created the framework for the token bucket algo

Author: evanmcneely

src/rateLimiters/tokenBucket.ts

@@ -34,14 +34,60 @@ class TokenBucket implements RateLimiter {
         timestamp: number,
         tokens = 1
     ): Promise<RateLimiterResponse> {
-        throw Error(`TokenBucket.processRequest not implemented, ${this}`);
+        // set an expiry for key-pairs in redis to 24 hours
+        const bucketExpiry = 86400000;
+
+        // attempt to get the value for the uuid from the redis cache
+        const bucketJSON = await this.client.get('uuid');
+
+        // if the response is null, we need to create bucket for the user
+        if (bucketJSON === null) {
+            if (tokens > this.capacity) {
+                // reject the request, not enough tokens in bucket
+                return {
+                    success: false,
+                    tokens: 10,
+                };
+            }
+            const newUserBucket: RedisBucket = {
+                tokens: this.capacity - tokens,
+                timestamp,
+            };
+            await this.client.setEx(uuid, bucketExpiry, JSON.stringify(newUserBucket));
+            return {
+                success: true,
+                tokens: newUserBucket.tokens,
+            };
+        }
+
+        const bucket: RedisBucket = await JSON.parse(bucketJSON);
+        // TODO check the timestamp on bucket and update however many tokens are supposed to be in there
+
+        const timeSinceLastQuery: number = timestamp - bucket.timestamp;
+
+        if (bucket.tokens < tokens) {
+            // reject the request, not enough tokens in bucket
+            return {
+                success: false,
+                tokens: bucket.tokens,
+            };
+        }
+        const updatedUserBucket = {
+            tokens: bucket.tokens - tokens,
+            timestamp,
+        };
+        await this.client.setEx(uuid, bucketExpiry, JSON.stringify(updatedUserBucket));
+        return {
+            success: true,
+            tokens: updatedUserBucket.tokens,
+        };
     }
 
     /**
      * Resets the rate limiter to the intial state by clearing the redis store.
      */
     reset(): void {
-        throw Error(`TokenBucket.reset not implemented, ${this}`);
+        this.client.flushAll();
     }
 }