Merge pull request #7253 from minrk/async-contents-handlers

allow ContentsManager methods to return Futures

IPython/html/base/handlers.py

@@ -1,508 +1,509
 """Base Tornado handlers for the notebook server."""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import functools
 import json
 import logging
 import os
 import re
 import sys
 import traceback
 try:
     # py3
     from http.client import responses
 except ImportError:
     from httplib import responses
 
 from jinja2 import TemplateNotFound
 from tornado import web
 
-try:
-    from tornado.log import app_log
-except ImportError:
-    app_log = logging.getLogger()
+from tornado import gen
+from tornado.log import app_log
+
 
 import IPython
 from IPython.utils.sysinfo import get_sys_info
 
 from IPython.config import Application
 from IPython.utils.path import filefind
 from IPython.utils.py3compat import string_types
 from IPython.html.utils import is_hidden, url_path_join, url_escape
 
 from IPython.html.services.security import csp_report_uri
 
 #-----------------------------------------------------------------------------
 # Top-level handlers
 #-----------------------------------------------------------------------------
 non_alphanum = re.compile(r'[^A-Za-z0-9]')
 
 sys_info = json.dumps(get_sys_info())
 
 class AuthenticatedHandler(web.RequestHandler):
     """A RequestHandler with an authenticated user."""
 
     def set_default_headers(self):
         headers = self.settings.get('headers', {})
 
         if "Content-Security-Policy" not in headers:
             headers["Content-Security-Policy"] = (
                     "frame-ancestors 'self'; "
                     # Make sure the report-uri is relative to the base_url
                     "report-uri " + url_path_join(self.base_url, csp_report_uri) + ";"
             )
 
         # Allow for overriding headers
         for header_name,value in headers.items() :
             try:
                 self.set_header(header_name, value)
             except Exception as e:
                 # tornado raise Exception (not a subclass)
                 # if method is unsupported (websocket and Access-Control-Allow-Origin
                 # for example, so just ignore)
                 self.log.debug(e)
     
     def clear_login_cookie(self):
         self.clear_cookie(self.cookie_name)
     
     def get_current_user(self):
         if self.login_handler is None:
             return 'anonymous'
         return self.login_handler.get_user(self)
 
     @property
     def cookie_name(self):
         default_cookie_name = non_alphanum.sub('-', 'username-{}'.format(
             self.request.host
         ))
         return self.settings.get('cookie_name', default_cookie_name)
     
     @property
     def logged_in(self):
         """Is a user currently logged in?"""
         user = self.get_current_user()
         return (user and not user == 'anonymous')
 
     @property
     def login_handler(self):
         """Return the login handler for this application, if any."""
         return self.settings.get('login_handler_class', None)
 
     @property
     def login_available(self):
         """May a user proceed to log in?
 
         This returns True if login capability is available, irrespective of
         whether the user is already logged in or not.
 
         """
         if self.login_handler is None:
             return False
         return bool(self.login_handler.login_available(self.settings))
 
 
 class IPythonHandler(AuthenticatedHandler):
     """IPython-specific extensions to authenticated handling
     
     Mostly property shortcuts to IPython-specific settings.
     """
     
     @property
     def config(self):
         return self.settings.get('config', None)
     
     @property
     def log(self):
         """use the IPython log by default, falling back on tornado's logger"""
         if Application.initialized():
             return Application.instance().log
         else:
             return app_log
     
     #---------------------------------------------------------------
     # URLs
     #---------------------------------------------------------------
     
     @property
     def version_hash(self):
         """The version hash to use for cache hints for static files"""
         return self.settings.get('version_hash', '')
     
     @property
     def mathjax_url(self):
         return self.settings.get('mathjax_url', '')
     
     @property
     def base_url(self):
         return self.settings.get('base_url', '/')
 
     @property
     def ws_url(self):
         return self.settings.get('websocket_url', '')
 
     @property
     def contents_js_source(self):
         self.log.debug("Using contents: %s", self.settings.get('contents_js_source',
             'services/contents'))
         return self.settings.get('contents_js_source', 'services/contents')
     
     #---------------------------------------------------------------
     # Manager objects
     #---------------------------------------------------------------
     
     @property
     def kernel_manager(self):
         return self.settings['kernel_manager']
 
     @property
     def contents_manager(self):
         return self.settings['contents_manager']
     
     @property
     def cluster_manager(self):
         return self.settings['cluster_manager']
     
     @property
     def session_manager(self):
         return self.settings['session_manager']
     
     @property
     def terminal_manager(self):
         return self.settings['terminal_manager']
     
     @property
     def kernel_spec_manager(self):
         return self.settings['kernel_spec_manager']
 
     @property
     def config_manager(self):
         return self.settings['config_manager']
 
     #---------------------------------------------------------------
     # CORS
     #---------------------------------------------------------------
     
     @property
     def allow_origin(self):
         """Normal Access-Control-Allow-Origin"""
         return self.settings.get('allow_origin', '')
     
     @property
     def allow_origin_pat(self):
         """Regular expression version of allow_origin"""
         return self.settings.get('allow_origin_pat', None)
     
     @property
     def allow_credentials(self):
         """Whether to set Access-Control-Allow-Credentials"""
         return self.settings.get('allow_credentials', False)
     
     def set_default_headers(self):
         """Add CORS headers, if defined"""
         super(IPythonHandler, self).set_default_headers()
         if self.allow_origin:
             self.set_header("Access-Control-Allow-Origin", self.allow_origin)
         elif self.allow_origin_pat:
             origin = self.get_origin()
             if origin and self.allow_origin_pat.match(origin):
                 self.set_header("Access-Control-Allow-Origin", origin)
         if self.allow_credentials:
             self.set_header("Access-Control-Allow-Credentials", 'true')
     
     def get_origin(self):
         # Handle WebSocket Origin naming convention differences
         # The difference between version 8 and 13 is that in 8 the
         # client sends a "Sec-Websocket-Origin" header and in 13 it's
         # simply "Origin".
         if "Origin" in self.request.headers:
             origin = self.request.headers.get("Origin")
         else:
             origin = self.request.headers.get("Sec-Websocket-Origin", None)
         return origin
     
     #---------------------------------------------------------------
     # template rendering
     #---------------------------------------------------------------
     
     def get_template(self, name):
         """Return the jinja template object for a given name"""
         return self.settings['jinja2_env'].get_template(name)
     
     def render_template(self, name, **ns):
         ns.update(self.template_namespace)
         template = self.get_template(name)
         return template.render(**ns)
     
     @property
     def template_namespace(self):
         return dict(
             base_url=self.base_url,
             ws_url=self.ws_url,
             logged_in=self.logged_in,
             login_available=self.login_available,
             static_url=self.static_url,
             sys_info=sys_info,
             contents_js_source=self.contents_js_source,
             version_hash=self.version_hash,
         )
     
     def get_json_body(self):
         """Return the body of the request as JSON data."""
         if not self.request.body:
             return None
         # Do we need to call body.decode('utf-8') here?
         body = self.request.body.strip().decode(u'utf-8')
         try:
             model = json.loads(body)
         except Exception:
             self.log.debug("Bad JSON: %r", body)
             self.log.error("Couldn't parse JSON", exc_info=True)
             raise web.HTTPError(400, u'Invalid JSON in body of request')
         return model
 
     def write_error(self, status_code, **kwargs):
         """render custom error pages"""
         exc_info = kwargs.get('exc_info')
         message = ''
         status_message = responses.get(status_code, 'Unknown HTTP Error')
         if exc_info:
             exception = exc_info[1]
             # get the custom message, if defined
             try:
                 message = exception.log_message % exception.args
             except Exception:
                 pass
             
             # construct the custom reason, if defined
             reason = getattr(exception, 'reason', '')
             if reason:
                 status_message = reason
         
         # build template namespace
         ns = dict(
             status_code=status_code,
             status_message=status_message,
             message=message,
             exception=exception,
         )
         
         self.set_header('Content-Type', 'text/html')
         # render the template
         try:
             html = self.render_template('%s.html' % status_code, **ns)
         except TemplateNotFound:
             self.log.debug("No template for %d", status_code)
             html = self.render_template('error.html', **ns)
         
         self.write(html)
         
 
 
 class Template404(IPythonHandler):
     """Render our 404 template"""
     def prepare(self):
         raise web.HTTPError(404)
 
 
 class AuthenticatedFileHandler(IPythonHandler, web.StaticFileHandler):
     """static files should only be accessible when logged in"""
 
     @web.authenticated
     def get(self, path):
         if os.path.splitext(path)[1] == '.ipynb':
             name = path.rsplit('/', 1)[-1]
             self.set_header('Content-Type', 'application/json')
             self.set_header('Content-Disposition','attachment; filename="%s"' % name)
         
         return web.StaticFileHandler.get(self, path)
     
     def set_headers(self):
         super(AuthenticatedFileHandler, self).set_headers()
         # disable browser caching, rely on 304 replies for savings
         if "v" not in self.request.arguments:
             self.add_header("Cache-Control", "no-cache")
     
     def compute_etag(self):
         return None
     
     def validate_absolute_path(self, root, absolute_path):
         """Validate and return the absolute path.
         
         Requires tornado 3.1
         
         Adding to tornado's own handling, forbids the serving of hidden files.
         """
         abs_path = super(AuthenticatedFileHandler, self).validate_absolute_path(root, absolute_path)
         abs_root = os.path.abspath(root)
         if is_hidden(abs_path, abs_root):
             self.log.info("Refusing to serve hidden file, via 404 Error")
             raise web.HTTPError(404)
         return abs_path
 
 
 def json_errors(method):
     """Decorate methods with this to return GitHub style JSON errors.
     
     This should be used on any JSON API on any handler method that can raise HTTPErrors.
     
     This will grab the latest HTTPError exception using sys.exc_info
     and then:
     
     1. Set the HTTP status code based on the HTTPError
     2. Create and return a JSON body with a message field describing
        the error in a human readable form.
     """
     @functools.wraps(method)
+    @gen.coroutine
     def wrapper(self, *args, **kwargs):
         try:
-            result = method(self, *args, **kwargs)
+            result = yield gen.maybe_future(method(self, *args, **kwargs))
         except web.HTTPError as e:
             status = e.status_code
             message = e.log_message
             self.log.warn(message)
             self.set_status(e.status_code)
             reply = dict(message=message, reason=e.reason)
             self.finish(json.dumps(reply))
         except Exception:
             self.log.error("Unhandled error in API request", exc_info=True)
             status = 500
             message = "Unknown server error"
             t, value, tb = sys.exc_info()
             self.set_status(status)
             tb_text = ''.join(traceback.format_exception(t, value, tb))
             reply = dict(message=message, reason=None, traceback=tb_text)
             self.finish(json.dumps(reply))
         else:
-            return result
+            # FIXME: can use regular return in generators in py3
+            raise gen.Return(result)
     return wrapper
 
 
 
 #-----------------------------------------------------------------------------
 # File handler
 #-----------------------------------------------------------------------------
 
 # to minimize subclass changes:
 HTTPError = web.HTTPError
 
 class FileFindHandler(web.StaticFileHandler):
     """subclass of StaticFileHandler for serving files from a search path"""
     
     # cache search results, don't search for files more than once
     _static_paths = {}
     
     def set_headers(self):
         super(FileFindHandler, self).set_headers()
         # disable browser caching, rely on 304 replies for savings
         if "v" not in self.request.arguments or \
                 any(self.request.path.startswith(path) for path in self.no_cache_paths):
             self.add_header("Cache-Control", "no-cache")
     
     def initialize(self, path, default_filename=None, no_cache_paths=None):
         self.no_cache_paths = no_cache_paths or []
         
         if isinstance(path, string_types):
             path = [path]
         
         self.root = tuple(
             os.path.abspath(os.path.expanduser(p)) + os.sep for p in path
         )
         self.default_filename = default_filename
     
     def compute_etag(self):
         return None
     
     @classmethod
     def get_absolute_path(cls, roots, path):
         """locate a file to serve on our static file search path"""
         with cls._lock:
             if path in cls._static_paths:
                 return cls._static_paths[path]
             try:
                 abspath = os.path.abspath(filefind(path, roots))
             except IOError:
                 # IOError means not found
                 return ''
             
             cls._static_paths[path] = abspath
             return abspath
     
     def validate_absolute_path(self, root, absolute_path):
         """check if the file should be served (raises 404, 403, etc.)"""
         if absolute_path == '':
             raise web.HTTPError(404)
         
         for root in self.root:
             if (absolute_path + os.sep).startswith(root):
                 break
         
         return super(FileFindHandler, self).validate_absolute_path(root, absolute_path)
 
 
 class ApiVersionHandler(IPythonHandler):
 
     @json_errors
     def get(self):
         # not authenticated, so give as few info as possible
         self.finish(json.dumps({"version":IPython.__version__}))
 
 
 class TrailingSlashHandler(web.RequestHandler):
     """Simple redirect handler that strips trailing slashes
     
     This should be the first, highest priority handler.
     """
     
     def get(self):
         self.redirect(self.request.uri.rstrip('/'))
     
     post = put = get
 
 
 class FilesRedirectHandler(IPythonHandler):
     """Handler for redirecting relative URLs to the /files/ handler"""
     def get(self, path=''):
         cm = self.contents_manager
         if cm.dir_exists(path):
             # it's a *directory*, redirect to /tree
             url = url_path_join(self.base_url, 'tree', path)
         else:
             orig_path = path
             # otherwise, redirect to /files
             parts = path.split('/')
 
             if not cm.file_exists(path=path) and 'files' in parts:
                 # redirect without files/ iff it would 404
                 # this preserves pre-2.0-style 'files/' links
                 self.log.warn("Deprecated files/ URL: %s", orig_path)
                 parts.remove('files')
                 path = '/'.join(parts)
 
             if not cm.file_exists(path=path):
                 raise web.HTTPError(404)
 
             url = url_path_join(self.base_url, 'files', path)
         url = url_escape(url)
         self.log.debug("Redirecting %s to %s", self.request.path, url)
         self.redirect(url)
 
 
 #-----------------------------------------------------------------------------
 # URL pattern fragments for re-use
 #-----------------------------------------------------------------------------
 
 # path matches any number of `/foo[/bar...]` or just `/` or ''
 path_regex = r"(?P<path>(?:(?:/[^/]+)+|/?))"
 notebook_path_regex = r"(?P<path>(?:/[^/]+)+\.ipynb)"
 
 #-----------------------------------------------------------------------------
 # URL to handler mappings
 #-----------------------------------------------------------------------------
 
 
 default_handlers = [
     (r".*/", TrailingSlashHandler),
     (r"api", ApiVersionHandler)
 ]

IPython/html/services/contents/handlers.py

@@ -1,322 +1,336
 """Tornado handlers for the contents web service."""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import json
 
-from tornado import web
+from tornado import gen, web
 
 from IPython.html.utils import url_path_join, url_escape
 from IPython.utils.jsonutil import date_default
 
 from IPython.html.base.handlers import (
     IPythonHandler, json_errors, path_regex,
 )
 
 
 def sort_key(model):
     """key function for case-insensitive sort by name and type"""
     iname = model['name'].lower()
     type_key = {
         'directory' : '0',
         'notebook'  : '1',
         'file'      : '2',
     }.get(model['type'], '9')
     return u'%s%s' % (type_key, iname)
 
 
 def validate_model(model, expect_content):
     """
     Validate a model returned by a ContentsManager method.
 
     If expect_content is True, then we expect non-null entries for 'content'
     and 'format'.
     """
     required_keys = {
         "name",
         "path",
         "type",
         "writable",
         "created",
         "last_modified",
         "mimetype",
         "content",
         "format",
     }
     missing = required_keys - set(model.keys())
     if missing:
         raise web.HTTPError(
             500,
             u"Missing Model Keys: {missing}".format(missing=missing),
         )
 
     maybe_none_keys = ['content', 'format']
     if model['type'] == 'file':
         # mimetype should be populated only for file models
         maybe_none_keys.append('mimetype')
     if expect_content:
         errors = [key for key in maybe_none_keys if model[key] is None]
         if errors:
             raise web.HTTPError(
                 500,
                 u"Keys unexpectedly None: {keys}".format(keys=errors),
             )
     else:
         errors = {
             key: model[key]
             for key in maybe_none_keys
             if model[key] is not None
         }
         if errors:
             raise web.HTTPError(
                 500,
                 u"Keys unexpectedly not None: {keys}".format(keys=errors),
             )
 
 
 class ContentsHandler(IPythonHandler):
 
     SUPPORTED_METHODS = (u'GET', u'PUT', u'PATCH', u'POST', u'DELETE')
 
     def location_url(self, path):
         """Return the full URL location of a file.
 
         Parameters
         ----------
         path : unicode
             The API path of the file, such as "foo/bar.txt".
         """
         return url_escape(url_path_join(
             self.base_url, 'api', 'contents', path
         ))
 
     def _finish_model(self, model, location=True):
         """Finish a JSON request with a model, setting relevant headers, etc."""
         if location:
             location = self.location_url(model['path'])
             self.set_header('Location', location)
         self.set_header('Last-Modified', model['last_modified'])
         self.set_header('Content-Type', 'application/json')
         self.finish(json.dumps(model, default=date_default))
 
     @web.authenticated
     @json_errors
+    @gen.coroutine
     def get(self, path=''):
         """Return a model for a file or directory.
 
         A directory model contains a list of models (without content)
         of the files and directories it contains.
         """
         path = path or ''
         type = self.get_query_argument('type', default=None)
         if type not in {None, 'directory', 'file', 'notebook'}:
             raise web.HTTPError(400, u'Type %r is invalid' % type)
 
         format = self.get_query_argument('format', default=None)
         if format not in {None, 'text', 'base64'}:
             raise web.HTTPError(400, u'Format %r is invalid' % format)
 
-        model = self.contents_manager.get(path=path, type=type, format=format)
+        model = yield gen.maybe_future(self.contents_manager.get(path=path, type=type, format=format))
         if model['type'] == 'directory':
             # group listing by type, then by name (case-insensitive)
             # FIXME: sorting should be done in the frontends
             model['content'].sort(key=sort_key)
         validate_model(model, expect_content=True)
         self._finish_model(model, location=False)
 
     @web.authenticated
     @json_errors
+    @gen.coroutine
     def patch(self, path=''):
         """PATCH renames a file or directory without re-uploading content."""
         cm = self.contents_manager
         model = self.get_json_body()
         if model is None:
             raise web.HTTPError(400, u'JSON body missing')
-        model = cm.update(model, path)
+        model = yield gen.maybe_future(cm.update(model, path))
         validate_model(model, expect_content=False)
         self._finish_model(model)
-
+    
+    @gen.coroutine
     def _copy(self, copy_from, copy_to=None):
         """Copy a file, optionally specifying a target directory."""
         self.log.info(u"Copying {copy_from} to {copy_to}".format(
             copy_from=copy_from,
             copy_to=copy_to or '',
         ))
-        model = self.contents_manager.copy(copy_from, copy_to)
+        model = yield gen.maybe_future(self.contents_manager.copy(copy_from, copy_to))
         self.set_status(201)
         validate_model(model, expect_content=False)
         self._finish_model(model)
 
+    @gen.coroutine
     def _upload(self, model, path):
         """Handle upload of a new file to path"""
         self.log.info(u"Uploading file to %s", path)
-        model = self.contents_manager.new(model, path)
+        model = yield gen.maybe_future(self.contents_manager.new(model, path))
         self.set_status(201)
         validate_model(model, expect_content=False)
         self._finish_model(model)
-        
+    
+    @gen.coroutine
     def _new_untitled(self, path, type='', ext=''):
         """Create a new, empty untitled entity"""
         self.log.info(u"Creating new %s in %s", type or 'file', path)
-        model = self.contents_manager.new_untitled(path=path, type=type, ext=ext)
+        model = yield gen.maybe_future(self.contents_manager.new_untitled(path=path, type=type, ext=ext))
         self.set_status(201)
         validate_model(model, expect_content=False)
         self._finish_model(model)
-
+    
+    @gen.coroutine
     def _save(self, model, path):
         """Save an existing file."""
         self.log.info(u"Saving file at %s", path)
-        model = self.contents_manager.save(model, path)
+        model = yield gen.maybe_future(self.contents_manager.save(model, path))
         validate_model(model, expect_content=False)
         self._finish_model(model)
 
     @web.authenticated
     @json_errors
+    @gen.coroutine
     def post(self, path=''):
         """Create a new file in the specified path.
 
         POST creates new files. The server always decides on the name.
 
         POST /api/contents/path
           New untitled, empty file or directory.
         POST /api/contents/path
           with body {"copy_from" : "/path/to/OtherNotebook.ipynb"}
           New copy of OtherNotebook in path
         """
 
         cm = self.contents_manager
 
         if cm.file_exists(path):
             raise web.HTTPError(400, "Cannot POST to files, use PUT instead.")
 
         if not cm.dir_exists(path):
             raise web.HTTPError(404, "No such directory: %s" % path)
 
         model = self.get_json_body()
 
         if model is not None:
             copy_from = model.get('copy_from')
             ext = model.get('ext', '')
             type = model.get('type', '')
             if copy_from:
-                self._copy(copy_from, path)
+                yield self._copy(copy_from, path)
             else:
-                self._new_untitled(path, type=type, ext=ext)
+                yield self._new_untitled(path, type=type, ext=ext)
         else:
-            self._new_untitled(path)
+            yield self._new_untitled(path)
 
     @web.authenticated
     @json_errors
+    @gen.coroutine
     def put(self, path=''):
         """Saves the file in the location specified by name and path.
 
         PUT is very similar to POST, but the requester specifies the name,
         whereas with POST, the server picks the name.
 
         PUT /api/contents/path/Name.ipynb
           Save notebook at ``path/Name.ipynb``. Notebook structure is specified
           in `content` key of JSON request body. If content is not specified,
           create a new empty notebook.
         """
         model = self.get_json_body()
         if model:
             if model.get('copy_from'):
                 raise web.HTTPError(400, "Cannot copy with PUT, only POST")
-            if self.contents_manager.file_exists(path):
-                self._save(model, path)
+            exists = yield gen.maybe_future(self.contents_manager.file_exists(path))
+            if exists:
+                yield gen.maybe_future(self._save(model, path))
             else:
-                self._upload(model, path)
+                yield gen.maybe_future(self._upload(model, path))
         else:
-            self._new_untitled(path)
+            yield gen.maybe_future(self._new_untitled(path))
 
     @web.authenticated
     @json_errors
+    @gen.coroutine
     def delete(self, path=''):
         """delete a file in the given path"""
         cm = self.contents_manager
         self.log.warn('delete %s', path)
-        cm.delete(path)
+        yield gen.maybe_future(cm.delete(path))
         self.set_status(204)
         self.finish()
 
 
 class CheckpointsHandler(IPythonHandler):
 
     SUPPORTED_METHODS = ('GET', 'POST')
 
     @web.authenticated
     @json_errors
+    @gen.coroutine
     def get(self, path=''):
         """get lists checkpoints for a file"""
         cm = self.contents_manager
-        checkpoints = cm.list_checkpoints(path)
+        checkpoints = yield gen.maybe_future(cm.list_checkpoints(path))
         data = json.dumps(checkpoints, default=date_default)
         self.finish(data)
 
     @web.authenticated
     @json_errors
+    @gen.coroutine
     def post(self, path=''):
         """post creates a new checkpoint"""
         cm = self.contents_manager
-        checkpoint = cm.create_checkpoint(path)
+        checkpoint = yield gen.maybe_future(cm.create_checkpoint(path))
         data = json.dumps(checkpoint, default=date_default)
         location = url_path_join(self.base_url, 'api/contents',
             path, 'checkpoints', checkpoint['id'])
         self.set_header('Location', url_escape(location))
         self.set_status(201)
         self.finish(data)
 
 
 class ModifyCheckpointsHandler(IPythonHandler):
 
     SUPPORTED_METHODS = ('POST', 'DELETE')
 
     @web.authenticated
     @json_errors
+    @gen.coroutine
     def post(self, path, checkpoint_id):
         """post restores a file from a checkpoint"""
         cm = self.contents_manager
-        cm.restore_checkpoint(checkpoint_id, path)
+        yield gen.maybe_future(cm.restore_checkpoint(checkpoint_id, path))
         self.set_status(204)
         self.finish()
 
     @web.authenticated
     @json_errors
+    @gen.coroutine
     def delete(self, path, checkpoint_id):
         """delete clears a checkpoint for a given file"""
         cm = self.contents_manager
-        cm.delete_checkpoint(checkpoint_id, path)
+        yield gen.maybe_future(cm.delete_checkpoint(checkpoint_id, path))
         self.set_status(204)
         self.finish()
 
 
 class NotebooksRedirectHandler(IPythonHandler):
     """Redirect /api/notebooks to /api/contents"""
     SUPPORTED_METHODS = ('GET', 'PUT', 'PATCH', 'POST', 'DELETE')
 
     def get(self, path):
         self.log.warn("/api/notebooks is deprecated, use /api/contents")
         self.redirect(url_path_join(
             self.base_url,
             'api/contents',
             path
         ))
 
     put = patch = post = delete = get
 
 
 #-----------------------------------------------------------------------------
 # URL to handler mappings
 #-----------------------------------------------------------------------------
 
 
 _checkpoint_id_regex = r"(?P<checkpoint_id>[\w-]+)"
 
 default_handlers = [
     (r"/api/contents%s/checkpoints" % path_regex, CheckpointsHandler),
     (r"/api/contents%s/checkpoints/%s" % (path_regex, _checkpoint_id_regex),
         ModifyCheckpointsHandler),
     (r"/api/contents%s" % path_regex, ContentsHandler),
     (r"/api/notebooks/?(.*)", NotebooksRedirectHandler),
 ]