cista-storage/cista/preview.py
2025-08-15 09:51:40 -06:00

245 lines
8.2 KiB
Python

import asyncio
import gc
import io
import mimetypes
import urllib.parse
from pathlib import PurePosixPath
from time import perf_counter
from urllib.parse import unquote
from wsgiref.handlers import format_date_time
import av
import fitz # PyMuPDF
import numpy as np
import pillow_heif
from PIL import Image
from sanic import Blueprint, empty, raw
from sanic.exceptions import NotFound
from sanic.log import logger
from cista import config
from cista.util.filename import sanitize
pillow_heif.register_heif_opener()
bp = Blueprint("preview", url_prefix="/preview")
@bp.get("/<path:path>")
async def preview(req, path):
"""Preview a file"""
maxsize = int(req.args.get("px", 1024))
maxzoom = float(req.args.get("zoom", 2.0))
quality = int(req.args.get("q", 40))
rel = PurePosixPath(sanitize(unquote(path)))
path = config.config.path / rel
stat = path.lstat()
etag = config.derived_secret(
"preview", rel, stat.st_mtime_ns, quality, maxsize, maxzoom
).hex()
savename = PurePosixPath(path.name).with_suffix(".avif")
headers = {
"etag": etag,
"last-modified": format_date_time(stat.st_mtime),
"cache-control": "max-age=604800, immutable"
+ ("" if config.config.public else ", private"),
"content-type": "image/avif",
"content-disposition": f"inline; filename*=UTF-8''{urllib.parse.quote(savename.as_posix())}",
}
if req.headers.if_none_match == etag:
# The client has it cached, respond 304 Not Modified
return empty(304, headers=headers)
if not path.is_file():
raise NotFound("File not found")
img = await asyncio.get_event_loop().run_in_executor(
req.app.ctx.threadexec, dispatch, path, quality, maxsize, maxzoom
)
return raw(img, headers=headers)
def dispatch(path, quality, maxsize, maxzoom):
if path.suffix.lower() in (".pdf", ".xps", ".epub", ".mobi"):
return process_pdf(path, quality=quality, maxsize=maxsize, maxzoom=maxzoom)
type, _ = mimetypes.guess_type(path.name)
if type and type.startswith("video/"):
return process_video(path, quality=quality, maxsize=maxsize)
return process_image(path, quality=quality, maxsize=maxsize)
def process_image(path, *, maxsize, quality):
t_load_start = perf_counter()
img = Image.open(path)
# Force decode to include I/O in load timing
img.load()
t_load_end = perf_counter()
# Resize and orientation fix (processing)
orig_w, orig_h = img.size
t_proc_start = perf_counter()
img.thumbnail((min(orig_w, maxsize), min(orig_h, maxsize)))
try:
rotate_values = {3: 180, 6: 270, 8: 90}
orientation = img.getexif().get(274)
if orientation in rotate_values:
logger.debug(f"Rotating preview {path} by {rotate_values[orientation]}")
img = img.rotate(rotate_values[orientation], expand=True)
except Exception as e:
logger.error(f"Error rotating preview image: {e}")
t_proc_end = perf_counter()
# Save as AVIF
imgdata = io.BytesIO()
t_save_start = perf_counter()
img.save(imgdata, format="avif", quality=quality)
t_save_end = perf_counter()
ret = imgdata.getvalue()
load_ms = (t_load_end - t_load_start) * 1000
proc_ms = (t_proc_end - t_proc_start) * 1000
save_ms = (t_save_end - t_save_start) * 1000
logger.info(
"Preview image %s: load=%.1fms process=%.1fms save=%.1fms out=%.1fKB %dx%d -> %dx%d q=%d",
path.name,
load_ms,
proc_ms,
save_ms,
len(ret) / 1024,
orig_w,
orig_h,
getattr(img, "width", 0),
getattr(img, "height", 0),
quality,
)
return ret
def process_pdf(path, *, maxsize, maxzoom, quality, page_number=0):
t_load_start = perf_counter()
pdf = fitz.open(path)
page = pdf.load_page(page_number)
w, h = page.rect[2:4]
zoom = min(maxsize / w, maxsize / h, maxzoom)
mat = fitz.Matrix(zoom, zoom)
pix = page.get_pixmap(matrix=mat) # type: ignore[attr-defined]
t_load_end = perf_counter()
t_save_start = perf_counter()
ret = pix.pil_tobytes(format="avif", quality=quality, method=4)
t_save_end = perf_counter()
logger.info(
"Preview pdf %s: load+render=%.1fms save=%.1fms out=%.1fKB page=%d zoom=%.2f",
path.name,
(t_load_end - t_load_start) * 1000,
(t_save_end - t_save_start) * 1000,
len(ret) / 1024,
page_number,
zoom,
)
return ret
def process_video(path, *, maxsize, quality):
frame = None
imgdata = io.BytesIO()
istream = ostream = icc = occ = frame = None
t_load_start = perf_counter()
# Initialize to avoid "possibly unbound" in static analysis when exceptions occur
t_load_end = t_load_start
t_save_start = t_load_start
t_save_end = t_load_start
with (
av.open(str(path)) as icontainer,
av.open(imgdata, "w", format="avif") as ocontainer,
):
istream = icontainer.streams.video[0]
istream.codec_context.skip_frame = "NONKEY"
icontainer.seek((icontainer.duration or 0) // 8)
for frame in icontainer.decode(istream):
if frame.dts is not None:
break
else:
raise RuntimeError("No frames found in video")
# Resize frame to thumbnail size
if frame.width > maxsize or frame.height > maxsize:
scale_factor = min(maxsize / frame.width, maxsize / frame.height)
new_width = int(frame.width * scale_factor)
new_height = int(frame.height * scale_factor)
frame = frame.reformat(width=new_width, height=new_height)
# Simple rotation detection and logging
if frame.rotation:
try:
fplanes = frame.to_ndarray()
# Split into Y, U, V planes of proper dimensions
planes = [
fplanes[: frame.height],
fplanes[frame.height : frame.height + frame.height // 4].reshape(
frame.height // 2, frame.width // 2
),
fplanes[frame.height + frame.height // 4 :].reshape(
frame.height // 2, frame.width // 2
),
]
# Rotate
planes = [np.rot90(p, frame.rotation // 90) for p in planes]
# Restore PyAV format
planes = np.hstack([p.flat for p in planes]).reshape(
-1, planes[0].shape[1]
)
frame = av.VideoFrame.from_ndarray(planes, format=frame.format.name)
del planes, fplanes
except Exception as e:
if "not yet supported" in str(e):
logger.warning(
f"Not rotating {path.name} preview image by {frame.rotation}°:\n PyAV: {e}"
)
else:
logger.exception(f"Error rotating video frame: {e}")
t_load_end = perf_counter()
t_save_start = perf_counter()
crf = str(int(63 * (1 - quality / 100) ** 2)) # Closely matching PIL quality-%
ostream = ocontainer.add_stream(
"av1", options={"crf": crf, "usage": "realtime"}
)
assert isinstance(ostream, av.VideoStream)
ostream.width = frame.width
ostream.height = frame.height
icc = istream.codec_context
occ = ostream.codec_context
# Copy HDR metadata from input video stream
occ.color_primaries = icc.color_primaries
occ.color_trc = icc.color_trc
occ.colorspace = icc.colorspace
occ.color_range = icc.color_range
ocontainer.mux(ostream.encode(frame))
ocontainer.mux(ostream.encode(None)) # Flush the stream
t_save_end = perf_counter()
# Capture frame dimensions before cleanup
fw = getattr(frame, "width", 0) if frame else 0
fh = getattr(frame, "height", 0) if frame else 0
ret = imgdata.getvalue()
logger.info(
"Preview video %s: load+decode=%.1fms save=%.1fms out=%.1fKB dims=%dx%d q=%d",
path.name,
(t_load_end - t_load_start) * 1000,
(t_save_end - t_save_start) * 1000,
len(ret) / 1024,
fw,
fh,
quality,
)
del imgdata, istream, ostream, icc, occ, frame
gc.collect()
return ret