From e75914f9bcf5b74ede57e4dfbcf99a5c8522a9b2 Mon Sep 17 00:00:00 2001
From: Alex Root Junior <jroot.junior@gmail.com>
Date: Thu, 30 Nov 2017 01:53:44 +0200
Subject: [PATCH] Implement throttling manager.

---
 aiogram/dispatcher/throttle.py | 148 +++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 aiogram/dispatcher/throttle.py

diff --git a/aiogram/dispatcher/throttle.py b/aiogram/dispatcher/throttle.py
new file mode 100644
index 00000000..d655c9e2
--- /dev/null
+++ b/aiogram/dispatcher/throttle.py
@@ -0,0 +1,148 @@
+import asyncio
+import time
+
+from aiogram.dispatcher import BaseStorage, Dispatcher, ctx
+
+DEFAULT_RATE_LIMIT = .1
+
+KEY = 'key'
+LAST_CALL = 'called_at'
+RATE_LIMIT = 'rate_limit'
+RESULT = 'result'
+EXCEEDED_COUNT = 'exceeded'
+DELTA = 'delta'
+THROTTLE_MANAGER = '$throttle_manager'
+
+
+class ThrottleError(Exception):
+    def __init__(self, **kwargs):
+        self.key = kwargs.pop(KEY, '<None>')
+        self.called_at = kwargs.pop(LAST_CALL, time.time())
+        self.rate = kwargs.pop(RATE_LIMIT, None)
+        self.result = kwargs.pop(RESULT, False)
+        self.exceeded_count = kwargs.pop(EXCEEDED_COUNT, 0)
+        self.delta = kwargs.pop(DELTA, 0)
+        self.user = kwargs.pop('user', None)
+        self.chat = kwargs.pop('chat', None)
+
+    def __str__(self):
+        return f"Rate limit exceeded! (Limit: {self.rate} s, " \
+               f"exceeded: {self.exceeded_count}, " \
+               f"time delta: {round(self.delta, 3)} s)"
+
+
+class Bucket:
+    """
+    Throttling manager
+    """
+
+    def __init__(self, dispatcher, rate_limit=DEFAULT_RATE_LIMIT, storage: BaseStorage = None, no_error=False):
+        """
+        Initialize throttle manager
+
+        :param dispatcher: instance of Dispatcher
+        :param rate_limit: limit in seconds
+        :param storage:
+        :param no_error: return boolean value instead of raising error
+        """
+        if storage is None:
+            storage = dispatcher.storage
+        if not storage.has_bucket():
+            raise TypeError('This storage does not provide Bucket!')
+
+        self._dispatcher: Dispatcher = dispatcher
+        self._loop: asyncio.BaseEventLoop = self._dispatcher.loop
+        self._rate_limit = rate_limit
+        self._storage = storage
+        self._no_error = no_error
+
+        dispatcher.bot[THROTTLE_MANAGER] = self
+
+    async def throttle(self, key, *, rate=None, user=None, chat=None, no_error=None) -> bool:
+        """
+        Execute throttling manager.
+        Return True limit is not exceeded otherwise raise ThrottleError or return False
+
+        :param key: key in storage
+        :param rate: limit (by default is equals with default rate limit)
+        :param user: user id
+        :param chat: chat id
+        :param no_error: return boolean value instead of raising error
+        :return: bool
+        """
+        if no_error is None:
+            no_error = self._no_error
+        if rate is None:
+            rate = self._rate_limit
+        if user is None and chat is None:
+            user = ctx.get_user()
+            chat = ctx.get_chat()
+
+        # Detect current time
+        now = time.time()
+
+        bucket = await self._storage.get_bucket(chat=chat, user=user)
+
+        # Fix bucket
+        if bucket is None:
+            bucket = {key: {}}
+        if key not in bucket:
+            bucket[key] = {}
+        data = bucket[key]
+
+        # Calculate
+        called = data.get(LAST_CALL, now)
+        delta = now - called
+        result = delta >= rate or delta <= 0
+
+        # Save results
+        data[RESULT] = result
+        data[RATE_LIMIT] = rate
+        data[LAST_CALL] = now
+        data[DELTA] = delta
+        if not result:
+            data[EXCEEDED_COUNT] += 1
+        else:
+            data[EXCEEDED_COUNT] = 1
+        bucket[key].update(data)
+        await self._storage.set_bucket(chat=chat, user=user, bucket=bucket)
+
+        if not result and not no_error:
+            # Raise if that is allowed
+            raise ThrottleError(key=key, chat=chat, user=user, **data)
+        return result
+
+    async def release_key(self, key, chat=None, user=None):
+        """
+        Release blocked key
+
+        :param key:
+        :param chat:
+        :param user:
+        :return:
+        """
+        if user is None and chat is None:
+            user = ctx.get_user()
+            chat = ctx.get_chat()
+        bucket = await self._storage.get_bucket(chat=chat, user=user)
+        if bucket and key in bucket:
+            del bucket['key']
+            await self._storage.set_bucket(chat=chat, user=user, bucket=bucket)
+            return True
+        return False
+
+
+async def throttle(key, rate=None, no_error=None):
+    """
+    Alias for Bucket.throttle(...)
+
+    :param key:
+    :param rate:
+    :param no_error:
+    :return:
+    """
+    bot = ctx.get_bot()
+    bucket = bot.get(THROTTLE_MANAGER)
+    if not bucket:
+        raise RuntimeError('Can\'t be found Bucket!')
+    return await bucket.throttle(key=key, rate=rate, no_error=no_error)