Add assignment mutation on server side

server/assignments/schema/inputs.py

@@ -0,0 +1,7 @@
+import graphene
+from graphene import InputObjectType
+
+
+class AssignmentInput(InputObjectType):
+    id = graphene.ID(required=True)
+    answer = graphene.String(required=True)

server/assignments/schema/mutations.py

@@ -0,0 +1,28 @@
+from graphene import relay
+import graphene
+
+from api.utils import get_object
+from assignments.models import Assignment
+from assignments.schema.types import AssignmentNode
+from .inputs import AssignmentInput
+
+
+class UpdateAssignment(relay.ClientIDMutation):
+    class Input:
+        assignment = graphene.Argument(AssignmentInput)
+
+    updated_assignment = graphene.Field(AssignmentNode)
+    errors = graphene.List(graphene.String)
+
+    @classmethod
+    def mutate_and_get_payload(cls, root, info, **kwargs):
+        assignment_data = kwargs.get('assignment')
+        assignment = get_object(Assignment, assignment_data.get('id'))
+        (submission, created) = assignment.submissions.get_or_create(student=info.context.user)
+        submission.text = assignment_data.get('answer')
+        submission.save()
+        return cls(updated_assignment=assignment, errors=None)
+
+
+class AssignmentMutations(object):
+    update_assignment = UpdateAssignment.Field()

server/assignments/schema/types.py

@@ -0,0 +1,23 @@
+import graphene
+from graphene import relay
+from graphene_django import DjangoObjectType
+
+from assignments.models import Assignment, StudentSubmission
+
+
+class StudentSubmissionNode(DjangoObjectType):
+    class Meta:
+        model = StudentSubmission
+        interfaces = (relay.Node,)
+
+
+class AssignmentNode(DjangoObjectType):
+    submission = graphene.Field(StudentSubmissionNode)
+    submissions = graphene.List(StudentSubmissionNode)
+
+    class Meta:
+        model = Assignment
+        interfaces = (relay.Node,)
+
+    def resolve_submission(self, info, **kwargs):
+        return self.submissions.get(student=info.context.user)