Support multiple policies for a key with RoutePatternFactory.Pattern (#6593)

src/Http/Routing/src/Patterns/RoutePatternFactory.cs

@@ -1,7 +1,8 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// 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;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
@@ -51,6 +52,7 @@ namespace Microsoft.AspNetCore.Routing.Patterns
         /// Additional parameter policies to associated with the route pattern. May be null.
         /// The provided object will be converted to key-value pairs using <see cref="RouteValueDictionary"/>
         /// and then merged into the parsed route pattern.
+        /// Multiple policies can be specified for a key by providing a collection as the value.
         /// </param>
         /// <returns>The <see cref="RoutePattern"/>.</returns>
         public static RoutePattern Parse(string pattern, object defaults, object parameterPolicies)
@@ -78,6 +80,7 @@ namespace Microsoft.AspNetCore.Routing.Patterns
         /// Additional parameter policies to associated with the route pattern. May be null.
         /// The provided object will be converted to key-value pairs using <see cref="RouteValueDictionary"/>
         /// and then merged into the parsed route pattern.
+        /// Multiple policies can be specified for a key by providing a collection as the value.
         /// </param>
         /// <param name="requiredValues">
         /// Route values that can be substituted for parameters in the route pattern. See remarks on <see cref="RoutePattern.RequiredValues"/>.
@@ -138,6 +141,7 @@ namespace Microsoft.AspNetCore.Routing.Patterns
         /// Additional parameter policies to associated with the route pattern. May be null.
         /// The provided object will be converted to key-value pairs using <see cref="RouteValueDictionary"/>
         /// and then merged into the route pattern.
+        /// Multiple policies can be specified for a key by providing a collection as the value.
         /// </param>
         /// <param name="segments">The collection of segments.</param>
         /// <returns>The <see cref="RoutePattern"/>.</returns>
@@ -168,6 +172,7 @@ namespace Microsoft.AspNetCore.Routing.Patterns
         /// Additional parameter policies to associated with the route pattern. May be null.
         /// The provided object will be converted to key-value pairs using <see cref="RouteValueDictionary"/>
         /// and then merged into the route pattern.
+        /// Multiple policies can be specified for a key by providing a collection as the value.
         /// </param>
         /// <param name="segments">The collection of segments.</param>
         /// <returns>The <see cref="RoutePattern"/>.</returns>
@@ -229,6 +234,7 @@ namespace Microsoft.AspNetCore.Routing.Patterns
         /// Additional parameter policies to associated with the route pattern. May be null.
         /// The provided object will be converted to key-value pairs using <see cref="RouteValueDictionary"/>
         /// and then merged into the route pattern.
+        /// Multiple policies can be specified for a key by providing a collection as the value.
         /// </param>
         /// <param name="segments">The collection of segments.</param>
         /// <returns>The <see cref="RoutePattern"/>.</returns>
@@ -259,6 +265,7 @@ namespace Microsoft.AspNetCore.Routing.Patterns
         /// Additional parameter policies to associated with the route pattern. May be null.
         /// The provided object will be converted to key-value pairs using <see cref="RouteValueDictionary"/>
         /// and then merged into the route pattern.
+        /// Multiple policies can be specified for a key by providing a collection as the value.
         /// </param>
         /// <param name="segments">The collection of segments.</param>
         /// <returns>The <see cref="RoutePattern"/>.</returns>
@@ -312,12 +319,33 @@ namespace Microsoft.AspNetCore.Routing.Patterns
 
                 foreach (var kvp in parameterPolicies)
                 {
-                    updatedParameterPolicies.Add(kvp.Key, new List<RoutePatternParameterPolicyReference>()
+                    var policyReferences = new List<RoutePatternParameterPolicyReference>();
+
+                    if (kvp.Value is IParameterPolicy parameterPolicy)
                     {
-                        kvp.Value is IParameterPolicy parameterPolicy
-                            ? ParameterPolicy(parameterPolicy)
-                            : Constraint(kvp.Value), // Constraint will convert string values into regex constraints
-                    });
+                        policyReferences.Add(ParameterPolicy(parameterPolicy));
+                    }
+                    else if (kvp.Value is string)
+                    {
+                        // Constraint will convert string values into regex constraints
+                        policyReferences.Add(Constraint(kvp.Value));
+                    }
+                    else if (kvp.Value is IEnumerable multiplePolicies)
+                    {
+                        foreach (var item in multiplePolicies)
+                        {
+                            // Constraint will convert string values into regex constraints
+                            policyReferences.Add(item is IParameterPolicy p ? ParameterPolicy(p) : Constraint(item));
+                        }
+                    }
+                    else
+                    {
+                        throw new InvalidOperationException(Resources.FormatRoutePattern_InvalidConstraintReference(
+                            kvp.Value ?? "null",
+                            typeof(IRouteConstraint)));
+                    }
+
+                    updatedParameterPolicies.Add(kvp.Key, policyReferences);
                 }
             }
 

src/Http/Routing/test/UnitTests/Patterns/RoutePatternFactoryTest.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// 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;
@@ -218,6 +218,104 @@ namespace Microsoft.AspNetCore.Routing.Patterns
                 });
         }
 
+        [Fact]
+        public void Pattern_ExtraConstraints_MultipleConstraintsForKey()
+        {
+            // Arrange
+            var template = "{a}/{b}/{c}";
+            var defaults = new { };
+            var constraints = new { d = new object[] { new RegexRouteConstraint("foo"), new RegexRouteConstraint("bar"), "baz" } };
+
+            var original = RoutePatternFactory.Parse(template);
+
+            // Act
+            var actual = RoutePatternFactory.Pattern(
+                original.RawText,
+                defaults,
+                constraints,
+                original.PathSegments);
+
+            // Assert
+            Assert.Collection(
+                actual.ParameterPolicies.OrderBy(kvp => kvp.Key),
+                kvp =>
+                {
+                    Assert.Equal("d", kvp.Key);
+                    Assert.Collection(
+                        kvp.Value,
+                        c => Assert.Equal("foo", Assert.IsType<RegexRouteConstraint>(c.ParameterPolicy).Constraint.ToString()),
+                        c => Assert.Equal("bar", Assert.IsType<RegexRouteConstraint>(c.ParameterPolicy).Constraint.ToString()),
+                        c => Assert.Equal("^(baz)$", Assert.IsType<RegexRouteConstraint>(c.ParameterPolicy).Constraint.ToString()));
+                });
+        }
+
+        [Fact]
+        public void Pattern_ExtraConstraints_MergeMultipleConstraintsForKey()
+        {
+            // Arrange
+            var template = "{a:int}/{b}/{c:int}";
+            var defaults = new { };
+            var constraints = new { b = "fizz", c = new object[] { new RegexRouteConstraint("foo"), new RegexRouteConstraint("bar"), "baz" } };
+
+            var original = RoutePatternFactory.Parse(template);
+
+            // Act
+            var actual = RoutePatternFactory.Pattern(
+                original.RawText,
+                defaults,
+                constraints,
+                original.PathSegments);
+
+            // Assert
+            Assert.Collection(
+                actual.ParameterPolicies.OrderBy(kvp => kvp.Key),
+                kvp =>
+                {
+                    Assert.Equal("a", kvp.Key);
+                    Assert.Collection(
+                        kvp.Value,
+                        c => Assert.Equal("int", c.Content));
+                },
+                kvp =>
+                {
+                    Assert.Equal("b", kvp.Key);
+                    Assert.Collection(
+                        kvp.Value,
+                        c => Assert.Equal("^(fizz)$", Assert.IsType<RegexRouteConstraint>(c.ParameterPolicy).Constraint.ToString()));
+                },
+                kvp =>
+                {
+                    Assert.Equal("c", kvp.Key);
+                    Assert.Collection(
+                        kvp.Value,
+                        c => Assert.Equal("foo", Assert.IsType<RegexRouteConstraint>(c.ParameterPolicy).Constraint.ToString()),
+                        c => Assert.Equal("bar", Assert.IsType<RegexRouteConstraint>(c.ParameterPolicy).Constraint.ToString()),
+                        c => Assert.Equal("^(baz)$", Assert.IsType<RegexRouteConstraint>(c.ParameterPolicy).Constraint.ToString()),
+                        c => Assert.Equal("int", c.Content));
+                });
+        }
+
+        [Fact]
+        public void Pattern_ExtraConstraints_NestedArray_Throws()
+        {
+            // Arrange
+            var template = "{a}/{b}/{c:int}";
+            var defaults = new { };
+            var constraints = new { c = new object[] { new object[0] } };
+
+            var original = RoutePatternFactory.Parse(template);
+
+            // Act & Assert
+            Assert.Throws<InvalidOperationException>(() =>
+            {
+                RoutePatternFactory.Pattern(
+                    original.RawText,
+                    defaults,
+                    constraints,
+                    original.PathSegments);
+            });
+        }
+
         [Fact]
         public void Pattern_ExtraConstraints_RouteConstraint()
         {