server/AyaNova/ControllerHelpers/PaginationLinkBuilder.cs

@@ -0,0 +1,89 @@
+using System;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.AspNetCore.Mvc;
+using Newtonsoft.Json;
+
+namespace AyaNova.Api.ControllerHelpers
+{
+
+    public class PaginationLinkBuilder
+    { //adapted from //https://www.jerriepelser.com/blog/paging-in-aspnet-webapi-pagination-links/
+        public Uri FirstPage { get; private set; }
+        public Uri LastPage { get; private set; }
+        public Uri NextPage { get; private set; }
+        public Uri PreviousPage { get; private set; }
+        public PagingOptions PagingOptions { get; }
+        public long TotalRecordCount { get; }
+
+        public PaginationLinkBuilder(IUrlHelper urlHelper, string routeName, object routeValues, PagingOptions pagingOptions, long totalRecordCount)
+        {
+            PagingOptions = pagingOptions;
+            TotalRecordCount = totalRecordCount;
+
+            // Determine total number of pages
+            var pageCount = totalRecordCount > 0
+                ? (int)Math.Ceiling(totalRecordCount / (double)pagingOptions.Limit)
+                : 0;
+
+            // Create page links 
+            
+            FirstPage = new Uri(urlHelper.Link(routeName, new RouteValueDictionary(routeValues)
+        {
+            {"pageNo", 1},
+            {"pageSize", pagingOptions.Limit}
+        }));
+
+
+            LastPage = new Uri(urlHelper.Link(routeName, new RouteValueDictionary(routeValues)
+        {
+            {"pageNo", pageCount},
+            {"pageSize", pagingOptions.Limit}
+        }));
+
+            if (pagingOptions.Offset > 1)
+            {
+                PreviousPage = new Uri(urlHelper.Link(routeName, new RouteValueDictionary(routeValues)
+            {
+                {"pageNo", pagingOptions.Offset - 1},
+                {"pageSize", pagingOptions.Limit}
+            }));
+            }
+
+
+
+            if (pagingOptions.Offset < pageCount)
+            {
+                NextPage = new Uri(urlHelper.Link(routeName, new RouteValueDictionary(routeValues)
+            {
+                {"pageNo", pagingOptions.Offset + 1},
+                {"pageSize", pagingOptions.Limit}
+            }));
+            }
+
+
+        }
+
+
+
+        /// <summary>
+        /// Return paging data suitable for API return
+        /// </summary>
+        /// <returns></returns>
+        public Object PagingLinksObject()
+        {
+            return new
+            {
+                Count = TotalRecordCount,
+                Offset = PagingOptions.Offset,
+                Limit = PagingOptions.Limit,
+                First = FirstPage,
+                Previous = PreviousPage,
+                Next = NextPage,
+                Last = LastPage
+            };
+        }
+
+
+    }
+
+}