[web] Allow the usage of url strategies without conditional imports (#77103)

packages/flutter_web_plugins/lib/flutter_web_plugins.dart

@@ -18,5 +18,6 @@ library flutter_web_plugins;
 export 'src/navigation/js_url_strategy.dart';
 export 'src/navigation/url_strategy.dart';
 export 'src/navigation/utils.dart';
+export 'src/navigation_common/url_strategy.dart';
 export 'src/plugin_event_channel.dart';
 export 'src/plugin_registry.dart';

packages/flutter_web_plugins/lib/src/navigation/js_url_strategy.dart

@@ -16,7 +16,7 @@ import 'dart:ui' as ui;
 import 'package:js/js.dart';
 import 'package:meta/meta.dart';
 
-import 'url_strategy.dart';
+import '../navigation_common/url_strategy.dart';
 
 typedef _JsSetUrlStrategy = void Function(JsUrlStrategy?);
 
@@ -33,7 +33,7 @@ typedef _PathGetter = String Function();
 
 typedef _StateGetter = Object? Function();
 
-typedef _AddPopStateListener = ui.VoidCallback Function(html.EventListener);
+typedef _AddPopStateListener = ui.VoidCallback Function(EventListener);
 
 typedef _StringToString = String Function(String);
 

packages/flutter_web_plugins/lib/src/navigation/url_strategy.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:html' as html;
 import 'dart:ui' as ui;
 
+import '../navigation_common/url_strategy.dart';
 import 'js_url_strategy.dart';
 import 'utils.dart';
 
@@ -40,53 +41,9 @@ void setUrlStrategy(UrlStrategy? strategy) {
   jsSetUrlStrategy(jsUrlStrategy);
 }
 
-/// Represents and reads route state from the browser's URL.
-///
-/// By default, the [HashUrlStrategy] subclass is used if the app doesn't
-/// specify one.
-abstract class UrlStrategy {
-  /// Abstract const constructor. This constructor enables subclasses to provide
-  /// const constructors so that they can be used in const expressions.
-  const UrlStrategy();
-
-  /// Adds a listener to the `popstate` event and returns a function that, when
-  /// invoked, removes the listener.
-  ui.VoidCallback addPopStateListener(html.EventListener fn);
-
-  /// Returns the active path in the browser.
-  String getPath();
-
-  /// The state of the current browser history entry.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/state
-  Object? getState();
-
-  /// Given a path that's internal to the app, create the external url that
-  /// will be used in the browser.
-  String prepareExternalUrl(String internalUrl);
-
-  /// Push a new history entry.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/pushState
-  void pushState(Object? state, String title, String url);
-
-  /// Replace the currently active history entry.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/replaceState
-  void replaceState(Object? state, String title, String url);
-
-  /// Moves forwards or backwards through the history stack.
-  ///
-  /// A negative [count] value causes a backward move in the history stack. And
-  /// a positive [count] value causes a forward move.
-  ///
-  /// Examples:
-  ///
-  /// * `go(-2)` moves back 2 steps in history.
-  /// * `go(3)` moves forward 3 steps in history.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/go
-  Future<void> go(int count);
+/// Use the [PathUrlStrategy] to handle the browser URL.
+void usePathUrlStrategy() {
+  setUrlStrategy(PathUrlStrategy());
 }
 
 /// Uses the browser URL's [hash fragments](https://en.wikipedia.org/wiki/Uniform_Resource_Locator#Syntax)
@@ -114,7 +71,7 @@ class HashUrlStrategy extends UrlStrategy {
   final PlatformLocation _platformLocation;
 
   @override
-  ui.VoidCallback addPopStateListener(html.EventListener fn) {
+  ui.VoidCallback addPopStateListener(EventListener fn) {
     _platformLocation.addPopStateListener(fn);
     return () => _platformLocation.removePopStateListener(fn);
   }
@@ -221,76 +178,6 @@ class PathUrlStrategy extends HashUrlStrategy {
   }
 }
 
-/// Encapsulates all calls to DOM apis, which allows the [UrlStrategy] classes
-/// to be platform agnostic and testable.
-///
-/// For convenience, the [PlatformLocation] class can be used by implementations
-/// of [UrlStrategy] to interact with DOM apis like pushState, popState, etc.
-abstract class PlatformLocation {
-  /// Abstract const constructor. This constructor enables subclasses to provide
-  /// const constructors so that they can be used in const expressions.
-  const PlatformLocation();
-
-  /// Registers an event listener for the `popstate` event.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onpopstate
-  void addPopStateListener(html.EventListener fn);
-
-  /// Unregisters the given listener (added by [addPopStateListener]) from the
-  /// `popstate` event.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onpopstate
-  void removePopStateListener(html.EventListener fn);
-
-  /// The `pathname` part of the URL in the browser address bar.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/Location/pathname
-  String get pathname;
-
-  /// The `query` part of the URL in the browser address bar.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/Location/search
-  String get search;
-
-  /// The `hash` part of the URL in the browser address bar.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/Location/hash
-  String get hash;
-
-  /// The `state` in the current history entry.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/state
-  Object? get state;
-
-  /// Adds a new entry to the browser history stack.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/pushState
-  void pushState(Object? state, String title, String url);
-
-  /// Replaces the current entry in the browser history stack.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/replaceState
-  void replaceState(Object? state, String title, String url);
-
-  /// Moves forwards or backwards through the history stack.
-  ///
-  /// A negative [count] value causes a backward move in the history stack. And
-  /// a positive [count] value causes a forward move.
-  ///
-  /// Examples:
-  ///
-  /// * `go(-2)` moves back 2 steps in history.
-  /// * `go(3)` moves forward 3 steps in history.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/go
-  void go(int count);
-
-  /// The base href where the Flutter app is being served.
-  ///
-  /// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base
-  String? getBaseHref();
-}
-
 /// Delegates to real browser APIs to provide platform location functionality.
 class BrowserPlatformLocation extends PlatformLocation {
   /// Default constructor for [BrowserPlatformLocation].

packages/flutter_web_plugins/lib/src/navigation_common/url_strategy.dart

@@ -0,0 +1,130 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:ui' as ui;
+
+/// Signature of an html event listener.
+///
+/// We have to redefine it because non-web platforms can't import dart:html.
+typedef EventListener = dynamic Function(Object event);
+
+/// Represents and reads route state from the browser's URL.
+///
+/// By default, the [HashUrlStrategy] subclass is used if the app doesn't
+/// specify one.
+abstract class UrlStrategy {
+  /// Abstract const constructor. This constructor enables subclasses to provide
+  /// const constructors so that they can be used in const expressions.
+  const UrlStrategy();
+
+  /// Adds a listener to the `popstate` event and returns a function that, when
+  /// invoked, removes the listener.
+  ui.VoidCallback addPopStateListener(EventListener fn);
+
+  /// Returns the active path in the browser.
+  String getPath();
+
+  /// The state of the current browser history entry.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/state
+  Object? getState();
+
+  /// Given a path that's internal to the app, create the external url that
+  /// will be used in the browser.
+  String prepareExternalUrl(String internalUrl);
+
+  /// Push a new history entry.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/pushState
+  void pushState(Object? state, String title, String url);
+
+  /// Replace the currently active history entry.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/replaceState
+  void replaceState(Object? state, String title, String url);
+
+  /// Moves forwards or backwards through the history stack.
+  ///
+  /// A negative [count] value causes a backward move in the history stack. And
+  /// a positive [count] value causes a forward move.
+  ///
+  /// Examples:
+  ///
+  /// * `go(-2)` moves back 2 steps in history.
+  /// * `go(3)` moves forward 3 steps in history.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/go
+  Future<void> go(int count);
+}
+
+/// Encapsulates all calls to DOM apis, which allows the [UrlStrategy] classes
+/// to be platform agnostic and testable.
+///
+/// For convenience, the [PlatformLocation] class can be used by implementations
+/// of [UrlStrategy] to interact with DOM apis like pushState, popState, etc.
+abstract class PlatformLocation {
+  /// Abstract const constructor. This constructor enables subclasses to provide
+  /// const constructors so that they can be used in const expressions.
+  const PlatformLocation();
+
+  /// Registers an event listener for the `popstate` event.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onpopstate
+  void addPopStateListener(EventListener fn);
+
+  /// Unregisters the given listener (added by [addPopStateListener]) from the
+  /// `popstate` event.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onpopstate
+  void removePopStateListener(EventListener fn);
+
+  /// The `pathname` part of the URL in the browser address bar.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/Location/pathname
+  String get pathname;
+
+  /// The `query` part of the URL in the browser address bar.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/Location/search
+  String get search;
+
+  /// The `hash` part of the URL in the browser address bar.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/Location/hash
+  String get hash;
+
+  /// The `state` in the current history entry.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/state
+  Object? get state;
+
+  /// Adds a new entry to the browser history stack.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/pushState
+  void pushState(Object? state, String title, String url);
+
+  /// Replaces the current entry in the browser history stack.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/replaceState
+  void replaceState(Object? state, String title, String url);
+
+  /// Moves forwards or backwards through the history stack.
+  ///
+  /// A negative [count] value causes a backward move in the history stack. And
+  /// a positive [count] value causes a forward move.
+  ///
+  /// Examples:
+  ///
+  /// * `go(-2)` moves back 2 steps in history.
+  /// * `go(3)` moves forward 3 steps in history.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/API/History/go
+  void go(int count);
+
+  /// The base href where the Flutter app is being served.
+  ///
+  /// See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base
+  String? getBaseHref();
+}

packages/flutter_web_plugins/lib/src/navigation_non_web/url_strategy.dart

@@ -0,0 +1,103 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:ui' as ui;
+
+import '../navigation_common/url_strategy.dart';
+
+/// Returns the present [UrlStrategy] for handling the browser URL.
+///
+/// In case null is returned, the browser integration has been manually
+/// disabled by [setUrlStrategy].
+UrlStrategy? get urlStrategy => null;
+
+/// Change the strategy to use for handling browser URL.
+///
+/// Setting this to null disables all integration with the browser history.
+void setUrlStrategy(UrlStrategy? strategy) {
+  // No-op in non-web platforms.
+}
+
+/// Use the [PathUrlStrategy] to handle the browser URL.
+void usePathUrlStrategy() {
+  // No-op in non-web platforms.
+}
+
+/// Uses the browser URL's [hash fragments](https://en.wikipedia.org/wiki/Uniform_Resource_Locator#Syntax)
+/// to represent its state.
+///
+/// By default, this class is used as the URL strategy for the app. However,
+/// this class is still useful for apps that want to extend it.
+///
+/// In order to use [HashUrlStrategy] for an app, it needs to be set like this:
+///
+/// ```dart
+/// import 'package:flutter_web_plugins/flutter_web_plugins.dart';
+///
+/// // Somewhere before calling `runApp()` do:
+/// setUrlStrategy(const HashUrlStrategy());
+/// ```
+class HashUrlStrategy extends UrlStrategy {
+  /// Creates an instance of [HashUrlStrategy].
+  ///
+  /// The [PlatformLocation] parameter is useful for testing to mock out browser
+  /// interations.
+  const HashUrlStrategy([PlatformLocation? _]);
+
+  @override
+  ui.VoidCallback addPopStateListener(EventListener fn) {
+    // No-op.
+    return () {};
+  }
+
+  @override
+  String getPath() => '';
+
+  @override
+  Object? getState() => null;
+
+  @override
+  String prepareExternalUrl(String internalUrl) => '';
+
+  @override
+  void pushState(Object? state, String title, String url) {
+    // No-op.
+  }
+
+  @override
+  void replaceState(Object? state, String title, String url) {
+    // No-op.
+  }
+
+  @override
+  Future<void> go(int count) async {
+    // No-op.
+  }
+}
+
+/// Uses the browser URL's pathname to represent Flutter's route name.
+///
+/// In order to use [PathUrlStrategy] for an app, it needs to be set like this:
+///
+/// ```dart
+/// import 'package:flutter_web_plugins/flutter_web_plugins.dart';
+///
+/// // Somewhere before calling `runApp()` do:
+/// setUrlStrategy(PathUrlStrategy());
+/// ```
+class PathUrlStrategy extends HashUrlStrategy {
+  /// Creates an instance of [PathUrlStrategy].
+  ///
+  /// The [PlatformLocation] parameter is useful for testing to mock out browser
+  /// interations.
+  PathUrlStrategy([PlatformLocation? _platformLocation])
+      : super(_platformLocation);
+
+  @override
+  String getPath() => '';
+
+  @override
+  String prepareExternalUrl(String internalUrl) => '';
+}

packages/flutter_web_plugins/lib/url_strategy.dart

@@ -0,0 +1,8 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+export 'src/navigation_common/url_strategy.dart';
+
+export 'src/navigation_non_web/url_strategy.dart'
+    if (dart.library.html) 'src/navigation/url_strategy.dart';

packages/flutter_web_plugins/test/navigation/url_strategy_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:html';
-
 @TestOn('chrome') // Uses web-only Flutter SDK
 
 import 'package:flutter_test/flutter_test.dart';