Fallback to download from transit tier if attachment not found on backup tier

ts/test-electron/util/downloadAttachment_test.ts

@@ -0,0 +1,242 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+import * as sinon from 'sinon';
+import { IMAGE_PNG } from '../../types/MIME';
+import {
+  AttachmentPermanentlyUndownloadableError,
+  downloadAttachment,
+} from '../../util/downloadAttachment';
+import { MediaTier } from '../../types/AttachmentDownload';
+import { HTTPError } from '../../textsecure/Errors';
+import { getCdnNumberForBackupTier } from '../../textsecure/downloadAttachment';
+import { MASTER_KEY } from '../backup/helpers';
+import { getMediaIdFromMediaName } from '../../services/backups/util/mediaId';
+
+describe('utils/downloadAttachment', () => {
+  const baseAttachment = {
+    size: 100,
+    contentType: IMAGE_PNG,
+  };
+
+  let sandbox: sinon.SinonSandbox;
+  const fakeServer = {};
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    sandbox.stub(window, 'textsecure').value({ server: fakeServer });
+  });
+  afterEach(() => {
+    sandbox.restore();
+  });
+
+  it('downloads from transit tier first if no backup information', async () => {
+    const stubDownload = sinon.stub();
+    const attachment = {
+      ...baseAttachment,
+      cdnKey: 'cdnKey',
+      cdnNumber: 2,
+    };
+    await downloadAttachment(attachment, {
+      downloadAttachmentFromServer: stubDownload,
+    });
+    assert.equal(stubDownload.callCount, 1);
+    assert.deepEqual(stubDownload.getCall(0).args, [
+      fakeServer,
+      attachment,
+      { mediaTier: MediaTier.STANDARD },
+    ]);
+  });
+
+  it('throw permanently missing error if attachment fails with 404 and no backup information', async () => {
+    const stubDownload = sinon
+      .stub()
+      .onFirstCall()
+      .throws(new HTTPError('not found', { code: 404, headers: {} }));
+
+    const attachment = {
+      ...baseAttachment,
+      cdnKey: 'cdnKey',
+      cdnNumber: 2,
+    };
+    await assert.isRejected(
+      downloadAttachment(attachment, {
+        downloadAttachmentFromServer: stubDownload,
+      }),
+      AttachmentPermanentlyUndownloadableError
+    );
+
+    assert.equal(stubDownload.callCount, 1);
+    assert.deepEqual(stubDownload.getCall(0).args, [
+      fakeServer,
+      attachment,
+      { mediaTier: MediaTier.STANDARD },
+    ]);
+  });
+
+  it('downloads from backup tier first if there is backup information', async () => {
+    const stubDownload = sinon.stub();
+    const attachment = {
+      ...baseAttachment,
+      cdnKey: 'cdnKey',
+      cdnNumber: 2,
+      backupLocator: {
+        mediaName: 'medianame',
+      },
+    };
+    await downloadAttachment(attachment, {
+      downloadAttachmentFromServer: stubDownload,
+    });
+    assert.equal(stubDownload.callCount, 1);
+    assert.deepEqual(stubDownload.getCall(0).args, [
+      fakeServer,
+      attachment,
+      { mediaTier: MediaTier.BACKUP },
+    ]);
+  });
+
+  it('falls back to transit tier if backup download fails with 404', async () => {
+    const stubDownload = sinon
+      .stub()
+      .onFirstCall()
+      .throws(new HTTPError('not found', { code: 404, headers: {} }));
+
+    const attachment = {
+      ...baseAttachment,
+      cdnKey: 'cdnKey',
+      cdnNumber: 2,
+      backupLocator: {
+        mediaName: 'medianame',
+      },
+    };
+    await downloadAttachment(attachment, {
+      downloadAttachmentFromServer: stubDownload,
+    });
+    assert.equal(stubDownload.callCount, 2);
+    assert.deepEqual(stubDownload.getCall(0).args, [
+      fakeServer,
+      attachment,
+      { mediaTier: MediaTier.BACKUP },
+    ]);
+    assert.deepEqual(stubDownload.getCall(1).args, [
+      fakeServer,
+      attachment,
+      { mediaTier: MediaTier.STANDARD },
+    ]);
+  });
+
+  it('falls back to transit tier if backup download fails with any other error', async () => {
+    const stubDownload = sinon
+      .stub()
+      .onFirstCall()
+      .throws(new Error('could not decrypt!'));
+
+    const attachment = {
+      ...baseAttachment,
+      cdnKey: 'cdnKey',
+      cdnNumber: 2,
+      backupLocator: {
+        mediaName: 'medianame',
+      },
+    };
+    await downloadAttachment(attachment, {
+      downloadAttachmentFromServer: stubDownload,
+    });
+    assert.equal(stubDownload.callCount, 2);
+    assert.deepEqual(stubDownload.getCall(0).args, [
+      fakeServer,
+      attachment,
+      { mediaTier: MediaTier.BACKUP },
+    ]);
+    assert.deepEqual(stubDownload.getCall(1).args, [
+      fakeServer,
+      attachment,
+      { mediaTier: MediaTier.STANDARD },
+    ]);
+  });
+
+  it('does not throw permanently missing error if not found on transit tier but there is backuplocator', async () => {
+    const stubDownload = sinon
+      .stub()
+      .throws(new HTTPError('not found', { code: 404, headers: {} }));
+
+    const attachment = {
+      ...baseAttachment,
+      cdnKey: 'cdnKey',
+      cdnNumber: 2,
+      backupLocator: {
+        mediaName: 'medianame',
+      },
+    };
+
+    await assert.isRejected(
+      downloadAttachment(attachment, {
+        downloadAttachmentFromServer: stubDownload,
+      }),
+      HTTPError
+    );
+    assert.equal(stubDownload.callCount, 2);
+    assert.deepEqual(stubDownload.getCall(0).args, [
+      fakeServer,
+      attachment,
+      { mediaTier: MediaTier.BACKUP },
+    ]);
+    assert.deepEqual(stubDownload.getCall(1).args, [
+      fakeServer,
+      attachment,
+      { mediaTier: MediaTier.STANDARD },
+    ]);
+  });
+});
+
+describe('getCdnNumberForBackupTier', () => {
+  let sandbox: sinon.SinonSandbox;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+    sandbox.stub(window.storage, 'get').callsFake(key => {
+      if (key === 'masterKey') {
+        return MASTER_KEY;
+      }
+      return undefined;
+    });
+  });
+
+  afterEach(async () => {
+    await window.Signal.Data.clearAllBackupCdnObjectMetadata();
+    sandbox.restore();
+  });
+
+  const baseAttachment = {
+    size: 100,
+    contentType: IMAGE_PNG,
+  };
+  it('uses cdnNumber on attachment', async () => {
+    const result = await getCdnNumberForBackupTier({
+      ...baseAttachment,
+      backupLocator: { mediaName: 'mediaName', cdnNumber: 4 },
+    });
+    assert.equal(result, 4);
+  });
+  it('uses default cdn number if none on attachment', async () => {
+    const result = await getCdnNumberForBackupTier({
+      ...baseAttachment,
+      backupLocator: { mediaName: 'mediaName' },
+    });
+    assert.equal(result, 3);
+  });
+  it('uses cdn number in DB if none on attachment', async () => {
+    await window.Signal.Data.saveBackupCdnObjectMetadata([
+      {
+        mediaId: getMediaIdFromMediaName('mediaName').string,
+        cdnNumber: 42,
+        sizeOnBackupCdn: 128,
+      },
+    ]);
+    const result = await getCdnNumberForBackupTier({
+      ...baseAttachment,
+      backupLocator: { mediaName: 'mediaName' },
+    });
+    assert.equal(result, 42);
+  });
+});