feat(controller): get total records

Author: jaredcnance

src/JsonApiDotNetCore/Controllers/JsonApiController.cs

@@ -64,6 +64,9 @@ public virtual async Task<IActionResult> GetAsync()
             if (_jsonApiContext.QuerySet != null && _jsonApiContext.QuerySet.IncludedRelationships != null && _jsonApiContext.QuerySet.IncludedRelationships.Count > 0)
                 entities = IncludeRelationships(entities, _jsonApiContext.QuerySet.IncludedRelationships);
 
+            if (_jsonApiContext.Options.IncludeTotalRecordCount)
+                _jsonApiContext.TotalRecords = await entities.CountAsync();
+
             // pagination should be done last since it will execute the query
             var pagedEntities = await ApplyPageQueryAsync(entities);
 

src/JsonApiDotNetCore/Services/IJsonApiContext.cs

@@ -15,5 +15,6 @@ public interface IJsonApiContext
         QuerySet QuerySet { get; set; }
         bool IsRelationshipData { get; set; }
         List<string> IncludedRelationships { get; set; }
+        int TotalRecords { get; set; }
     }
 }