feat: change cacher responses when the entry is not found. Resolves #824

moleculerjs · Jan 14, 2023 · 88d3b42 · 88d3b42
1 parent 03f598a
commit 88d3b42
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Showing 6 changed files with 62 additions and 42 deletions.
diff --git a/dev/cache.js b/dev/cache.js
@@ -10,7 +10,8 @@ let broker = new ServiceBroker({
 		type: "Memory",
 		options: {
 			max: 100,
-			ttl: 3
+			ttl: 3,
+			missingResponse: Symbol("MISSING")
 		}
 	}
 });
@@ -26,44 +27,61 @@ broker.createService({
 			},
 			handler(ctx) {
 				this.logger.debug(kleur.yellow("Execute handler"));
-				return `Hello ${ctx.params.name}`;
+				return null; //`Hello ${ctx.params.name}`;
 			}
 		}
 	}
 });
 
-broker
-	.start()
-	.then(() => broker.call("greeter.hello", { name: "Moleculer" }))
-	.then(() => broker.call("greeter.hello", { name: "Moleculer" }))
-	.then(() => broker.call("greeter.hello", { name: "Moleculer", noCache: true }))
-	.then(() => broker.call("greeter.hello", { name: "Moleculer" }))
-	.then(() => broker.call("greeter.hello", { name: "Moleculer" }, { meta: { $cache: false } }))
+(async () => {
+	await broker.start();
+
+	try {
+		broker.logger.info("---------------------", "(direct access)");
+		broker.logger.info("Value:", await broker.cacher.get('greeter.hello:name|"Moleculer"'));
+		broker.logger.info("---------------------", "(get, set)");
+		broker.logger.info("Res:", await broker.call("greeter.hello", { name: "Moleculer" }));
+		broker.logger.info("---------------------", "(found)");
+		broker.logger.info("Res:", await broker.call("greeter.hello", { name: "Moleculer" }));
+		broker.logger.info("---------------------", "(noCache)");
+		broker.logger.info(
+			"Res:",
+			await broker.call("greeter.hello", { name: "Moleculer", noCache: true })
+		);
+		broker.logger.info("---------------------", "(found)");
+		broker.logger.info("Res:", await broker.call("greeter.hello", { name: "Moleculer" }));
+		broker.logger.info("---------------------", "($cache: false)");
+		broker.logger.info(
+			"Res:",
+			await broker.call("greeter.hello", { name: "Moleculer" }, { meta: { $cache: false } })
+		);
+		broker.logger.info("---------------------", "(direct access)");
+		broker.logger.info("Value:", await broker.cacher.get('greeter.hello:name|"Moleculer"'));
 
-	.then(async () => {
 		/*for (let i = 0; i < 1000; i++) {
-			broker.cacher.set(`key-${i}`, i);
-			if (i % 10 == 0) {
-				broker.cacher.get(`key-${100}`);
-				broker.cacher.get(`key-${200}`);
-				broker.cacher.get(`key-${500}`);
-				broker.cacher.get(`key-${400}`);
-				broker.cacher.get(`key-${300}`);
-			}
-		}*/
+		broker.cacher.set(`key-${i}`, i);
+		if (i % 10 == 0) {
+			broker.cacher.get(`key-${100}`);
+			broker.cacher.get(`key-${200}`);
+			broker.cacher.get(`key-${500}`);
+			broker.cacher.get(`key-${400}`);
+			broker.cacher.get(`key-${300}`);
+		}
+	}*/
 
+		broker.logger.info("---------------------", "Cache entries:");
 		const keys = await broker.cacher.getCacheKeys();
 		broker.logger.info("Length:", keys.length);
 		broker.logger.info("keys:", keys);
-	})
 
-	.delay(35 * 1000)
-	.then(async () => {
-		broker.logger.info("=========================================");
-		const keys = await broker.cacher.getCacheKeys();
-		broker.logger.info("Length:", keys.length);
-		broker.logger.info("keys:", keys);
-	})
+		await broker.Promise.delay(35 * 1000);
 
-	.catch(err => broker.logger.error(err))
-	.then(() => broker.stop());
+		broker.logger.info("---------------------", "Cache entries:");
+		const keys2 = await broker.cacher.getCacheKeys();
+		broker.logger.info("Length:", keys2.length);
+		broker.logger.info("keys:", keys2);
+	} catch (err) {
+		broker.logger.error(err);
+	}
+	await broker.stop();
+})();
diff --git a/src/cachers/base.js b/src/cachers/base.js
@@ -28,7 +28,9 @@ class Cacher {
 		this.opts = _.defaultsDeep(opts, {
 			ttl: null,
 			keygen: null,
-			maxParamsLength: null
+			maxParamsLength: null,
+			/** @type {any}  Return with this if the key is missing in the cache */
+			missingResponse: undefined
 		});
 
 		/** @type {boolean} Flag indicating the connection status */
@@ -417,7 +419,7 @@ class Cacher {
 		}
 
 		return cachePromise.then(data => {
-			if (data != null) {
+			if (data !== this.opts.missingResponse) {
 				// Found in the cache! Don't call handler, return with the content
 				ctx.cachedResult = true;
 				return data;
@@ -460,7 +462,7 @@ class Cacher {
 	 */
 	middlewareWithoutLock(ctx, cacheKey, handler, opts) {
 		return this.get(cacheKey).then(content => {
-			if (content != null) {
+			if (content !== this.opts.missingResponse) {
 				// Found in the cache! Don't call handler, return with the content
 				ctx.cachedResult = true;
 				return content;

diff --git a/src/cachers/memory-lru.js b/src/cachers/memory-lru.js
@@ -1,6 +1,6 @@
 /*
  * moleculer
- * Copyright (c) 2018 MoleculerJS (https://github.com/moleculerjs/moleculer)
+ * Copyright (c) 2023 MoleculerJS (https://github.com/moleculerjs/moleculer)
  * MIT Licensed
  */
 
@@ -106,7 +106,7 @@ class MemoryLRUCacher extends BaseCacher {
 		} else {
 			timeEnd();
 		}
-		return this.broker.Promise.resolve(null);
+		return this.broker.Promise.resolve(this.opts.missingResponse);
 	}
 
 	/**

diff --git a/src/cachers/memory.js b/src/cachers/memory.js
@@ -1,6 +1,6 @@
 /*
  * moleculer
- * Copyright (c) 2018 MoleculerJS (https://github.com/moleculerjs/moleculer)
+ * Copyright (c) 2023 MoleculerJS (https://github.com/moleculerjs/moleculer)
  * MIT Licensed
  */
 
@@ -95,7 +95,7 @@ class MemoryCacher extends BaseCacher {
 				this.metrics.increment(METRIC.MOLECULER_CACHER_EXPIRED_TOTAL);
 				this.cache.delete(key);
 				timeEnd();
-				return this.broker.Promise.resolve(null);
+				return this.broker.Promise.resolve(this.opts.missingResponse);
 			}
 			const res = this.clone ? this.clone(item.data) : item.data;
 			timeEnd();
@@ -104,7 +104,7 @@ class MemoryCacher extends BaseCacher {
 		} else {
 			timeEnd();
 		}
-		return this.broker.Promise.resolve(null);
+		return this.broker.Promise.resolve(this.opts.missingResponse);
 	}
 
 	/**
@@ -194,7 +194,7 @@ class MemoryCacher extends BaseCacher {
 	 */
 	getWithTTL(key) {
 		this.logger.debug(`GET ${key}`);
-		let data = null;
+		let data = this.opts.missingResponse;
 		let ttl = null;
 		if (this.cache.has(key)) {
 			this.logger.debug(`FOUND ${key}`);

diff --git a/src/cachers/redis.js b/src/cachers/redis.js
@@ -1,6 +1,6 @@
 /*
  * moleculer
- * Copyright (c) 2020 MoleculerJS (https://github.com/moleculerjs/moleculer)
+ * Copyright (c) 2023 MoleculerJS (https://github.com/moleculerjs/moleculer)
  * MIT Licensed
  */
 
@@ -203,7 +203,7 @@ class RedisCacher extends BaseCacher {
 				}
 			}
 			timeEnd();
-			return null;
+			return this.opts.missingResponse;
 		});
 	}
 
@@ -335,7 +335,7 @@ class RedisCacher extends BaseCacher {
 						data = this.serializer.deserialize(data);
 					} catch (err) {
 						this.logger.error("Redis result parse error.", err, data);
-						data = null;
+						data = this.opts.missingResponse;
 					}
 				}
 				return { data, ttl };

diff --git a/src/serializers/json-extended.js b/src/serializers/json-extended.js
@@ -62,7 +62,7 @@ class JSONExtSerializer extends BaseSerializer {
 	 * @param {any} value
 	 */
 	reviver(key, value) {
-		if (typeof value === "string" && value.charAt(0) === "[") {
+		if (typeof value === "string" && value.charAt(0) === "[" && value.charAt(1) === "[") {
 			switch (value.slice(0, 6)) {
 				case PREFIX_BIGINT:
 					return BigInt(value.slice(6));