api: Expose event_queue_longpoll_timeout_seconds in /register.

Rename poll_timeout to event_queue_longpoll_timeout_seconds
and change its value from 90000 ms to 90 sec. Expose its
value in register api response when realm data is fetched.
Bump API_FEATURE_LEVEL to 74.

static/js/server_events.js

@@ -211,7 +211,7 @@ function get_events({dont_block = false} = {}) {
         url: "/json/events",
         data: get_events_params,
         idempotent: true,
-        timeout: page_params.poll_timeout,
+        timeout: page_params.event_queue_longpoll_timeout_seconds * 1000,
         success(data) {
             watchdog.set_suspect_offline(false);
             try {

templates/zerver/api/changelog.md

@@ -11,6 +11,12 @@ below features are supported.
 
 ## Changes in Zulip 5.0
 
+**Feature level 74**
+
+* [`POST /register`](/api/register-queue): Added `server_needs_upgrade`
+  and `event_queue_longpoll_timeout_seconds` field when fetching
+  realm data.
+
 **Feature level 73**
 
 * [`GET /users`](/api/get-users), [`GET /users/{user_id}`](/api/get-user),

version.py

@@ -33,7 +33,7 @@ DESKTOP_WARNING_VERSION = "5.4.3"
 # Changes should be accompanied by documentation explaining what the
 # new level means in templates/zerver/api/changelog.md, as well as
 # "**Changes**" entries in the endpoint's documentation in `zulip.yaml`.
-API_FEATURE_LEVEL = 73
+API_FEATURE_LEVEL = 74
 
 # Bump the minor PROVISION_VERSION to indicate that folks should provision
 # only when going from an old version of the code to a newer version. Bump

zerver/lib/events.py

@@ -277,6 +277,9 @@ def fetch_initial_state_data(
         state["giphy_rating_options"] = realm.GIPHY_RATING_OPTIONS
 
         state["server_needs_upgrade"] = is_outdated_server(user_profile)
+        state[
+            "event_queue_longpoll_timeout_seconds"
+        ] = settings.EVENT_QUEUE_LONGPOLL_TIMEOUT_SECONDS
 
         # TODO: Should these have the realm prefix replaced with server_?
         state["realm_push_notifications_enabled"] = push_notifications_enabled()

zerver/lib/home.py

@@ -183,7 +183,6 @@ def build_page_params_for_home_page_load(
     page_params = dict(
         ## Server settings.
         test_suite=settings.TEST_SUITE,
-        poll_timeout=settings.POLL_TIMEOUT,
         insecure_desktop_app=insecure_desktop_app,
         login_page=settings.HOME_NOT_LOGGED_IN,
         save_stacktraces=settings.SAVE_FRONTEND_STACKTRACES,

zerver/openapi/zulip.yaml

@@ -141,6 +141,13 @@ paths:
 
         This endpoint allows you to receive new events from
         [a registered event queue](/api/register-queue).
+
+        Long-lived clients should use the
+        `event_queue_longpoll_timeout_seconds` property returned by
+        `POST /register` as the client-side HTTP request timeout for
+        calls to this endpoint.  It is guaranteed to be higher than
+        heartbeat frequency and should be respected by clients to
+        avoid breaking when heartbeat frequency increases.
       parameters:
         - $ref: "#/components/parameters/QueueId"
         - name: last_event_id
@@ -8986,6 +8993,19 @@ paths:
                           such that the web app will display to the current user a prominent warning.
 
                           **Changes**: New in Zulip 5.0 (feature level 74).
+                      event_queue_longpoll_timeout_seconds:
+                        type: integer
+                        description: |
+                          Present if `realm` is present in `fetch_event_types`.
+
+                          Recommended client-side HTTP request timeout for [`GET /events`](/api/get-events) calls.
+                          This is guaranteed to be somewhat greater than the heartbeat frequency. It is important
+                          that clients respect this parameter, so that increases in the heartbeat frequency do not
+                          break clients.
+
+                          **Changes**: New in Zulip 5.0 (feature level 74). Previously,
+                          this was hardcoded to 90 seconds, and clients should use that as a fallback
+                          value when interacting with servers where this field is not present.
                       realm_notifications_stream_id:
                         type: integer
                         description: |

zerver/tests/test_home.py

@@ -83,6 +83,7 @@ class HomeTest(ZulipTestCase):
         "enable_stream_email_notifications",
         "enable_stream_push_notifications",
         "enter_sends",
+        "event_queue_longpoll_timeout_seconds",
         "first_in_realm",
         "fluid_layout_width",
         "full_name",
@@ -126,7 +127,6 @@ class HomeTest(ZulipTestCase):
         "password_min_guesses",
         "password_min_length",
         "pm_content_in_desktop_notifications",
-        "poll_timeout",
         "presence_enabled",
         "presences",
         "prompt_for_invites",

zproject/computed_settings.py

@@ -988,12 +988,12 @@ else:
 
 LOGIN_REDIRECT_URL = "/"
 
-# Client-side polling timeout for get_events, in milliseconds.
+# Client-side polling timeout for get_events, in seconds.
 # We configure this here so that the client test suite can override it.
 # We already kill the connection server-side with heartbeat events,
 # but it's good to have a safety.  This value should be greater than
 # (HEARTBEAT_MIN_FREQ_SECS + 10)
-POLL_TIMEOUT = 90 * 1000
+EVENT_QUEUE_LONGPOLL_TIMEOUT_SECONDS = 90
 
 ########################################################################
 # SSO AND LDAP SETTINGS

zproject/test_extra_settings.py

@@ -63,7 +63,7 @@ if "BAN_CONSOLE_OUTPUT" in os.environ:
 
 # Decrease the get_updates timeout to 1 second.
 # This allows frontend tests to proceed quickly to the next test step.
-POLL_TIMEOUT = 1000
+EVENT_QUEUE_LONGPOLL_TIMEOUT_SECONDS = 1
 
 # Stores the messages in `django.core.mail.outbox` rather than sending them.
 EMAIL_BACKEND = "django.core.mail.backends.locmem.EmailBackend"