improve error messages

src/agenda_culturel/importation.py

@@ -12,18 +12,36 @@ class EventsImporter:
 
         try:
             structure = json.loads(json_structure)
-
-            self.url = structure["header"]["url"]
-            self.date = structure["header"]["date"]
         except:
             return (False, "JSON file is not correctly structured")
 
+        if not "header" in structure:
+            return (False, "JSON is not correctly structured: missing header")
+
+        if "url" in structure["header"]:
+            self.url = structure["header"]["url"]
+        else:
+            return (False, "JSON is not correctly structured: missing url in header")
+
+        if "url" in structure["header"]:
+            self.date = structure["header"]["date"]
+
         # load events
         for event in structure["events"]:
             self.import_event(event)
 
+        # update object with infos from header, and with the list of imported objects
+        # TODO
+
+        # events that are missing from the import but in database are turned into drafts
+        # TODO
+
+        return (True, "")
+
     
     def import_event(self, event):
+        # TODO
+
         pass