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a49c70b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 | """File upload validation utilities."""
from __future__ import annotations
import uuid
from pathlib import Path
from PIL import Image
from src.exceptions import ValidationError
# Magic bytes for allowed image formats
_MAGIC_BYTES = {
b"\xff\xd8\xff": "jpg",
b"\x89PNG": "png",
}
ALLOWED_EXTENSIONS = {"png", "jpg", "jpeg"}
def validate_upload_file(
file,
max_size: int = 10 * 1024 * 1024,
min_dim: int = 512,
max_dim: int = 4096,
) -> dict:
"""Validate an uploaded image file.
Returns a dict with file info on success:
{"extension": str, "width": int, "height": int, "size": int}
Raises ValidationError on failure.
"""
if file is None or file.filename == "":
raise ValidationError("ファイルが選択されていません")
# Check extension
ext = _get_extension(file.filename)
if ext not in ALLOWED_EXTENSIONS:
raise ValidationError(f"対応していないファイル形式です。PNG/JPEG のみ対応しています。")
# Check file size
file.seek(0, 2)
size = file.tell()
file.seek(0)
if size > max_size:
mb = max_size // (1024 * 1024)
raise ValidationError(f"ファイルサイズが大きすぎます（上限: {mb}MB）")
if size == 0:
raise ValidationError("空のファイルです")
# Check magic bytes
header = file.read(8)
file.seek(0)
if not any(header.startswith(magic) for magic in _MAGIC_BYTES):
raise ValidationError("ファイルの内容が画像形式と一致しません")
# Verify as valid image and check dimensions
try:
img = Image.open(file)
img.verify()
file.seek(0)
img = Image.open(file)
width, height = img.size
file.seek(0)
except Exception:
raise ValidationError("画像ファイルを読み込めません")
if width < min_dim or height < min_dim:
raise ValidationError(f"画像が小さすぎます（最小: {min_dim}x{min_dim}px）")
if width > max_dim or height > max_dim:
raise ValidationError(f"画像が大きすぎます（最大: {max_dim}x{max_dim}px）")
return {"extension": ext, "width": width, "height": height, "size": size}
def generate_safe_filename(extension: str) -> str:
"""Generate a UUID-based safe filename."""
return f"{uuid.uuid4().hex}.{extension}"
def validate_difficulty(value: str) -> str:
"""Validate difficulty parameter. Returns normalised value."""
valid = {"easy", "medium", "hard"}
normalised = value.strip().lower()
if normalised not in valid:
raise ValidationError(f"無効な難易度です。選択可能: {', '.join(sorted(valid))}")
return normalised
def _get_extension(filename: str) -> str:
if "." not in filename:
return ""
return filename.rsplit(".", 1)[1].lower()
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