src/Http/Routing/src/Constraints/DecimalRouteConstraint.cs


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.Globalization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing.Matching;

namespace Microsoft.AspNetCore.Routing.Constraints;

/// <summary>
/// Constrains a route parameter to represent only decimal values.
/// </summary>
public class DecimalRouteConstraint : IRouteConstraint, IParameterLiteralNodeMatchingPolicy
{
    /// <inheritdoc />
    public bool Match(
        HttpContext? httpContext,
        IRouter? route,
        string routeKey,
        RouteValueDictionary values,
        RouteDirection routeDirection)
    {
        if (routeKey == null)
        {
            throw new ArgumentNullException(nameof(routeKey));
        }

        if (values == null)
        {
            throw new ArgumentNullException(nameof(values));
        }

        if (values.TryGetValue(routeKey, out var value) && value != null)
        {
            if (value is decimal)
            {
                return true;
            }

            var valueString = Convert.ToString(value, CultureInfo.InvariantCulture);
            return CheckConstraintCore(valueString);
        }

        return false;
    }

    private static bool CheckConstraintCore(string? valueString)
    {
        return decimal.TryParse(valueString, NumberStyles.Number, CultureInfo.InvariantCulture, out _);
    }

    bool IParameterLiteralNodeMatchingPolicy.MatchesLiteral(string parameterName, string literal)
    {
        return CheckConstraintCore(literal);
    }
}