submission exists api

submission/urls/oj.py

@@ -1,9 +1,10 @@
 from django.conf.urls import url
 
-from ..views.oj import SubmissionAPI, SubmissionListAPI, ContestSubmissionListAPI
+from ..views.oj import SubmissionAPI, SubmissionListAPI, ContestSubmissionListAPI, SubmissionExistsAPI
 
 urlpatterns = [
     url(r"^submission/?$", SubmissionAPI.as_view(), name="submission_api"),
     url(r"^submissions/?$", SubmissionListAPI.as_view(), name="submission_list_api"),
+    url(r"^submission_exists/?$", SubmissionExistsAPI.as_view(), name="submission_exists"),
     url(r"^contest_submissions/?$", ContestSubmissionListAPI.as_view(), name="contest_submission_list_api"),
 ]

submission/views/oj.py

@@ -200,3 +200,12 @@ class ContestSubmissionListAPI(APIView):
         data = self.paginate_data(request, submissions)
         data["results"] = SubmissionListSerializer(data["results"], many=True, user=request.user).data
         return self.success(data)
+
+
+class SubmissionExistsAPI(APIView):
+    def get(self, request):
+        if not request.GET.get("problem_id"):
+            return self.error("Parameter error, problem_id is required")
+        return self.success(request.user.is_authenticated and
+                            Submission.objects.filter(problem_id=request.GET["problem_id"],
+                                                      user_id=request.user.id).exists())