aspnetcore/src/Microsoft.AspNet.Routing/Constraints/RequiredRouteConstraint.cs

59 lines
1.8 KiB
C#

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Collections.Generic;
using System.Globalization;
using Microsoft.AspNet.Http;
namespace Microsoft.AspNet.Routing.Constraints
{
/// <summary>
/// Constraints a route parameter that must have a value.
/// </summary>
/// <remarks>
/// This constraint is primarily used to enforce that a non-parameter value is present during
/// URL generation.
/// </remarks>
public class RequiredRouteConstraint : IRouteConstraint
{
/// <inheritdoc />
public bool Match(
HttpContext httpContext,
IRouter route,
string routeKey,
IDictionary<string, object> values,
RouteDirection routeDirection)
{
if (httpContext == null)
{
throw new ArgumentNullException(nameof(httpContext));
}
if (route == null)
{
throw new ArgumentNullException(nameof(route));
}
if (routeKey == null)
{
throw new ArgumentNullException(nameof(routeKey));
}
if (values == null)
{
throw new ArgumentNullException(nameof(values));
}
object value;
if (values.TryGetValue(routeKey, out value) && value != null)
{
// In routing the empty string is equivalent to null, which is equivalent to an unset value.
var valueString = Convert.ToString(value, CultureInfo.InvariantCulture);
return !string.IsNullOrEmpty(valueString);
}
return false;
}
}
}