Add PreserveMatchedPathSegment to MapOptions #3762 (#15364)

src/Http/Http.Abstractions/ref/Microsoft.AspNetCore.Http.Abstractions.netcoreapp.cs

@@ -27,6 +27,7 @@ namespace Microsoft.AspNetCore.Builder
     public static partial class MapExtensions
     {
         public static Microsoft.AspNetCore.Builder.IApplicationBuilder Map(this Microsoft.AspNetCore.Builder.IApplicationBuilder app, Microsoft.AspNetCore.Http.PathString pathMatch, System.Action<Microsoft.AspNetCore.Builder.IApplicationBuilder> configuration) { throw null; }
+        public static Microsoft.AspNetCore.Builder.IApplicationBuilder Map(this Microsoft.AspNetCore.Builder.IApplicationBuilder app, Microsoft.AspNetCore.Http.PathString pathMatch, bool preserveMatchedPathSegment, System.Action<Microsoft.AspNetCore.Builder.IApplicationBuilder> configuration) { throw null; }
     }
     public static partial class MapWhenExtensions
     {
@@ -67,6 +68,7 @@ namespace Microsoft.AspNetCore.Builder.Extensions
         public MapOptions() { }
         public Microsoft.AspNetCore.Http.RequestDelegate Branch { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
         public Microsoft.AspNetCore.Http.PathString PathMatch { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
+        public bool PreserveMatchedPathSegment { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
     }
     public partial class MapWhenMiddleware
     {

src/Http/Http.Abstractions/src/Extensions/MapExtensions.cs

@@ -21,6 +21,20 @@ namespace Microsoft.AspNetCore.Builder
         /// <param name="configuration">The branch to take for positive path matches.</param>
         /// <returns>The <see cref="IApplicationBuilder"/> instance.</returns>
         public static IApplicationBuilder Map(this IApplicationBuilder app, PathString pathMatch, Action<IApplicationBuilder> configuration)
+        {
+            return Map(app, pathMatch, preserveMatchedPathSegment: false, configuration);
+        }
+
+        /// <summary>
+        /// Branches the request pipeline based on matches of the given request path. If the request path starts with
+        /// the given path, the branch is executed.
+        /// </summary>
+        /// <param name="app">The <see cref="IApplicationBuilder"/> instance.</param>
+        /// <param name="pathMatch">The request path to match.</param>
+        /// <param name="preserveMatchedPathSegment">if false, matched path would be removed from Request.Path and added to Request.PathBase.</param>
+        /// <param name="configuration">The branch to take for positive path matches.</param>
+        /// <returns>The <see cref="IApplicationBuilder"/> instance.</returns>
+        public static IApplicationBuilder Map(this IApplicationBuilder app, PathString pathMatch, bool preserveMatchedPathSegment, Action<IApplicationBuilder> configuration)
         {
             if (app == null)
             {
@@ -46,6 +60,7 @@ namespace Microsoft.AspNetCore.Builder
             {
                 Branch = branch,
                 PathMatch = pathMatch,
+                PreserveMatchedPathSegment = preserveMatchedPathSegment
             };
             return app.Use(next => new MapMiddleware(next, options).Invoke);
         }

src/Http/Http.Abstractions/src/Extensions/MapMiddleware.cs

@@ -48,16 +48,17 @@ namespace Microsoft.AspNetCore.Builder.Extensions
                 throw new ArgumentNullException(nameof(context));
             }
 
-            PathString matchedPath;
+            if (context.Request.Path.StartsWithSegments(_options.PathMatch, out var matchedPath, out var remainingPath))
-            PathString remainingPath;
-
-            if (context.Request.Path.StartsWithSegments(_options.PathMatch, out matchedPath, out remainingPath))
             {
-                // Update the path
                 var path = context.Request.Path;
                 var pathBase = context.Request.PathBase;
-                context.Request.PathBase = pathBase.Add(matchedPath);
+
-                context.Request.Path = remainingPath;
+                if (!_options.PreserveMatchedPathSegment)
+                {
+                    // Update the path
+                    context.Request.PathBase = pathBase.Add(matchedPath);
+                    context.Request.Path = remainingPath;
+                }
 
                 try
                 {
@@ -65,8 +66,11 @@ namespace Microsoft.AspNetCore.Builder.Extensions
                 }
                 finally
                 {
-                    context.Request.PathBase = pathBase;
+                    if (!_options.PreserveMatchedPathSegment)
-                    context.Request.Path = path;
+                    {
+                        context.Request.PathBase = pathBase;
+                        context.Request.Path = path;
+                    }
                 }
             }
             else

src/Http/Http.Abstractions/src/Extensions/MapOptions.cs

@@ -19,5 +19,11 @@ namespace Microsoft.AspNetCore.Builder.Extensions
         /// The branch taken for a positive match.
         /// </summary>
         public RequestDelegate Branch { get; set; }
+
+        /// <summary>
+        /// If false, matched path would be removed from Request.Path and added to Request.PathBase
+        /// Defaults to false.
+        /// </summary>
+        public bool PreserveMatchedPathSegment { get; set; }
     }
 }

src/Http/Http.Abstractions/test/MapPathMiddlewareTests.cs

@@ -95,6 +95,34 @@ namespace Microsoft.AspNetCore.Builder.Extensions
             Assert.Equal(requestPath.Substring(matchPath.Length), context.Items["test.Path"]);
         }
 
+        [Theory]
+        [InlineData("/foo", "", "/foo")]
+        [InlineData("/foo", "", "/foo/")]
+        [InlineData("/foo", "/Bar", "/foo")]
+        [InlineData("/foo", "/Bar", "/foo/cho")]
+        [InlineData("/foo", "/Bar", "/foo/cho/")]
+        [InlineData("/foo/cho", "/Bar", "/foo/cho")]
+        [InlineData("/foo/cho", "/Bar", "/foo/cho/do")]
+        [InlineData("/foo", "", "/Foo")]
+        [InlineData("/foo", "", "/Foo/")]
+        [InlineData("/foo", "/Bar", "/Foo")]
+        [InlineData("/foo", "/Bar", "/Foo/Cho")]
+        [InlineData("/foo", "/Bar", "/Foo/Cho/")]
+        [InlineData("/foo/cho", "/Bar", "/Foo/Cho")]
+        [InlineData("/foo/cho", "/Bar", "/Foo/Cho/do")]
+        public async Task PathMatchAction_BranchTaken_WithPreserveMatchedPathSegment(string matchPath, string basePath, string requestPath)
+        {
+            HttpContext context = CreateRequest(basePath, requestPath);
+            var builder = new ApplicationBuilder(serviceProvider: null);
+            builder.Map(matchPath, true, subBuilder => subBuilder.Run(Success));
+            var app = builder.Build();
+            await app.Invoke(context);
+
+            Assert.Equal(200, context.Response.StatusCode);
+            Assert.Equal(basePath, (string)context.Items["test.PathBase"]);
+            Assert.Equal(requestPath, context.Items["test.Path"]);
+        }
+
         [Theory]
         [InlineData("/")]
         [InlineData("/foo/")]