Simplify Tree handlers

- 404 on missing path
- only need one handler for each of redirect and dashboard,
  don't need duplicates.
- project property on Handlers is unclear

IPython/html/base/handlers.py

@@ -222,7 +222,7 b' class IPythonHandler(AuthenticatedHandler):'
         return self.settings['session_manager']
     
     @property
-    def project(self):
+    def project_dir(self):
         return self.notebook_manager.notebook_dir
     
     #---------------------------------------------------------------

IPython/html/templates/tree.html

@@ -13,7 +13,6 b''
 data-project={{project}}
 data-base-project-url={{base_project_url}}
 data-notebook-path={{notebook_path}}
-data-notebook-name={{notebook_name}}
 data-base-kernel-url={{base_kernel_url}}
 
 {% endblock %}
@@ -48,7 +47,7 b' data-base-kernel-url={{base_kernel_url}}'
           <div id="notebook_list_header" class="row-fluid list_header">
               <div id="project_name">
                 <ul class="breadcrumb">
-                    {% for component in project_component %}
+                    {% for component in tree_url_path.strip('/').split('/') %}
                         <li>{{component}} <span>/</span></li>
                     {% endfor %}
                 </ul>

IPython/html/tree/handlers.py

@@ -15,64 +15,49 b' Authors:'
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
+import os
 
 from tornado import web
 from ..base.handlers import IPythonHandler
+from ..utils import url_path_join, path2url, url2path
 
 #-----------------------------------------------------------------------------
 # Handlers
 #-----------------------------------------------------------------------------
 
 
-class ProjectDashboardHandler(IPythonHandler):
+class TreeHandler(IPythonHandler):
+    """Render the tree view, listing notebooks, clusters, etc."""
 
     @web.authenticated
-    def get(self):
-        self.write(self.render_template('tree.html',
-            project=self.project,
-            project_component=self.project.split('/'),
-            notebook_path= "/"
-        ))
-
-
-class ProjectPathDashboardHandler(IPythonHandler):
-
-    @web.authenticated
-    def get(self, notebook_path):
+    def get(self, notebook_path=""):
         nbm = self.notebook_manager
         name, path = nbm.named_notebook_path(notebook_path)
         if name is not None:
-            # ends with .ipynb
-            self.redirect(self.base_project_url + 'notebooks' + path + name)
+            # is a notebook, redirect to notebook handler
+            url = url_path_join(self.base_project_url, 'notebooks', path, name)
+            self.redirect(url)
         else:
-            project = self.project + path
-            path = nbm.url_encode(path)
+            location = nbm.get_os_path(path=path)
+            
+            if not os.path.exists(location):
+                # no such directory, 404
+                raise web.HTTPError(404)
+            
             self.write(self.render_template('tree.html',
-                project=project,
-                project_component=project.split('/')[:-1],
+                project=self.project_dir,
+                tree_url_path=path2url(location),
                 notebook_path=path,
-                notebook_name=name))
+            ))
 
 
 class TreeRedirectHandler(IPythonHandler):
-    
-    @web.authenticated
-    def get(self):
-        url = self.base_project_url + 'tree'
-        self.redirect(url)
-
-class TreePathRedirectHandler(IPythonHandler):
-
-    @web.authenticated
-    def get(self, notebook_path):
-        url = self.base_project_url + 'tree/'+ notebook_path+'/'
-        self.redirect(url)
+    """Redirect a request to the corresponding tree URL"""
 
-class ProjectRedirectHandler(IPythonHandler):
-    
     @web.authenticated
-    def get(self):
-        url = self.base_project_url + 'tree'
+    def get(self, notebook_path=''):
+        url = url_path_join(self.base_project_url, 'tree', notebook_path)
+        self.log.debug("Redirecting %s to %s", self.request.uri, url)
         self.redirect(url)
 
 
@@ -84,9 +69,9 b' class ProjectRedirectHandler(IPythonHandler):'
 _notebook_path_regex = r"(?P<notebook_path>.+)"
 
 default_handlers = [
-    (r"/tree/%s/" % _notebook_path_regex, ProjectPathDashboardHandler),
-    (r"/tree/%s" % _notebook_path_regex, TreePathRedirectHandler),
-    (r"/tree", ProjectDashboardHandler),
+    (r"/tree/%s/" % _notebook_path_regex, TreeRedirectHandler),
+    (r"/tree/%s" % _notebook_path_regex, TreeHandler),
     (r"/tree/", TreeRedirectHandler),
-    (r"/", ProjectRedirectHandler)
+    (r"/tree", TreeHandler),
+    (r"/", TreeRedirectHandler),
     ]