Check for duplicate trainee users in one folder

views/trainer/__init__.py

@@ -330,22 +330,41 @@ def add_users_to_folder( folder_id ):
         users_email_list = users_email_list.replace( "\n", ";" ).split( ";" )
 
         for user_email in users_email_list:
-            userid = config.db.query_fetchone( "SELECT nextval( 'username_trainee_seq' ) as id" )[ "id" ]
-            username = "trainee_{}".format( userid )
+            try:
+                sql = """
+                    SELECT count( email ) AS nb
+                    FROM users
+                    LEFT JOIN exercises_trainee_list ON users.id = exercises_trainee_list.user_id
+                    WHERE
+                        exercises_trainee_list.folder = %s AND
+                        email = %s
+                    GROUP BY email
+                """
+                nb = config.db.query_fetchone( sql, ( folder_id, user_email, ) )[ "nb" ]
+            except TypeError:
+                nb = 0
             
-            sql = utils.sql.sql_insert_generate( "users", [ "username", "email", "type" ], "id" )
-            data = ( username, user_email, 7 )
-            trainee_user_id = config.db.query_fetchone( sql, data )[ "id" ]
+            if nb == 0:
+                userid = config.db.query_fetchone( "SELECT nextval( 'username_trainee_seq' ) as id" )[ "id" ]
+                username = "trainee_{}".format( userid )
+                
+                sql = utils.sql.sql_insert_generate( "users", [ "username", "email", "type" ], "id" )
+                data = ( username, user_email, 7 )
+                trainee_user_id = config.db.query_fetchone( sql, data )[ "id" ]
+                
+                sql = utils.sql.sql_insert_generate( "exercises_trainee_list", [ "user_id", "folder" ], "id" )
+                data = ( trainee_user_id, folder_id, )
+                config.db.query_fetchone( sql, data )
             
-            sql = utils.sql.sql_insert_generate( "exercises_trainee_list", [ "user_id", "folder" ], "id" )
-            data = ( trainee_user_id, folder_id, )
-            config.db.query_fetchone( sql, data )
-        
+            else:
+                continue
+
         config.db.commit()
 
         return jsonify( {
             "error": False
         } )
+
     except:
         return jsonify( {
             "error": True