Setup basic code for login.

API/Middleware/ExceptionMiddleware.cs

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+using System;
+using System.Net;
+using System.Text.Json;
+using System.Threading.Tasks;
+using API.Errors;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace API.Middleware
+{
+    public class ExceptionMiddleware
+    {
+        private readonly RequestDelegate _next;
+        private readonly ILogger<ExceptionMiddleware> _logger;
+        private readonly IHostEnvironment _env;
+
+        public ExceptionMiddleware(RequestDelegate next, ILogger<ExceptionMiddleware> logger, IHostEnvironment env)
+        {
+            _next = next;
+            _logger = logger;
+            _env = env;
+        }
+
+        public async Task InvokeAsync(HttpContext context)
+        {
+            _logger.LogError("The middleware called");
+            try
+            {
+                await _next(context); // downstream middlewares or http call
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, ex.Message);
+                context.Response.ContentType = "application/json";
+                context.Response.StatusCode = (int) HttpStatusCode.InternalServerError;
+                
+                var response = _env.IsDevelopment() 
+                    ? new ApiException(context.Response.StatusCode, ex.Message, ex.StackTrace?.ToString())
+                    : new ApiException(context.Response.StatusCode, "Internal Server Error");
+                
+                var options = new JsonSerializerOptions
+                {
+                    PropertyNamingPolicy = 
+                        JsonNamingPolicy.CamelCase
+                };
+
+                var json = JsonSerializer.Serialize(response, options);
+
+                await context.Response.WriteAsync(json);
+
+            }
+        }
+    }
+}