Fix exceptions raised when a lazy text is used in json dump

openedx/core/lib/json_utils.py

@@ -0,0 +1,29 @@
+"""
+Helpers for json serialization
+"""
+
+import datetime
+from django.core.serializers.json import DjangoJSONEncoder
+from opaque_keys.edx.keys import CourseKey, UsageKey
+
+
+class EdxJSONEncoder(DjangoJSONEncoder):
+    """
+    Custom JSONEncoder that handles `Location` and `datetime.datetime` objects.
+
+    `Location`s are encoded as their url string form, and `datetime`s as
+    ISO date strings
+    """
+    def default(self, o):  # pylint: disable=method-hidden
+        if isinstance(o, (CourseKey, UsageKey)):
+            return unicode(o)
+        elif isinstance(o, datetime.datetime):
+            if o.tzinfo is not None:
+                if o.utcoffset() is None:
+                    return o.isoformat() + 'Z'
+                else:
+                    return o.isoformat()
+            else:
+                return o.isoformat()
+        else:
+            return super(EdxJSONEncoder, self).default(o)