Redo LocationManager to use HTML5 History API

runtime/bin/vmservice/client/lib/src/app/location_manager.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of app;
 
-/// The LocationManager class observes and parses the hash ('#') portion of the
-/// URL in window.location. The text after the '#' is used as the request
-/// string for the VM service.
-class LocationManager extends Observable {
-  static const String defaultHash = '#/vm';
+abstract class LocationManager extends Observable {
+  final _initialPath = '/vm';
+  ObservatoryApplication _app;
 
-  ObservatoryApplication _app;
-  @observable String currentHash = '';
+  String _lastUrl;
 
-  void init() {
-    window.onHashChange.listen((event) {
-      // Request the current anchor.
-      requestCurrentHash();
-    });
-
-    if (window.location.hash == '') {
-      // Fresh start, load the vm page.
-      window.location.hash = defaultHash;
-    } else {
-      // The page is being reloaded.
-      requestCurrentHash();
-    }
+  void _init(ObservatoryApplication app) {
+    // Called once.
+    assert(_app == null);
+    _app = app;
+    // Register for history events.
+    window.onPopState.listen(_onLocationChange);
+    _onStartup();
   }
 
-  /// Clear the current hash.
-  void clearCurrentHash() {
-    window.location.hash = '';
+  void _onStartup();
+  void _onLocationChange(_);

[turnidge, 2014/06/04 18:02:24]

Do you know what the _ parameter is supposed to be?  The subclasses know that
they do not use the parameter, but it might be good for the parent class to
declare it.

[Cutch, 2014/06/04 20:28:57]

Done.

+
+  /// Go to a specific url.
+  void go(String url) {
+    if (_lastUrl != url) {
+      Logger.root.info('Navigated to ${url}');
+      window.history.pushState(url, document.title, url);
+    }
+    _lastUrl = url;

[turnidge, 2014/06/04 18:02:24]

Could move this line inside above "if".

[Cutch, 2014/06/04 20:28:57]

Done.

+    _go(url);
   }
 
-  /// Refresh the service object reference in the location entry.
-  void requestCurrentHash() {
-    currentHash = window.location.hash;
-    if (!currentHash.startsWith('#/')) {
+  void _go(String url) {
+    // Chop off leading '#'.
+    if (url.startsWith('#')) {
+      url = url.substring(1);
+    }
+    // Fall through handles '#/'
+    // Chop off leading '/'.
+    if (url.startsWith('/')) {
+      url = url.substring(1);
+    }
+    _app._visit(url);
+  }
+
+  /// Go back.
+  void back() {
+    window.history.go(-1);
+  }
+
+  /// Go forward.
+  void forward() {
+    window.history.go(1);
+  }
+
+  /// Handle clicking on an application url link.
+  void onGoto(MouseEvent event, var detail, Element target) {
+    var href = target.attributes['href'];
+    if (event.button > 1 || event.metaKey || event.ctrlKey ||
+        event.shiftKey || event.altKey) {
+      // Not a left-click or a left-click with a modifier key:
+      // Let browser handle.
       return;
     }
-    var parts = currentHash.substring(2).split('#');
-    var location = parts[0];
-    var args = (parts.length > 1 ? parts[1] : '');
-    if (parts.length > 2) {
-      Logger.root.warning('Found more than 2 #-characters in $currentHash');
+    location.go(href);
+    event.preventDefault();
+  }
+
+  /// Given an application url, generate a link.
+  String makeLink(String url);
+}
+
+/// Uses location.hash to encode application urls.
+class HashLocationManager extends LocationManager {
+  void _onStartup() {
+    String initialPath = '/${window.location.hash}';
+    if ((window.location.hash == '') || (window.location.hash == '#')) {
+      initialPath = '/#${_initialPath}';
     }
-    _app.vm.get(currentHash.substring(2)).then((obj) {
-        _app.response = obj;
-        _app.args = args;
-      });
+    window.history.replaceState(initialPath, document.title, initialPath);
+    _go(window.location.hash);
+  }
+
+  void _onLocationChange(_) {
+    _go(window.location.hash);
+  }
+
+  /// Given an application url, generate a link for an anchor tag.
+  String makeLink(String url) {
+    return '#$url';
   }
 }
+
+/// Uses location.pathname to encode application urls. Requires server side
+/// rewriting to support copy and paste linking. pub serve makes this hard.
+/// STATUS: Work in progress.
+class LinkLocationManager extends LocationManager {
+  void _onStartup() {
+    Logger.root.warning('Using untested LinkLocationManager');
+    String initialPath = window.location.pathname;
+    if ((window.location.pathname == '/index.html') ||
+        (window.location.pathname == '/')) {
+      initialPath = '/vm';
+    }
+    window.history.replaceState(initialPath, document.title, initialPath);
+    _go(window.location.pathname);
+  }
+
+  void _onLocationChange(_) {
+    _go(window.location.pathname);
+  }
+
+  /// Given an application url, generate a link for an anchor tag.
+  String makeLink(String url) => url;
+}