Fix issue #796: Request path segments gets double unescaped

sample/ODataAlternateKeySample/Models/AlternateKeyRepositoryInMemory.cs

@@ -17,11 +17,11 @@ static AlternateKeyRepositoryInMemory()
         {
             // Customers
             var names = new[] { "Tom", "Jerry", "Mike", "Ben", "Sam", "Peter" };
-            _customers = Enumerable.Range(1, 5).Select(e => new Customer
+            _customers = Enumerable.Range(1, 5).Select((e, i) => new Customer
             {
                 Id = e,
                 Name = names[e - 1],
-                SSN = "SSN-" + e + "-" + (100 + e),
+                SSN = i % 2 == 0 ? "SSN-" + e + "-" + (100 + e) : "SSN-%25-" + e + "-" + (100 + e),
                 Titles = new string[] { "abc", null, "efg" }
             }).ToList();
 

src/Microsoft.AspNetCore.OData/Common/StringExtensions.cs

@@ -11,6 +11,22 @@ namespace Microsoft.AspNetCore.OData.Common
 {
     internal static class StringExtensions
     {
+        /// <summary>
+        /// Unescape Uri string for %2F
+        /// See details at: https://github.com/dotnet/aspnetcore/issues/14170#issuecomment-533342396
+        /// </summary>
+        /// <param name="uriString">The Uri string.</param>
+        /// <returns>Unescaped back slash Uri string.</returns>
+        public static string UnescapeBackSlashUriString(this string uriString)
+        {
+            if (uriString == null)
+            {
+                return null;
+            }
+
+            return uriString.Replace("%2f", "%2F").Replace("%2F", "/");
+        }
+
         /// <summary>
         /// Normalize the http method.
         /// </summary>

src/Microsoft.AspNetCore.OData/Microsoft.AspNetCore.OData.xml

@@ -1047,6 +1047,14 @@
             <returns>a fast getter.</returns>
             <remarks>This method is more memory efficient than a dynamically compiled lambda, and about the same speed.</remarks>
         </member>
+        <member name="M:Microsoft.AspNetCore.OData.Common.StringExtensions.UnescapeBackSlashUriString(System.String)">
+            <summary>
+            Unescape Uri string for %2F
+            See details at: https://github.com/dotnet/aspnetcore/issues/14170#issuecomment-533342396
+            </summary>
+            <param name="uriString">The Uri string.</param>
+            <returns>Unescaped back slash Uri string.</returns>
+        </member>
         <member name="M:Microsoft.AspNetCore.OData.Common.StringExtensions.NormalizeHttpMethod(System.String)">
             <summary>
             Normalize the http method.

src/Microsoft.AspNetCore.OData/Routing/Template/KeySegmentTemplate.cs

@@ -172,8 +172,11 @@ public override bool TryTranslate(ODataTemplateTranslateContext context)
 
                     IEdmTypeReference edmType = keyProperty.Type;
                     string strValue = rawValue as string;
+
                     string newStrValue = context.GetParameterAliasOrSelf(strValue);
-                    newStrValue = Uri.UnescapeDataString(newStrValue);
+
+                    // rawValue from Request route values, it's unescaped except the back-slash.
+                    newStrValue = newStrValue.UnescapeBackSlashUriString();
                     if (newStrValue != strValue)
                     {
                         updateValues[templateName] = newStrValue;

test/Microsoft.AspNetCore.OData.Tests/Routing/Template/KeySegmentTemplateTests.cs

@@ -497,7 +497,7 @@ public void TryTranslateKeySegmentTemplate_WorksWithKeyValue_UsingEscapedString(
             EdmEntityContainer container = new EdmEntityContainer("NS", "Default");
             EdmEntitySet customers = container.AddEntitySet("Customers", customerType);
             model.AddElement(container);
-            RouteValueDictionary routeValueDictionary = new RouteValueDictionary(new { First = "'Zhang'", Last = "'Gan%2Fnng%23%20T'" });
+            RouteValueDictionary routeValueDictionary = new RouteValueDictionary(new { First = "'Zhang'", Last = "'Gan%2Fnng# T'" });
             IDictionary<string, string> keys = new Dictionary<string, string>
             {
                 { "FirstName", "{first}" },