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src/Umbraco.Web.Common/Extensions/ViewDataExtensions.cs

@@ -1,7 +1,12 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
 using Semver;
-
+using Umbraco.Core;
+using Umbraco.Core.Security;
+using Umbraco.Core.Serialization;
 
 namespace Umbraco.Extensions
 {
@@ -21,6 +26,49 @@ namespace Umbraco.Extensions
             return true;
         }
 
+        /// <summary>
+        /// Copies data from a request cookie to view data and then clears the cookie in the response
+        /// </summary>
+        /// <param name="viewData"></param>
+        /// <param name="httpContext"></param>
+        /// <param name="cookieName"></param>
+        /// <returns></returns>
+        /// <remarks>
+        /// <para>
+        /// This is similar to TempData but in some cases we cannot use TempData which relies on the temp data provider and session.
+        /// The cookie value can either be a simple string value
+        /// </para>
+        /// </remarks>
+        public static bool FromBase64CookieData<T>(this ViewDataDictionary viewData, HttpContext httpContext, string cookieName, IJsonSerializer serializer)
+        {
+            var hasCookie = httpContext.Request.Cookies.ContainsKey(cookieName);
+            if (!hasCookie) return false;
+
+            // get the cookie value
+            if (!httpContext.Request.Cookies.TryGetValue(cookieName, out var cookieVal))
+            {
+                return false;
+            }
+
+            // ensure the cookie is expired (must be done after reading the value)
+            httpContext.Response.Cookies.Delete(cookieName);
+
+            if (cookieVal.IsNullOrWhiteSpace())
+                return false;
+
+            try
+            {
+                var decoded = Encoding.UTF8.GetString(Convert.FromBase64String(System.Net.WebUtility.UrlDecode(cookieVal)));
+                // deserialize to T and store in viewdata
+                viewData[cookieName] = serializer.Deserialize<T>(decoded);
+                return true;
+            }
+            catch (Exception)
+            {
+                return false;
+            }
+        }
+
         public static string GetUmbracoPath(this ViewDataDictionary viewData)
         {
             return (string)viewData[TokenUmbracoPath];
@@ -60,14 +108,24 @@ namespace Umbraco.Extensions
             return (SemVersion) viewData[TokenUmbracoVersion];
         }
 
-        public static IEnumerable<string> GetExternalSignInError(this ViewDataDictionary viewData)
+        /// <summary>
+        /// Used by the back office login screen to get any registered external login provider errors
+        /// </summary>
+        /// <param name="viewData"></param>
+        /// <returns></returns>
+        public static BackOfficeExternalLoginProviderErrors GetExternalSignInProviderErrors(this ViewDataDictionary viewData)
         {
-            return (IEnumerable<string>)viewData[TokenExternalSignInError];
+            return (BackOfficeExternalLoginProviderErrors)viewData[TokenExternalSignInError];
         }
 
-        public static void SetExternalSignInError(this ViewDataDictionary viewData, IEnumerable<string> value)
+        /// <summary>
+        /// Used by the back office controller to register any external login provider errors
+        /// </summary>
+        /// <param name="viewData"></param>
+        /// <param name="errors"></param>
+        public static void SetExternalSignInProviderErrors(this ViewDataDictionary viewData, BackOfficeExternalLoginProviderErrors errors)
         {
-            viewData[TokenExternalSignInError] = value;
+            viewData[TokenExternalSignInError] = errors;
         }
 
         public static string GetPasswordResetCode(this ViewDataDictionary viewData)