :

netsh advfirewall firewall add rule name=” ASPnetCoreRazor ” dir=in action=allow protocol=TCP localport=5000


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2. Modify the Template Program.cs script

And add this line : .UseUrls(http://*:5000)


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Publish again :

dotnet publish -r win8-arm

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Copy the files back over to your RPI3 :

C:\CoreIoT\ASPnetCoreRazor\bin\Debug\netcoreapp2.0\win8-arm\publish\


Next connect to RPI3 using PowerShell and start the app ….

.\ASPnetCoreRazor.exe


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Open the browser and go to : http://rpi3:5000

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It runs as expected !! Smile

So now we know how to create RAZOR pages, the door is open to start experimenting with the RAZOR syntax.

As well as integrating SQLite database using the ASP .NetCore Razor Front End….

Enjoy !


Windows Core IoT – SQLite on a Raspberry PI3

April 15, 2018

As shown in the previous post you can run use Dotnet Core to compile apps for Windows IoT on a RPI3

See here how to get started with Dotnet Core

On the net you can find how to use Dotnet Core and SQLite :

https://developersoapbox.com/connecting-to-a-sqlite-database-using-net-core/

But the example uses the Dotnet Core v1.0 Framework and run on Windows.

I will show here how to use the latest Dotnet Core v2.0 Framework and publish it for Windows ARM on RPI3 Winking smile

Run command Dotnet new console –n Sqlite –o C:\DotNetCoreApps\Sqlite

And check the result here :

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Copy the program.cs as backup, and copy the program code from the site above into the program.cs file.

Change the namespace to SQLite (see-n SQLite in first command)

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Change the sqlite.csproj file content by adding a few lines

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Add these line :

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<Project Sdk=”Microsoft.NET.Sdk”>

  <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>netcoreapp2.0</TargetFramework>
     <RuntimeIdentifiers>win8-arm;ubuntu.14.04-arm;ubuntu.16.04-arm</RuntimeIdentifiers>
   </PropertyGroup>
   <ItemGroup>
<PackageReference Include=”Microsoft.EntityFrameworkCore.Sqlite” Version=”2.0.2″ />
<PackageReference Include=”SQLitePCLRaw.bundle_green” Version=”1.1.10″ />

  </ItemGroup>
   <ItemGroup>
     <DotNetCliToolReference Include=”Microsoft.EntityFrameworkCore.Tools.DotNet” Version=”2.0.0″ />
   </ItemGroup>
</Project>

Run command : dotnet Restore

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As you can see it will use some Nuget packages as included in the sqlite.csproj file

Next run this command : dotnet publish -r win8-arm

And copy the files to your RPI3

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Next open PowerShell do a remote session and run the .\SQLite.exe

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When the SQLite DB doesn’t exist yet, it will be created automatically.

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DotNet Core is really a cross-platform language !

It runs flawlessly on a RPI3 – ARM Architecture, by just re-using the same code base we use on a Windows machine Smile

See here for more info on .NET Core Data Access data sources :

https://blogs.msdn.microsoft.com/dotnet/2016/11/09/net-core-data-access/

Enjoy !


Windows Core IoT – DotNet Core on a Raspberry PI3

April 15, 2018

Before we can start creating a project using .NET Core for RPI3, we first need to explain what and why we use .NET CORE !

.NET Core supports three app models:

  • ASP.NET apps and services
  • Console apps
  • Universal Windows Platform (UWP) apps

First of all .Net CORE is a Cross-Platform Framework opposed to the regular .Net Framework.

Supporting the following platforms:

  • Windows

  • OS X

  • Linux

Read more about .Net Frameworks here

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More info you can find here and here

Since RPI3 runs on an ARM architecture we can’t just use Standard .Net Assemblies to build projects…

You can now easily convert a platform-specific class library into a portable class library by publishing to another platform.

I will show you an example as we go along.

Getting Started

As being a scripter I hate to install all the overhead on my PC just to do simple things !

That’s why will only use the Command Line Interface (CLI) and NO Visual Studio Smile


Prerequisites :

We first have to install the .Net Core SDK on you desktop PC.

At the moment MS has arrived at .Net Core SDK version 2.1.103, Download here

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This is all you need to do a quick start Smile

Once installed open the Command Prompt and let’s check the version installed.

Run command : dotnet /? to get all options.

To get the version info we run the command:

dotnet –version or even better is dotnet –info

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.Net Core Extensions

In contrast to the .NET Framework, the .NET Core platform will be delivered as a set of NuGet packages.

These extension are needed to build your applications. We will come back to this later on showing the examples…

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TIP :

You can download packages manually from the Nuget Site and open them using 7-zip.

And extract the libraries you need for your environment…

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As mentioned before instead of using Visual Studio to start our for project.

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We will just use the DotNet Core Command line Tools, to build the first Console App in .Net Core for RPI3.

.Net Core has the same Template Apps as you can get through Visual Studio, let’s see what is available.

Run command : dotnet new

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Also RAZOR pages are possible as you can see Smile

.Net Core Console App

1. Console app Template :

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Run command : dotnet new console

optional parameters are :

–n specifies the name of the project

-o specifies the output location, if omitted it will create the project in the %userprofile%  dir.

dotnet new console -n MyFirstCoreApp -o c:\coreiot

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The Template app has generated this code

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2. Run the console app.

cd c:\coreiot

Dotnet run

dotnet publish -r win8-arm

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3. Publish to RPI3

In order to use it on RPI3 or Linux we need to add a few lines in the MyFirstCoreApp.csproj file

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<RuntimeFrameworkVersion>2.0.6</RuntimeFrameworkVersion>
<RuntimeIdentifiers>win8-arm;ubuntu.14.04-arm;ubuntu.16.04-arm</RuntimeIdentifiers>

Remember the RuntimeFrameworkVersion you can find in the .Net Core Info see

See dotnet –Info

Next run the dotnet restore command

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Next run the dotnet publish -r win8-arm command

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or if you focus a Linux distribution you run the command

dotnet publish -r ubuntu.16.04-arm

4. Copy the app to the RPI3

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C:\coreiot\bin\Debug\netcoreapp2.0\win8-arm\publish

5. Using PowerShell to run it

cd to your app folder

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Runs as expected Smile

6. Change the code using an input parameter

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Console.WriteLine(“\nWhat is your name? “);
var name = Console.ReadLine();
var date = DateTime.Now;
Console.WriteLine($”\nHello, {name}, on {date:d} at {date:t}!”);
Console.Write(“\nPress any key to exit…”);
Console.ReadKey(true);


Run command : dotnet run

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Next run command : dotnet publish -r win8-arm

And copy it back to RPI3 and test it using PowerShell

Next see here for an SQLite Example on RPI3

Next see here for an ASP .Net Core Example on RPI3

PS :

Keep in mind that for Windows there is a nice Extension Library.

That gives you access to about 20.000 Windows API’s

Enjoy !


SharePoint – Online access to a Windows Core IoT on RPI3

December 31, 2017

After converting my HW & SW Inventory Tool to SharePoint Online…

https://audministrator.wordpress.com/2013/05/14/sharepoint-computer-hw-sw-inventory/

I guessed why not try this against a Windows IoT on a Raspberry PI3 ?

And indeed it went as expected … so cool not Smile

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Possibilities are unlimited … I can check to see if the RPI3 is still online (when the button lights up green) where ever I am

Next bonus effect is that I can do a reboot remotely.

Technology :

Technology used behind the scene is just SharePoint and Client Side – JavaScript.

Maybe I will share the scripts, but not for free… Winking smile

Happy New Year …


Windows Server 2008 – Task Schedule Error 2147746323

December 18, 2017

When you schedule a Task you might run into the Error 2147746323.

The code appears after you schedule an Email Action

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When you convert this error number to a HEX number it will disclose the root cause.

Use this PowerShell script to convert it to HEX

CLS

$Value = 2147746323

"0x"+ ('{0:x}' -f $Value)

It will look like this :

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Meaning : The transport failed to connect to the Email server

So you need to investigate where it goes wrong in connecting to the server.

For more codes see here  :

https://msdn.microsoft.com/en-us/library/windows/desktop/aa383604(v=vs.85).aspx

Enjoy!