judge, problem_settings, problem_upload

hydro/service/db.js

@@ -10,6 +10,7 @@ let db = null;
 Mongo.MongoClient.connect(mongourl, { useNewUrlParser: true, useUnifiedTopology: true })
     .then(Database => {
         db = Database.db(options.db.name);
+        db.Db = Database;
         global.bus.emit('connected');
     });
 

hydro/service/gridfs.js

@@ -0,0 +1,5 @@
+const
+    { GridFSBucket } = require('mongodb'),
+    db = require('./db');
+if (!db.s) db.s = {};
+module.exports = new GridFSBucket(db);

hydro/service/server.js

@@ -12,7 +12,12 @@ let app = new Koa();
 let server = http.createServer(app.callback());
 app.keys = options.session.keys;
 app.use(morgan(':method :url :status :res[content-length] - :response-time ms'));
-app.use(Body());
+app.use(Body({
+    multipart: true,
+    formidable: {
+        maxFileSize: 256 * 1024 * 1024
+    }
+}));
 let router = new Router();
 
 /**