Minimal API-Key Solution

Problem

[German] I was looking for a solution to provide a minimal solution for API key checks with minimal effort.

Solution

ApiKeyMiddleware.cs:

public class ApiKeyMiddleware
{
    private readonly RequestDelegate _next;
    private const string APIKEYNAME = "ApiKey";
    
    public ApiKeyMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        if (!context.Request.Headers.TryGetValue(APIKEYNAME, out var extractedApiKey))
        {
            context.Response.StatusCode = 401;
            await context.Response.WriteAsync("Api Key was not provided. (Using ApiKeyMiddleware) ");
            return;
        }
        
        var appSettings = context.RequestServices.GetRequiredService<IConfiguration>();
        var apiKey = appSettings.GetValue<string>(APIKEYNAME);
        if (!apiKey.Equals(extractedApiKey))
        {
            context.Response.StatusCode = 401;
            await context.Response.WriteAsync("Unauthorized client. (Using ApiKeyMiddleware)");
            return;
        }
        
        await _next(context);
    }

}

After that i added in Program.cs:

app.UseMiddleware<ApiKeyMiddleware>();