Expose the value of odata.maxpagesize on ODataQueryOptions

src/Microsoft.AspNet.OData.Shared/Query/ODataQueryOptions.cs

@@ -268,6 +268,22 @@ public bool IsSupportedQueryOption(string queryOptionName)
             return IsSystemQueryOption(lowcaseQueryOptionName, this._enableNoDollarSignQueryOptions);
         }
 
+        /// <summary>
+        /// Gets the maxpagesize from the request Prefer header.
+        /// </summary>
+        public int? RequestPrefersMaxPageSize
+        {
+            get
+            {
+                if (RequestPreferenceHelpers.RequestPrefersMaxPageSize(InternalRequest.Headers, out int pageSize))
+                {
+                    return pageSize;
+                }
+
+                return null;
+            }
+        }
+
         /// <summary>
         /// Apply the individual query to the given IQueryable in the right order.
         /// </summary>
@@ -428,10 +444,10 @@ internal IQueryable ApplyPaging(IQueryable result, ODataQuerySettings querySetti
                 pageSize = querySettings.ModelBoundPageSize.Value;
             }
 
-            int preferredPageSize = -1;
-            if (RequestPreferenceHelpers.RequestPrefersMaxPageSize(InternalRequest.Headers, out preferredPageSize))
+            int? preferredPageSize = RequestPrefersMaxPageSize;
+            if (preferredPageSize.HasValue)
             {
-                pageSize = Math.Min(pageSize, preferredPageSize);
+                pageSize = Math.Min(pageSize, preferredPageSize.Value);
             }
 
             if (pageSize > 0)

test/UnitTest/Microsoft.AspNet.OData.Test/PublicApi/Microsoft.AspNet.OData.PublicApi.bsl

@@ -2454,6 +2454,7 @@ public class Microsoft.AspNet.OData.Query.ODataQueryOptions {
 	OrderByQueryOption OrderBy  { public get; }
 	ODataRawQueryOptions RawValues  { public get; }
 	System.Net.Http.HttpRequestMessage Request  { public get; }
+	System.Nullable`1[[System.Int32]] RequestPrefersMaxPageSize  { public get; }
 	SelectExpandQueryOption SelectExpand  { public get; }
 	SkipQueryOption Skip  { public get; }
 	SkipTokenQueryOption SkipToken  { public get; }

test/UnitTest/Microsoft.AspNetCore.OData.Test/PublicApi/Microsoft.AspNetCore.OData.PublicApi.bsl

@@ -2609,6 +2609,7 @@ public class Microsoft.AspNet.OData.Query.ODataQueryOptions {
 	OrderByQueryOption OrderBy  { public get; }
 	ODataRawQueryOptions RawValues  { public get; }
 	Microsoft.AspNetCore.Http.HttpRequest Request  { public get; }
+	System.Nullable`1[[System.Int32]] RequestPrefersMaxPageSize  { public get; }
 	SelectExpandQueryOption SelectExpand  { public get; }
 	SkipQueryOption Skip  { public get; }
 	SkipTokenQueryOption SkipToken  { public get; }

test/UnitTest/Microsoft.AspNetCore.OData.Test/PublicApi/Microsoft.AspNetCore3x.OData.PublicApi.bsl

@@ -2780,6 +2780,7 @@ public class Microsoft.AspNet.OData.Query.ODataQueryOptions {
 	OrderByQueryOption OrderBy  { public get; }
 	ODataRawQueryOptions RawValues  { public get; }
 	Microsoft.AspNetCore.Http.HttpRequest Request  { public get; }
+	System.Nullable`1[[System.Int32]] RequestPrefersMaxPageSize  { public get; }
 	SelectExpandQueryOption SelectExpand  { public get; }
 	SkipQueryOption Skip  { public get; }
 	SkipTokenQueryOption SkipToken  { public get; }