Define types for WebSocket messages and migrate WebSocket actions to TS #34603

hmhealey · 2025-11-26T23:48:32Z

Summary

Typing the WebSocket code means we're less likely to break stuff in the future, and it provides an interface for people working with WebSocket code so that they know what to expect when handling WebSocket events. We could also generate some docs from these type defintions now as well.

For developers adding a new WS event, they will now:

Instead of adding a message type constant to utils/constants or mattermost-redux/constants/websocket, add that to platform/client/src/websocket_events.ts. Now, there's only one place for that to go instead of having multiple confliciting places for that.
To add the type for the event message, add a new type to platform/client/src/websocket_message.ts for the message body, and then add that type to the union type in platform/client/src/websocket_messages.ts so that the type inference for the WS messages works.
Finally, add a new case in websocket_actions as before. The type inference should all give you a properly typed event and everything

Ticket Link

Release Note

NONE

…ypes

hmhealey · 2025-12-10T21:47:41Z

This is going to conflict with the burn-on-read feature branch which adds some new WS event types (#34601) and new WS event handling

github-actions · 2026-01-06T22:35:28Z

⚠️ One or more flaky tests detected ⚠️

Failing job: github.com/mattermost/mattermost:Postgres
Double check your code to ensure you haven't introduced a flaky test.
If this seems to be unrelated to your changes, submit a separate pull request to skip the flaky tests (e.g. 23360) and file JIRA ticket (e.g. MM-52743) for later investigation.

Test	Retries
Postgres (Results)
com/mattermost/mattermost/server/v8/channels/app.TestAddUserToChannelCreatesChannelMemberHistoryRecord	1

hmhealey · 2026-01-13T17:19:46Z

server/public/model/websocket_message.go

 	WebsocketEventReactionRemoved                     WebsocketEventType = "reaction_removed"
 	WebsocketEventResponse                            WebsocketEventType = "response"
 	WebsocketEventEmojiAdded                          WebsocketEventType = "emoji_added"
-	WebsocketEventChannelViewed                       WebsocketEventType = "channel_viewed"


I removed a few events that aren't used any more. This one was replaced by multiple_channels_viewed, and I couldn't find any references to that Cloud one

hmhealey · 2026-01-13T17:20:41Z

webapp/channels/src/actions/notification_actions.tsx


-    const msgPropsPost: Post = JSON.parse(msgProps.post);
-    const attachments = isMessageAttachmentArray(msgPropsPost?.props?.attachments) ? msgPropsPost.props.attachments : [];
+    const attachments = isMessageAttachmentArray(post.props?.attachments) ? post.props.attachments : [];


We already parsed the post before, so I don't know why we were parsing it again

hmhealey · 2026-01-13T17:21:28Z

webapp/channels/src/actions/post_actions.ts

+        dispatch(completePostReceive(post, websocketMessageProps, myChannelMemberDoesntExist));

-        if (msg && msg.data) {
+        if (msg && msg.data && 'channel_type' in msg.data) {


This is to differentiate between posted and ephemeral_post events

hmhealey · 2026-01-13T17:25:12Z

webapp/channels/src/utils/constants.tsx

 };

+/**
+ * @deprecated Use WebSocketEvents from @mattermost/client instead.


I would've removed this entirely, but there's a few extra WS events left over which come from the Apps plugin which I didn't want to move into the new code

hmhealey · 2026-01-13T17:30:19Z

webapp/platform/client/src/index.ts

 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.

+import type * as WebSocketMessages from './websocket_messages';


Instead of just re-exporting these types like we do below, I decided to do this slightly differently to wrap all of these message types in sort of a namespace. That means you have to use these types like WebSocketMessages.Posted instead of something like WebSocketPostedMessage, but it also means that we don't need to import 80+ individual message types into websocket_actions.ts. If we went back to writing more imports like import * as Utils from ..., that would be less of a problem, but I think this is a reasonable middleground

hmhealey · 2026-01-13T17:31:27Z

webapp/platform/client/src/websocket_message.ts

+import type {WebSocketEvents} from './websocket_events';
+import type * as Messages from './websocket_messages';
+
+export type WebSocketMessage = (


Ideally, you wouldn't need to define this union type, the constant, and the actual type separately, but without looking into generating TS types (which I've briefly tried multiple times), we're stuck with a bit of boilerplate

hmhealey · 2026-01-13T17:32:43Z

webapp/platform/client/src/websocket_messages.ts

This should probably be split up, but I felt like that would make the boilerplate feeling worse

github-actions · 2026-01-13T17:56:34Z

⚠️ One or more flaky tests detected ⚠️

Failing job: github.com/mattermost/mattermost:Postgres
Double check your code to ensure you haven't introduced a flaky test.
If this seems to be unrelated to your changes, submit a separate pull request to skip the flaky tests (e.g. 23360) and file JIRA ticket (e.g. MM-52743) for later investigation.

Test	Retries
Postgres (Results)
com/mattermost/mattermost/server/v8/channels/api4.TestCreatePost/should_prevent_creating_post_with_files_when_user_lacks_upload_file_permission_in_target_channel	1
com/mattermost/mattermost/server/v8/channels/api4.TestCreatePost/should_allow_creating_post_with_files_when_user_has_upload_file_permission	1
com/mattermost/mattermost/server/v8/channels/api4.TestCreatePost	1

github-actions · 2026-01-13T21:02:19Z

E2E test run is starting for commit 7efb1ec7a4dd0381037dc857594c30bf349f7f62.
To check the run progress:

Cypress: look for commit status E2E Tests/test or the access the Automation Dashboard Cycle URL.
Playwright: look for commit status E2E Tests/test-playwright.

You can also look at the E2E test's Workflow Run URL (run ID 20972454362).

github-actions · 2026-01-13T23:05:10Z

E2E test has completed for commit 7efb1ec7a4dd0381037dc857594c30bf349f7f62.
Results summary:

Cypress: pass rate is unknown (see Automation Dashboard and commit status check E2E Tests/test).
Playwright: pass rate is 100.00% (see Playwright Report URL and commit status check E2E Tests/test-playwright).

The run summary artifacts are available in the corresponding Workflow Run.

larkox

❤️

larkox · 2026-01-19T16:59:11Z

webapp/channels/src/actions/notification_actions.tsx

            display_name: msgProps.channel_display_name,
            type: msgProps.channel_type,
-        };
+        } as Channel;


How often do we go through this branch? How safe is to do this?

It's no less safe than what we're currently doing. I think you might actually be the one who added this fallback previously 😛

Looking through the code below though, we only use the 4 fields specified here in every case except for when we pass it to a plugin hook (registerDesktopNotificationHook) where there's an as any. It's totally safe then except for the plugin case which was previously a potential issue anyway.

Thinking about the code as a whole though, we currently assume that the user has all of their channels loaded, so this branch should never actually trigger

github-actions · 2026-01-19T17:14:21Z

E2E test run is starting for commit f62ffc6bea02fa4bd9389bae1715f80ab5559356.
To check the run progress:

Cypress: look for commit status E2E Tests/test or the access the Automation Dashboard Cycle URL.
Playwright: look for commit status E2E Tests/test-playwright.

You can also look at the E2E test's Workflow Run URL (run ID 21146071287).

github-actions · 2026-01-19T19:20:06Z

E2E test has completed for commit f62ffc6bea02fa4bd9389bae1715f80ab5559356.
Results summary:

Cypress: pass rate is unknown (see Automation Dashboard and commit status check E2E Tests/test).
Playwright: pass rate is 99.44% (see Playwright Report URL and commit status check E2E Tests/test-playwright).

The run summary artifacts are available in the corresponding Workflow Run.

github-actions · 2026-01-20T17:24:40Z

E2E test run is starting for commit 26bc2d69d618367ef8721f183b383ffddc18192b.
To check the run progress:

Cypress: look for commit status E2E Tests/test or the access the Automation Dashboard Cycle URL.
Playwright: look for commit status E2E Tests/test-playwright.

You can also look at the E2E test's Workflow Run URL (run ID 21180952212).

github-actions · 2026-01-20T18:08:10Z

E2E test has completed for commit 26bc2d69d618367ef8721f183b383ffddc18192b.
Results summary:

Cypress: pass rate is 100.00% (see Automation Dashboard and commit status check E2E Tests/test).
Playwright: pass rate is 100.00% (see Playwright Report URL and commit status check E2E Tests/test-playwright).

The run summary artifacts are available in the corresponding Workflow Run.

harshilsharma63

Approved ✅

hmhealey · 2026-01-21T19:18:48Z

@yasserfaraazkhan This is another PR that shouldn't have any effect on users, and any functional changes are hopefully just for handling edge cases which may or may not be possible. I'm not sure if you want to smoke test this or if the E2E tests passing is sufficient

mm-cloud-bot · 2026-01-23T15:29:47Z

Mattermost Spinwick PR #34603 🎉

Test server created!

Access here: https://mattermost-pr-34603-aba57.test.mattermost.cloud

Installation ID: ucxo7rbntpd5bbr6s7cq5hqdio
Logs: Click here

Credentials: Posted securely in this Mattermost channel - Look for PR #34603

mm-cloud-bot · 2026-01-23T19:29:45Z

Test server destroyed

hmhealey added 9 commits November 26, 2025 17:03

Add TS definitions for every WebSocket event

f8d30a4

Remove unused WebSocket events

606cedf

Add a few extra fields to POSTED events

227e289

Stop reusing WS event types as Redux actions

029cdfb

Remove now-unused WS event types from mattermost-redux

c56957d

Rename some types to be clearer

af1d4c5

Use new WebSocketEvents and WebSocketMessage type everywhere

eba785d

Reorganize and export named types for WS messages

33d4624

Use new types in websocket_actions.jsx the best we can

3832ee4

mm-cloud-bot added the release-note-none Denotes a PR that doesn't merit a release note. label Nov 26, 2025

hmhealey added 7 commits November 28, 2025 16:58

Rename websocket_actions.jsx to websocket_actions.tsx

0f3b9c4

Migrate websocket_actions.tsx to TypeScript

bfe1b33

Break up websocket_messages.ts and group together WebSocketMessages t…

5fa8985

…ypes

Rename websocket_actions.tsx to websocket_actions.ts

bfc96fb

Merge branch 'master' into hh_nov26-websocket-events

edf75d6

Merge branch 'master' into hh_nov26-websocket-events

e2eb7b6

Merge branch 'master' into hh_nov26-websocket-events

0ac37af

Merge branch 'master' into hh_nov26-websocket-events

9af5ce1

Merge branch 'master' into hh_nov26-websocket-events

7efb1ec

hmhealey changed the title ~~Add TS type defintions for all WebSocket messages~~ Define types for WebSocket messages and migrate WebSocket handling to TS Jan 13, 2026

hmhealey changed the title ~~Define types for WebSocket messages and migrate WebSocket handling to TS~~ Define types for WebSocket messages and migrate WebSocket actions to TS Jan 13, 2026

hmhealey commented Jan 13, 2026

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hmhealey added the E2E/Run Initiate an E2E run in a PR label Jan 13, 2026

unified-ci-app bot removed the E2E/Run Initiate an E2E run in a PR label Jan 13, 2026

Merge branch 'master' into hh_nov26-websocket-events

f62ffc6

hmhealey added E2E/Run Initiate an E2E run in a PR 2: Dev Review Requires review by a developer 3: QA Review Requires review by a QA tester. May occur at the same time as Dev Review labels Jan 19, 2026

hmhealey requested review from harshilsharma63 and larkox January 19, 2026 16:49

hmhealey marked this pull request as ready for review January 19, 2026 16:50

larkox approved these changes Jan 19, 2026

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unified-ci-app bot removed the E2E/Run Initiate an E2E run in a PR label Jan 19, 2026

Merge branch 'master' into hh_nov26-websocket-events

26bc2d6

hmhealey added the E2E/Run Initiate an E2E run in a PR label Jan 20, 2026

unified-ci-app bot removed the E2E/Run Initiate an E2E run in a PR label Jan 20, 2026

harshilsharma63 approved these changes Jan 21, 2026

View reviewed changes

hmhealey requested a review from yasserfaraazkhan January 21, 2026 19:17

yasserfaraazkhan added the Setup Cloud Test Server Setup an on-prem test server label Jan 23, 2026

yasserfaraazkhan approved these changes Jan 23, 2026

View reviewed changes

hmhealey added 4: Reviews Complete All reviewers have approved the pull request and removed 2: Dev Review Requires review by a developer 3: QA Review Requires review by a QA tester. May occur at the same time as Dev Review labels Jan 23, 2026

hmhealey merged commit 777867d into master Jan 23, 2026
99 checks passed

hmhealey deleted the hh_nov26-websocket-events branch January 23, 2026 19:29

mattermost-build removed the Setup Cloud Test Server Setup an on-prem test server label Jan 23, 2026

Define types for WebSocket messages and migrate WebSocket actions to TS #34603

Define types for WebSocket messages and migrate WebSocket actions to TS #34603

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