chore: add postgresql

Backend/Backend.csproj

@@ -10,6 +10,8 @@
 
     <ItemGroup>
         <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="8.0.10"/>
+        <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.0" />
+        <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="9.0.2" />
         <PackageReference Include="Swashbuckle.AspNetCore" Version="6.6.2"/>
     </ItemGroup>
 

Backend/Database/PostgresDbContext.cs

@@ -0,0 +1,23 @@
+using Backend.Models;
+using Microsoft.EntityFrameworkCore;
+
+namespace Backend.Database;
+
+/// <summary>
+/// Contains all information on the postgresql database, for the object-database mapping.
+/// This allows using C# to run SQL queries on the database.
+/// </summary>
+public class PostgresDbContext : DbContext
+{
+    /// <summary>Reference to the Activities relational table. </summary>
+    public DbSet<Activity> Activities { get; set; }
+    /// <summary>Reference to the Enrollments relational table. </summary>
+    public DbSet<Enrollment> Enrollments { get; set; }
+
+    /// <summary>
+    /// Creates information how to set up the object-database mapping, from C# to SQL, on the postgresql database.
+    /// </summary>
+    /// <param name="options">All parameters that define the database connection.</param>
+    public PostgresDbContext(DbContextOptions<PostgresDbContext> options) : base(options)
+    { }
+}

Backend/Models/Activity.cs

@@ -1,6 +1,9 @@
+using Microsoft.EntityFrameworkCore;
+
 #pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring as nullable.
 namespace Backend.Models;
 
+[PrimaryKey(nameof(Id))]
 public class Activity
 {
     /// <summary>
@@ -10,7 +13,7 @@ public class Activity
     /// <summary>
     /// The name of the activity.
     /// </summary>
-    public string Name        { get; set; }
+    public string Name        { get; set; } // TODO: set max string length for performance?
     /// <summary>
     /// A description or arbitrary length, explaining everything there is to know about the activity.
     /// </summary>

Backend/Models/Participation.cs → Backend/Models/Enrollment.cs

@@ -1,14 +1,14 @@
 #pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring as nullable.
 namespace Backend.Models;
 
-public class Participation
+public class Enrollment
 {
     /// <summary>
-    /// Reference to the unique identifier of the activity which is participated.
+    /// Reference to the unique identifier of the activity which is enrolled for.
     /// </summary>
     public uint   ActivityId { get; set; }
     /// <summary>
-    /// The ID of the user, as determined by the used OAuth application, which participated in the activity.
+    /// The ID of the user, as determined by the used OAuth application, which enrolls for the activity.
     /// </summary>
     public string UserId     { get; set; }
 }

Backend/Program.cs

@@ -1,11 +1,14 @@
+using Backend.Database;
 using Backend.Models;
+using Microsoft.AspNetCore.Http.HttpResults;
 
 var builder = WebApplication.CreateBuilder(args);
 
 // Add services to the container.
 // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
 builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen();
+builder.Services.AddNpgsql<PostgresDbContext>(connectionString: builder.Configuration.GetConnectionString("Postgresql"));
 
 var app = builder.Build();
 
@@ -18,17 +21,41 @@
 
 app.UseHttpsRedirection();
 
-app.MapGet("/activity", (uint activityId) =>
+app.MapGet("/activity", async (PostgresDbContext db, uint activityId) =>
     {
-        return new Activity()
-        {
-            Id = activityId,
-            Name = "Some activity",
-            Description = "Some activity description",
-            DateTimeStart = DateTimeOffset.Now,
-        };
+        // Simply fetch and return
+        Activity? activity = await db.Activities.FindAsync(activityId);
+        return activity != null ? Results.Ok(activity) : Results.NotFound();
+    })
+	// .WithName("GetWeatherForecast")
+	.WithOpenApi();
+
+app.MapPost("/activity", async (PostgresDbContext db, Activity activity) =>
+    {
+        // First, ensure activity with same id does not exist yet
+        Activity? currentActivity = await db.Activities.FindAsync(activity.Id);
+        if (currentActivity != null)
+            return Results.BadRequest("Activity already exists with this Id.");
+
+        // Activity does not exist yet, create it
+        db.Activities.Add(activity);
+        await db.SaveChangesAsync();
+        return Results.Ok(activity.Id);
+    })
+	.WithOpenApi();
+
+app.MapDelete("/activity", async (PostgresDbContext db, uint activityId) =>
+    {
+        // First, check if activity exists
+        Activity? activity = await db.Activities.FindAsync(activityId);
+        if (activity == null)
+            return Results.NotFound();
+
+        // Remove activity
+        db.Activities.Remove(activity);
+        await db.SaveChangesAsync();
+        return Results.Ok();
     })
-	.WithName("GetWeatherForecast")
 	.WithOpenApi();
 
 app.Run();

Backend/Tavern.http

@@ -1,6 +1,6 @@
-@Tavern_HostAddress = http://localhost:5273
+@Tavern_HostAddress = http://localhost:8080
 
-GET {{Tavern_HostAddress}}/weatherforecast/
+GET {{Tavern_HostAddress}}/activity?activityId=1
 Accept: application/json
 
 ###

Backend/appsettings.json

@@ -1,4 +1,7 @@
 {
+  "ConnectionStrings": {
+    "Postgresql": "postgres"
+  },
   "Logging": {
     "LogLevel": {
       "Default": "Information",

compose.yaml

@@ -1,6 +1,26 @@
 services:
-  tavern-backend:
-    image: backend
+  backend:
+    restart: unless-stopped
+    ports:
+      - "8080:8080"
     build:
       context: .
       dockerfile: Backend/Dockerfile
+    networks:
+      - postgres-network
+
+  postgres:
+    image: postgres:17
+    restart: always
+    environment:
+      POSTGRES_PASSWORD: docker-secret # TODO: use docker secrets to store this password
+    volumes:
+      - postgres-data:$PGDATA
+    networks:
+      - postgres-network
+
+volumes:
+  postgres-data:
+
+networks:
+  postgres-network: