feat: support image prompts across IM channels

test/channels/feishu/message-utils.test.mjs

@@ -1,13 +1,20 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
+import { Readable } from 'node:stream';
 import {
   conversationKey,
+  extractInboundMessage,
   extractText,
   isAllowedSender,
   isBotSender,
   splitText,
 } from '../../../src/channels/feishu/message-utils.mjs';
 
+const PNG_1X1 = Buffer.from(
+  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII=',
+  'base64',
+);
+
 test('extractText removes bot mentions', () => {
   const event = {
     message: {
@@ -19,6 +26,121 @@ test('extractText removes bot mentions', () => {
   assert.equal(extractText(event), '你好');
 });
 
+test('extractInboundMessage lazily downloads a Feishu image resource as a bounded stream', async () => {
+  const calls = [];
+  const event = {
+    message: {
+      message_id: 'om_image',
+      message_type: 'image',
+      content: JSON.stringify({ image_key: 'img_test' }),
+    },
+  };
+  const client = { im: { v1: { messageResource: { get: async (request) => {
+    calls.push(request);
+    return {
+      headers: { 'content-length': String(PNG_1X1.length) },
+      getReadableStream: () => Readable.from([
+        PNG_1X1.subarray(0, 12),
+        PNG_1X1.subarray(12),
+      ]),
+    };
+  } } } } };
+
+  const message = extractInboundMessage(event, client);
+  assert.equal(message.content, '');
+  assert.equal(message.images.length, 1);
+  assert.deepEqual(await message.images[0].load({ maxBytes: 1024 }), PNG_1X1);
+  assert.deepEqual(calls, [{
+    path: { message_id: 'om_image', file_key: 'img_test' },
+    params: { type: 'image' },
+  }]);
+});
+
+test('extractInboundMessage preserves visible Feishu post text and every embedded image', async () => {
+  const calls = [];
+  const event = {
+    message: {
+      message_id: 'om_post',
+      message_type: 'post',
+      mentions: [{ key: '@_bot_1' }],
+      content: JSON.stringify({
+        title: '截图比较',
+        content: [
+          [
+            { tag: 'at', user_id: '@_bot_1', user_name: '机器人' },
+            { tag: 'text', text: '@_bot_1 请查看 ' },
+            { tag: 'a', text: '第一处', href: 'https://example.com/one' },
+            { tag: 'link', text: ' 和第二处', href: 'https://example.com/two' },
+          ],
+          [{ tag: 'img', image_key: 'img_first' }],
+          [{ tag: 'text', text: '补充说明' }],
+          [
+            { tag: 'img', image_key: 'img_second' },
+            { tag: 'img', image_key: '  ' },
+          ],
+        ],
+      }),
+    },
+  };
+  const client = { im: { v1: { messageResource: { get: async (request) => {
+    calls.push(request);
+    return {
+      headers: { 'content-length': String(PNG_1X1.length) },
+      getReadableStream: () => Readable.from([PNG_1X1]),
+    };
+  } } } } };
+
+  const message = extractInboundMessage(event, client);
+  assert.equal(extractText(event), null, 'rich posts must not become interaction replies');
+  assert.equal(message.content, '截图比较\n请查看 第一处 和第二处\n补充说明');
+  assert.equal(message.images.length, 2);
+  assert.deepEqual(await Promise.all(message.images.map((image) => image.load({ maxBytes: 1024 }))), [
+    PNG_1X1,
+    PNG_1X1,
+  ]);
+  assert.deepEqual(calls, [
+    {
+      path: { message_id: 'om_post', file_key: 'img_first' },
+      params: { type: 'image' },
+    },
+    {
+      path: { message_id: 'om_post', file_key: 'img_second' },
+      params: { type: 'image' },
+    },
+  ]);
+});
+
+test('Feishu image loading rejects declared or streamed data above the caller limit', async () => {
+  for (const resource of [
+    {
+      headers: { 'content-length': '5' },
+      getReadableStream: () => Readable.from([Buffer.alloc(5)]),
+    },
+    {
+      headers: {},
+      getReadableStream: () => Readable.from([Buffer.alloc(2), Buffer.alloc(3)]),
+    },
+  ]) {
+    const message = extractInboundMessage({
+      message: {
+        message_id: 'om_large',
+        message_type: 'image',
+        content: JSON.stringify({ image_key: 'img_large' }),
+      },
+    }, { im: { v1: { messageResource: { get: async () => resource } } } });
+    await assert.rejects(message.images[0].load({ maxBytes: 4 }), /limit|exceeds/);
+  }
+});
+
+test('malformed Feishu image content does not create a downloadable image reference', () => {
+  assert.deepEqual(extractInboundMessage({
+    message: { message_type: 'image', content: '{not-json' },
+  }, {}), { content: '', images: [] });
+  assert.deepEqual(extractInboundMessage({
+    message: { message_type: 'post', content: '{not-json' },
+  }, {}), { content: '', images: [] });
+});
+
 test('conversationKey isolates p2p users and groups', () => {
   assert.equal(conversationKey({
     sender: { sender_id: { open_id: 'ou_test' } },