Merge branch 'master' into threads

HOW-TO-UPDATE.md

@@ -0,0 +1,31 @@
+# How to Update `piazza-link-bot`
+
+So you've got an outdated Piazza bot, huh? Well don't worry, here's how to quickly update your deployment!
+
+## Method A: Command Line
+
+This is the most straightforward method. It requires that you have the heroku CLI installed.
+
+1. Check to see if any new Environment variables were added in the update. If so, you should update these in your Heroku app's settings before proceeding.
+1. Clone the up-to-date `piazza-link-bot` repo to your local machine
+    ```
+    $ git clone https://github.com/BGR360/piazza-link-bot
+    ```
+1. Force push the code directly to your Heroku app instance
+    ```
+    $ heroku login
+	$ git remote add heroku https://git.heroku.com/YOUR-PIAZZA-LINK-BOT-APP-NAME.git
+	$ git push -f heroku master
+    ```
+
+## Method B: Fork and Browser
+
+If you really don't wanna install Heroku CLI, then you can try this method.
+
+1. Check to see if any new Environment variables were added in the update. If so, you should update these in your Heroku app's settings before proceeding.
+1. Fork this repo to your GitHub account.
+1. Go to your heroku dashboard and click on your piazza link bot app.
+1. Go to the "Deploy" menu.
+1. Under "Deployment method", select GitHub as the option.
+1. Grant Heroku permissions.
+1. Select your fork of the repo and use that to deploy.

README.md

@@ -9,8 +9,15 @@ Based on [regexbot](https://github.com/sjmelia/regexbot) by sjmelia.
 
 ![Example image](https://i.gyazo.com/3fbcb71b81845b5ca65cef08af1334d8.png)
 
+
+Got an out-of-date deployment?
+------------------------------
+
+Go to [HOW-TO-UPDATE.md](HOW_TO_UPDATE.md) for instructions on how to update your deployment to the latest version.
+
+
 Full instructions
------
+-----------------
 
 ### Create Slack App
 

app.json

@@ -28,8 +28,11 @@
     },
     "REPLY_AS_THREAD": {
             "description": "Should the bot reply as a thread? Leave empty for no, put any value for yes.",
-            "required": false,
-            "value": "LEAVE EMPTY FOR NO, PUT ANY VALUE FOR YES"
+            "required": false
     },
+    "RETRY_MEMORY": {
+            "description": "Number of message ids to hold in memory to prevent duplicate messages (linear search involved) (default=100)",
+            "required": false
+    }
   }
 }

package.json

@@ -1,13 +1,12 @@
 {
-  "name": "regexbot",
+  "name": "piazza-link-bot",
   "version": "1.0.0",
-  "description": "Regular expression responder for slack",
-  "repository": "https://github.com/sjmelia/regexbot",
+  "description": "Slackbot that responds with links to Piazza posts",
+  "repository": "https://github.com/bgr360/piazza-link-bot",
   "main": "src/index.js",
   "dependencies": {
     "@slack/client": "^4.8.0",
     "@slack/events-api": "^2.1.1",
-    "app.json": "^1.3.0",
     "jira-client": "^4.2.0",
     "node-schedule": "^1.2.0"
   },
@@ -25,6 +24,6 @@
     "start": "node src/index.js",
     "test": "eslint src && mocha"
   },
-  "author": "Steve Melia",
+  "author": "Ben Reeves",
   "license": "MIT"
 }

src/config.js

@@ -27,6 +27,9 @@ var config = {
 
   schedules: [],
 
+  // Number of message ids to keep in memory in order to prevent duplicate replies.
+  retryMemory: process.env['RETRY_MEMORY'] || 100,
+
   build: function (id) {
     this.regexes.push({ regex: /@(\d+)/g, message: this.piazza_base_url + '?cid=[1]' });
   }

src/index.js

@@ -1,10 +1,12 @@
 /* vim: set ft=javascript ts=2 et sw=2 tw=80: */
 var config = require('./config');
 var RegexBot = require('./regexbot');
+var RetryFilter = require('./retryfilter');
 var randomiser = function (max) {
   return Math.floor(Math.random() * max);
 };
 var regexbot = new RegexBot(config, randomiser);
+var retryFilter = new RetryFilter(config);
 
 const { RTMClient, WebClient, ErrorCode } = require('@slack/client');
 const { createEventAdapter } = require('@slack/events-api');
@@ -43,25 +45,35 @@ client.on('message', (message) => {
 
   console.log('Accepted a message: ' + JSON.stringify(message));
 
-  regexbot.respond(message.text, (reply) => {
-    console.log('Responding with: ' + reply);
+  function messageOkay (message) {
+    // Make the retry filter remember this message
+    retryFilter.addMessage(message);
 
-    var replyMessage = {
-      channel: message.channel,
-      text: reply,
-      as_user: true
-    };
+    regexbot.respond(message.text, (reply) => {
+      console.log('Responding with: ' + reply);
 
-    // If bot is configured to reply as a thread, or if the message that 
-    // triggered the bot was already a threaded reply, then add a 'thread_ts'
-    // so that the bot replies inside the thread.
-    if (config.reply_as_thread || message.thread_ts !== undefined) {
-      console.log("has it!")
-      replyMessage.thread_ts = message.thread_ts || message.ts;
-    }
+      var replyMessage = {
+        channel: message.channel,
+        text: reply,
+        as_user: true
+      };
 
-    postMessage(replyMessage);
-  });
+      // If bot is configured to reply as a thread, or if the message that
+      // triggered the bot was already a threaded reply, then add a 'thread_ts'
+      // so that the bot replies inside the thread.
+      if (config.reply_as_thread || message.thread_ts !== undefined) {
+        replyMessage.thread_ts = message.thread_ts || message.ts;
+      }
+
+      postMessage(replyMessage);
+    });
+  };
+
+  function messageIsDuplicate (message) {
+    console.log('Message is a duplicate');
+  }
+
+  retryFilter.filter(message, messageOkay, messageIsDuplicate);
 });
 
 client.on('error', console.error);

src/retryfilter.js

@@ -0,0 +1,71 @@
+/**
+ * Slack API will retry messages if they take too long.
+ * When a Heroku dyno is starting up, it typically receives
+ * the same message 3 times due to this retry, causing the bot
+ * to send 3 identical replies. This is a solution to this problem.
+ *
+ * SECURITY / PRIVACY NOTE:
+ * None of the contents of messages are kept in memory longer than needed.
+ * Only the unique timestamp and channel id of the message are stored
+ * in the previousMessages array.
+ */
+function RetryFilter (config) {
+  this.config = config;
+  this.previousMessages = [];
+
+  this.addMessage = addMessage;
+  this.filter = filter;
+  this.isRetry = isRetry;
+
+  /**
+   * Adds a message to the memory and removes an old one if necessary.
+   * Returns the message that was popped from the front, if it was, otherwise null.
+   */
+  function addMessage (message) {
+    this.previousMessages.push({
+      ts: message.ts,
+      channel: message.channel
+    });
+
+    // Remove first item of array if array too big
+    while (this.previousMessages.length > this.config.retryMemory) {
+      let popped = this.previousMessages[0];
+      this.previousMessages.shift();
+      return popped;
+    }
+
+    return null;
+  }
+
+  /**
+   * Calls callback only if the message is not a repeat,
+   * otherwise calls ifRetry
+   */
+  function filter (message, callback, ifRetry) {
+    if (this.isRetry(message)) {
+      if (ifRetry !== undefined) {
+        ifRetry(message);
+      }
+    } else {
+      callback(message);
+    }
+  }
+
+  function isRetry (message) {
+    if (this.previousMessages.length === 0) {
+      return false;
+    }
+
+    // Search through to see if any of them have the same timestamp and channel number
+    for (let i = 0; i < this.previousMessages.length; i++) {
+      let prevMsg = this.previousMessages[i];
+      if (prevMsg.ts === message.ts && prevMsg.channel === message.channel) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+}
+
+module.exports = RetryFilter;