Drop group messages that don't change group

ts/textsecure.d.ts

@@ -62,6 +62,11 @@ export type TextSecureType = {
     remove: (key: string | Array<string>) => Promise<void>;
     protocol: StorageProtocolType;
   };
+  messageReceiver: {
+    downloadAttachment: (
+      attachment: AttachmentPointerClass
+    ) => Promise<DownloadAttachmentType>;
+  };
   messaging: {
     sendStickerPackSync: (
       operations: Array<{
@@ -172,6 +177,23 @@ export declare class AttachmentPointerClass {
   cdnNumber?: number;
 }
 
+export type DownloadAttachmentType = {
+  data: ArrayBuffer;
+  cdnId?: ProtoBigNumberType;
+  cdnKey?: string;
+  contentType?: string;
+  size?: number;
+  thumbnail?: ProtoBinaryType;
+  fileName?: string;
+  flags?: number;
+  width?: number;
+  height?: number;
+  caption?: string;
+  blurHash?: string;
+  uploadTimestamp?: ProtoBigNumberType;
+  cdnNumber?: number;
+};
+
 export declare class ContactDetailsClass {
   static decode: (
     data: ArrayBuffer | ByteBufferClass,

ts/textsecure/MessageReceiver.ts

@@ -20,8 +20,8 @@ import { IncomingIdentityKeyError } from './Errors';
 import {
   AttachmentPointerClass,
   DataMessageClass,
+  DownloadAttachmentType,
   EnvelopeClass,
-  ProtoBigNumberType,
   ReceiptMessageClass,
   SyncMessageClass,
   TypingMessageClass,
@@ -62,22 +62,6 @@ declare global {
   }
 }
 
-type AttachmentType = {
-  cdnId?: string;
-  cdnKey?: string;
-  data: ArrayBuffer;
-  contentType?: string;
-  size?: number;
-  fileName?: string;
-  flags?: number;
-  width?: number;
-  height?: number;
-  caption?: string;
-  blurHash?: string;
-  uploadTimestamp?: ProtoBigNumberType;
-  cdnNumber?: number;
-};
-
 type CacheAddItemType = {
   envelope: EnvelopeClass;
   data: UnprocessedType;
@@ -1591,7 +1575,9 @@ class MessageReceiverInner extends EventTarget {
       digest: attachment.digest ? attachment.digest.toString('base64') : null,
     };
   }
-  async downloadAttachment(attachment: AttachmentPointerClass) {
+  async downloadAttachment(
+    attachment: AttachmentPointerClass
+  ): Promise<DownloadAttachmentType> {
     const encrypted = await this.server.getAttachment(
       attachment.cdnId || attachment.cdnKey,
       attachment.cdnNumber || 0
@@ -1623,7 +1609,7 @@ class MessageReceiverInner extends EventTarget {
   }
   async handleAttachment(
     attachment: AttachmentPointerClass
-  ): Promise<AttachmentType> {
+  ): Promise<DownloadAttachmentType> {
     const cleaned = this.cleanAttachment(attachment);
     return this.downloadAttachment(cleaned);
   }
@@ -1866,7 +1852,7 @@ export default class MessageReceiver {
   close: () => Promise<void>;
   downloadAttachment: (
     attachment: AttachmentPointerClass
-  ) => Promise<AttachmentType>;
+  ) => Promise<DownloadAttachmentType>;
   stopProcessing: () => Promise<void>;
   unregisterBatchers: () => void;
 

ts/util/downloadAttachment.ts

@@ -0,0 +1,32 @@
+import {
+  AttachmentPointerClass,
+  DownloadAttachmentType,
+} from '../textsecure.d';
+
+type AttachmentData = AttachmentPointerClass & {
+  id?: string;
+};
+
+export async function downloadAttachment(
+  attachmentData: AttachmentData
+): Promise<DownloadAttachmentType | null> {
+  let downloaded;
+  try {
+    if (attachmentData.id) {
+      // eslint-disable-next-line no-param-reassign
+      attachmentData.cdnId = attachmentData.id;
+    }
+    downloaded = await window.textsecure.messageReceiver.downloadAttachment(
+      attachmentData
+    );
+  } catch (error) {
+    // Attachments on the server expire after 30 days, then start returning 404
+    if (error && error.code === 404) {
+      return null;
+    }
+
+    throw error;
+  }
+
+  return downloaded;
+}

ts/util/index.ts

@@ -4,6 +4,7 @@ import { arrayBufferToObjectURL } from './arrayBufferToObjectURL';
 import { combineNames } from './combineNames';
 import { createBatcher } from './batcher';
 import { createWaitBatcher } from './waitBatcher';
+import { downloadAttachment } from './downloadAttachment';
 import { hasExpired } from './hasExpired';
 import { isFileDangerous } from './isFileDangerous';
 import { makeLookup } from './makeLookup';
@@ -16,6 +17,7 @@ export {
   combineNames,
   createBatcher,
   createWaitBatcher,
+  downloadAttachment,
   GoogleChrome,
   hasExpired,
   isFileDangerous,