thumbnail: Advertize the thumbnail formats at client registration.

api_docs/changelog.md

@@ -20,6 +20,11 @@ format used by the Zulip server that they are interacting with.
 
 ## Changes in Zulip 9.0
 
+**Feature level 273**
+
+* [`POST /register`](/api/register-queue): Added `server_thumbnail_formats`
+  describing what formats the server will thumbnail images into.
+
 **Feature level 272**
 
 * [`POST /user_uploads`](/api/upload-file): `uri` was renamed

tools/test-js-with-node

@@ -252,6 +252,7 @@ EXEMPT_FILES = make_set(
         "web/src/submessage.ts",
         "web/src/subscriber_api.ts",
         "web/src/theme.ts",
+        "web/src/thumbnail.ts",
         "web/src/timerender.ts",
         "web/src/tippyjs.ts",
         "web/src/todo_widget.js",

version.py

@@ -34,7 +34,7 @@ DESKTOP_WARNING_VERSION = "5.9.3"
 # new level means in api_docs/changelog.md, as well as "**Changes**"
 # entries in the endpoint's documentation in `zulip.yaml`.
 
-API_FEATURE_LEVEL = 272  # Last bumped for "POST /user_uploads"
+API_FEATURE_LEVEL = 273  # Last bumped for server_thumbnail_formats
 
 
 # Bump the minor PROVISION_VERSION to indicate that folks should provision

web/src/state_data.ts

@@ -179,6 +179,14 @@ const one_time_notice_schema = z.object({
     type: z.literal("one_time_notice"),
 });
 
+export const thumbnail_format_schema = z.object({
+    name: z.string(),
+    max_width: z.number(),
+    max_height: z.number(),
+    format: z.string(),
+    animated: z.boolean(),
+});
+
 /* We may introduce onboarding step of types other than 'one time notice'
 in future. Earlier, we had 'hotspot' and 'one time notice' as the two
 types. We can simply do:
@@ -374,6 +382,7 @@ const realm_schema = z.object({
         stream: z.record(group_permission_setting_schema),
         group: z.record(group_permission_setting_schema),
     }),
+    server_thumbnail_formats: z.array(thumbnail_format_schema),
     server_typing_started_expiry_period_milliseconds: z.number(),
     server_typing_started_wait_period_milliseconds: z.number(),
     server_typing_stopped_wait_period_milliseconds: z.number(),

web/src/thumbnail.ts

@@ -0,0 +1,36 @@
+import type {z} from "zod";
+
+import {realm} from "./state_data";
+import type {thumbnail_format_schema} from "./state_data";
+
+type ThumbnailFormat = z.infer<typeof thumbnail_format_schema>;
+
+export const thumbnail_formats: ThumbnailFormat[] = [];
+
+export let preferred_format: ThumbnailFormat;
+export let animated_format: ThumbnailFormat;
+
+export function initialize(): void {
+    // Go looking for the size closest to 300x200, of the smallest format.  We assume all browsers
+    // support webp.
+    const format_preferences = ["webp", "jpg", "gif"];
+    const sorted_formats = realm.server_thumbnail_formats.sort((a, b) => {
+        if (a.max_width !== b.max_width) {
+            return Math.abs(a.max_width - 300) < Math.abs(b.max_width - 300) ? -1 : 1;
+        } else if (a.format !== b.format) {
+            let a_index = format_preferences.indexOf(a.format);
+            if (a_index === -1) {
+                a_index = format_preferences.length;
+            }
+            let b_index = format_preferences.indexOf(b.format);
+            if (b_index === -1) {
+                b_index = format_preferences.length;
+            }
+            return a_index - b_index;
+        }
+
+        return 0;
+    });
+    preferred_format = sorted_formats.find((format) => !format.animated)!;
+    animated_format = sorted_formats.find((format) => format.animated)!;
+}

web/src/ui_init.js

@@ -126,6 +126,7 @@ import * as stream_topic_history from "./stream_topic_history";
 import * as stream_topic_history_util from "./stream_topic_history_util";
 import * as sub_store from "./sub_store";
 import * as theme from "./theme";
+import * as thumbnail from "./thumbnail";
 import * as timerender from "./timerender";
 import * as tippyjs from "./tippyjs";
 import * as topic_list from "./topic_list";
@@ -426,6 +427,7 @@ export function initialize_everything(state_data) {
     if (page_params.is_spectator) {
         theme.initialize_theme_for_spectator();
     }
+    thumbnail.initialize();
     widgets.initialize();
     tippyjs.initialize();
     compose_tooltips.initialize();

zerver/lib/events.py

@@ -54,6 +54,7 @@ from zerver.lib.subscription_info import (
     gather_subscriptions_helper,
     get_web_public_subs,
 )
+from zerver.lib.thumbnail import THUMBNAIL_OUTPUT_FORMATS
 from zerver.lib.timestamp import datetime_to_timestamp
 from zerver.lib.timezone import canonicalize_timezone
 from zerver.lib.topic import TOPIC_NAME
@@ -381,6 +382,16 @@ def fetch_initial_state_data(
         state["password_min_guesses"] = settings.PASSWORD_MIN_GUESSES
         state["server_inline_image_preview"] = settings.INLINE_IMAGE_PREVIEW
         state["server_inline_url_embed_preview"] = settings.INLINE_URL_EMBED_PREVIEW
+        state["server_thumbnail_formats"] = [
+            {
+                "name": str(thumbnail_format),
+                "max_width": thumbnail_format.max_width,
+                "max_height": thumbnail_format.max_height,
+                "format": thumbnail_format.extension,
+                "animated": thumbnail_format.animated,
+            }
+            for thumbnail_format in THUMBNAIL_OUTPUT_FORMATS
+        ]
         state["server_avatar_changes_disabled"] = settings.AVATAR_CHANGES_DISABLED
         state["server_name_changes_disabled"] = settings.NAME_CHANGES_DISABLED
         state["server_web_public_streams_enabled"] = settings.WEB_PUBLIC_STREAMS_ENABLED

zerver/openapi/zulip.yaml

@@ -16397,6 +16397,43 @@ paths:
                           Clients containing administrative UI for changing
                           `realm_inline_url_embed_preview` should consult this field before offering
                           that feature.
+                      server_thumbnail_formats:
+                        description: |
+                          A list describing the image formats that uploaded
+                          images will be thumbnailed into. Any image with a
+                          source starting with `/user_uploads/thumbnail/` can
+                          have its last path component replaced with any of the
+                          names contained in this list, to obtain the desired
+                          thumbnail size.
+
+                          **Changes**: New in Zulip 9.0 (feature level 273).
+                        type: array
+                        items:
+                          type: object
+                          additionalProperties: false
+                          properties:
+                            name:
+                              type: string
+                              description: |
+                                The file path component of the thumbnail format.
+                            max_width:
+                              type: integer
+                              description: |
+                                The maximum width of this format.
+                            max_height:
+                              type: integer
+                              description: |
+                                The maximum height of this format.
+                            format:
+                              type: string
+                              description: |
+                                The extension of this format.
+                            animated:
+                              type: boolean
+                              description: |
+                                If this file format is animated. These formats
+                                are only generated for uploaded imates which
+                                themselves are animated.
                       server_avatar_changes_disabled:
                         type: boolean
                         description: |

zerver/tests/test_home.py

@@ -219,6 +219,7 @@ class HomeTest(ZulipTestCase):
         "server_presence_offline_threshold_seconds",
         "server_presence_ping_interval_seconds",
         "server_supported_permission_settings",
+        "server_thumbnail_formats",
         "server_timestamp",
         "server_typing_started_expiry_period_milliseconds",
         "server_typing_started_wait_period_milliseconds",