documentcloud · December 11, 2009 22:46 · Dec 11, 2009 · Dec 11, 2009
diff --git a/gistfile1.txt → history.js b/gistfile1.txt → history.js
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,82 @@
+// Handles JavaScript history management and callbacks. To use, register a
+// regexp that matches the history hash with its corresponding callback:
+//
+//     dc.history.register(/^#search/, controller.runSearch);
+//
+// And then you can save arbitrary history fragments.
+//
+//     dc.history.save('search/freedom/p3');
+//
+DV.history = {
+
+  // The interval at which the window location is polled.
+  URL_CHECK_INTERVAL : 500,
+
+  // We need to use an iFrame to save history if we're in an old version of IE.
+  USE_IFRAME : jQuery.browser.msie && jQuery.browser.version < 8,
+
+  // The ordered list of history handlers matchers and callbacks.
+  handlers : [],
+  defaultCallback: null,
+
+  // The current recorded window.location.hash.
+  hash : window.location.hash,
+
+  // Initialize history with an empty set of handlers.
+  // Bind to the HTML5 'onhashchange' callback, if it exists. Otherwise,
+  // start polling the window location.
+  initialize : function() {
+    _.bindAll(this, 'checkURL');
+    if (this.USE_IFRAME) this.iframe = jQuery('<iframe src="javascript:0"/>').hide().appendTo('body')[0].contentWindow;
+    if ('onhashchange' in window) {
+      window.onhashchange = this.checkURL;
+    } else {
+      setInterval(this.checkURL, this.URL_CHECK_INTERVAL);
+    }
+  },
+
+  // Register a history handler. Pass a regular expression that can be used to
+  // match your URLs, and the callback to be invoked with the remainder of the
+  // hash, when matched. 
+  register : function(matcher, callback, defaultRoute) {
+    this.handlers.push({matcher : matcher, callback : callback});      
+  },
+
+  // Save a moment into browser history. Make sure you've registered a handler
+  // for it. You're responsible for pre-escaping the URL fragment.
+  save : function(hash) {
+    window.location.hash = this.hash = (hash ? '#' + hash : '');
+    if (this.USE_IFRAME && (this.hash != this.iframe.location.hash)) {
+      this.iframe.document.open().close();
+      this.iframe.location.hash = this.hash;
+    }
+  },
+
+  // Check the current URL hash against the recorded one, firing callbacks.
+  checkURL : function() {
+    var current = (this.USE_IFRAME ? this.iframe : window).location.hash;
+    if (current == this.hash || current == decodeURIComponent(this.hash)) return false;
+    if (this.USE_IFRAME) window.location.hash = current;
+    this.loadURL();
+  },
+
+  // Load the history callback associated with the current page fragment. On
+  // pages that support history, this method should be called at page load,
+  // after all the history callbacks have been registered.
+  loadURL : function() {
+    var hash = this.hash = window.location.hash;
+
+    // go through matches in reverse order so that oldest rules are executed last
+    for(var i = this.handlers.length-1; i >= 0; i--){
+      var match = hash.match(this.handlers[i].matcher);
+      if (match) {
+        this.handlers[i].callback(match.slice(1,match.length));
+        return;
+      }
+    }
+    if(this.defaultCallback != null) this.defaultCallback();
+  }
+
+};
+
+jQuery(document).ready(function(){ DV.history.initialize(); });