signal-desktop/ts/util/downloadAttachment.ts

105 lines
3.3 KiB
TypeScript

// Copyright 2020 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
import {
type AttachmentType,
mightBeOnBackupTier,
AttachmentVariant,
} from '../types/Attachment';
import { downloadAttachment as doDownloadAttachment } from '../textsecure/downloadAttachment';
import { MediaTier } from '../types/AttachmentDownload';
import * as log from '../logging/log';
import { redactGenericText } from './privacy';
import { HTTPError } from '../textsecure/Errors';
import { toLogFormat } from '../types/errors';
import type { ReencryptedAttachmentV2 } from '../AttachmentCrypto';
export class AttachmentPermanentlyUndownloadableError extends Error {}
export async function downloadAttachment({
attachment,
variant = AttachmentVariant.Default,
dependencies = { downloadAttachmentFromServer: doDownloadAttachment },
}: {
attachment: AttachmentType;
variant?: AttachmentVariant;
dependencies?: { downloadAttachmentFromServer: typeof doDownloadAttachment };
}): Promise<ReencryptedAttachmentV2> {
const redactedDigest = redactGenericText(attachment.digest ?? '');
const variantForLogging =
variant !== AttachmentVariant.Default ? `[${variant}]` : '';
const dataId = `${redactedDigest}${variantForLogging}`;
const logId = `downloadAttachmentUtil(${dataId})`;
const { server } = window.textsecure;
if (!server) {
throw new Error('window.textsecure.server is not available!');
}
let migratedAttachment: AttachmentType;
const { id: legacyId } = attachment;
if (legacyId === undefined) {
migratedAttachment = attachment;
} else {
migratedAttachment = {
...attachment,
cdnId: String(legacyId),
};
}
if (mightBeOnBackupTier(migratedAttachment)) {
try {
return await dependencies.downloadAttachmentFromServer(
server,
migratedAttachment,
{
variant,
mediaTier: MediaTier.BACKUP,
logPrefix: dataId,
}
);
} catch (error) {
if (error instanceof HTTPError && error.code === 404) {
// This is an expected occurrence if restoring from a backup before the
// attachment has been moved to the backup tier
log.warn(`${logId}: attachment not found on backup CDN`);
} else {
// We also just log this error instead of throwing, since we want to still try to
// find it on the attachment tier.
log.error(
`${logId}: error when downloading from backup CDN; will try transit tier`,
toLogFormat(error)
);
}
}
}
try {
return await dependencies.downloadAttachmentFromServer(
server,
migratedAttachment,
{
variant,
mediaTier: MediaTier.STANDARD,
logPrefix: dataId,
}
);
} catch (error) {
if (mightBeOnBackupTier(migratedAttachment)) {
// We don't want to throw the AttachmentPermanentlyUndownloadableError because we
// may just need to wait for this attachment to end up on the backup tier
throw error;
}
// Attachments on the transit tier expire after 30 days, then start returning 404 or
// 403
if (
error instanceof HTTPError &&
(error.code === 404 || error.code === 403)
) {
throw new AttachmentPermanentlyUndownloadableError();
} else {
throw error;
}
}
}