Add task completion mails

src/util/ratelimit-taskdonemail.ts

@@ -0,0 +1,63 @@
+/*
+ * server component for the TimeLimit App
+ * Copyright (C) 2019 - 2020 Jonas Lochmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import { RateLimiterAbstract, RateLimiterMemory } from 'rate-limiter-flexible'
+
+const individualMailLimitMinute: RateLimiterAbstract = new RateLimiterMemory({
+  keyPrefix: 'timelimit:sendmail-taskdone:individual:minute',
+  points: 1,
+  duration: 60  // 1 minute
+})
+
+const individualMailLimitFiveMinutes: RateLimiterAbstract = new RateLimiterMemory({
+  keyPrefix: 'timelimit:sendmail-taskdone:individual:fiveminutes',
+  points: 3,
+  duration: 60 * 5  // 5 minutes
+})
+
+const individualMailLimitHourly: RateLimiterAbstract = new RateLimiterMemory({
+  keyPrefix: 'timelimit:sendmail-taskdone:individual:hourly',
+  points: 5,
+  duration: 60 * 60  // 1 hour
+})
+
+const individualMailLimitDay: RateLimiterAbstract = new RateLimiterMemory({
+  keyPrefix: 'timelimit:sendmail-taskdone:individual:day',
+  points: 10,
+  duration: 60 * 60 * 24  // 1 day
+})
+
+const checkIndividualMailSendLimit = async (receiver: string) => {
+  await individualMailLimitMinute.consume(receiver)
+  await individualMailLimitFiveMinutes.consume(receiver)
+  await individualMailLimitHourly.consume(receiver)
+  await individualMailLimitDay.consume(receiver)
+}
+
+const checkMailSendLimit = async (receiver: string) => {
+  await checkIndividualMailSendLimit(receiver)
+}
+
+export const canSendTaskDoneMail = async (receiver: string) => {
+  try {
+    await checkMailSendLimit(receiver)
+
+    return true
+  } catch (ex) {
+    return false
+  }
+}