Honour no-store reads through Obsidian's Internal API

src/modules/services/ObsidianAPIService.unit.spec.ts

@@ -1,6 +1,14 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { RequestUrlParam } from "@/deps";
 
 const mocks = vi.hoisted(() => ({
+    requestUrl: vi.fn<
+        (request: RequestUrlParam) => Promise<{
+            status: number;
+            headers: Record<string, string>;
+            arrayBuffer: ArrayBuffer;
+        }>
+    >(),
     platform: {
         isMobile: false,
     },
@@ -8,12 +16,12 @@ const mocks = vi.hoisted(() => ({
 
 vi.mock("@/deps.ts", () => ({
     Platform: mocks.platform,
-    requestUrl: vi.fn(),
+    requestUrl: mocks.requestUrl,
 }));
 
 vi.mock("@/deps", () => ({
     Platform: mocks.platform,
-    requestUrl: vi.fn(),
+    requestUrl: mocks.requestUrl,
 }));
 
 vi.mock("@/modules/essentialObsidian/APILib/ObsHttpHandler", () => ({
@@ -36,6 +44,8 @@ function createService(workspace: Record<string, unknown>, isMobile = false): Ob
 beforeEach(() => {
     mocks.platform.isMobile = false;
     vi.clearAllMocks();
+    mocks.requestUrl.mockReset();
+    mocks.requestUrl.mockResolvedValue({ status: 200, headers: {}, arrayBuffer: new ArrayBuffer(0) });
 });
 
 describe("ObsidianAPIService.showWindowOnRight", () => {
@@ -65,3 +75,94 @@ describe("ObsidianAPIService.showWindowOnRight", () => {
         expect(workspace.revealLeaf).toHaveBeenCalledWith(rightLeaf);
     });
 });
+
+describe("ObsidianAPIService.nativeFetch cache control", () => {
+    const url = "https://couchdb.example.test/vault/f%3Ametadata";
+
+    function sentHeaders(): Headers {
+        expect(mocks.requestUrl).toHaveBeenCalledOnce();
+        return new Headers(mocks.requestUrl.mock.calls[0][0].headers);
+    }
+
+    it.each(["GET", "HEAD", "get", "head"])("bypasses cached responses for an explicit no-store %s", async (method) => {
+        const headers = {
+            Authorization: "Basic fixture",
+            "Cache-Control": "public, max-age=3600",
+            "cAcHe-CoNtRoL": "max-stale",
+            Pragma: "cache",
+        };
+
+        await createService({}).nativeFetch(url, { method, cache: "no-store", headers });
+
+        expect(sentHeaders().get("cache-control")).toBe("no-cache, no-store");
+        expect(sentHeaders().get("pragma")).toBe("no-cache");
+        expect(sentHeaders().get("authorization")).toBe("Basic fixture");
+        expect(headers["Cache-Control"]).toBe("public, max-age=3600");
+        expect(mocks.requestUrl.mock.calls[0][0]).toMatchObject({ url, method });
+    });
+
+    it("uses the Request cache mode when the options do not override it", async () => {
+        const request = new Request(url, {
+            method: "HEAD",
+            cache: "no-store",
+            headers: { "X-Fixture": "request" },
+        });
+        const headers = new Headers({ "X-Other": "options" });
+
+        await createService({}).nativeFetch(request, { headers });
+
+        expect(sentHeaders().get("cache-control")).toBe("no-cache, no-store");
+        expect(sentHeaders().get("pragma")).toBe("no-cache");
+        expect(sentHeaders().get("x-fixture")).toBe("request");
+        expect(sentHeaders().get("x-other")).toBe("options");
+        expect(headers.has("cache-control")).toBe(false);
+        expect(request.headers.has("cache-control")).toBe(false);
+    });
+
+    it("lets the options request no-store for an otherwise cacheable Request", async () => {
+        await createService({}).nativeFetch(new Request(url, { cache: "force-cache" }), { cache: "no-store" });
+
+        expect(sentHeaders().get("cache-control")).toBe("no-cache, no-store");
+    });
+
+    it("lets an explicit default cache mode override a no-store Request", async () => {
+        await createService({}).nativeFetch(new Request(url, { cache: "no-store" }), { cache: "default" });
+
+        expect(sentHeaders().has("cache-control")).toBe(false);
+        expect(sentHeaders().has("pragma")).toBe(false);
+    });
+
+    it.each([undefined, "default", "no-cache", "reload", "force-cache"] as const)(
+        "preserves caller headers for cache mode %s",
+        async (cache) => {
+            const headers = { "Cache-Control": "max-age=60", Pragma: "fixture" };
+
+            await createService({}).nativeFetch(url, { cache, headers });
+
+            expect(mocks.requestUrl.mock.calls[0][0].headers).toEqual(headers);
+        }
+    );
+
+    it("does not add cache directives to an ordinary request", async () => {
+        await createService({}).nativeFetch(url);
+
+        expect(sentHeaders().has("cache-control")).toBe(false);
+        expect(sentHeaders().has("pragma")).toBe(false);
+    });
+
+    it.each(["POST", "PUT", "DELETE"])("preserves a no-store %s request", async (method) => {
+        const headers = { "Cache-Control": "no-transform" };
+
+        await createService({}).nativeFetch(url, { method, cache: "no-store", headers });
+
+        expect(mocks.requestUrl.mock.calls[0][0]).toMatchObject({ url, method, headers });
+        expect(sentHeaders().has("pragma")).toBe(false);
+    });
+
+    it("uses the effective method from the options", async () => {
+        await createService({}).nativeFetch(new Request(url, { cache: "no-store" }), { method: "POST" });
+
+        expect(sentHeaders().has("cache-control")).toBe(false);
+        expect(sentHeaders().has("pragma")).toBe(false);
+    });
+});