fix: import Slack files as attachments instead of raw URLs (RocketChat#41285)

Author: ricardogarim

.changeset/deep-ways-poke.md

@@ -0,0 +1,7 @@
+---
+'@rocket.chat/core-typings': patch
+'@rocket.chat/models': patch
+'@rocket.chat/meteor': patch
+---
+
+Fixes the Slack importer storing shared files as raw URLs in the message body. Imported file messages now stay hidden until "Download Pending Files" button fetches them, then display as native attachments with image previews. Failed downloads (e.g. invalidated export links) are no longer silently saved as the file's content — they are counted as errors and can be retried.

apps/meteor/server/lib/import/classes/converters/MessageConverter.ts

@@ -104,6 +104,7 @@ export class MessageConverter extends RecordConverter<IImportMessageRecord> {
 			mentions,
 			channels,
 			_importFile: data._importFile,
+			_hidden: data._hidden,
 			url: data.url,
 			attachments: data.attachments,
 			bot: data.bot,

apps/meteor/server/lib/import/pending-files/PendingFileImporter.ts

@@ -3,10 +3,11 @@ import https from 'node:https';
 
 import { api } from '@rocket.chat/core-services';
 import type { IImport, MessageAttachment, IUpload, IImporterShortSelection } from '@rocket.chat/core-typings';
-import { Messages } from '@rocket.chat/models';
+import { Messages, Users } from '@rocket.chat/models';
 import { Random } from '@rocket.chat/random';
 
 import { Importer, ProgressStep } from '..';
+import { parseFileIntoMessageAttachments } from '../../../meteor-methods/messages/sendFileMessage';
 import { FileUpload } from '../../media/file-upload';
 import type { ConverterOptions } from '../classes/ImportDataConverter';
 import type { ImporterProgress } from '../classes/ImporterProgress';
@@ -79,6 +80,12 @@ export class PendingFileImporter extends Importer {
 			currentSize -= details.size;
 		};
 
+		const failFile = async (details: { size: number }) => {
+			await this.addCountError(1);
+			count--;
+			currentSize -= details.size;
+		};
+
 		const logError = this.logger.error.bind(this.logger);
 
 		try {
@@ -107,7 +114,6 @@ export class PendingFileImporter extends Importer {
 						rid: message.rid,
 					};
 
-					const requestModule = /https/i.test(url) ? https : http;
 					const fileStore = FileUpload.getStore('Uploads');
 
 					nextSize = details.size;
@@ -116,41 +122,25 @@ export class PendingFileImporter extends Importer {
 					currentSize += nextSize;
 					downloadedFileIds.push(_importFile.id);
 
-					requestModule.get(url, (res) => {
-						const contentType = res.headers['content-type'];
-						if (!details.type && contentType) {
-							details.type = contentType;
-						}
+					void this.downloadFile(url, details)
+						.then(async (rawData) => {
+							// Bypass the fileStore filters
+							const file = await fileStore._doInsert(details, rawData);
 
-						const rawData: Uint8Array[] = [];
-						res.on('data', (chunk) => {
-							rawData.push(chunk);
+							const rocketChatUrl = FileUpload.getPath(`${file._id}/${encodeURI(file.name || '')}`);
+							const user = await Users.findOneById(message.u._id);
+							const attachment = user
+								? (await parseFileIntoMessageAttachments(file, message.rid, user)).attachments[0]
+								: this.getMessageAttachment(file, rocketChatUrl);
 
-							// Update progress more often on large files
-							this.reportProgress();
-						});
-						res.on('error', async (err) => {
+							await Messages.setImportFileRocketChatAttachment(_importFile.id, rocketChatUrl, attachment);
 							await completeFile(details);
-							logError({ err });
+							importedRoomIds.add(message.rid);
+						})
+						.catch(async (err) => {
+							logError({ msg: 'Failed to download pending file', url, err });
+							await failFile(details);
 						});
-
-						res.on('end', async () => {
-							try {
-								// Bypass the fileStore filters
-								const file = await fileStore._doInsert(details, Buffer.concat(rawData));
-
-								const url = FileUpload.getPath(`${file._id}/${encodeURI(file.name || '')}`);
-								const attachment = this.getMessageAttachment(file, url);
-
-								await Messages.setImportFileRocketChatAttachment(_importFile.id, url, attachment);
-								await completeFile(details);
-								importedRoomIds.add(message.rid);
-							} catch (err) {
-								await completeFile(details);
-								logError({ err });
-							}
-						});
-					});
 				} catch (err) {
 					this.logger.error({ err });
 				}
@@ -172,6 +162,39 @@ export class PendingFileImporter extends Importer {
 		return this.getProgress();
 	}
 
+	private downloadFile(url: string, details: { type?: string }): Promise<Buffer> {
+		return new Promise((resolve, reject) => {
+			const requestModule = /https/i.test(url) ? https : http;
+
+			requestModule
+				.get(url, (res) => {
+					res.on('error', reject);
+
+					if (!res.statusCode || res.statusCode < 200 || res.statusCode >= 300) {
+						// Error responses (e.g. a redirect to a login page) would otherwise be saved as the file's content.
+						res.resume(); // discard the body and free the socket
+						reject(new Error(`Unexpected response status ${res.statusCode}`));
+						return;
+					}
+
+					const contentType = res.headers['content-type'];
+					if (!details.type && contentType) {
+						details.type = contentType;
+					}
+
+					const rawData: Uint8Array[] = [];
+					res.on('data', (chunk) => {
+						rawData.push(chunk);
+
+						// Update progress more often on large files
+						this.reportProgress();
+					});
+					res.on('end', () => resolve(Buffer.concat(rawData)));
+				})
+				.on('error', reject);
+		});
+	}
+
 	getMessageAttachment(file: IUpload, url: string): MessageAttachment {
 		if (file.type) {
 			if (/^image\/.+/.test(file.type)) {

apps/meteor/server/lib/import/slack/SlackImporter.ts

@@ -496,7 +496,8 @@ export class SlackImporter extends Importer {
 						_id: fileId,
 						rid: newMessage.rid,
 						ts: newMessage.ts,
-						msg: message.file.url_private_download || '',
+						msg: '',
+						_hidden: true,
 						_importFile: this.convertSlackFileToPendingFile(message.file),
 						u: {
 							_id: newMessage.u._id,
@@ -568,7 +569,8 @@ export class SlackImporter extends Importer {
 						_id: fileId,
 						rid: slackChannelId,
 						ts: newMessage.ts,
-						msg: file.url_private_download || '',
+						msg: '',
+						_hidden: true,
 						_importFile: this.convertSlackFileToPendingFile(file),
 						u: {
 							_id: this._replaceSlackUserId(message.user),