DEV: Validate models returned from ContentsManager methods.

IPython/html/services/contents/handlers.py

@@ -1,266 +1,312
 """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 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):
+    required_keys = {
+        "name"
+        , "path"
+        , "type"
+        , "writable"
+        , "created"
+        # Note: This key is specified as just 'modified' in IPEP-27
+        , "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),
+        )
+
+    # Note: Per IPEP-27, 'mimetype' should be present in this list.
+    maybe_none_keys = ['content', 'format']
+    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 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
     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)
         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
     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)
+        validate_model(model, expect_content=False)
         self._finish_model(model)
 
     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)
         self.set_status(201)
+        validate_model(model, expect_content=False)
         self._finish_model(model)
 
     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)
         self.set_status(201)
+        validate_model(model, expect_content=False)
         self._finish_model(model)
         
     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)
         self.set_status(201)
+        validate_model(model, expect_content=False)
         self._finish_model(model)
 
     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)
+        validate_model(model, expect_content=False)
         self._finish_model(model)
 
     @web.authenticated
     @json_errors
     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)
             else:
                 self._new_untitled(path, type=type, ext=ext)
         else:
             self._new_untitled(path)
 
     @web.authenticated
     @json_errors
     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)
             else:
                 self._upload(model, path)
         else:
             self._new_untitled(path)
 
     @web.authenticated
     @json_errors
     def delete(self, path=''):
         """delete a file in the given path"""
         cm = self.contents_manager
         self.log.warn('delete %s', path)
         cm.delete(path)
         self.set_status(204)
         self.finish()
 
 
 class CheckpointsHandler(IPythonHandler):
 
     SUPPORTED_METHODS = ('GET', 'POST')
 
     @web.authenticated
     @json_errors
     def get(self, path=''):
         """get lists checkpoints for a file"""
         cm = self.contents_manager
         checkpoints = cm.list_checkpoints(path)
         data = json.dumps(checkpoints, default=date_default)
         self.finish(data)
 
     @web.authenticated
     @json_errors
     def post(self, path=''):
         """post creates a new checkpoint"""
         cm = self.contents_manager
         checkpoint = 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
     def post(self, path, checkpoint_id):
         """post restores a file from a checkpoint"""
         cm = self.contents_manager
         cm.restore_checkpoint(checkpoint_id, path)
         self.set_status(204)
         self.finish()
 
     @web.authenticated
     @json_errors
     def delete(self, path, checkpoint_id):
         """delete clears a checkpoint for a given file"""
         cm = self.contents_manager
         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),
 ]