Raspberry PI – ASP.net Core Web App + SQLite database

Now that we have .Net Core Framework running on the RPI,

and already build a Console App + SQLite database

It’s time to create a ASP.Net Core App that is linked to an SQLite database.

Instead of coding everything from scratch, we again can start again from a tutorial source code :

See here for an ASP.net Core MVC Example

See here for an ASP.net Core Razor Page Example.

In these tutorials the development was done using Visual Studio.

I will demonstrator that you don’t need the big elephant IDE on your machine

You can use the either more slim Visual Sudio Code, which is distributed out of the box in your Raspbian.

Or as being a scripter or Linux user, you can do all from the command line too

I used this tutorial code to start with but I modified it to be more cross-platfrom compatible.

For example I replace the MS SQL database with a SQLite database

Let me guide your through the steps…

SOLUTION :

1. Check the EF framework is available :

If you see this Error:

Cannot find a manifest file.

For a list of locations searched, specify the “-d” option before the tool name.

If you intended to install a global tool, add `–global` to the command.

If you would like to create a manifest, use `dotnet new tool-manifest`, usually in the repo root directory.

Update the DotNet Manifest File.

If you are developing on Windows use this cmd :

dotnet new tool-manifest

dotnet tool install --local dotnet-ef --version 3.1.19

If you are developing in a RPI it is the same command.

To know which version you should use you can check your DotNet Core version like this :

dotnet --info

2. Start a new ASP.net App

Depending on when you want to go for an ASP MVC or Razor Pages build use this cmd.

dotnet new mvc -o C:\dotnet\ASPnetMVC

I went for the MVC version in this Example.

It will create a Template Application in your output directory like this

it will have a few less directories, but the tutorial will explain later on when to add the missing ones.

Next follow these steps in the MVC Tutorial ::

Starting with : Open Views/Shared/_Layout.cshtml and copy the code

Like this :

3. Install the Global dotnet EF Tools

Use this command for the ASP.net Core 3.1 version

dotnet tool install --global dotnet-ef --version 3.1.0

4. Add these entries in your Project File

These package versions work for 3.1.19 SDK :

<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="3.1.19" />
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.1.19" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="3.1.19">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.1.19" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.19">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="3.1.5" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Utils" Version="3.1.5" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="2.1.0-preview1-final" />
    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.11.0" />
    <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="2.0.0" />
    <PackageReference Include="SQLitePCLRaw.bundle_green" Version="1.1.10" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="3.1.19" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite.Core" Version="3.1.19" />
  </ItemGroup>
</Project>

Depending on which NUGET packages you had already downloaded in the past,

You will to either update to the correct version.

Download here : https://www.nuget.org/packages

Enter the Package name name in the search bar, like this

Select the relevant package and make sure you download the 3.1 CORE version like this :

Scroll down ans select the 3.1.19 version

Next copy the cmd and run it :

dotnet add package Microsoft.AspNetCore.Identity.EntityFrameworkCore --version 3.1.19

Next repeat this for all the other Package references mentioned in your Project file.

5. Update your code using the Tutorial source code

Next proceed with the Tutorial at the Create the data model section :

In the Models folder, create the Student class with the following code

Source code is in the Tutorial

Next proceed with Enrollment and Course

 

Next register the School Context

optionsBuilder.UseSqlite(@"Datasource=C:\CoreIoT\ASPnetMVC\Data\School.db");

Keep in mind that we are NOT going to use the SQL local database but SQLite

 

Open Startup.cs, and copy the code in there.

Keep in mind that we are NOT going to use the SQL local database but SQLite

services.AddEntityFrameworkSqlite().AddDbContext<SchoolContext>();

So I had to change the code, see indicated in the print screen

Next continue In the Data folder,

Create a new class named DbInitializer with Tutorial code

6. Creating Controller and Views

Since we do not use Visual Studio we are going to use the command line for these steps.

We are going to use the Scaffolding tool to create the VIEWS

dotnet aspnet-codegenerator razorpage -m Course -dc SchoolContext -sqlite -outDir Pages\Courses

Keep in mind the SQLite parameter

Proceed with these 2 commands for Enrollment and Student Views

dotnet aspnet-codegenerator razorpage -m Enrollment -dc SchoolContext -sqlite -outDir Pages\Enrollments

dotnet aspnet-codegenerator razorpage -m Student -dc SchoolContext -sqlite -outDir Pages\Students

Next generate the Controllers

dotnet aspnet-codegenerator controller -name StudentsController -m Student -dc SchoolContext -scripts -sqlite -outDir Controllers

You are now ready to test the ASP.net Core app

It works but looks ugly …

You need to change the Layout of each page to this

Layout = "_Layout";

7. Test your app :

dotnet run

If all is OK you can publish using the targetting runtime archtecture :

In our case we are going to use the RPI, wich is an ARM archtitecture.

dotnet publish -f netcoreapp3.1 -r linux-arm

If you want to add a Web Service API see here on how to

 

RESULT :

The end result is a dynamic web site linked to an SQLite database.

View the database records in a list

Add new record to the database page

View record details page

Delete a record from the database

Run it on your RPI

Once you have it published for the ARM architecture, you can copy the file over to the RPI

And run it on the Linux web server NGINX, see here how to set it up

It runs lightning fast on my RPI 3B+ with 1 Gb of memory

The ASP.net Core Web Application has a small footprint as well :

+55 Mb of memory used when started using the NGINX web server

PS :

If you are too much struggling with the source code, I can share this no problem

Just drop a message in this post

Enjoy !