last ...

Controllers/XFileProviderControllerBase.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -8,6 +9,7 @@ using Microsoft.Extensions.Logging;
 using xCommons.Configurations;
 using xCommons.Extensions;
 using xCommons.Providers;
+using xDataService.Models;
 using xExceptions.Constants;
 using xFileService.Interfaces;
 using xFileService.Models.Dtos;
@@ -217,6 +219,54 @@ namespace xFileService.Controllers
                 return result;
             }
         }
+
+        /// <summary>
+        /// Retrieve References of Specified Itemfor providedFor ...
+        /// </summary>
+        /// <param name="id"></param>
+        /// <param name="providedFor"></param>
+        /// <param name="cancellationToken"></param>
+        /// <typeparam name="TReferenceKey"></typeparam>
+        /// <returns></returns>
+        [HttpGet("{id}/References")]
+        public virtual async Task<ActionResult<IEnumerable<XReference<string>>>> GetReferences(
+            [FromRoute] Guid id,
+            [FromQuery] string providedFor,
+            CancellationToken cancellationToken = default
+        )
+        {
+            //
+            try
+            {
+                //
+                // Validate ...
+                if (!ModelState.IsValid)
+                {
+                    XException.InvalidArgs.Throw();
+                }
+                await ValidationProvider
+                    .GroupValidationBuilder()
+                    .AddNotNull(id)
+                    .AddNotEmpty(providedFor)
+                    .ValidateGroupAsync();
+
+                //
+                var result = await provider.GetReferences(
+                    id: id,
+                    providedFor: providedFor,
+                    cancellationToken: cancellationToken
+                );
+
+                //
+                return Ok(result.ToDynamicObject());
+            }
+            catch (Exception ex)
+            {
+                //
+                var result = GetExceptionActionResult(ex);
+                return result;
+            }
+        }
         #endregion
     }
 }

Interfaces/IXFileProvider.cs

@@ -7,6 +7,6 @@ using xTagService.Interfaces;
 
 namespace xFileService.Interfaces
 {
-    public interface IXFileProvider : IXBaseProvidedHasTag<XFile, XFileDto, Guid, XFileDtoHub>, IXBaseReferenced
+    public interface IXFileProvider : IXBaseProvidedHasTag<XFile, XFileDto, Guid, XFileDtoHub>, IXBaseReferenced<XFile, Guid>
-    {}
+    { }
 }

Providers/XFileProvider.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -18,6 +19,8 @@ namespace xFileService.Providers
 {
     public class XFileProvider : XBaseProvidedHasTag<XFile, XFileDto, Guid, XFileDtoHub>, IXFileProvider
     {
+        private readonly IXFileServiceProvider provider;
+
         public XFileProvider(
             IXFileTagProvider tagProvider,
             IXFileServiceProvider provider
@@ -26,10 +29,12 @@ namespace xFileService.Providers
             tagProvider: tagProvider,
             permittedRoles: new string[] { "admin" }
         )
-        { }
+        {
+            this.provider = provider;
+        }
 
         public override bool IsOwned(
-            XFile item, 
+            XFile item,
             XUserClaimsInfoDto userInfo
         )
         {
@@ -45,7 +50,7 @@ namespace xFileService.Providers
         }
 
         public override bool IsOwned(
-            XFileDto item, 
+            XFileDto item,
             XUserClaimsInfoDto userInfo
         )
         {
@@ -68,9 +73,9 @@ namespace xFileService.Providers
         /// <param name="providedFor"></param>
         /// <param name="forProvidedId"></param>
         /// <returns></returns>
-        public string GetIdentifier<TKey>(
+        public string GetIdentifier<TReferenceKey>(
             string providedFor,
-            TKey forProvidedId
+            TReferenceKey forProvidedId
         )
         {
             //
@@ -88,9 +93,9 @@ namespace xFileService.Providers
         /// <param name="id"></param>
         /// <param name="cancellationToken"></param>
         /// <returns></returns>
-        public async Task<bool> IsProvidedFor<TKey>(
+        public async Task<bool> IsProvidedFor<TReferenceKey>(
             string providedFor,
-            TKey forProvidedId,
+            TReferenceKey forProvidedId,
             Guid id,
             CancellationToken cancellationToken = default
         )
@@ -155,9 +160,9 @@ namespace xFileService.Providers
         /// <param name="connectionId"></param>
         /// <param name="cancellationToken"></param>
         /// <returns></returns>
-        public async Task AddReference<TKey>(
+        public async Task AddReference<TReferenceKey>(
             string providedFor,
-            TKey forProvidedId,
+            TReferenceKey forProvidedId,
             Guid id,
             int forIndex = 0,
             XUserClaimsInfoDto userInfo = null,
@@ -239,9 +244,9 @@ namespace xFileService.Providers
         /// <param name="connectionId"></param>
         /// <param name="cancellationToken"></param>
         /// <returns></returns>
-        public async Task RemoveReference<TKey>(
+        public async Task RemoveReference<TReferenceKey>(
             string providedFor,
-            TKey forProvidedId,
+            TReferenceKey forProvidedId,
             Guid id,
             int forIndex = 0,
             XUserClaimsInfoDto userInfo = null,
@@ -317,6 +322,48 @@ namespace xFileService.Providers
                 cancellationToken: cancellationToken
             );
         }
+
+        /// <summary>
+        /// Get Specified References ...
+        /// </summary>
+        /// <param name="providedFor"></param>
+        /// <param name="id"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        public async Task<IEnumerable<XReference<string>>> GetReferences(
+            string providedFor,
+            Guid id,
+            CancellationToken cancellationToken = default
+        )
+        {
+            //
+            IList<XReference<string>> result = new List<XReference<string>>();
+
+            //
+            var item = await provider.GetAsync(
+                id: id,
+                includeBuilder: null,
+                ignoreSoftDeleteds: true,
+                cancellationToken: cancellationToken
+            );
+            var isValid = !item.IsNullOrDefault();
+            if (!isValid)
+            {
+                return result;
+            }
+
+            //
+            result = item.GetReferences();
+
+            //
+            result = result.Where(r =>
+                r.ProvidedFor == providedFor
+            )
+            .ToList();
+
+            //
+            return result;
+        }
         #endregion
     }
 }