Thomas Faour
35e80c6d1c
A new widget type showing a single user-uploaded image with no live upstream to poll -- decoded once at upload time (PDF's first page via pypdfium2, BSD-3-Clause/Apache-2.0, no copyleft exposure) into plain RGB PNG bytes, then composed per a crop/stretch/letterbox display mode like the photos widget.
55 lines
2.3 KiB
Python
55 lines
2.3 KiB
Python
"""Decodes an arbitrary uploaded file (PNG/JPEG/GIF/BMP/WEBP/TIFF/PDF/...)
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into a plain RGB PIL image, for the static-image widget (see routers/
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api_widgets.py's api_widget_static_upload, app/widgets/static_image.py).
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The result is stored (as PNG bytes) rather than the original upload, so
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render() never needs to re-run PDF/GIF decoding on every panel refresh --
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this module only runs once, at upload time.
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PDF decoding uses pypdfium2 (Google's PDFium bindings -- BSD-3-Clause/
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Apache-2.0, no copyleft exposure) rather than a GPL/AGPL alternative
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like PyMuPDF, per CLAUDE.md's copyleft-dependency convention (a check
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that only applies to copyleft/unclear licenses -- this one's plainly
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permissive, so no explicit flag was needed here)."""
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from __future__ import annotations
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import io
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import pypdfium2 as pdfium
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from fastapi import HTTPException
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from PIL import Image, UnidentifiedImageError
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MAX_UPLOAD_BYTES = 25 * 1024 * 1024 # generous for a single image/PDF page; stops an accidental huge upload
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# ~144 DPI off a PDF's 72-DPI native unit -- comfortably above the panel's
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# own 800x480, without ballooning render time/memory on a poster-sized page.
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PDF_RENDER_SCALE = 2.0
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def decode_upload(data: bytes) -> Image.Image:
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"""Raises HTTPException(400) for anything that isn't a recognizable
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image or PDF. Detects PDF by magic bytes, not the client-supplied
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filename/content-type (neither is trustworthy). A PDF renders only
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its first page -- there's no "which page" concept for a single-image
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widget."""
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if len(data) > MAX_UPLOAD_BYTES:
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raise HTTPException(400, f"File is too large (max {MAX_UPLOAD_BYTES // (1024 * 1024)}MB)")
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if data.startswith(b"%PDF-"):
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return _decode_pdf(data)
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try:
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img = Image.open(io.BytesIO(data))
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img.load()
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except UnidentifiedImageError:
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raise HTTPException(400, "Not a recognizable image or PDF file") from None
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return img.convert("RGB")
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def _decode_pdf(data: bytes) -> Image.Image:
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try:
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pdf = pdfium.PdfDocument(data)
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if len(pdf) == 0:
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raise HTTPException(400, "PDF has no pages")
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bitmap = pdf[0].render(scale=PDF_RENDER_SCALE)
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except pdfium.PdfiumError as e:
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raise HTTPException(400, f"Could not read PDF: {e}") from e
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return bitmap.to_pil().convert("RGB")
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