Jest and TS Config with initial Token Bucket tests

.eslintrc.json

@@ -15,16 +15,13 @@
     "parser": "@typescript-eslint/parser",
     "parserOptions": {
         "ecmaVersion": "latest",
-        "project": "./tsconfig.eslint.json"
+        "project": "./tsconfig.json"
     },
-    "plugins": ["import"],
+    "plugins": ["import", "prettier"],
     "rules": {
-        "indent": [
-            "warn",
-            4,
-            {
-                "SwitchCase": 2
-            }
+
+        "prettier/prettier": [
+            "error"
         ]
     }, 
     "ignorePatterns": ["jest.config.js"]

README.md

@@ -1,3 +1,3 @@
-# graph-beaver
+# GraphQL-Gate
 
 A GraphQL rate limiting library using query complexity analysis.

package.json

@@ -1,12 +1,12 @@
 {
-    "name": "graphql-complexity-limit",
+    "name": "graphql-gate",
     "version": "1.0.0",
     "description": "A GraphQL rate limiting library using query complexity analysis.",
     "main": "index.js",
     "scripts": {
         "test": "jest --passWithNoTests",
-        "lint": "eslint src",
-        "lint:fix": "eslint --fix src",
+        "lint": "eslint src test",
+        "lint:fix": "eslint --fix src test",
         "prettier": "prettier --write .",
         "prepare": "husky install"
     },
@@ -26,6 +26,7 @@
         "@babel/preset-env": "^7.17.12",
         "@babel/preset-typescript": "^7.17.12",
         "@types/jest": "^27.5.1",
+        "@types/redis-mock": "^0.17.1",
         "@typescript-eslint/eslint-plugin": "^5.24.0",
         "@typescript-eslint/parser": "^5.24.0",
         "babel-jest": "^28.1.0",
@@ -34,10 +35,12 @@
         "eslint-config-airbnb-typescript": "^17.0.0",
         "eslint-config-prettier": "^8.5.0",
         "eslint-plugin-import": "^2.26.0",
+        "eslint-plugin-prettier": "^4.0.0",
         "husky": "^8.0.1",
         "jest": "^28.1.0",
         "lint-staged": "^12.4.1",
         "prettier": "2.6.2",
+        "redis-mock": "^0.56.3",
         "ts-jest": "^28.0.2",
         "typescript": "^4.6.4"
     },
@@ -46,6 +49,7 @@
         "*.{js,ts,css,md}": "prettier --write --ignore-unknown"
     },
     "dependencies": {
+        "redis": "^4.1.0",
         "graphql": "^16.5.0"
     }
 }

src/@types/rateLimit.d.ts

@@ -2,13 +2,23 @@ interface RateLimiter {
     /**
      * Checks if a request is allowed under the given conditions and withdraws the specified number of tokens
      * @param uuid Unique identifier for the user associated with the request
+     * @param timestamp UNIX format timestamp of when request was received
      * @param tokens Number of tokens being used in this request. Optional
-     * @returns true if the request is allowed
+     * @returns a RateLimiterResponse indicating with a sucess and tokens property indicating the number of tokens remaining
      */
-    processRequest: (uuid: string, tokens?: number) => boolean;
-    /**
-     * Connects the RateLimiter instance to a db to cache current token usage for connected users
-     * @param uri database connection string
-     */
-    connect: (uri: string) => void;
+    processRequest: (
+        uuid: string,
+        timestamp: number,
+        tokens?: number
+    ) => Promise<RateLimiterResponse>;
+}
+
+interface RateLimiterResponse {
+    success: boolean;
+    tokens?: number;
+}
+
+interface RedisBucket {
+    tokens: number;
+    timestamp: number;
 }

src/rateLimiters/tokenBucket.ts

@@ -1,34 +1,47 @@
+import { RedisClientType } from 'redis';
+
 /**
- *
+ * The TokenBucket instance of a RateLimiter limits requests based on a unique user ID.
+ * Whenever a user makes a request the following steps are performed:
+ *  1. Refill the bucket based on time elapsed since the previous request
+ *  2. Update the timestamp of the last request.
+ *  3. Allow the request and remove the requested amount of tokens from the bucket if the user has enough.
+ *  4. Otherwise, disallow the request and do not update the token total.
  */
 class TokenBucket implements RateLimiter {
     capacity: number;
 
     refillRate: number;
 
+    client: RedisClientType;
+
     /**
      * Create a new instance of a TokenBucket rate limiter that can be connected to any database store
      * @param capacity max token bucket capacity
      * @param refillRate rate at which the token bucket is refilled
+     * @param client redis client where rate limiter will cache information
      */
-    constructor(capacity: number, refillRate: number) {
+    constructor(capacity: number, refillRate: number, client: RedisClientType) {
         this.capacity = capacity;
         this.refillRate = refillRate;
+        this.client = client;
+        if (refillRate <= 0 || capacity <= 0)
+            throw Error('TokenBucket refillRate and capacity must be positive');
     }
 
-    processRequest(uuid: string, tokens?: number): boolean {
+    async processRequest(
+        uuid: string,
+        timestamp: number,
+        tokens = 1
+    ): Promise<RateLimiterResponse> {
         throw Error(`TokenBucket.processRequest not implemented, ${this}`);
     }
 
-    connect(uri: string) {
-        throw Error(`TokenBucket.connect not implemented, ${this}`);
-    }
-
     /**
-     * @returns current size of the token bucket.
+     * Resets the rate limiter to the intial state by clearing the redis store.
      */
-    getSize(uuid: string): number {
-        throw Error(`TokenBucket.connect not implemented, ${this}`);
+    reset(): void {
+        throw Error(`TokenBucket.reset not implemented, ${this}`);
     }
 }