feat: add Serve version to accept flag

__init__.py

@@ -0,0 +1,86 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# @Date    : 2018/2/14 12:56
+# @Author  : Xu
+# @Site    : https://xuccc.github.io/
+# @Version : $
+
+import arrow
+
+from flask import render_template, Blueprint
+from flask import request, jsonify
+
+from CTFd.plugins.keys import BaseKey,KEY_CLASSES
+from CTFd.models import db, Keys
+from CTFd.utils import admins_only, is_admin
+
+dynamic = Blueprint('dynamic', __name__)
+
+
+class DynamicKey(BaseKey):
+    id = 2
+    name = "dynamic"
+
+    @staticmethod
+    def compare(saved, provided):
+        if len(saved) != len(provided):
+            return False
+        result = 0
+        for x, y in zip(saved, provided):
+            result |= ord(x) ^ ord(y)
+        return result == 0
+
+
+def filter(token=None):
+    k = Keys.query.filter_by(data=token).first()
+    return k
+
+def save(k, flag):
+    """
+
+    :param k: class 'CTFd.models.Keys'
+    :param token:
+    :param flag:
+    :return:
+    """
+    k.flag = flag
+    db.session.commit()
+    db.session.close()
+    return True
+
+
+def load(app):
+    @dynamic.route('/dynamic/keys', methods=['POST', 'GET'])
+    def show():
+        if request.method == 'GET':
+            flag = request.args.get('flag')
+            token = request.args.get('token')
+            time = request.args.get('time')
+            if flag and token and time:
+                k = filter(token)
+                if k is not None:
+                    data = {
+                        'check': True,
+                        'old'  : k.flag,
+                        'new'  : flag,
+                        'time' : time or arrow.now().timestamp
+                    }
+                    save(k,flag)
+                else:
+                    data = {
+                        'check' : False,
+                        'reason': 'token wrong',
+                        'time'  : time or arrow.now().timestamp
+                    }
+                return jsonify(data)
+            else:
+                return jsonify({'check': 'wrong'})
+        elif request.method == 'POST':
+            # TODO
+            data = {}
+            return jsonify(data)
+
+
+    KEY_CLASSES['dynamic'] = DynamicKey
+    app.register_blueprint(dynamic)
+