expose no-op caches in getBindingsProxy (#4847)

* expose no-op `caches` in getBindingsProxy

---------

Co-authored-by: MrBBot <[email protected]>

.changeset/happy-pandas-sparkle.md

@@ -0,0 +1,12 @@
+---
+"wrangler": minor
+---
+
+feat: expose new (no-op) `caches` field in `getBindingsProxy` result
+
+Add a new `caches` field to the `getBindingsProxy` result, such field implements a
+no operation (no-op) implementation of the runtime `caches`
+
+Note: Miniflare exposes a proper `caches` mock, we will want to use that one in
+the future but issues regarding it must be ironed out first, so for the
+time being a no-op will have to do

fixtures/get-bindings-proxy/package.json

@@ -10,6 +10,7 @@
 	"devDependencies": {
 		"@cloudflare/workers-tsconfig": "workspace:*",
 		"@cloudflare/workers-types": "^4.20221111.1",
-		"wrangler": "workspace:*"
+		"wrangler": "workspace:*",
+		"undici": "^5.28.2"
 	}
 }

fixtures/get-bindings-proxy/tests/get-bindings-proxy.test.ts

@@ -6,6 +6,7 @@ import {
 	Fetcher,
 	R2Bucket,
 } from "@cloudflare/workers-types";
+import { Request, Response } from "undici";
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
 import {
 	getBindingsProxy as originalGetBindingsProxy,
@@ -227,6 +228,25 @@ describe("getBindingsProxy", () => {
 			await dispose();
 		}
 	});
+
+	describe("caches", () => {
+		(["default", "named"] as const).forEach((cacheType) =>
+			it(`correctly obtains a no-op ${cacheType} cache`, async () => {
+				const { caches, dispose } = await getBindingsProxy<Bindings>({
+					configPath: wranglerTomlFilePath,
+				});
+				try {
+					const cache =
+						cacheType === "default"
+							? caches.default
+							: await caches.open("my-cache");
+					testNoOpCache(cache);
+				} finally {
+					await dispose();
+				}
+			})
+		);
+	});
 });
 
 /**
@@ -263,3 +283,17 @@ async function testDoBinding(
 	const doRespText = await doResp.text();
 	expect(doRespText).toBe(expectedResponse);
 }
+
+async function testNoOpCache(
+	cache: Awaited<ReturnType<typeof getBindingsProxy>>["caches"]["default"]
+) {
+	let match = await cache.match("http://0.0.0.0/test");
+	expect(match).toBeUndefined();
+
+	const req = new Request("http://0.0.0.0/test");
+	await cache.put(req, new Response("test"));
+	const resp = await cache.match(req);
+	expect(resp).toBeUndefined();
+	const deleted = await cache.delete(req);
+	expect(deleted).toBe(false);
+}

packages/wrangler/src/api/integrations/bindings/caches.ts

@@ -0,0 +1,62 @@
+/* eslint-disable unused-imports/no-unused-vars */
+
+/**
+ * Note about this file:
+ *
+ * Here we are providing a no-op implementation of the runtime Cache API instead of using
+ * the miniflare implementation (via `mf.getCaches()`).
+ *
+ * We are not using miniflare's implementation because that would require the user to provide
+ * miniflare-specific Request objects and they would receive back miniflare-specific Response
+ * objects, this (in particular the Request part) is not really suitable for `getBindingsProxy`
+ * as people would ideally interact with their bindings in a very production-like manner and
+ * requiring them to deal with miniflare-specific classes defeats a bit the purpose of the utility.
+ *
+ * Similarly the Request and Response types here are set to `undefined` as not to use specific ones
+ * that would require us to make a choice right now or the user to adapt their code in order to work
+ * with the api.
+ *
+ * We need to find a better/generic manner in which we can reuse the miniflare cache implementation,
+ * but until then the no-op implementation below will have to do.
+ */
+
+/**
+ * No-op implementation of CacheStorage
+ */
+export class CacheStorage {
+	async open(cacheName: string): Promise<Cache> {
+		return new Cache();
+	}
+
+	get default(): Cache {
+		return new Cache();
+	}
+}
+
+type CacheRequest = unknown;
+type CacheResponse = unknown;
+
+/**
+ * No-op implementation of Cache
+ */
+class Cache {
+	async delete(
+		request: CacheRequest,
+		options?: CacheQueryOptions
+	): Promise<boolean> {
+		return false;
+	}
+
+	async match(
+		request: CacheRequest,
+		options?: CacheQueryOptions
+	): Promise<CacheResponse | undefined> {
+		return undefined;
+	}
+
+	async put(request: CacheRequest, response: CacheResponse): Promise<void> {}
+}
+
+type CacheQueryOptions = {
+	ignoreMethod?: boolean;
+};

packages/wrangler/src/api/integrations/bindings/index.ts

@@ -4,6 +4,7 @@ import { getBindings } from "../../../dev";
 import { getBoundRegisteredWorkers } from "../../../dev-registry";
 import { getVarsForDev } from "../../../dev/dev-vars";
 import { buildMiniflareBindingOptions } from "../../../dev/miniflare";
+import { CacheStorage } from "./caches";
 import { getServiceBindings } from "./services";
 import type { Config } from "../../../config";
 import type { MiniflareOptions } from "miniflare";
@@ -39,6 +40,10 @@ export type BindingsProxy<Bindings = Record<string, unknown>> = {
 	 * Object containing the various proxies
 	 */
 	bindings: Bindings;
+	/**
+	 * Caches object emulating the Workers Cache runtime API
+	 */
+	caches: CacheStorage;
 	/**
 	 * Function used to dispose of the child process providing the bindings implementation
 	 */
@@ -83,6 +88,7 @@ export async function getBindingsProxy<Bindings = Record<string, unknown>>(
 			...vars,
 			...bindings,
 		},
+		caches: new CacheStorage(),
 		dispose: () => mf.dispose(),
 	};
 }