74 lines
2.1 KiB
Python
74 lines
2.1 KiB
Python
from dataclasses import dataclass
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from io import BytesIO
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from fastapi import HTTPException, UploadFile
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from PIL import Image, UnidentifiedImageError
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MAX_IMAGE_SIDE = 1600
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JPEG_QUALITY = 80
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JPEG_MIME_TYPE = "image/jpeg"
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@dataclass(slots=True)
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class ProcessedImage:
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blob: bytes
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mime_type: str
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width: int
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height: int
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def process_upload(file: UploadFile | None) -> ProcessedImage | None:
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if file is None or not file.filename:
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return None
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try:
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raw_bytes = file.file.read()
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if not raw_bytes:
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raise HTTPException(status_code=400, detail="上传的图片内容为空")
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with Image.open(BytesIO(raw_bytes)) as source_image:
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processed_image = _prepare_image(source_image)
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except UnidentifiedImageError as exc:
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raise HTTPException(status_code=400, detail="上传的文件不是合法图片") from exc
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except HTTPException:
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raise
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except Exception as exc:
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raise HTTPException(status_code=400, detail="图片处理失败，请尝试更换图片") from exc
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finally:
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file.file.close()
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return processed_image
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def _prepare_image(source_image: Image.Image) -> ProcessedImage:
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prepared = _strip_metadata_and_convert(source_image)
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prepared.thumbnail((MAX_IMAGE_SIDE, MAX_IMAGE_SIDE))
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output = BytesIO()
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prepared.save(output, format="JPEG", quality=JPEG_QUALITY, optimize=True)
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blob = output.getvalue()
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return ProcessedImage(
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blob=blob,
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mime_type=JPEG_MIME_TYPE,
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width=prepared.width,
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height=prepared.height,
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)
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def _strip_metadata_and_convert(source_image: Image.Image) -> Image.Image:
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if source_image.mode in ("RGBA", "LA"):
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background = Image.new("RGB", source_image.size, (255, 255, 255))
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alpha = source_image.getchannel("A")
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background.paste(source_image.convert("RGBA"), mask=alpha)
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return background
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if source_image.mode == "P":
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return source_image.convert("RGB")
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if source_image.mode != "RGB":
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return source_image.convert("RGB")
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return source_image.copy()
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