Added property prompts to xblock.

TNL-708

openassessment/xblock/data_conversion.py

@@ -2,6 +2,7 @@
 Data Conversion utility methods for handling ORA2 XBlock data transformations.
 
 """
+import json
 
 
 def convert_training_examples_list_to_dict(examples_list):
@@ -56,13 +57,42 @@ def convert_training_examples_list_to_dict(examples_list):
     ]
 
 
-def create_rubric_dict(prompt, criteria):
+def create_prompts_list(prompt_or_serialized_prompts):
+    """
+    Construct a list of prompts.
+
+    Initially a block had a single prompt which was saved as a simple string.
+    In that case a new prompt dict is constructed from it.
+
+    Args:
+        prompt_or_serialized_prompts (unicode): A string which can either
+        be a single prompt text or json for a list of prompts.
+
+    Returns:
+        list of dict
+    """
+
+    if prompt_or_serialized_prompts is None:
+        prompt_or_serialized_prompts = ''
+
+    try:
+        prompts = json.loads(prompt_or_serialized_prompts)
+    except ValueError:
+        prompts = [
+            {
+                'description': prompt_or_serialized_prompts,
+            }
+        ]
+    return prompts
+
+
+def create_rubric_dict(prompts, criteria):
     """
     Construct a serialized rubric model in the format expected
     by the assessments app.
 
     Args:
-        prompt (unicode): The rubric prompt.
+        prompts (list of dict): The rubric prompts.
         criteria (list of dict): The serialized rubric criteria.
 
     Returns:
@@ -70,7 +100,7 @@ def create_rubric_dict(prompt, criteria):
 
     """
     return {
-        "prompt": prompt,
+        "prompts" : prompts,
         "criteria": criteria
     }
 

openassessment/xblock/openassessmentblock.py

@@ -31,7 +31,7 @@ from openassessment.workflow.errors import AssessmentWorkflowError
 from openassessment.xblock.student_training_mixin import StudentTrainingMixin
 from openassessment.xblock.validation import validator
 from openassessment.xblock.resolve_dates import resolve_dates, DISTANT_PAST, DISTANT_FUTURE
-from openassessment.xblock.data_conversion import create_rubric_dict
+from openassessment.xblock.data_conversion import create_prompts_list, create_rubric_dict
 
 
 logger = logging.getLogger(__name__)
@@ -144,7 +144,7 @@ class OpenAssessmentBlock(
     prompt = String(
         default=DEFAULT_PROMPT,
         scope=Scope.content,
-        help="A prompt to display to a student (plain text)."
+        help="The prompts to display to a student."
     )
 
     rubric_criteria = List(
@@ -445,6 +445,40 @@ class OpenAssessmentBlock(
         return i18nService.ugettext
 
     @property
+    def prompts(self):
+        """
+        Return the prompts.
+
+        Initially a block had a single prompt which was saved as a simple
+        string in the prompt field. Now prompts are saved as a serialized
+        list of dicts in the same field. If prompt field contains valid json,
+        parse and return it. Otherwise, assume it is a simple string prompt
+        and return it in a list of dict.
+
+        Returns:
+            list of dict
+        """
+        return create_prompts_list(self.prompt)
+
+    @prompts.setter
+    def prompts(self, value):
+        """
+        Serialize the prompts and save to prompt field.
+
+        Args:
+            value (list of dict): The prompts to set.
+        """
+
+        if value is None:
+            self.prompt = ''
+        elif len(value) == 1:
+            # For backwards compatibility. To be removed after all code
+            # is migrated to use prompts property instead of prompt field.
+            self.prompt = value[0]['description']
+        else:
+            self.prompt = json.dumps(value)
+
+    @property
     def valid_assessments(self):
         """
         Return a list of assessment dictionaries that we recognize.