fix(desktop): fetch media bytes via the local resource proxy (#3263)

fluxer_app/src/features/channel/components/embeds/attachments/TextualAttachmentPreviewFetch.test.ts

@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import {afterEach, beforeEach, describe, expect, it, vi} from 'vitest';
+
+const runtime = vi.hoisted(() => ({desktop: false}));
+
+vi.mock('@lingui/core/macro', () => ({msg: (descriptor: unknown) => descriptor}));
+
+vi.mock('@app/features/platform/DesktopLocalAppRuntime', async (importOriginal) => ({
+	...(await importOriginal<typeof import('@app/features/platform/DesktopLocalAppRuntime')>()),
+	isDesktopLocalAppDocument: () => runtime.desktop,
+}));
+vi.mock('@app/features/app/state/RuntimeConfig', () => ({
+	default: {
+		mediaEndpoint: 'https://fluxerusercontent.com',
+		staticCdnEndpoint: 'https://fluxerstatic.com',
+		uploadRelayEndpoint: null,
+		getSnapshot: () => ({apiEndpoint: 'https://api.fluxer.app'}),
+	},
+}));
+vi.mock('@app/features/app/state/InstanceSnapshotStore', () => ({runtimeInstanceKey: () => 'instance-key'}));
+vi.mock('@app/features/messaging/state/AttachmentUrlRefresher', () => ({
+	default: {refresh: async (url: string) => url},
+}));
+
+const {fetchTextualPreviewText} = await import(
+	'@app/features/channel/components/embeds/attachments/TextualAttachmentPreviewFetch'
+);
+
+const ATTACHMENT_URL = 'https://fluxerusercontent.com/attachments/1/2/message.txt?ex=1&is=2&hm=3';
+
+describe('fetchTextualPreviewText', () => {
+	const fetchMock = vi.fn(async (_input: RequestInfo | URL, _init?: RequestInit) => new Response('hello'));
+
+	beforeEach(() => {
+		vi.stubGlobal('fetch', fetchMock);
+		vi.stubGlobal('window', {location: {href: 'fluxer-app://app/channels/@me'}});
+	});
+
+	afterEach(() => {
+		vi.unstubAllGlobals();
+		fetchMock.mockClear();
+		runtime.desktop = false;
+	});
+
+	it('routes media fetches through the desktop resource proxy', async () => {
+		runtime.desktop = true;
+		await expect(fetchTextualPreviewText(ATTACHMENT_URL, new AbortController().signal)).resolves.toBe('hello');
+		const requested = new URL(String(fetchMock.mock.calls[0]?.[0]));
+		expect(requested.protocol).toBe('fluxer-app:');
+		expect(requested.pathname).toBe('/proxy/instance-key');
+		expect(requested.searchParams.get('url')).toBe(ATTACHMENT_URL);
+	});
+
+	it('fetches media directly on the web', async () => {
+		await expect(fetchTextualPreviewText(ATTACHMENT_URL, new AbortController().signal)).resolves.toBe('hello');
+		expect(fetchMock.mock.calls[0]?.[0]).toBe(ATTACHMENT_URL);
+	});
+});

fluxer_app/src/features/channel/components/embeds/attachments/TextualAttachmentPreviewFetch.ts

@@ -2,6 +2,7 @@
 
 import AttachmentUrlRefresher from '@app/features/messaging/state/AttachmentUrlRefresher';
 import {TEXT_PREVIEW_MAX_BYTES} from '@app/features/messaging/utils/AttachmentPreviewUtils';
+import {wrapDesktopLocalResourceURL} from '@app/features/messaging/utils/DesktopResourceUrl';
 
 const SIGNATURE_REFUSAL_STATUSES = new Set([401, 403, 404, 410]);
 
@@ -65,7 +66,7 @@ function requestFailed(response: Response): Error {
 
 export async function fetchTextualPreviewText(url: string, signal: AbortSignal): Promise<string> {
 	const target = await AttachmentUrlRefresher.refresh(url);
-	const response = await fetch(target, {signal});
+	const response = await fetch(wrapDesktopLocalResourceURL(target), {signal});
 	if (response.ok) {
 		return readPreviewText(response);
 	}
@@ -76,7 +77,7 @@ export async function fetchTextualPreviewText(url: string, signal: AbortSignal):
 	if (refreshed === target) {
 		throw requestFailed(response);
 	}
-	const retried = await fetch(refreshed, {signal});
+	const retried = await fetch(wrapDesktopLocalResourceURL(refreshed), {signal});
 	if (!retried.ok) {
 		throw requestFailed(retried);
 	}