feat(dart_frog): expose captured request params

packages/dart_frog/lib/src/request.dart

@@ -135,6 +135,12 @@ class Request {
     );
   }
 
+  /// Returns the url parameters captured by the [Router].
+  /// Returns an empty map if no parameters are captured.
+  ///
+  /// The returned map is unmodifiable.
+  Map<String, String> get params => _request.params;
+
   /// Returns a [Stream] representing the body.
   Stream<List<int>> bytes() => _request.read();
 

packages/dart_frog/test/src/request_test.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:collection';
 import 'dart:convert';
 import 'dart:io';
 
@@ -79,6 +80,14 @@ ${HttpMethod.values.map((m) => m.value.toUpperCase()).join(', ')}.'''),
       expect(request.headers['foo'], equals(headers['foo']));
     });
 
+    test('has correct params (empty)', () {
+      final request = Request('GET', localhost);
+      expect(
+        request.params,
+        equals(UnmodifiableMapView<String, String>(const {})),
+      );
+    });
+
     test('body can be read multiple times (sync)', () {
       final body = json.encode({'test': 'body'});
       final request = Request('GET', localhost, body: body);

packages/dart_frog/test/src/router_test.dart

@@ -16,6 +16,7 @@
 @TestOn('vm')
 library;
 
+import 'dart:collection';
 import 'dart:convert';
 import 'dart:io';
 
@@ -291,10 +292,90 @@ void main() {
     expect(response.body, equals('hello'));
   });
 
+  test('request exposes captured params (empty)', () async {
+    final context = _MockRequestContext();
+    final app = Router()
+      ..get('/hello', (RequestContext context) {
+        expect(
+          context.request.params,
+          equals(UnmodifiableMapView<String, String>(const {})),
+        );
+        return Response(body: 'hello world');
+      });
+
+    server.mount((request) async {
+      when(() => context.request).thenReturn(
+        Request(request.method, request.requestedUri),
+      );
+      final response = await app(context);
+      final body = await response.body();
+      return shelf.Response(response.statusCode, body: body);
+    });
+
+    final response = await http.get(Uri.parse('${server.url}/hello'));
+    expect(response.statusCode, equals(HttpStatus.ok));
+    expect(response.body, equals('hello world'));
+  });
+
+  test('request exposes captured params (single)', () async {
+    final context = _MockRequestContext();
+    final app = Router()
+      ..get('/users/<id>/greet', (RequestContext context, String id) {
+        expect(
+          context.request.params,
+          equals(UnmodifiableMapView<String, String>({'id': id})),
+        );
+        return Response(body: 'hello $id');
+      });
+
+    server.mount((request) async {
+      when(() => context.request).thenReturn(
+        Request(request.method, request.requestedUri),
+      );
+      final response = await app(context);
+      final body = await response.body();
+      return shelf.Response(response.statusCode, body: body);
+    });
+
+    final response = await http.get(Uri.parse('${server.url}/users/42/greet'));
+    expect(response.statusCode, equals(HttpStatus.ok));
+    expect(response.body, equals('hello 42'));
+  });
+
+  test('request exposes captured params (multiple)', () async {
+    final context = _MockRequestContext();
+    final app = Router()
+      ..get('/users/<id>/greet/<name>', (
+        RequestContext context,
+        String id,
+        String name,
+      ) {
+        expect(
+          context.request.params,
+          equals(UnmodifiableMapView<String, String>({'id': id, 'name': name})),
+        );
+        return Response(body: 'hello $name ($id)');
+      });
+
+    server.mount((request) async {
+      when(() => context.request).thenReturn(
+        Request(request.method, request.requestedUri),
+      );
+      final response = await app(context);
+      final body = await response.body();
+      return shelf.Response(response.statusCode, body: body);
+    });
+
+    final response =
+        await http.get(Uri.parse('${server.url}/users/42/greet/felangel'));
+    expect(response.statusCode, equals(HttpStatus.ok));
+    expect(response.body, equals('hello felangel (42)'));
+  });
+
   test('mount(Router)', () async {
     final context = _MockRequestContext();
     final api = Router()
-      ..all('/user/<user>/info', (RequestContext request, String user) {
+      ..all('/user/<user>/info', (RequestContext context, String user) {
         return Response(body: 'Hello $user');
       });