modelstate and exception handling for public apis

src/Core/Models/Api/Public/Response/ErrorResponseModel.cs

@@ -0,0 +1,79 @@
+using System.Linq;
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using System.ComponentModel.DataAnnotations;
+
+namespace Bit.Core.Models.Api.Public
+{
+    public class ErrorResponseModel : IResponseModel
+    {
+        public ErrorResponseModel(string message)
+        {
+            Message = message;
+        }
+
+        public ErrorResponseModel(ModelStateDictionary modelState)
+        {
+            Message = "The request's model state is invalid.";
+            Errors = new Dictionary<string, IEnumerable<string>>();
+
+            var keys = modelState.Keys.ToList();
+            var values = modelState.Values.ToList();
+
+            for(var i = 0; i < values.Count; i++)
+            {
+                var value = values[i];
+                if(keys.Count <= i)
+                {
+                    // Keys not available for some reason.
+                    break;
+                }
+
+                var key = keys[i];
+                if(value.ValidationState != ModelValidationState.Invalid || value.Errors.Count == 0)
+                {
+                    continue;
+                }
+
+                var errors = value.Errors.Select(e => e.ErrorMessage);
+                Errors.Add(key, errors);
+            }
+        }
+
+        public ErrorResponseModel(Dictionary<string, IEnumerable<string>> errors)
+            : this("Errors have occurred.", errors)
+        { }
+
+        public ErrorResponseModel(string errorKey, string errorValue)
+            : this(errorKey, new string[] { errorValue })
+        { }
+
+        public ErrorResponseModel(string errorKey, IEnumerable<string> errorValues)
+            : this(new Dictionary<string, IEnumerable<string>> { { errorKey, errorValues } })
+        { }
+
+        public ErrorResponseModel(string message, Dictionary<string, IEnumerable<string>> errors)
+        {
+            Message = message;
+            Errors = errors;
+        }
+
+        /// <summary>
+        /// String representing the object's type. Objects of the same type share the same properties.
+        /// </summary>
+        /// <example>error</example>
+        [Required]
+        public string Object => "error";
+        /// <summary>
+        /// A human-readable message providing details about the error.
+        /// </summary>
+        /// <example>The request model is invalid.</example>
+        [Required]
+        public string Message { get; set; }
+        /// <summary>
+        /// If multiple errors occurred, they are listed in dictionary. Errors related to a specific
+        /// request parameter will include a dictionary key describing that parameter.
+        /// </summary>
+        public Dictionary<string, IEnumerable<string>> Errors { get; set; }
+    }
+}