refactor: switch webchat from sse to websocket (#1808)

* refactor: switch webchat from sse to websocket

* perf: image preview dialog

* chore: remove console.log

src/langbot/pkg/api/http/controller/groups/files.py

@@ -28,8 +28,56 @@ class FilesRouterGroup(group.RouterGroup):
 
             return quart.Response(image_bytes, mimetype=mime_type)
 
+        @self.route('/images', methods=['POST'], auth_type=group.AuthType.USER_TOKEN)
+        async def upload_image() -> quart.Response:
+            request = quart.request
+
+            # Check file size limit before reading the file
+            content_length = request.content_length
+            if content_length and content_length > group.MAX_FILE_SIZE:
+                return self.fail(400, 'Image size exceeds 10MB limit.')
+
+            # get file bytes from 'file'
+            files = await request.files
+            if 'file' not in files:
+                return self.fail(400, 'No image file provided')
+
+            file = files['file']
+            assert isinstance(file, quart.datastructures.FileStorage)
+
+            file_bytes = await asyncio.to_thread(file.stream.read)
+
+            # Double-check actual file size after reading
+            if len(file_bytes) > group.MAX_FILE_SIZE:
+                return self.fail(400, 'Image size exceeds 10MB limit.')
+
+            # Validate image file extension
+            allowed_extensions = {'jpg', 'jpeg', 'png', 'gif', 'webp'}
+            if '.' in file.filename:
+                file_name, extension = file.filename.rsplit('.', 1)
+                extension = extension.lower()
+            else:
+                return self.fail(400, 'Invalid image file: no file extension')
+
+            if extension not in allowed_extensions:
+                return self.fail(400, f'Invalid image format. Allowed formats: {", ".join(allowed_extensions)}')
+
+            # check if file name contains '/' or '\'
+            if '/' in file_name or '\\' in file_name:
+                return self.fail(400, 'File name contains invalid characters')
+
+            file_key = file_name + '_' + str(uuid.uuid4())[:8] + '.' + extension
+
+            # save file to storage
+            await self.ap.storage_mgr.storage_provider.save(file_key, file_bytes)
+            return self.success(
+                data={
+                    'file_key': file_key,
+                }
+            )
+
         @self.route('/documents', methods=['POST'], auth_type=group.AuthType.USER_TOKEN)
-        async def _() -> quart.Response:
+        async def upload_document() -> quart.Response:
             request = quart.request
 
             # Check file size limit before reading the file