pushed api files

pushed middlewares

backend/API/Middlewares/ApiKeyValidationMiddleware.cs

@@ -0,0 +1,42 @@
+namespace API.Middlewares;
+
+public class ApiKeyValidationMiddleware
+{
+    private readonly RequestDelegate _next;
+    private const string APIKEYNAME = "ApiKey";
+
+    public ApiKeyValidationMiddleware(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.");
+            return;
+        }
+
+        var appSettings = context.RequestServices.GetRequiredService<IConfiguration>();
+
+        var apiKey = appSettings.GetValue<string>("ApiKey");
+
+        if (string.IsNullOrEmpty(apiKey))
+        {
+            context.Response.StatusCode = 400;
+            await context.Response.WriteAsync("Unable to retrieve API key.");
+            return;
+        }
+
+        if (!apiKey.Equals(extractedApiKey))
+        {
+            context.Response.StatusCode = 401;
+            await context.Response.WriteAsync("Unauthorized client.");
+            return;
+        }
+
+        await _next(context);
+    }
+}