Merge pull request #156 from MRuy/147-add-cache-for-gettopusers

Add cache for getTopUsers

config.json.example

@@ -23,6 +23,7 @@
     "readOnly": false,
     "webhooks": [],
     "categoryList": ["sponsor", "intro", "outro", "interaction", "selfpromo", "music_offtopic"], // List of supported categories any other category will be rejected
+    "getTopUsersCacheTimeMinutes": 5, // cacheTime for getTopUsers result in minutes
     "maxNumberOfActiveWarnings": 3, // Users with this number of warnings will be blocked until warnings expire
     "hoursAfterWarningExpire": 24,
     "rateLimit": {

src/routes/getTopUsers.js

@@ -1,6 +1,68 @@
 var db = require('../databases/databases.js').db;
+const logger = require('../utils/logger.js');
+const createMemoryCache = require('../utils/createMemoryCache.js');
+const config = require('../config.js');
 
-module.exports = function getTopUsers (req, res) {
+const MILLISECONDS_IN_MINUTE = 60000;
+const getTopUsersWithCache = createMemoryCache(generateTopUsersStats, config.getTopUsersCacheTimeMinutes * MILLISECONDS_IN_MINUTE);
+
+function generateTopUsersStats(sortBy, categoryStatsEnabled = false) {
+  return new Promise((resolve, reject) => {
+    const userNames = [];
+    const viewCounts = [];
+    const totalSubmissions = [];
+    const minutesSaved = [];
+    const categoryStats = categoryStatsEnabled ? [] : undefined;
+    
+    let additionalFields = '';
+    if (categoryStatsEnabled) {
+      additionalFields += "SUM(CASE WHEN category = 'sponsor' THEN 1 ELSE 0 END) as categorySponsor, " +
+                          "SUM(CASE WHEN category = 'intro' THEN 1 ELSE 0 END) as categorySumIntro, " +
+                          "SUM(CASE WHEN category = 'outro' THEN 1 ELSE 0 END) as categorySumOutro, " +
+                          "SUM(CASE WHEN category = 'interaction' THEN 1 ELSE 0 END) as categorySumInteraction, " +
+                          "SUM(CASE WHEN category = 'selfpromo' THEN 1 ELSE 0 END) as categorySelfpromo, " +
+                          "SUM(CASE WHEN category = 'music_offtopic' THEN 1 ELSE 0 END) as categoryMusicOfftopic, ";
+    }
+
+    const rows = db.prepare('all', "SELECT COUNT(*) as totalSubmissions, SUM(views) as viewCount," + 
+                    "SUM((sponsorTimes.endTime - sponsorTimes.startTime) / 60 * sponsorTimes.views) as minutesSaved, " +
+                    "SUM(votes) as userVotes, " +
+                    additionalFields +
+                    "IFNULL(userNames.userName, sponsorTimes.userID) as userName FROM sponsorTimes LEFT JOIN userNames ON sponsorTimes.userID=userNames.userID " +
+                    "LEFT JOIN privateDB.shadowBannedUsers ON sponsorTimes.userID=privateDB.shadowBannedUsers.userID " +
+                    "WHERE sponsorTimes.votes > -1 AND sponsorTimes.shadowHidden != 1 AND privateDB.shadowBannedUsers.userID IS NULL " +
+                    "GROUP BY IFNULL(userName, sponsorTimes.userID) HAVING userVotes > 20 " +
+                    "ORDER BY " + sortBy + " DESC LIMIT 100", []);
+    
+    for (let i = 0; i < rows.length; i++) {
+        userNames[i] = rows[i].userName;
+
+        viewCounts[i] = rows[i].viewCount;
+        totalSubmissions[i] = rows[i].totalSubmissions;
+        minutesSaved[i] = rows[i].minutesSaved;
+        if (categoryStatsEnabled) {
+          categoryStats[i] = [
+            rows[i].categorySponsor,
+            rows[i].categorySumIntro,
+            rows[i].categorySumOutro,
+            rows[i].categorySumInteraction,
+            rows[i].categorySelfpromo,
+            rows[i].categoryMusicOfftopic,
+          ];
+        }
+    }
+    
+    resolve({
+      userNames,
+      viewCounts,
+      totalSubmissions,
+      minutesSaved,
+      categoryStats
+    });
+  });
+}
+
+module.exports = async function getTopUsers (req, res) {
   let sortType = req.query.sortType;
   let categoryStatsEnabled = req.query.categoryStats;
 
@@ -9,71 +71,22 @@ module.exports = function getTopUsers (req, res) {
       res.sendStatus(400);
       return;
   }
-
+  
   //setup which sort type to use
-  let sortBy = "";
+  let sortBy = '';
   if (sortType == 0) {
-      sortBy = "minutesSaved";
+    sortBy = 'minutesSaved';
   } else if (sortType == 1) {
-      sortBy = "viewCount";
+    sortBy = 'viewCount';
   } else if (sortType == 2) {
-      sortBy = "totalSubmissions";
+    sortBy = 'totalSubmissions';
   } else {
-      //invalid request
+    //invalid request
-      res.sendStatus(400);
+    return res.sendStatus(400);
-      return;
   }
-
-  let userNames = [];
-  let viewCounts = [];
-  let totalSubmissions = [];
-  let minutesSaved = [];
-  let categoryStats = categoryStatsEnabled ? [] : undefined;
   
-  let additionalFields = '';
+  const stats = await getTopUsersWithCache(sortBy, categoryStatsEnabled);
-  if (categoryStatsEnabled) {
-    additionalFields += "SUM(CASE WHEN category = 'sponsor' THEN 1 ELSE 0 END) as categorySponsor, " +
-                        "SUM(CASE WHEN category = 'intro' THEN 1 ELSE 0 END) as categorySumIntro, " +
-                        "SUM(CASE WHEN category = 'outro' THEN 1 ELSE 0 END) as categorySumOutro, " +
-                        "SUM(CASE WHEN category = 'interaction' THEN 1 ELSE 0 END) as categorySumInteraction, " +
-                        "SUM(CASE WHEN category = 'selfpromo' THEN 1 ELSE 0 END) as categorySelfpromo, " +
-                        "SUM(CASE WHEN category = 'music_offtopic' THEN 1 ELSE 0 END) as categoryMusicOfftopic, ";
-  }
-
-  let rows = db.prepare('all', "SELECT COUNT(*) as totalSubmissions, SUM(views) as viewCount," + 
-                  "SUM((sponsorTimes.endTime - sponsorTimes.startTime) / 60 * sponsorTimes.views) as minutesSaved, " +
-                  "SUM(votes) as userVotes, " +
-                  additionalFields +
-                  "IFNULL(userNames.userName, sponsorTimes.userID) as userName FROM sponsorTimes LEFT JOIN userNames ON sponsorTimes.userID=userNames.userID " +
-                  "LEFT JOIN privateDB.shadowBannedUsers ON sponsorTimes.userID=privateDB.shadowBannedUsers.userID " +
-                  "WHERE sponsorTimes.votes > -1 AND sponsorTimes.shadowHidden != 1 AND privateDB.shadowBannedUsers.userID IS NULL " +
-                  "GROUP BY IFNULL(userName, sponsorTimes.userID) HAVING userVotes > 20 " +
-                  "ORDER BY " + sortBy + " DESC LIMIT 100", []);
   
-  for (let i = 0; i < rows.length; i++) {
-      userNames[i] = rows[i].userName;
-
-      viewCounts[i] = rows[i].viewCount;
-      totalSubmissions[i] = rows[i].totalSubmissions;
-      minutesSaved[i] = rows[i].minutesSaved;
-      if (categoryStatsEnabled) {
-        categoryStats[i] = [
-          rows[i].categorySponsor,
-          rows[i].categorySumIntro,
-          rows[i].categorySumOutro,
-          rows[i].categorySumInteraction,
-          rows[i].categorySelfpromo,
-          rows[i].categoryMusicOfftopic,
-        ];
-      }
-  }
-
   //send this result
-  res.send({
+  res.send(stats);
-      userNames,
+}
-      viewCounts,
-      totalSubmissions,
-      minutesSaved,
-      categoryStats
-  });
-}

src/utils/createMemoryCache.js

@@ -0,0 +1,42 @@
+module.exports = function createMemoryCache(memoryFn, cacheTimeMs) {
+  // holds the promise results
+  const cache = new Map();
+  // holds the promises that are not fulfilled
+  const promiseMemory = new Map();
+  return (...args) => {
+    // create cacheKey by joining arguments as string
+    const cacheKey = args.join('.');
+    // check if promising is already running
+    if (promiseMemory.has(cacheKey)) {
+      return promiseMemory.get(cacheKey);
+    }
+    else {
+      // check if result is in cache
+      if (cache.has(cacheKey)) {
+        const cacheItem = cache.get(cacheKey);
+        const now = Date.now();
+        // check if cache is valid
+        if (!(cacheItem.cacheTime + cacheTimeMs < now)) {
+          return Promise.resolve(cacheItem.result);
+        }
+      }
+      // create new promise
+      const promise = new Promise(async (resolve, reject) => {
+        resolve((await memoryFn(...args)));
+      });
+      // store promise reference until fulfilled
+      promiseMemory.set(cacheKey, promise);
+      return promise.then(result => {
+        // store promise result in cache
+        cache.set(cacheKey, {
+          result,
+          cacheTime: Date.now(),
+        });
+        // remove fulfilled promise from memory
+        promiseMemory.delete(cacheKey);
+        // return promise result
+        return result;
+      });
+    }
+  };
+};