Fix caching headers.

backend/src/Squidex.Web/Pipeline/CachingManager.cs

@@ -115,16 +115,18 @@ namespace Squidex.Web.Pipeline
                     {
                         foreach (var key in keys)
                         {
+                            var encoded = Uri.EscapeDataString(key);
+
                             if (stringBuilder.Length == 0)
                             {
-                                if (stringBuilder.Length + key.Length > maxKeysSize)
+                                if (stringBuilder.Length + encoded.Length > maxKeysSize)
                                 {
                                     break;
                                 }
                             }
                             else
                             {
-                                if (stringBuilder.Length + key.Length + 1 > maxKeysSize)
+                                if (stringBuilder.Length + encoded.Length + 1 > maxKeysSize)
                                 {
                                     break;
                                 }
@@ -132,7 +134,7 @@ namespace Squidex.Web.Pipeline
                                 stringBuilder.Append(' ');
                             }
 
-                            stringBuilder.Append(key);
+                            stringBuilder.Append(encoded);
                         }
 
                         if (stringBuilder.Length > 0)

backend/tests/Squidex.Web.Tests/Pipeline/CachingKeysMiddlewareTests.cs

@@ -214,6 +214,21 @@ namespace Squidex.Web.Pipeline
             Assert.Equal(string.Empty, httpContext.Response.Headers[HeaderNames.ETag]);
         }
 
+        [Fact]
+        public async Task Should_append_surrogate_and_ecape_if_necessary()
+        {
+            var id = DomainId.Create("id@domain");
+
+            cachingOptions.MaxSurrogateKeysSize = 100;
+
+            await MakeRequestAsync(() =>
+            {
+                cachingManager.AddDependency(id, 12);
+            });
+
+            Assert.Equal("id%40domain", httpContext.Response.Headers["Surrogate-Key"]);
+        }
+
         [Fact]
         public async Task Should_append_surrogate_keys()
         {