From c92e5d03a7f1db4ef72474797842dcdc4ba75dbd Mon Sep 17 00:00:00 2001
From: Hampus <hampus@fluxer.app>
Date: Tue, 22 Sep 2026 21:18:35 +0200
Subject: [PATCH] fix(api): accept any image or video attachment as embed media
 (#2901)

---
 .../message/MessageEmbedAttachmentResolver.ts | 13 +++++----
 .../EmbedAttachmentUrlResolution.test.ts      | 28 +++++++++++++++++++
 2 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/fluxer_api/src/api/channel/services/message/MessageEmbedAttachmentResolver.ts b/fluxer_api/src/api/channel/services/message/MessageEmbedAttachmentResolver.ts
index 628113cec..7e0efe454 100644
--- a/fluxer_api/src/api/channel/services/message/MessageEmbedAttachmentResolver.ts
+++ b/fluxer_api/src/api/channel/services/message/MessageEmbedAttachmentResolver.ts
@@ -3,7 +3,7 @@
 import type {AttachmentID, ChannelID} from '@app/api/BrandedTypes';
 import type {AttachmentRequestData} from '@app/api/channel/AttachmentDTOs';
 import type {RichEmbedMediaWithMetadata} from '@app/api/channel/EmbedTypes';
-import {makeAttachmentCdnUrl} from '@app/api/channel/services/message/MessageHelpers';
+import {getContentType, makeAttachmentCdnUrl} from '@app/api/channel/services/message/MessageHelpers';
 import {ValidationErrorCodes} from '@fluxer/constants/src/ValidationErrorCodes';
 import {InputValidationError} from '@fluxer/errors/src/domains/core/InputValidationError';
 import type {RichEmbedRequest} from '@fluxer/schema/src/domains/message/MessageRequestSchemas';
@@ -26,7 +26,10 @@ interface RichEmbedRequestWithMetadata extends Omit<RichEmbedRequest, 'image' |
 	thumbnail?: RichEmbedMediaWithMetadata | null;
 }
 
-const SUPPORTED_IMAGE_EXTENSIONS = new Set(['png', 'jpg', 'jpeg', 'webp', 'gif']);
+function isEmbeddableMediaType(contentType: string): boolean {
+	const normalized = contentType.toLowerCase();
+	return normalized.startsWith('image/') || normalized.startsWith('video/');
+}
 
 export class MessageEmbedAttachmentResolver {
 	validateAttachmentReferences(params: {
@@ -69,8 +72,7 @@ export class MessageEmbedAttachmentResolver {
 					{filename},
 				);
 			}
-			const extension = filename.split('.').pop()?.toLowerCase();
-			if (!extension || !SUPPORTED_IMAGE_EXTENSIONS.has(extension)) {
+			if (!isEmbeddableMediaType(getContentType(filename))) {
 				throw InputValidationError.fromCode(
 					`embeds[${embedIndex}].${field}`,
 					ValidationErrorCodes.ATTACHMENT_MUST_BE_IMAGE,
@@ -137,8 +139,7 @@ export class MessageEmbedAttachmentResolver {
 			if (!attachmentData) {
 				throw InputValidationError.fromCode(field, ValidationErrorCodes.REFERENCED_ATTACHMENT_NOT_FOUND, {filename});
 			}
-			const extension = filename.split('.').pop()?.toLowerCase();
-			if (!extension || !SUPPORTED_IMAGE_EXTENSIONS.has(extension)) {
+			if (!isEmbeddableMediaType(attachmentData.metadata.content_type)) {
 				throw InputValidationError.fromCode(field, ValidationErrorCodes.ATTACHMENT_MUST_BE_IMAGE, {filename});
 			}
 			return attachmentData;
diff --git a/fluxer_api/src/api/channel/tests/EmbedAttachmentUrlResolution.test.ts b/fluxer_api/src/api/channel/tests/EmbedAttachmentUrlResolution.test.ts
index d3dd92acd..680ac046d 100644
--- a/fluxer_api/src/api/channel/tests/EmbedAttachmentUrlResolution.test.ts
+++ b/fluxer_api/src/api/channel/tests/EmbedAttachmentUrlResolution.test.ts
@@ -512,6 +512,34 @@ describe('Embed Attachment URL Resolution', () => {
 			expect(json.embeds).toHaveLength(1);
 			expect(json.embeds![0].image?.url).not.toContain('attachment://');
 		});
+		it('should accept image and video attachments beyond the legacy image extensions', async () => {
+			const account = await createTestAccount(harness);
+			const guild = await createGuild(harness, account.token, 'Media Type Guild');
+			const channel = await createChannel(harness, account.token, guild.id, 'test-channel');
+			const channelId = guild.system_channel_id ?? channel.id;
+			const payload = {
+				content: 'Test with jxl and mp4 embed media',
+				attachments: [
+					{id: 0, filename: 'photo.jxl'},
+					{id: 1, filename: 'clip.mp4'},
+				],
+				embeds: [
+					{
+						title: 'Media Embed',
+						image: {url: 'attachment://clip.mp4'},
+						thumbnail: {url: 'attachment://photo.jxl'},
+					},
+				],
+			};
+			const {response, json} = await sendMessageWithAttachments(harness, account.token, channelId, payload, [
+				{index: 0, filename: 'photo.jxl', data: Buffer.from('jxl bytes')},
+				{index: 1, filename: 'clip.mp4', data: Buffer.from('mp4 bytes')},
+			]);
+			expect(response.status).toBe(200);
+			expect(json.embeds).toHaveLength(1);
+			expect(json.embeds![0].image?.url).not.toContain('attachment://');
+			expect(json.embeds![0].thumbnail?.url).not.toContain('attachment://');
+		});
 	});
 	describe('Multiple Embeds and Files', () => {
 		it('should handle multiple embeds with different URL types', async () => {