Make tests pass when running on cms

common/lib/keystore/__init__.py

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+"""
+This module provides an abstraction for working objects that conceptually have
+the following attributes:
+
+    location: An identifier for an item, of which there might be many revisions
+    children: A list of urls for other items required to fully define this object
+    data: A set of nested data needed to define this object
+    editor: The editor/owner of the object
+    parents: Url pointers for objects that this object was derived from
+    revision: What revision of the item this is
+"""
+
+
+class Location(object):
+    ''' Encodes a location.
+        Can be:
+        * String (url)
+        * Tuple
+        * Dictionary
+    '''
+    def __init__(self, location):
+        self.update(location)
+
+    def update(self, location):
+        if isinstance(location, basestring):
+            self.tag = location.split('/')[0][:-1]
+            (self.org, self.course, self.category, self.name) = location.split('/')[2:]
+        elif isinstance(location, list):
+            (self.tag, self.org, self.course, self.category, self.name) = location
+        elif isinstance(location, dict):
+            self.tag = location['tag']
+            self.org = location['org']
+            self.course = location['course']
+            self.category = location['category']
+            self.name = location['name']
+        elif isinstance(location, Location):
+            self.update(location.list())
+
+    def url(self):
+        return "{tag}://{org}/{course}/{category}/{name}".format(**self.dict())
+
+    def list(self):
+        return [self.tag, self.org, self.course, self.category, self.name]
+
+    def dict(self):
+        return {'tag': self.tag,
+                'org': self.org,
+                'course': self.course,
+                'category': self.category,
+                'name': self.name}
+
+    def to_json(self):
+        return self.dict()
+
+
+class KeyStore(object):
+    def get_item(self, location):
+        """
+        Returns an XModuleDescriptor instance for the item at location
+
+        If no object is found at that location, raises keystore.exceptions.ItemNotFoundError
+
+        Searches for all matches of a partially specifed location, but raises an
+        keystore.exceptions.InsufficientSpecificationError if more
+        than a single object matches the query.
+
+        location: Something that can be passed to Location
+        """
+        raise NotImplementedError
+
+    def create_item(self, location, editor):
+        """
+        Create an empty item at the specified location with the supplied editor
+
+        location: Something that can be passed to Location
+        """
+        raise NotImplementedError
+
+    def update_item(self, location, data):
+        """
+        Set the data in the item specified by the location to
+        data
+
+        location: Something that can be passed to Location
+        data: A nested dictionary of problem data
+        """
+        raise NotImplementedError
+
+    def update_children(self, location, children):
+        """
+        Set the children for the item specified by the location to
+        data
+
+        location: Something that can be passed to Location
+        children: A list of child item identifiers
+        """
+        raise NotImplementedError
+
+
+class KeyStoreItem(object):
+    """
+    An object from a KeyStore, which can be saved back to that keystore
+    """
+    def __init__(self, location, children, data, editor, parents, revision):
+        self.location = location
+        self.children = children
+        self.data = data
+        self.editor = editor
+        self.parents = parents
+        self.revision = revision
+
+    def save(self):
+        raise NotImplementedError

common/lib/keystore/django.py

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+"""
+Module that provides a connection to the keystore specified in the django settings.
+
+Passes settings.KEYSTORE as kwargs to MongoKeyStore
+"""
+
+from __future__ import absolute_import
+
+from django.conf import settings
+from .mongo import MongoKeyStore
+
+keystore = MongoKeyStore(**settings.KEYSTORE)

common/lib/keystore/exceptions.py

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+"""
+Exceptions thrown by KeyStore objects
+"""
+
+
+class ItemNotFoundError(Exception):
+    pass
+
+
+class InsufficientSpecificationError(Exception):
+    pass

common/lib/keystore/mongo.py

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+import pymongo
+from . import KeyStore, Location
+from .exceptions import ItemNotFoundError, InsufficientSpecificationError
+from xmodule.x_module import XModuleDescriptor
+
+
+class MongoKeyStore(KeyStore):
+    """
+    A Mongodb backed KeyStore
+    """
+    def __init__(self, host, db, collection, port=27017):
+        self.collection = pymongo.connection.Connection(
+            host=host,
+            port=port
+        )[db][collection]
+
+        # Force mongo to report errors, at the expense of performance
+        self.collection.safe = True
+
+    def get_item(self, location):
+        """
+        Returns an XModuleDescriptor instance for the item at location
+
+        If no object is found at that location, raises keystore.exceptions.ItemNotFoundError
+
+        Searches for all matches of a partially specifed location, but raises an
+        keystore.exceptions.InsufficientSpecificationError if more
+        than a single object matches the query.
+
+        location: Something that can be passed to Location
+        """
+        query = dict(
+            ('location.{key}'.format(key=key), val)
+            for (key, val)
+            in Location(location).dict().items()
+            if val is not None
+        )
+        items = self.collection.find(
+            query,
+            sort=[('revision', pymongo.ASCENDING)],
+            limit=1,
+        )
+        if items.count() > 1:
+            raise InsufficientSpecificationError(location)
+
+        if items.count() == 0:
+            raise ItemNotFoundError(location)
+
+        return XModuleDescriptor.load_from_json(items[0], self.get_item)
+
+    def create_item(self, location, editor):
+        """
+        Create an empty item at the specified location with the supplied editor
+
+        location: Something that can be passed to Location
+        """
+        self.collection.insert({
+            'location': Location(location).dict(),
+            'editor': editor
+        })
+
+    def update_item(self, location, data):
+        """
+        Set the data in the item specified by the location to
+        data
+
+        location: Something that can be passed to Location
+        data: A nested dictionary of problem data
+        """
+        self.collection.update(
+            {'location': Location(location).dict()},
+            {'$set': {'data': data}}
+        )
+
+    def update_children(self, location, children):
+        """
+        Set the children for the item specified by the location to
+        data
+
+        location: Something that can be passed to Location
+        children: A list of child item identifiers
+        """
+        self.collection.update(
+            {'location': Location(location).dict()},
+            {'$set': {'children': children}}
+        )