feat(canvas): 条件读取与历史 - 减少画布同步传输并校准版本

web/test/canvas-conditional-get.test.ts

@@ -0,0 +1,31 @@
+import { afterEach, describe, expect, test } from "bun:test";
+
+import { getRemoteCanvasProject } from "../src/services/api/user-data";
+import { apiClient } from "../src/services/api/request";
+import type { CanvasProject } from "../src/stores/canvas/use-canvas-store";
+
+const originalAdapter = apiClient.defaults.adapter;
+
+afterEach(() => {
+    apiClient.defaults.adapter = originalAdapter;
+});
+
+describe("conditional canvas reads", () => {
+    test("reuses a verified project when the server returns 304", async () => {
+        const known = {
+            id: "canvas-1",
+            title: "Cached canvas",
+            revision: 4,
+            updatedAt: "2026-09-28T12:00:00.000Z",
+        } as CanvasProject;
+        let requestEtag = "";
+        apiClient.defaults.adapter = async (config) => {
+            const headers = config.headers as { get?: (name: string) => string | undefined; [key: string]: unknown } | undefined;
+            requestEtag = String(headers?.get?.("If-None-Match") ?? headers?.["If-None-Match"] ?? "");
+            return { config, status: 304, statusText: "Not Modified", headers: {}, data: null };
+        };
+
+        await expect(getRemoteCanvasProject(known.id, known)).resolves.toEqual({ project: known, notModified: true });
+        expect(requestEtag).toBe('"canvas-4"');
+    });
+});