Feature/embedding (#879)

* Backend work.

* Frontend work.

backend/i18n/frontend_en.json

@@ -798,6 +798,8 @@
   "schemas.field.hide": "Hide in API",
   "schemas.field.hintsHint": "Describe this field for documentation and the UI.",
   "schemas.field.inlineEditable": "Inline Editable",
+  "schemas.field.isEmbeddable": "Is embedding contents and assets",
+  "schemas.field.isEmbeddableHint": "With this option a custom format is returned in GraphQL, where the linked assets or contents can be fetched.",
   "schemas.field.labelHint": "Display name for documentation and the UI.",
   "schemas.field.localizable": "Localizable",
   "schemas.field.localizableHint": "You can mark the field as localizable. It means that is dependent on the language, for example a city name.",

backend/i18n/frontend_it.json

@@ -798,6 +798,8 @@
   "schemas.field.hide": "Nascondi nelle API",
   "schemas.field.hintsHint": "Descrivi questo schema per la documentazione e le interfacce utente.",
   "schemas.field.inlineEditable": "Modificabile sulla stessa linea",
+  "schemas.field.isEmbeddable": "Is embedding contents and assets",
+  "schemas.field.isEmbeddableHint": "With this option a custom format is returned in GraphQL, where the linked assets or contents can be fetched.",
   "schemas.field.labelHint": "Nome da visualizzare per la documentazione e le interfacce utente.",
   "schemas.field.localizable": "Consente la localizzazione",
   "schemas.field.localizableHint": "Puoi impostare il campo per consentire la localizzazione, ossia che dipende dalla lingua che utilizzi come ad esempio i nomi delle città.",

backend/i18n/frontend_nl.json

@@ -798,6 +798,8 @@
   "schemas.field.hide": "Verbergen in API",
   "schemas.field.hintsHint": "Beschrijf dit schema voor documentatie en gebruikersinterfaces.",
   "schemas.field.inlineEditable": "Inline bewerkbaar",
+  "schemas.field.isEmbeddable": "Is embedding contents and assets",
+  "schemas.field.isEmbeddableHint": "With this option a custom format is returned in GraphQL, where the linked assets or contents can be fetched.",
   "schemas.field.labelHint": "Weergavenaam voor documentatie en gebruikersinterfaces.",
   "schemas.field.localizable": "Localizable",
   "schemas.field.localizableHint": "Je kunt het veld markeren als lokaliseerbaar. Dit betekent dat het afhankelijk is van de taal, bijvoorbeeld de naam van een stad.",

backend/i18n/frontend_zh.json

@@ -798,6 +798,8 @@
   "schemas.field.hide": "隐藏在 API",
   "schemas.field.hintsHint": "为文档和 UI 描述这个字段。",
   "schemas.field.inlineEditable": "内联可编辑",
+  "schemas.field.isEmbeddable": "Is embedding contents and assets",
+  "schemas.field.isEmbeddableHint": "With this option a custom format is returned in GraphQL, where the linked assets or contents can be fetched.",
   "schemas.field.labelHint": "文档和 UI 的显示名称。",
   "schemas.field.localizable": "Localizable",
   "schemas.field.localizableHint": "您可以将字段标记为可本地化。这意味着这取决于语言，例如城市名称。",

backend/i18n/source/frontend_en.json

@@ -798,6 +798,8 @@
   "schemas.field.hide": "Hide in API",
   "schemas.field.hintsHint": "Describe this field for documentation and the UI.",
   "schemas.field.inlineEditable": "Inline Editable",
+  "schemas.field.isEmbeddable": "Is embedding contents and assets",
+  "schemas.field.isEmbeddableHint": "With this option a custom format is returned in GraphQL, where the linked assets or contents can be fetched.",
   "schemas.field.labelHint": "Display name for documentation and the UI.",
   "schemas.field.localizable": "Localizable",
   "schemas.field.localizableHint": "You can mark the field as localizable. It means that is dependent on the language, for example a city name.",

backend/src/Squidex.Domain.Apps.Core.Model/FieldDescriptions.Designer.cs

@@ -861,6 +861,33 @@ namespace Squidex.Domain.Apps.Core {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to The referenced assets..
+        /// </summary>
+        public static string StringFieldAssets {
+            get {
+                return ResourceManager.GetString("StringFieldAssets", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The referenced content items..
+        /// </summary>
+        public static string StringFieldReferences {
+            get {
+                return ResourceManager.GetString("StringFieldReferences", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The text of this field..
+        /// </summary>
+        public static string StringFieldText {
+            get {
+                return ResourceManager.GetString("StringFieldText", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to The current number of calls..
         /// </summary>

backend/src/Squidex.Domain.Apps.Core.Model/FieldDescriptions.resx

@@ -384,6 +384,15 @@
   <data name="SchemaId" xml:space="preserve">
     <value>The ID of the schema.</value>
   </data>
+  <data name="StringFieldAssets" xml:space="preserve">
+    <value>The referenced assets.</value>
+  </data>
+  <data name="StringFieldReferences" xml:space="preserve">
+    <value>The referenced content items.</value>
+  </data>
+  <data name="StringFieldText" xml:space="preserve">
+    <value>The text of this field.</value>
+  </data>
   <data name="UsageCallsCurrent" xml:space="preserve">
     <value>The current number of calls.</value>
   </data>

backend/src/Squidex.Domain.Apps.Core.Model/Schemas/StringFieldProperties.cs

@@ -5,6 +5,7 @@
 //  All rights reserved. Licensed under the MIT license.
 // ==========================================================================
 
+using Squidex.Infrastructure;
 using Squidex.Infrastructure.Collections;
 
 namespace Squidex.Domain.Apps.Core.Schemas
@@ -37,6 +38,8 @@ namespace Squidex.Domain.Apps.Core.Schemas
 
         public bool IsUnique { get; init; }
 
+        public bool IsEmbeddable { get; init; }
+
         public bool InlineEditable { get; init; }
 
         public bool CreateEnum { get; init; }
@@ -45,6 +48,8 @@ namespace Squidex.Domain.Apps.Core.Schemas
 
         public StringFieldEditor Editor { get; init; }
 
+        public ReadonlyList<DomainId>? SchemaIds { get; init; }
+
         public override T Accept<T, TArgs>(IFieldPropertiesVisitor<T, TArgs> visitor, TArgs args)
         {
             return visitor.Visit(this, args);

backend/src/Squidex.Domain.Apps.Core.Operations/ExtractReferenceIds/StringReferenceExtractor.cs

@@ -0,0 +1,106 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.Text.RegularExpressions;
+using Squidex.Infrastructure;
+
+namespace Squidex.Domain.Apps.Core.ExtractReferenceIds
+{
+    public sealed class StringReferenceExtractor
+    {
+        private readonly List<Regex> contentsPatterns = new  List<Regex>();
+        private readonly List<Regex> assetsPatterns = new List<Regex>();
+
+        public StringReferenceExtractor(IUrlGenerator urlGenerator)
+        {
+            AddAssetPattern(@"assets?:(?<Id>[a-z0-9\-_9]+)");
+            AddAssetUrlPatterns(urlGenerator.AssetContentBase());
+            AddAssetUrlPatterns(urlGenerator.AssetContentCDNBase());
+
+            AddContentPattern(@"contents?:(?<Id>[a-z0-9\-_9]+)");
+            AddContentUrlPatterns(urlGenerator.ContentBase());
+            AddContentUrlPatterns(urlGenerator.ContentCDNBase());
+        }
+
+        private void AddContentUrlPatterns(string baseUrl)
+        {
+            if (string.IsNullOrWhiteSpace(baseUrl))
+            {
+                return;
+            }
+
+            if (!baseUrl.EndsWith('/'))
+            {
+                baseUrl += "/";
+            }
+
+            baseUrl = Regex.Escape(baseUrl);
+
+            AddContentPattern(baseUrl + @"(.+)\/(.+)\/(?<Id>[a-z0-9\-_9]+)");
+        }
+
+        private void AddAssetUrlPatterns(string baseUrl)
+        {
+            if (string.IsNullOrWhiteSpace(baseUrl))
+            {
+                return;
+            }
+
+            if (!baseUrl.EndsWith('/'))
+            {
+                baseUrl += "/";
+            }
+
+            baseUrl = Regex.Escape(baseUrl);
+
+            AddAssetPattern(baseUrl + @"(?<Id>[a-z0-9\-_9]+)");
+            AddAssetPattern(baseUrl + @"(.+)\/(?<Id>[a-z0-9\-_9]+)");
+        }
+
+        private void AddAssetPattern(string pattern)
+        {
+            assetsPatterns.Add(new Regex(pattern, RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.ExplicitCapture));
+        }
+
+        private void AddContentPattern(string pattern)
+        {
+            contentsPatterns.Add(new Regex(pattern, RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.ExplicitCapture));
+        }
+
+        public IEnumerable<DomainId> GetEmbeddedContentIds(string text)
+        {
+            if (string.IsNullOrWhiteSpace(text))
+            {
+                yield break;
+            }
+
+            foreach (var pattern in contentsPatterns)
+            {
+                foreach (Match match in pattern.Matches(text))
+                {
+                    yield return DomainId.Create(match.Groups["Id"].Value);
+                }
+            }
+        }
+
+        public IEnumerable<DomainId> GetEmbeddedAssetIds(string text)
+        {
+            if (string.IsNullOrWhiteSpace(text))
+            {
+                yield break;
+            }
+
+            foreach (var pattern in assetsPatterns)
+            {
+                foreach (Match match in pattern.Matches(text))
+                {
+                    yield return DomainId.Create(match.Groups["Id"].Value);
+                }
+            }
+        }
+    }
+}

backend/src/Squidex.Domain.Apps.Core.Operations/IUrlGenerator.cs

@@ -12,14 +12,14 @@ namespace Squidex.Domain.Apps.Core
 {
     public interface IUrlGenerator
     {
-        bool CanGenerateAssetSourceUrl { get; }
-
         string? AssetSource(NamedId<DomainId> appId, DomainId assetId, long fileVersion);
 
         string? AssetThumbnail(NamedId<DomainId> appId, string idOrSlug, AssetType assetType);
 
         string AssetsUI(NamedId<DomainId> appId, string? @ref = null);
 
+        string AssetContentCDNBase();
+
         string AssetContent(NamedId<DomainId> appId, string idOrSlug);
 
         string AssetContentBase();
@@ -30,6 +30,10 @@ namespace Squidex.Domain.Apps.Core
 
         string ClientsUI(NamedId<DomainId> appId);
 
+        string ContentCDNBase();
+
+        string ContentBase();
+
         string ContentsUI(NamedId<DomainId> appId, NamedId<DomainId> schemaId);
 
         string ContentUI(NamedId<DomainId> appId, NamedId<DomainId> schemaId, DomainId contentId);

backend/src/Squidex.Domain.Apps.Entities/Assets/AssetOptions.cs

@@ -19,6 +19,8 @@ namespace Squidex.Domain.Apps.Entities.Assets
 
         public long MaxSize { get; set; } = 5 * 1024 * 1024;
 
+        public string? CDN { get; set; }
+
         public TimeSpan TimeoutFind { get; set; } = TimeSpan.FromSeconds(1);
 
         public TimeSpan TimeoutQuery { get; set; } = TimeSpan.FromSeconds(5);

backend/src/Squidex.Domain.Apps.Entities/Contents/ContentOptions.cs

@@ -15,6 +15,8 @@ namespace Squidex.Domain.Apps.Entities.Contents
 
         public int MaxResults { get; set; } = 200;
 
+        public string? CDN { get; set; }
+
         public TimeSpan TimeoutFind { get; set; } = TimeSpan.FromSeconds(1);
 
         public TimeSpan TimeoutQuery { get; set; } = TimeSpan.FromSeconds(5);

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/GraphQLExecutionContext.cs

@@ -77,12 +77,18 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
             return content;
         }
 
-        public async Task<IReadOnlyList<IEnrichedAssetEntity>> GetReferencedAssetsAsync(IJsonValue value, TimeSpan cacheDuration,
+        public Task<IReadOnlyList<IEnrichedAssetEntity>> GetReferencedAssetsAsync(IJsonValue value, TimeSpan cacheDuration,
             CancellationToken ct)
         {
             var ids = ParseIds(value);
 
-            if (ids == null)
+            return GetAssetsAsync(ids, cacheDuration, ct);
+        }
+
+        public async Task<IReadOnlyList<IEnrichedAssetEntity>> GetAssetsAsync(List<DomainId>? ids, TimeSpan cacheDuration,
+            CancellationToken ct)
+        {
+            if (ids == null || ids.Count == 0)
             {
                 return EmptyAssets;
             }
@@ -107,12 +113,18 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
             return await LoadAsync(ids);
         }
 
-        public async Task<IReadOnlyList<IEnrichedContentEntity>> GetReferencedContentsAsync(IJsonValue value, TimeSpan cacheDuration,
+        public Task<IReadOnlyList<IEnrichedContentEntity>> GetReferencedContentsAsync(IJsonValue value, TimeSpan cacheDuration,
             CancellationToken ct)
         {
             var ids = ParseIds(value);
 
-            if (ids == null)
+            return GetContentsAsync(ids, cacheDuration, ct);
+        }
+
+        public async Task<IReadOnlyList<IEnrichedContentEntity>> GetContentsAsync(List<DomainId>? ids, TimeSpan cacheDuration,
+            CancellationToken ct)
+        {
+            if (ids == null || ids.Count == 0)
             {
                 return EmptyContents;
             }

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/Types/Builder.cs

@@ -6,7 +6,6 @@
 // ==========================================================================
 
 using GraphQL;
-using GraphQL.Resolvers;
 using GraphQL.Types;
 using Squidex.Domain.Apps.Core;
 using Squidex.Domain.Apps.Core.Contents;
@@ -24,6 +23,7 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types
         private readonly Dictionary<SchemaInfo, ComponentGraphType> componentTypes = new Dictionary<SchemaInfo, ComponentGraphType>(ReferenceEqualityComparer.Instance);
         private readonly Dictionary<SchemaInfo, ContentGraphType> contentTypes = new Dictionary<SchemaInfo, ContentGraphType>(ReferenceEqualityComparer.Instance);
         private readonly Dictionary<SchemaInfo, ContentResultGraphType> contentResultTypes = new Dictionary<SchemaInfo, ContentResultGraphType>(ReferenceEqualityComparer.Instance);
+        private readonly Dictionary<FieldInfo, EmbeddableStringGraphType> embeddableStringTypes = new Dictionary<FieldInfo, EmbeddableStringGraphType>(); 
         private readonly Dictionary<string, EnumerationGraphType?> enumTypes = new Dictionary<string, EnumerationGraphType?>();
         private readonly FieldVisitor fieldVisitor;
         private readonly FieldInputVisitor fieldInputVisitor;
@@ -107,6 +107,11 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types
             return newSchema;
         }
 
+        public FieldGraphSchema GetGraphType(FieldInfo fieldInfo)
+        {
+            return fieldInfo.Field.Accept(fieldVisitor, fieldInfo);
+        }
+
         public IFieldPartitioning ResolvePartition(Partitioning key)
         {
             return partitionResolver(key);
@@ -117,11 +122,6 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types
             return fieldInfo.Field.Accept(fieldInputVisitor, fieldInfo);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) GetGraphType(FieldInfo fieldInfo)
-        {
-            return fieldInfo.Field.Accept(fieldVisitor, fieldInfo);
-        }
-
         public IObjectGraphType GetContentResultType(SchemaInfo schemaId)
         {
             return contentResultTypes.GetOrDefault(schemaId);
@@ -149,6 +149,11 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types
             return componentTypes.GetOrDefault(schema);
         }
 
+        public EmbeddableStringGraphType GetEmbeddableString(FieldInfo fieldInfo, StringFieldProperties properties)
+        {
+            return embeddableStringTypes.GetOrAdd(fieldInfo, x => new EmbeddableStringGraphType(this, x, properties));
+        }
+
         public EnumerationGraphType? GetEnumeration(string name, IEnumerable<string> values)
         {
             return enumTypes.GetOrAdd(name, x => FieldEnumType.TryCreate(name, values));

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/Types/Contents/ContentFields.cs

@@ -9,6 +9,7 @@ using GraphQL.Resolvers;
 using GraphQL.Types;
 using Squidex.Domain.Apps.Core;
 using Squidex.Domain.Apps.Core.Contents;
+using Squidex.Domain.Apps.Core.ExtractReferenceIds;
 using Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Primitives;
 using Squidex.Infrastructure.Json.Objects;
 
@@ -16,6 +17,24 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
 {
     internal static class ContentFields
     {
+        public static readonly IFieldResolver ResolveStringFieldAssets = Resolvers.Async<string, object>(async (value, fieldContext, context) =>
+        {
+            var cacheDuration = fieldContext.CacheDuration();
+
+            var ids = context.Resolve<StringReferenceExtractor>().GetEmbeddedAssetIds(value).ToList();
+
+            return await context.GetAssetsAsync(ids, cacheDuration, fieldContext.CancellationToken);
+        });
+
+        public static readonly IFieldResolver ResolveStringFieldContents = Resolvers.Async<string, object>(async (value, fieldContext, context) =>
+        {
+            var cacheDuration = fieldContext.CacheDuration();
+
+            var ids = context.Resolve<StringReferenceExtractor>().GetEmbeddedContentIds(value).ToList();
+
+            return await context.GetContentsAsync(ids, cacheDuration, fieldContext.CancellationToken);
+        });
+
         public static readonly FieldType Id = new FieldType
         {
             Name = "id",
@@ -136,6 +155,22 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
             Description = FieldDescriptions.EditToken
         };
 
+        public static readonly FieldType StringFieldText = new FieldType
+        {
+            Name = "text",
+            ResolvedType = AllTypes.String,
+            Resolver = Resolvers.Sync<string, string>(x => x),
+            Description = FieldDescriptions.StringFieldText
+        };
+
+        public static readonly FieldType StringFieldAssets = new FieldType
+        {
+            Name = "assets",
+            ResolvedType = new NonNullGraphType(SharedTypes.AssetsList),
+            Resolver = ResolveStringFieldAssets,
+            Description = FieldDescriptions.StringFieldAssets
+        };
+
         private static IFieldResolver Resolve<T>(Func<JsonObject, T> resolver)
         {
             return Resolvers.Sync(resolver);

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/Types/Contents/EmbeddableStringGraphType.cs

@@ -0,0 +1,64 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using GraphQL.Types;
+using Squidex.Domain.Apps.Core;
+using Squidex.Domain.Apps.Core.Schemas;
+using Squidex.Infrastructure;
+using Squidex.Infrastructure.Collections;
+
+namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
+{
+    internal sealed class EmbeddableStringGraphType : ObjectGraphType<string>
+    {
+        public EmbeddableStringGraphType(Builder builder, FieldInfo fieldInfo, StringFieldProperties properties)
+        {
+            // The name is used for equal comparison. Therefore it is important to treat it as readonly.
+            Name = fieldInfo.EmbeddableStringType;
+
+            AddField(ContentFields.StringFieldText);
+            AddField(ContentFields.StringFieldAssets);
+
+            var referenceType = ResolveReferences(builder, fieldInfo, properties.SchemaIds);
+
+            if (referenceType != null)
+            {
+                AddField(new FieldType
+                {
+                    Name = "contents",
+                    ResolvedType = new NonNullGraphType(new ListGraphType(new NonNullGraphType(referenceType))),
+                    Resolver = ContentFields.ResolveStringFieldContents,
+                    Description = FieldDescriptions.StringFieldReferences
+                });
+            }
+        }
+
+        private static IGraphType? ResolveReferences(Builder builder, FieldInfo fieldInfo, ReadonlyList<DomainId>? schemaIds)
+        {
+            IGraphType? contentType = null;
+
+            if (schemaIds?.Count == 1)
+            {
+                contentType = builder.GetContentType(schemaIds[0]);
+            }
+
+            if (contentType == null)
+            {
+                var union = new ReferenceUnionGraphType(builder, fieldInfo, schemaIds);
+
+                if (!union.HasType)
+                {
+                    return default;
+                }
+
+                contentType = union;
+            }
+
+            return contentType;
+        }
+    }
+}

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/Types/Contents/FieldEnumType.cs

@@ -14,6 +14,7 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
     {
         public FieldEnumType(string name, IEnumerable<string> values)
         {
+            // The name is used for equal comparison. Therefore it is important to treat it as readonly.
             Name = name;
 
             foreach (var value in values)

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/Types/Contents/FieldGraphSchema.cs

@@ -0,0 +1,16 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using GraphQL.Resolvers;
+using GraphQL.Types;
+
+#pragma warning disable SA1313 // Parameter names should begin with lower-case letter
+
+namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
+{
+    public record struct FieldGraphSchema(IGraphType? Type, IFieldResolver? Resolver, QueryArguments? Arguments);
+}

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/Types/Contents/FieldVisitor.cs

@@ -19,7 +19,7 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
 {
     public delegate object ValueResolver(IJsonValue value, IResolveFieldContext fieldContext, GraphQLExecutionContext context);
 
-    internal sealed class FieldVisitor : IFieldVisitor<(IGraphType?, IFieldResolver?, QueryArguments?), FieldInfo>
+    internal sealed class FieldVisitor : IFieldVisitor<FieldGraphSchema, FieldInfo>
     {
         public static readonly IFieldResolver JsonNoop = CreateValueResolver((value, fieldContext, contex) => value);
         public static readonly IFieldResolver JsonPath = CreateValueResolver(ContentActions.Json.Resolver);
@@ -100,7 +100,7 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
             this.builder = builder;
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IArrayField field, FieldInfo args)
+        public FieldGraphSchema Visit(IArrayField field, FieldInfo args)
         {
             if (args.Fields.Count == 0)
             {
@@ -114,20 +114,20 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
                 return default;
             }
 
-            return (new ListGraphType(new NonNullGraphType(type)), JsonNoop, null);
+            return new (new ListGraphType(new NonNullGraphType(type)), JsonNoop, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<AssetsFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<AssetsFieldProperties> field, FieldInfo args)
         {
-            return (SharedTypes.AssetsList, Assets, null);
+            return new (SharedTypes.AssetsList, Assets, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<BooleanFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<BooleanFieldProperties> field, FieldInfo args)
         {
-            return (AllTypes.Boolean, JsonBoolean, null);
+            return new (AllTypes.Boolean, JsonBoolean, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<ComponentFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<ComponentFieldProperties> field, FieldInfo args)
         {
             var type = ResolveComponent(args, field.Properties.SchemaIds);
 
@@ -136,10 +136,10 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
                 return default;
             }
 
-            return (type, JsonNoop, null);
+            return new (type, JsonNoop, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<ComponentsFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<ComponentsFieldProperties> field, FieldInfo args)
         {
             var type = ResolveComponent(args, field.Properties.SchemaIds);
 
@@ -148,34 +148,38 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
                 return default;
             }
 
-            return (new ListGraphType(new NonNullGraphType(type)), JsonNoop, null);
+            return new (new ListGraphType(new NonNullGraphType(type)), JsonNoop, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<DateTimeFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<DateTimeFieldProperties> field, FieldInfo args)
         {
-            return (AllTypes.DateTime, JsonDateTime, null);
+            return new (AllTypes.DateTime, JsonDateTime, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<JsonFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<JsonFieldProperties> field, FieldInfo args)
         {
-            return (AllTypes.Json, JsonPath, ContentActions.Json.Arguments);
+            return new (AllTypes.Json, JsonPath, ContentActions.Json.Arguments);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<GeolocationFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<GeolocationFieldProperties> field, FieldInfo args)
         {
-            return (AllTypes.Json, JsonPath, ContentActions.Json.Arguments);
+            return new (AllTypes.Json, JsonPath, ContentActions.Json.Arguments);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<NumberFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<NumberFieldProperties> field, FieldInfo args)
         {
-            return (AllTypes.Float, JsonNumber, null);
+            return new (AllTypes.Float, JsonNumber, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<StringFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<StringFieldProperties> field, FieldInfo args)
         {
             var type = AllTypes.String;
 
-            if (field.Properties?.AllowedValues?.Count > 0 && field.Properties.CreateEnum)
+            if (field.Properties.IsEmbeddable)
+            {
+                type = builder.GetEmbeddableString(args, field.Properties);
+            }
+            else if (field.Properties?.AllowedValues?.Count > 0 && field.Properties.CreateEnum)
             {
                 var @enum = builder.GetEnumeration(args.EnumName, field.Properties.AllowedValues);
 
@@ -185,10 +189,10 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
                 }
             }
 
-            return (type, JsonString, null);
+            return new (type, JsonString, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<TagsFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<TagsFieldProperties> field, FieldInfo args)
         {
             var type = AllTypes.Strings;
 
@@ -202,10 +206,10 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
                 }
             }
 
-            return (type, JsonStrings, null);
+            return new (type, JsonStrings, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<ReferencesFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<ReferencesFieldProperties> field, FieldInfo args)
         {
             var type = ResolveReferences(args, field.Properties.SchemaIds);
 
@@ -214,10 +218,10 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
                 return default;
             }
 
-            return (new ListGraphType(new NonNullGraphType(type)), References, null);
+            return new (new ListGraphType(new NonNullGraphType(type)), References, null);
         }
 
-        public (IGraphType?, IFieldResolver?, QueryArguments?) Visit(IField<UIFieldProperties> field, FieldInfo args)
+        public FieldGraphSchema Visit(IField<UIFieldProperties> field, FieldInfo args)
         {
             return default;
         }

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/Types/Contents/SchemaInfo.cs

@@ -108,6 +108,8 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
 
         public string ReferenceType { get; }
 
+        public string EmbeddableStringType { get; }
+
         public IReadOnlyList<FieldInfo> Fields { get; }
 
         private FieldInfo(IField field, string typeName, Names names, Names parentNames, IReadOnlyList<FieldInfo> fields)
@@ -116,11 +118,12 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Contents
 
             ComponentType = names[$"{typeName}ComponentUnionDto"];
             DisplayName = field.DisplayName();
+            EmbeddableStringType = names[$"{typeName}EmbeddableString"];
+            EnumName = names[$"{fieldName}Enum"];
             Field = field;
-            Fields = fields;
             FieldName = fieldName;
             FieldNameDynamic = names[$"{fieldName}__Dynamic"];
-            EnumName = names[$"{fieldName}Enum"];
+            Fields = fields;
             LocalizedInputType = names[$"{typeName}InputDto"];
             LocalizedType = names[$"{typeName}Dto"];
             LocalizedTypeDynamic = names[$"{typeName}Dto__Dynamic"];

backend/src/Squidex.Domain.Apps.Entities/Contents/GraphQL/Types/SharedTypes.cs

@@ -39,7 +39,7 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types
         {
             Name = "queryAssets",
             Arguments = AssetActions.Query.Arguments,
-            ResolvedType = AssetsList,
+            ResolvedType = new NonNullGraphType(AssetsList),
             Resolver = AssetActions.Query.Resolver,
             Description = "Get assets."
         };
@@ -48,7 +48,7 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL.Types
         {
             Name = "queryAssetsWithTotal",
             Arguments = AssetActions.Query.Arguments,
-            ResolvedType = AssetsResult,
+            ResolvedType = new NonNullGraphType(AssetsResult),
             Resolver = AssetActions.Query.ResolverWithTotal,
             Description = "Get assets and total count."
         };

backend/src/Squidex.Web/Services/UrlGenerator.cs

@@ -5,9 +5,11 @@
 //  All rights reserved. Licensed under the MIT license.
 // ==========================================================================
 
+using Microsoft.Extensions.Options;
 using Squidex.Domain.Apps.Core;
 using Squidex.Domain.Apps.Core.Assets;
 using Squidex.Domain.Apps.Entities.Assets;
+using Squidex.Domain.Apps.Entities.Contents;
 using Squidex.Infrastructure;
 using IGenericUrlGenerator = Squidex.Hosting.IUrlGenerator;
 
@@ -17,16 +19,17 @@ namespace Squidex.Web.Services
     {
         private readonly IAssetFileStore assetFileStore;
         private readonly IGenericUrlGenerator urlGenerator;
+        private readonly AssetOptions assetOptions;
+        private readonly ContentOptions contentOptions;
 
-        public bool CanGenerateAssetSourceUrl { get; }
+        public UrlGenerator(IGenericUrlGenerator urlGenerator, IAssetFileStore assetFileStore,
-
+            IOptions<AssetOptions> assetOptions,
-        public UrlGenerator(IGenericUrlGenerator urlGenerator, IAssetFileStore assetFileStore, bool allowAssetSourceUrl)
+            IOptions<ContentOptions> contentOptions)
         {
+            this.contentOptions = contentOptions.Value;
             this.assetFileStore = assetFileStore;
-
+            this.assetOptions = assetOptions.Value;
             this.urlGenerator = urlGenerator;
-
-            CanGenerateAssetSourceUrl = allowAssetSourceUrl;
         }
 
         public string? AssetThumbnail(NamedId<DomainId> appId, string idOrSlug, AssetType assetType)
@@ -39,6 +42,11 @@ namespace Squidex.Web.Services
             return urlGenerator.BuildUrl($"api/assets/{appId.Name}/{idOrSlug}?width=100&mode=Max");
         }
 
+        public string AssetContentCDNBase()
+        {
+            return contentOptions.CDN ?? string.Empty;
+        }
+
         public string AssetContentBase()
         {
             return urlGenerator.BuildUrl("api/assets/");
@@ -79,6 +87,16 @@ namespace Squidex.Web.Services
             return urlGenerator.BuildUrl($"app/{appId.Name}/settings/clients", false);
         }
 
+        public string ContentCDNBase()
+        {
+            return contentOptions.CDN ?? string.Empty;
+        }
+
+        public string ContentBase()
+        {
+            return urlGenerator.BuildUrl("api/content/", false);
+        }
+
         public string ContentsUI(NamedId<DomainId> appId, NamedId<DomainId> schemaId)
         {
             return urlGenerator.BuildUrl($"app/{appId.Name}/content/{schemaId.Name}", false);

backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/Fields/StringFieldPropertiesDto.cs

@@ -6,6 +6,7 @@
 // ==========================================================================
 
 using Squidex.Domain.Apps.Core.Schemas;
+using Squidex.Infrastructure;
 using Squidex.Infrastructure.Collections;
 using Squidex.Infrastructure.Reflection;
 
@@ -73,11 +74,21 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models.Fields
         /// </summary>
         public ReadonlyList<string>? AllowedValues { get; set; }
 
+        /// <summary>
+        /// The allowed schema ids that can be embedded.
+        /// </summary>
+        public ReadonlyList<DomainId>? SchemaIds { get; init; }
+
         /// <summary>
         /// Indicates if the field value must be unique. Ignored for nested fields and localized fields.
         /// </summary>
         public bool IsUnique { get; set; }
 
+        /// <summary>
+        /// Indicates that other content items or references are embedded.
+        /// </summary>
+        public bool IsEmbeddable { get; set; }
+
         /// <summary>
         /// Indicates that the inline editor is enabled for this field.
         /// </summary>

backend/src/Squidex/Config/Domain/QueryServices.cs

@@ -6,6 +6,7 @@
 // ==========================================================================
 
 using Squidex.Domain.Apps.Core;
+using Squidex.Domain.Apps.Core.ExtractReferenceIds;
 using Squidex.Domain.Apps.Entities.Contents.GraphQL;
 using Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Primitives;
 using Squidex.Web.Services;
@@ -16,12 +17,13 @@ namespace Squidex.Config.Domain
     {
         public static void AddSquidexQueries(this IServiceCollection services, IConfiguration config)
         {
-            var exposeSourceUrl = config.GetOptionalValue("assetStore:exposeSourceUrl", true);
-
             services.Configure<GraphQLOptions>(config,
                 "graphql");
 
-            services.AddSingletonAs(c => ActivatorUtilities.CreateInstance<UrlGenerator>(c, exposeSourceUrl))
+            services.AddSingletonAs<StringReferenceExtractor>()
+                .AsSelf();
+
+            services.AddSingletonAs<UrlGenerator>()
                 .As<IUrlGenerator>();
 
             services.AddSingletonAs<InstantGraphType>()

backend/tests/Squidex.Domain.Apps.Core.Tests/Operations/ExtractReferenceIds/StringReferenceExtractorTests.cs

@@ -0,0 +1,64 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using FakeItEasy;
+using Squidex.Domain.Apps.Core.ExtractReferenceIds;
+using Squidex.Infrastructure;
+using Xunit;
+
+namespace Squidex.Domain.Apps.Core.Operations.ExtractReferenceIds
+{
+    public class StringReferenceExtractorTests
+    {
+        private readonly StringReferenceExtractor sut;
+
+        public StringReferenceExtractorTests()
+        {
+            var urlGenerator = A.Fake<IUrlGenerator>();
+
+            A.CallTo(() => urlGenerator.ContentBase())
+                .Returns("https://cloud.squidex.io/api/content/");
+
+            A.CallTo(() => urlGenerator.ContentCDNBase())
+                .Returns("https://contents.squidex.io/");
+
+            A.CallTo(() => urlGenerator.AssetContentBase())
+                .Returns("https://cloud.squidex.io/api/assets/");
+
+            A.CallTo(() => urlGenerator.AssetContentCDNBase())
+                .Returns("https://assets.squidex.io/");
+
+            sut = new StringReferenceExtractor(urlGenerator);
+        }
+
+        [Theory]
+        [InlineData("before content:a_b-123|after")]
+        [InlineData("before contents:a_b-123|after")]
+        [InlineData("before https://cloud.squidex.io/api/content/my-app/my-schema/a_b-123|after")]
+        [InlineData("before https://contents.squidex.io/my-app/my-schema/a_b-123|after")]
+        public void Should_extract_content_id(string input)
+        {
+            var ids = sut.GetEmbeddedContentIds(input);
+
+            Assert.Contains(DomainId.Create("a_b-123"), ids.ToList());
+        }
+
+        [Theory]
+        [InlineData("before asset:a_b-123|after")]
+        [InlineData("before assets:a_b-123|after")]
+        [InlineData("before https://cloud.squidex.io/api/assets/a_b-123|after")]
+        [InlineData("before https://cloud.squidex.io/api/assets/my-app/a_b-123|after")]
+        [InlineData("before https://assets.squidex.io/a_b-123|after")]
+        [InlineData("before https://assets.squidex.io/my-app/a_b-123|after")]
+        public void Should_extract_asset_id(string input)
+        {
+            var ids = sut.GetEmbeddedAssetIds(input);
+
+            Assert.Contains(DomainId.Create("a_b-123"), ids.ToList());
+        }
+    }
+}

backend/tests/Squidex.Domain.Apps.Entities.Tests/Contents/GraphQL/GraphQLQueriesTests.cs

@@ -400,6 +400,89 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
             AssertResult(expected, result);
         }
 
+        [Fact]
+        public async Task Should_also_fetch_embedded_contents_if_field_is_included_in_query()
+        {
+            var contentRefId = DomainId.NewGuid();
+            var contentRef = TestContent.CreateRef(TestSchemas.Ref1Id, contentRefId, "schemaRef1Field", "ref1");
+
+            var contentId = DomainId.NewGuid();
+            var content = TestContent.Create(contentId, contentRefId);
+
+            var query = CreateQuery(@"
+                query {
+                  findMySchemaContent(id: '<ID>') {
+                    id
+                    data {
+                      myEmbeds {
+                        iv {
+                          text
+                          contents {
+                            ... on Content {
+                              id
+                            }
+                            ... on MyRefSchema1 {
+                              data {
+                                schemaRef1Field {
+                                  iv
+                                }
+                              }
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                }", contentId);
+
+            A.CallTo(() => contentQuery.QueryAsync(MatchsContentContext(),
+                    A<Q>.That.HasIdsWithoutTotal(contentRefId), A<CancellationToken>._))
+                .Returns(ResultList.CreateFrom(0, contentRef));
+
+            A.CallTo(() => contentQuery.QueryAsync(MatchsContentContext(),
+                    A<Q>.That.HasIdsWithoutTotal(contentId), A<CancellationToken>._))
+                .Returns(ResultList.CreateFrom(1, content));
+
+            var result = await ExecuteAsync(new ExecutionOptions { Query = query });
+
+            var expected = new
+            {
+                data = new
+                {
+                    findMySchemaContent = new
+                    {
+                        id = content.Id,
+                        data = new
+                        {
+                            myEmbeds = new
+                            {
+                                iv = new
+                                {
+                                    text = $"assets:{DomainId.Empty}, contents:{contentRefId}",
+                                    contents = new[]
+                                    {
+                                        new
+                                        {
+                                            id = contentRefId,
+                                            data = new
+                                            {
+                                                schemaRef1Field = new
+                                                {
+                                                    iv = "ref1"
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            };
+
+            AssertResult(expected, result);
+        }
+
         [Fact]
         public async Task Should_also_fetch_referenced_contents_if_field_is_included_in_query()
         {
@@ -904,6 +987,73 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
             AssertResult(expected, result);
         }
 
+        [Fact]
+        public async Task Should_also_fetch_embedded_assets_if_field_is_included_in_query()
+        {
+            var assetRefId = DomainId.NewGuid();
+            var assetRef = TestAsset.Create(assetRefId);
+
+            var contentId = DomainId.NewGuid();
+            var content = TestContent.Create(contentId, assetId: assetRefId);
+
+            var query = CreateQuery(@"
+                query {
+                  findMySchemaContent(id: '<ID>') {
+                    id
+                    data {
+                      myEmbeds {
+                        iv {
+                          text
+                          assets {
+                            id
+                          }
+                        }
+                      }
+                    }
+                  }
+                }", contentId);
+
+            A.CallTo(() => contentQuery.QueryAsync(MatchsContentContext(),
+                    A<Q>.That.HasIdsWithoutTotal(contentId), A<CancellationToken>._))
+                .Returns(ResultList.CreateFrom(1, content));
+
+            A.CallTo(() => assetQuery.QueryAsync(MatchsAssetContext(), null,
+                    A<Q>.That.HasIdsWithoutTotal(assetRefId), A<CancellationToken>._))
+                .Returns(ResultList.CreateFrom(0, assetRef));
+
+            var result = await ExecuteAsync(new ExecutionOptions { Query = query });
+
+            var expected = new
+            {
+                data = new
+                {
+                    findMySchemaContent = new
+                    {
+                        id = content.Id,
+                        data = new
+                        {
+                            myEmbeds = new
+                            {
+                                iv = new
+                                {
+                                    text = $"assets:{assetRefId}, contents:{DomainId.Empty}",
+                                    assets = new[]
+                                    {
+                                        new
+                                        {
+                                            id = assetRefId
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            };
+
+            AssertResult(expected, result);
+        }
+
         [Fact]
         public async Task Should_also_fetch_referenced_assets_if_field_is_included_in_query()
         {

backend/tests/Squidex.Domain.Apps.Entities.Tests/Contents/GraphQL/GraphQLTestBase.cs

@@ -17,6 +17,7 @@ using Microsoft.Extensions.Options;
 using Newtonsoft.Json;
 using Squidex.Caching;
 using Squidex.Domain.Apps.Core;
+using Squidex.Domain.Apps.Core.ExtractReferenceIds;
 using Squidex.Domain.Apps.Core.TestHelpers;
 using Squidex.Domain.Apps.Entities.Assets;
 using Squidex.Domain.Apps.Entities.Contents.GraphQL.Types.Primitives;
@@ -60,12 +61,12 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
             requestContext = new Context(Mocks.FrontendUser(), TestApp.Default);
         }
 
-        protected void AssertResult(object expected, ExecutionResult result)
+        protected void AssertResult(object lhs, ExecutionResult result)
         {
-            var resultJson = serializer.Serialize(result, true);
+            var rhsJson = serializer.Serialize(result, true);
-            var expectJson = serializer.Serialize(expected, true);
+            var lhsJson = serializer.Serialize(lhs, true);
 
-            Assert.Equal(expectJson, resultJson);
+            Assert.Equal(lhsJson, rhsJson);
         }
 
         protected Task<ExecutionResult> ExecuteAsync(ExecutionOptions options, string? permissionId = null)
@@ -138,6 +139,7 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
                     .AddSingleton<InstantGraphType>()
                     .AddSingleton<JsonGraphType>()
                     .AddSingleton<JsonNoopGraphType>()
+                    .AddSingleton<StringReferenceExtractor>()
                     .BuildServiceProvider();
 
             var schemasHash = A.Fake<ISchemasHash>();

backend/tests/Squidex.Domain.Apps.Entities.Tests/Contents/GraphQL/TestContent.cs

@@ -236,6 +236,13 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
                                     .Add("nested-number", 20)
                                     .Add("nested-boolean", false))));
 
+            if (assetId != default || refId != default)
+            {
+                data.AddField("my-embeds",
+                    new ContentFieldData()
+                        .AddInvariant(JsonValue.Create($"assets:{assetId}, contents:{refId}")));
+            }
+
             var content = new ContentEntity
             {
                 Id = id,
@@ -483,6 +490,14 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
                 };
             }
 
+            if (assetId != default || refId != default)
+            {
+                result["myEmbeds"] = new
+                {
+                    iv = $"assets:{assetId}, contents:{refId}"
+                };
+            }
+
             return result;
         }
 

backend/tests/Squidex.Domain.Apps.Entities.Tests/Contents/GraphQL/TestSchemas.cs

@@ -76,6 +76,8 @@ namespace Squidex.Domain.Apps.Entities.Contents.GraphQL
                             new BooleanFieldProperties())
                         .AddNumber(122, "nested-number",
                             new NumberFieldProperties()))
+                    .AddString(16, "my-embeds", Partitioning.Invariant,
+                        new StringFieldProperties { IsEmbeddable = true, SchemaIds = ReadonlyList.Create(Ref1.Id, Ref2.Id) })
                     .SetScripts(new SchemaScripts { Query = "<query-script>" }));
         }
     }

backend/tests/Squidex.Domain.Apps.Entities.Tests/Contents/TestData/FakeUrlGenerator.cs

@@ -35,12 +35,27 @@ namespace Squidex.Domain.Apps.Entities.Contents.TestData
             return $"contents/{schemaId.Name}/{contentId}";
         }
 
-        public string AssetsUI(NamedId<DomainId> appId, string? @ref = null)
+        public string AssetContentBase()
         {
-            throw new NotSupportedException();
+            return "$assets/";
         }
 
-        public string AssetContentBase()
+        public string AssetContentCDNBase()
+        {
+            return $"cdn/assets/";
+        }
+
+        public string ContentBase()
+        {
+            return $"contents/";
+        }
+
+        public string ContentCDNBase()
+        {
+            return $"cdn/contents/";
+        }
+
+        public string AssetsUI(NamedId<DomainId> appId, string? @ref = null)
         {
             throw new NotSupportedException();
         }

frontend/src/app/features/api/pages/graphql/graphql-page.component.scss

@@ -35,6 +35,11 @@
         }
     }
 
+    /* stylelint-disable-next-line selector-class-pattern */
+    .CodeMirror {
+        padding: 0;
+    }
+
     /* stylelint-disable-next-line selector-class-pattern */
     .CodeMirror-linenumbers {
         min-width: 29px;

frontend/src/app/features/content/shared/forms/field-editor.component.html

@@ -184,13 +184,23 @@
 							<textarea class="form-control" [formControl]="$any(fieldForm)" [placeholder]="field.displayPlaceholder" rows="5"></textarea>
 						</ng-container>
 						<ng-container *ngSwitchCase="'RichText'">
-							<sqx-rich-editor [formControl]="$any(fieldForm)" #editor [folderId]="field.rawProperties.folderId"></sqx-rich-editor>
+							<sqx-rich-editor [formControl]="$any(fieldForm)" #editor
+                                [folderId]="field.rawProperties.folderId"
+                                [language]="language"
+                                [languages]="languages"
+                                [schemaIds]="field.rawProperties.schemaIds">
+                            </sqx-rich-editor>
 						</ng-container>
 						<ng-container *ngSwitchCase="'Html'">
 							<sqx-code-editor [formControl]="$any(fieldForm)" #editor mode="ace/mode/html" [height]="350"  ></sqx-code-editor>
 						</ng-container>
 						<ng-container *ngSwitchCase="'Markdown'">
-							<sqx-markdown-editor [formControl]="$any(fieldForm)" #editor [folderId]="field.rawProperties.folderId"></sqx-markdown-editor>
+							<sqx-markdown-editor [formControl]="$any(fieldForm)" #editor 
+                                [folderId]="field.rawProperties.folderId"
+                                [language]="language"
+                                [languages]="languages"
+                                [schemaIds]="field.rawProperties.schemaIds">
+                            </sqx-markdown-editor>
 						</ng-container>
 						<ng-container *ngSwitchCase="'StockPhoto'">
 							<sqx-stock-photo-editor [formControl]="$any(fieldForm)"></sqx-stock-photo-editor>

frontend/src/app/features/schemas/pages/schema/fields/types/component-validation.component.html

@@ -1,6 +1,6 @@
 <div [formGroup]="fieldForm">
     <div class="form-group row">
-        <label class="col-3 col-form-label" for="{{field.fieldId}}_fieldSchemaId">{{ 'common.schemas' | sqxTranslate }}</label>
+        <label class="col-3 col-form-label" for="{{field.fieldId}}_fieldSchemaIds">{{ 'common.schemas' | sqxTranslate }}</label>
 
         <div class="col-9">
             <sqx-tag-editor placeholder="{{ 'common.tagAddSchema' | sqxTranslate }}" formControlName="schemaIds" 

frontend/src/app/features/schemas/pages/schema/fields/types/components-validation.component.html

@@ -18,7 +18,7 @@
     </div>
 
     <div class="form-group row">
-        <label class="col-3 col-form-label" for="{{field.fieldId}}_fieldSchemaId">{{ 'common.schemas' | sqxTranslate }}</label>
+        <label class="col-3 col-form-label" for="{{field.fieldId}}_fieldSchemaIds">{{ 'common.schemas' | sqxTranslate }}</label>
 
         <div class="col-9">
             <sqx-tag-editor placeholder="{{ 'common.tagAddSchema' | sqxTranslate }}" formControlName="schemaIds" 

frontend/src/app/features/schemas/pages/schema/fields/types/references-validation.component.html

@@ -1,6 +1,6 @@
 <div [formGroup]="fieldForm">
     <div class="form-group row">
-        <label class="col-3 col-form-label" for="{{field.fieldId}}_fieldSchemaId">{{ 'common.schemas' | sqxTranslate }}</label>
+        <label class="col-3 col-form-label" for="{{field.fieldId}}_fieldSchemaIds">{{ 'common.schemas' | sqxTranslate }}</label>
 
         <div class="col-9">
             <sqx-tag-editor placeholder="{{ 'common.tagAddSchema' | sqxTranslate }}" formControlName="schemaIds" 

frontend/src/app/features/schemas/pages/schema/fields/types/string-ui.component.html

@@ -33,6 +33,18 @@
         </div>
     </div>
 
+    <div class="form-group row">
+        <label class="col-3 col-form-label" for="{{field.fieldId}}_folderId">{{ 'schemas.fieldTypes.string.folderId' | sqxTranslate }}</label>
+
+        <div class="col-9">
+            <sqx-asset-folder-dropdown formControlName="folderId"></sqx-asset-folder-dropdown>
+
+            <sqx-form-hint>
+                {{ 'schemas.fieldTypes.string.folderIdHint' | sqxTranslate }}
+            </sqx-form-hint>
+        </div>
+    </div>
+
     <div class="form-group row" [class.hidden]="hideAllowedValues | async">
         <div class="col-9 offset-3">
             <div class="form-check">
@@ -60,14 +72,27 @@
     </div>
 
     <div class="form-group row">
-        <label class="col-3 col-form-label" for="{{field.fieldId}}_folderId">{{ 'schemas.fieldTypes.string.folderId' | sqxTranslate }}</label>
+        <div class="col-9 offset-3">
-
+            <div class="form-check">
-        <div class="col-9">
+                <input class="form-check-input" type="checkbox" id="{{field.fieldId}}_fieldIsEmbeddable" formControlName="isEmbeddable">
-            <sqx-asset-folder-dropdown formControlName="folderId"></sqx-asset-folder-dropdown>
+                <label class="form-check-label" for="{{field.fieldId}}_fieldIsEmbeddable">
+                    {{ 'schemas.field.isEmbeddable' | sqxTranslate }}
+                </label>
+            </div>
 
             <sqx-form-hint>
-                {{ 'schemas.fieldTypes.string.folderIdHint' | sqxTranslate }}
+                {{ 'schemas.field.isEmbeddableHint' | sqxTranslate }}
             </sqx-form-hint>
         </div>
     </div>
+
+    <div class="form-group row" [class.hidden]="hideSchemaIds | async">
+        <label class="col-3 col-form-label" for="{{field.fieldId}}_fieldSchemaIds">{{ 'common.schemas' | sqxTranslate }}</label>
+
+        <div class="col-9">
+            <sqx-tag-editor placeholder="{{ 'common.tagAddSchema' | sqxTranslate }}" formControlName="schemaIds" 
+                [converter]="(schemasSource.converter | async)!" [suggestions]="(schemasSource.converter | async)?.suggestions">
+            </sqx-tag-editor>
+        </div>
+    </div>
 </div>

frontend/src/app/features/schemas/pages/schema/fields/types/string-ui.component.ts

@@ -8,7 +8,7 @@
 import { Component, Input, OnChanges, SimpleChanges } from '@angular/core';
 import { FormGroup } from '@angular/forms';
 import { Observable } from 'rxjs';
-import { FieldDto, ResourceOwner, STRING_FIELD_EDITORS, StringFieldPropertiesDto, valueProjection$ } from '@app/shared';
+import { FieldDto, ResourceOwner, STRING_FIELD_EDITORS, StringFieldPropertiesDto, valueProjection$, SchemaTagSource } from '@app/shared';
 
 @Component({
     selector: 'sqx-string-ui[field][fieldForm][properties]',
@@ -29,6 +29,13 @@ export class StringUIComponent extends ResourceOwner implements OnChanges {
 
     public hideAllowedValues?: Observable<boolean>;
     public hideInlineEditable?: Observable<boolean>;
+    public hideSchemaIds?: Observable<boolean>;
+
+    constructor(
+        public readonly schemasSource: SchemaTagSource,
+    ) {
+        super();
+    }
 
     public ngOnChanges(changes: SimpleChanges) {
         if (changes['fieldForm']) {
@@ -42,6 +49,9 @@ export class StringUIComponent extends ResourceOwner implements OnChanges {
             this.hideInlineEditable =
                 valueProjection$(editor, x => !(x && (x === 'Input' || x === 'Dropdown' || x === 'Slug')));
 
+            this.hideSchemaIds =
+                valueProjection$(this.fieldForm.controls['isEmbeddable'], x => !x);
+
             this.own(
                 this.hideAllowedValues.subscribe(isSelection => {
                     if (isSelection) {

frontend/src/app/shared/components/forms/markdown-editor.component.html

@@ -11,3 +11,12 @@
         (select)="insertAssets($event)">
     </sqx-assets-selector>
 </ng-container>
+
+<ng-container *sqxModal="contentsDialog">
+    <sqx-content-selector
+        [language]="language"
+        [languages]="languages"
+        [schemaIds]="schemaIds"
+        (select)="insertContents($event)">
+    </sqx-content-selector>
+</ng-container>

frontend/src/app/shared/components/forms/markdown-editor.component.ts

@@ -8,7 +8,8 @@
 import { AfterViewInit, ChangeDetectionStrategy, ChangeDetectorRef, Component, ElementRef, forwardRef, Input, Renderer2, ViewChild } from '@angular/core';
 import { NG_VALUE_ACCESSOR } from '@angular/forms';
 import { marked } from 'marked';
-import { ApiUrlConfig, AssetDto, AssetUploaderState, DialogModel, ResourceLoaderService, StatefulControlComponent, Types, UploadCanceled } from '@app/shared/internal';
+import { ApiUrlConfig, AssetDto, AssetUploaderState, DialogModel, getContentValue, LanguageDto, ResourceLoaderService, StatefulControlComponent, Types, UploadCanceled } from '@app/shared/internal';
+import { ContentDto } from '@app/shared';
 
 declare const SimpleMDE: any;
 
@@ -34,6 +35,15 @@ export class MarkdownEditorComponent extends StatefulControlComponent<State, str
     private simplemde: any;
     private value?: string;
 
+    @Input()
+    public schemaIds?: ReadonlyArray<string>;
+
+    @Input()
+    public language!: LanguageDto;
+
+    @Input()
+    public languages!: ReadonlyArray<LanguageDto>;
+
     @Input()
     public folderId?: string;
 
@@ -53,6 +63,8 @@ export class MarkdownEditorComponent extends StatefulControlComponent<State, str
 
     public assetsDialog = new DialogModel();
 
+    public contentsDialog = new DialogModel();
+
     constructor(changeDetector: ChangeDetectorRef,
         private readonly apiUrl: ApiUrlConfig,
         private readonly assetUploader: AssetUploaderState,
@@ -78,7 +90,7 @@ export class MarkdownEditorComponent extends StatefulControlComponent<State, str
         }
     }
 
-    private showSelector = () => {
+    private showAssetSelector = () => {
         if (this.snapshot.isDisabled) {
             return;
         }
@@ -86,6 +98,14 @@ export class MarkdownEditorComponent extends StatefulControlComponent<State, str
         this.assetsDialog.show();
     };
 
+    private showContentsSelector = () => {
+        if (this.snapshot.isDisabled) {
+            return;
+        }
+
+        this.contentsDialog.show();
+    };
+
     public ngAfterViewInit() {
         Promise.all([
             this.resourceLoader.loadLocalStyle('dependencies/simplemde/simplemde.min.css'),
@@ -170,10 +190,17 @@ export class MarkdownEditorComponent extends StatefulControlComponent<State, str
                     '|',
                     {
                         name: 'assets',
-                        action: this.showSelector,
+                        action: this.showAssetSelector,
                         className: 'icon-assets icon-bold',
                         title: 'Insert Assets',
                     },
+                    this.schemaIds && this.schemaIds.length > 0 ?
+                    {
+                        name: 'contents',
+                        action: this.showContentsSelector,
+                        className: 'icon-contents icon-bold',
+                        title: 'Insert Contents',
+                    } : null,
                 ],
                 element: this.editor.nativeElement,
             });
@@ -204,7 +231,7 @@ export class MarkdownEditorComponent extends StatefulControlComponent<State, str
     }
 
     public insertAssets(assets: ReadonlyArray<AssetDto>) {
-        const content = this.buildMarkups(assets);
+        const content = this.buildAssetsMarkup(assets);
 
         if (content.length > 0) {
             this.simplemde.codemirror.replaceSelection(content);
@@ -213,6 +240,16 @@ export class MarkdownEditorComponent extends StatefulControlComponent<State, str
         this.assetsDialog.hide();
     }
 
+    public insertContents(contents: ReadonlyArray<ContentDto>) {
+        const content = this.buildContentsMarkup(contents);
+
+        if (content.length > 0) {
+            this.simplemde.codemirror.replaceSelection(content);
+        }
+
+        this.contentsDialog.hide();
+    }
+
     public insertFiles(files: ReadonlyArray<File>) {
         const doc = this.simplemde.codemirror.getDoc();
 
@@ -251,7 +288,7 @@ export class MarkdownEditorComponent extends StatefulControlComponent<State, str
             .subscribe({
                 next: asset => {
                     if (Types.is(asset, AssetDto)) {
-                        replaceText(this.buildMarkup(asset));
+                        replaceText(this.buildAssetMarkup(asset));
                     }
                 },
                 error: error => {
@@ -274,17 +311,39 @@ export class MarkdownEditorComponent extends StatefulControlComponent<State, str
         this.next({ isFullscreen });
     }
 
-    private buildMarkups(assets: readonly AssetDto[]) {
+    private buildAssetsMarkup(assets: ReadonlyArray<AssetDto>) {
-        let content = '';
+        let markup = '';
 
         for (const asset of assets) {
-            content += this.buildMarkup(asset);
+            markup += this.buildAssetMarkup(asset);
+        }
+
+        return markup;
+    }
+
+    private buildContentsMarkup(contents: ReadonlyArray<ContentDto>) {
+        let markup = '';
+
+        for (const content of contents) {
+            markup += this.buildContentMarkup(content);
         }
 
-        return content;
+        return markup;
+    }
+
+    private buildContentMarkup(content: ContentDto) {
+        const name =
+            content.referenceFields
+                .map(f => getContentValue(content, this.language, f, false))
+                .map(v => v.formatted)
+                .defined()
+                .join(', ')
+            || 'content';
+            
+        return `[${name}](${this.apiUrl.buildUrl(content._links['self'].href)}')`;
     }
 
-    private buildMarkup(asset: AssetDto) {
+    private buildAssetMarkup(asset: AssetDto) {
         const name = asset.fileNameWithoutExtension;
 
         if (asset.type === 'Image' || asset.mimeType === 'image/svg+xml' || asset.fileName.endsWith('.svg')) {

frontend/src/app/shared/components/forms/rich-editor.component.html

@@ -7,3 +7,12 @@
         (select)="insertAssets($event)">
     </sqx-assets-selector>
 </ng-container>
+
+<ng-container *sqxModal="contentsDialog">
+    <sqx-content-selector
+        [language]="language"
+        [languages]="languages"
+        [schemaIds]="schemaIds"
+        (select)="insertContents($event)">
+    </sqx-content-selector>
+</ng-container>

frontend/src/app/shared/components/forms/rich-editor.component.ts

@@ -7,7 +7,8 @@
 
 import { AfterViewInit, ChangeDetectionStrategy, ChangeDetectorRef, Component, ElementRef, EventEmitter, forwardRef, Input, OnDestroy, Output, ViewChild } from '@angular/core';
 import { NG_VALUE_ACCESSOR } from '@angular/forms';
-import { ApiUrlConfig, AssetDto, AssetUploaderState, DialogModel, LocalizerService, ResourceLoaderService, StatefulControlComponent, Types, UploadCanceled } from '@app/shared/internal';
+import { ContentDto } from '@app/shared';
+import { ApiUrlConfig, AssetDto, AssetUploaderState, DialogModel, getContentValue, LanguageDto, ResourceLoaderService, StatefulControlComponent, Types, UploadCanceled } from '@app/shared/internal';
 
 declare const tinymce: any;
 
@@ -31,6 +32,15 @@ export class RichEditorComponent extends StatefulControlComponent<{}, string> im
     @Output()
     public assetPluginClick = new EventEmitter<any>();
 
+    @Input()
+    public schemaIds?: ReadonlyArray<string>;
+
+    @Input()
+    public language!: LanguageDto;
+
+    @Input()
+    public languages!: ReadonlyArray<LanguageDto>;
+
     @Input()
     public folderId = '';
 
@@ -44,11 +54,12 @@ export class RichEditorComponent extends StatefulControlComponent<{}, string> im
 
     public assetsDialog = new DialogModel();
 
+    public contentsDialog = new DialogModel();
+
     constructor(changeDetector: ChangeDetectorRef,
         private readonly apiUrl: ApiUrlConfig,
         private readonly assetUploader: AssetUploaderState,
         private readonly resourceLoader: ResourceLoaderService,
-        private readonly localizer: LocalizerService,
     ) {
         super(changeDetector, {});
     }
@@ -82,7 +93,7 @@ export class RichEditorComponent extends StatefulControlComponent<{}, string> im
         });
     }
 
-    private showSelector = () => {
+    private showAssetsSelector = () => {
         if (this.snapshot.isDisabled) {
             return;
         }
@@ -90,6 +101,14 @@ export class RichEditorComponent extends StatefulControlComponent<{}, string> im
         this.assetsDialog.show();
     };
 
+    private showContentsSelector = () => {
+        if (this.snapshot.isDisabled) {
+            return;
+        }
+
+        this.contentsDialog.show();
+    };
+
     private getEditorOptions(target: any): any {
         // eslint-disable-next-line @typescript-eslint/no-this-alias
         const self = this;
@@ -117,11 +136,20 @@ export class RichEditorComponent extends StatefulControlComponent<{}, string> im
 
             setup: (editor: any) => {
                 editor.ui.registry.addButton('assets', {
-                    onAction: self.showSelector,
+                    onAction: self.showAssetsSelector,
                     icon: 'gallery',
                     text: '',
-                    tooltip: this.localizer.getOrKey('assets.insertAssets'),
+                    tooltip: 'Insert Assets',
+                });
+
+                if (this.schemaIds && this.schemaIds.length > 0) {
+                    editor.ui.registry.addButton('contents', {
+                        onAction: self.showContentsSelector,
+                        icon: 'duplicate',
+                        text: '',
+                        tooltip: 'Insert Contents',
                     });
+                }
 
                 editor.on('init', () => {
                     self.tinyEditor = editor;
@@ -222,7 +250,7 @@ export class RichEditorComponent extends StatefulControlComponent<{}, string> im
     }
 
     public insertAssets(assets: ReadonlyArray<AssetDto>) {
-        const content = this.buildMarkups(assets);
+        const content = this.buildAssetsMarkup(assets);
 
         if (content.length > 0) {
             this.tinyEditor.execCommand('mceInsertContent', false, content);
@@ -231,6 +259,16 @@ export class RichEditorComponent extends StatefulControlComponent<{}, string> im
         this.assetsDialog.hide();
     }
 
+    public insertContents(contents: ReadonlyArray<ContentDto>) {
+        const content = this.buildContentsMarkup(contents);
+
+        if (content.length > 0) {
+            this.tinyEditor.execCommand('mceInsertContent', false, content);
+        }
+
+        this.contentsDialog.hide();
+    }
+
     public insertFiles(files: ReadonlyArray<File>) {
         for (const file of files) {
             this.uploadFile(file);
@@ -252,7 +290,7 @@ export class RichEditorComponent extends StatefulControlComponent<{}, string> im
             .subscribe({
                 next: asset => {
                     if (Types.is(asset, AssetDto)) {
-                        replaceText(this.buildMarkup(asset));
+                        replaceText(this.buildAssetMarkup(asset));
                     }
                 },
                 error: error => {
@@ -263,17 +301,39 @@ export class RichEditorComponent extends StatefulControlComponent<{}, string> im
             });
     }
 
-    private buildMarkups(assets: readonly AssetDto[]) {
+    private buildAssetsMarkup(assets: ReadonlyArray<AssetDto>) {
-        let content = '';
+        let markup = '';
 
         for (const asset of assets) {
-            content += this.buildMarkup(asset);
+            markup += this.buildAssetMarkup(asset);
         }
 
-        return content;
+        return markup;
+    }
+
+    private buildContentsMarkup(contents: ReadonlyArray<ContentDto>) {
+        let markup = '';
+
+        for (const content of contents) {
+            markup += this.buildContentMarkup(content);
+        }
+
+        return markup;
+    }
+
+    private buildContentMarkup(content: ContentDto) {
+        const name =
+            content.referenceFields
+                .map(f => getContentValue(content, this.language, f, false))
+                .map(v => v.formatted)
+                .defined()
+                .join(', ')
+            || 'content';
+            
+        return `<a href="${this.apiUrl.buildUrl(content._links['self'].href)}" alt="${name}">${name}</a>`;
     }
 
-    private buildMarkup(asset: AssetDto) {
+    private buildAssetMarkup(asset: AssetDto) {
         const name = asset.fileNameWithoutExtension;
 
         if (asset.type === 'Image' || asset.mimeType === 'image/svg+xml' || asset.fileName.endsWith('.svg')) {
@@ -295,5 +355,5 @@ const DEFAULT_PROPS = {
     max_height: 800,
     removed_menuitems: 'newdocument',
     resize: true,
-    toolbar: 'undo redo | styleselect | bold italic | alignleft aligncenter | bullist numlist outdent indent | link image media | assets',
+    toolbar: 'undo redo | styleselect | bold italic | alignleft aligncenter | bullist numlist outdent indent | link image media | assets contents',
 };

frontend/src/app/shared/services/schemas.types.ts

@@ -429,22 +429,24 @@ export class StringFieldPropertiesDto extends FieldPropertiesDto {
     public readonly fieldType = 'String';
 
     public readonly allowedValues?: ReadonlyArray<string>;
+    public readonly contentType?: StringContentType;
     public readonly createEnum: boolean = false;
     public readonly defaultValue?: string;
     public readonly defaultValues?: DefaultValue<string>;
     public readonly editor: StringFieldEditor = 'Input';
+    public readonly folderId?: string;
     public readonly inlineEditable: boolean = false;
+    public readonly isEmbeddable: boolean = false;
     public readonly isUnique: boolean = false;
-    public readonly folderId?: string;
+    public readonly maxCharacters?: number;
     public readonly maxLength?: number;
-    public readonly minLength?: number;
     public readonly maxWords?: number;
-    public readonly minWords?: number;
-    public readonly maxCharacters?: number;
     public readonly minCharacters?: number;
-    public readonly contentType?: StringContentType;
+    public readonly minLength?: number;
+    public readonly minWords?: number;
     public readonly pattern?: string;
     public readonly patternMessage?: string;
+    public readonly schemaIds?: ReadonlyArray<string>;
 
     public get isComplexUI() {
         return this.editor !== 'Input' && this.editor !== 'Color' && this.editor !== 'Radio' && this.editor !== 'Slug' && this.editor !== 'TextArea';

frontend/src/app/shared/state/schemas.forms.ts

@@ -331,6 +331,7 @@ export class EditFieldFormVisitor implements FieldPropertiesVisitor<any> {
         this.config['defaultValues'] = new FormControl(undefined);
         this.config['folderId'] = new FormControl(undefined);
         this.config['inlineEditable'] = new FormControl(undefined);
+        this.config['isEmbeddable'] = new FormControl(undefined);
         this.config['isUnique'] = new FormControl(undefined);
         this.config['maxCharacters'] = new FormControl(undefined);
         this.config['maxLength'] = new FormControl(undefined);
@@ -340,6 +341,7 @@ export class EditFieldFormVisitor implements FieldPropertiesVisitor<any> {
         this.config['minWords'] = new FormControl(undefined);
         this.config['pattern'] = new FormControl(undefined);
         this.config['patternMessage'] = new FormControl(undefined);
+        this.config['schemaIds'] = new FormControl(undefined);
     }
 
     public visitTags() {