import logging import time from dataclasses import asdict from io import BytesIO from typing import Any import pyvips from django.db import transaction from typing_extensions import override from zerver.actions.message_edit import do_update_embedded_data from zerver.lib.mime_types import guess_type from zerver.lib.thumbnail import ( MarkdownImageMetadata, StoredThumbnailFormat, get_default_thumbnail_url, get_image_thumbnail_path, missing_thumbnails, rewrite_thumbnailed_images, ) from zerver.lib.upload import save_attachment_contents, upload_backend from zerver.models import ArchivedMessage, ImageAttachment, Message from zerver.worker.base import QueueProcessingWorker, assign_queue logger = logging.getLogger(__name__) @assign_queue("thumbnail") class ThumbnailWorker(QueueProcessingWorker): @override def consume(self, event: dict[str, Any]) -> None: start = time.time() with transaction.atomic(savepoint=False): try: # This lock prevents us from racing with the on-demand # rendering that can be triggered if a request is made # directly to a thumbnail URL we have not made yet. # This may mean that we may generate 0 thumbnail # images once we get the lock. row = ImageAttachment.objects.select_for_update().get(id=event["id"]) except ImageAttachment.DoesNotExist: # nocoverage logger.info("ImageAttachment row %d missing", event["id"]) return uploaded_thumbnails = ensure_thumbnails(row) end = time.time() logger.info( "Processed %d thumbnails (%dms)", uploaded_thumbnails, (end - start) * 1000, ) def ensure_thumbnails(image_attachment: ImageAttachment) -> int: needed_thumbnails = missing_thumbnails(image_attachment) if not needed_thumbnails: return 0 written_images = 0 image_bytes = BytesIO() save_attachment_contents(image_attachment.path_id, image_bytes) try: # TODO: We could save some computational time by using the same # bytes if multiple resolutions are larger than the source # image. That is, if the input is 10x10, a 100x100.jpg is # going to be the same as a 200x200.jpg, since those set the # max dimensions, and we do not scale up. for thumbnail_format in needed_thumbnails: # This will scale to fit within the given dimensions; it # may be smaller one one or more of them. logger.info( "Resizing to %d x %d, from %d x %d", thumbnail_format.max_width, thumbnail_format.max_height, image_attachment.original_width_px, image_attachment.original_height_px, ) load_opts = "" if image_attachment.frames > 1: # If the original has multiple frames, we want to load # one of them if we're outputting to a static format, # otherwise we load them all. if thumbnail_format.animated: load_opts = "n=-1" else: load_opts = "n=1" resized = pyvips.Image.thumbnail_buffer( image_bytes.getbuffer(), thumbnail_format.max_width, height=thumbnail_format.max_height, option_string=load_opts, size=pyvips.Size.DOWN, ) thumbnailed_bytes = resized.write_to_buffer( f".{thumbnail_format.extension}[{thumbnail_format.opts}]" ) content_type = guess_type(f"image.{thumbnail_format.extension}")[0] assert content_type is not None thumbnail_path = get_image_thumbnail_path(image_attachment, thumbnail_format) logger.info("Uploading %d bytes to %s", len(thumbnailed_bytes), thumbnail_path) upload_backend.upload_message_attachment( thumbnail_path, str(thumbnail_format), content_type, thumbnailed_bytes, None, ) height = resized.get("page-height") if thumbnail_format.animated else resized.height image_attachment.thumbnail_metadata.append( asdict( StoredThumbnailFormat( extension=thumbnail_format.extension, content_type=content_type, max_width=thumbnail_format.max_width, max_height=thumbnail_format.max_height, animated=thumbnail_format.animated, width=resized.width, height=height, byte_size=len(thumbnailed_bytes), ) ) ) written_images += 1 except pyvips.Error as e: logger.exception(e) if written_images == 0 and len(image_attachment.thumbnail_metadata) == 0: # We have never thumbnailed this -- it most likely had # bad data. Remove the ImageAttachment row, since it is # not valid for thumbnailing. update_message_rendered_content( image_attachment.realm_id, image_attachment.path_id, None ) image_attachment.delete() return 0 else: # nocoverage # TODO: Clean up any dangling thumbnails we may have # produced? Seems unlikely that we'd fail on one size, # but not another, but anything's possible. pass image_attachment.save(update_fields=["thumbnail_metadata"]) url, is_animated = get_default_thumbnail_url(image_attachment) update_message_rendered_content( image_attachment.realm_id, image_attachment.path_id, MarkdownImageMetadata( url=url, is_animated=is_animated, original_width_px=image_attachment.original_width_px, original_height_px=image_attachment.original_height_px, ), ) return written_images def update_message_rendered_content( realm_id: int, path_id: str, image_data: MarkdownImageMetadata | None ) -> None: for message_class in (Message, ArchivedMessage): messages_with_image = ( message_class.objects.filter(realm_id=realm_id, attachment__path_id=path_id) .select_for_update(of=("self",)) .order_by("id") ) for message in messages_with_image: assert message.rendered_content is not None rendered_content = rewrite_thumbnailed_images( message.rendered_content, {} if image_data is None else {path_id: image_data}, {path_id} if image_data is None else set(), )[0] if rendered_content is None: # There were no updates -- for instance, if we re-run # ensure_thumbnails on an ImageAttachment we already # ran it on once. Do not bother to no-op update # clients. continue if isinstance(message, Message): # Perform a silent update push to the clients do_update_embedded_data(message.sender, message, rendered_content) else: message.rendered_content = rendered_content message.save(update_fields=["rendered_content"])