How do you access HttpContext.Session in an ASP.NET Core 7 Web API?

Question

I've created an ASP.NET Core 7 Web API, and I need to store some values in session memory, but I am getting this exception:

Unable to resolve service for type 'Microsoft.AspNetCore.DataProtection.IDataProtectionProvider' while attempting to activate 'Microsoft.AspNetCore.Session.SessionMiddleware'.

Program.cs - based on the documentation I could find the addition of the 2 indicated lines of code should work.

internal class Program
{
    private static void Main(string[] args)
    {
        var builder = WebApplication.CreateBuilder(args);

        // Add services to the container.

        builder.Services.AddControllers();
        // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
        builder.Services.AddEndpointsApiExplorer();
        builder.Services.AddSwaggerGen();
        
        //added to access session
        builder.Services.AddDistributedMemoryCache();

        var app = builder.Build();

        // Configure the HTTP request pipeline.
        if (app.Environment.IsDevelopment())
        {
            app.UseSwagger();
            app.UseSwaggerUI();
        }

        app.UseHttpsRedirection();

        app.UseAuthorization();

        //added to access session
        app.UseSession();

        app.MapControllers();

        app.Run();
    }
}

Answer 1

I tried many different ways to be able to use session variables but continued to get exceptions so I switched to memory cache. Program.Main

private static void Main(string[] args)
{
    var builder = WebApplication.CreateBuilder(args);

    // Add services to the container.

    builder.Services.AddControllers();
    builder.Services.AddEndpointsApiExplorer();
    builder.Services.AddSwaggerGen();
    builder.Services.AddMemoryCache();  //Added this service
    var app = builder.Build();

    // Configure the HTTP request pipeline.
    if (app.Environment.IsDevelopment())
    {
        app.UseSwagger();
        app.UseSwaggerUI();
    }

    app.UseHttpsRedirection();

    app.UseAuthorization();

    app.MapControllers();

    app.Run();
}

Controller

[Route("api/[controller]")]
[ApiController]
public class DatabaseController : ControllerBase
{
    private Database? _database = null;
    private IMemoryCache _memoryCache;

    public DatabaseController(IMemoryCache memoryCache)
    {
        _memoryCache = memoryCache;

        try
        {
            _database = _memoryCache.Get<Database>("database");
            if (_database == null)
            {
                SmDbActions smDbActions = new SmDbActions();
                DataAccess.ActionResult actionResult = smDbActions.LoadDatabase();
                if (!actionResult.Success) { throw actionResult.Exception; }
                _database = (Database?)actionResult.Result;
                _memoryCache.Set("database", _database);
            }
        }
        catch (Exception ex)
        {
            Log.LogEvent(new LogItem(ex.ToString()));

            throw;
        }
    }
}