Merge pull request #409 from mchangrh/redisHashCache

getHash redis cache

src/utils/getHash.ts

@@ -10,4 +10,4 @@ export function getHash<T extends string>(value: T, times = 5000): T & HashedVal
     }
 
     return value as T & HashedValue;
-}
+}

src/utils/getHashCache.ts

@@ -0,0 +1,35 @@
+import redis from "../utils/redis";
+import { shaHashKey } from "../utils/redisKeys";
+import { HashedValue } from "../types/hash.model";
+import { Logger } from "../utils/logger";
+import { getHash } from "../utils/getHash";
+
+const defaultedHashTimes = 5000;
+const cachedHashTimes = defaultedHashTimes - 1;
+
+export async function getHashCache<T extends string>(value: T, times = defaultedHashTimes): Promise<T & HashedValue> {
+    if (times === defaultedHashTimes) {
+        const hashKey = getHash(value, 1);
+        const result: HashedValue = await getFromRedis(hashKey);
+        return result  as T & HashedValue;
+    }
+    return getHash(value, times);
+}
+
+async function getFromRedis<T extends string>(key: HashedValue): Promise<T & HashedValue> {
+    const redisKey = shaHashKey(key);
+    const { err, reply } = await redis.getAsync(redisKey);
+
+    if (!err && reply) {
+        try {
+            Logger.debug(`Got data from redis: ${reply}`);
+            return reply as T & HashedValue;
+        } catch (e) {
+            // If all else, continue on hashing
+        }
+    }
+    const data = getHash(key, cachedHashTimes);
+
+    redis.setAsync(key, data);
+    return data as T & HashedValue;
+}

src/utils/redisKeys.ts

@@ -1,5 +1,6 @@
 import { Service, VideoID, VideoIDHash } from "../types/segments.model";
 import { UserID } from "../types/user.model";
+import { HashedValue } from "../types/hash.model";
 import { Logger } from "./logger";
 
 export function skipSegmentsKey(videoID: VideoID, service: Service): string {
@@ -22,4 +23,10 @@ export function ratingHashKey(hashPrefix: VideoIDHash, service: Service): string
     if (hashPrefix.length !== 4) Logger.warn(`Redis rating hash-prefix key is not length 4! ${hashPrefix}`);
 
     return `rating.${service}.${hashPrefix}`;
+}
+
+export function shaHashKey(singleIter: HashedValue): string {
+    if (singleIter.length !== 64) Logger.warn(`Redis sha.hash key is not length 64! ${singleIter}`);
+
+    return `sha.hash.${singleIter}`;
 }