return numpy 数组作为来自 fastapi 的图像

Question

我用 img = imageio.imread('hello.jpg') 加载图像。我想 return 这个 numpy 数组作为图像。我知道我可以做到 return FileResponse('hello.jpg')。但是以后我会将图片作为numpy数组。

我如何 return 来自 fastapi 的 numpy 数组 img 等同于 return FileResponse('hello.jpg')？

Answer 1

例如，您可以使用 StreamingResponse (https://fastapi.tiangolo.com/advanced/custom-response/#using-streamingresponse-with-file-like-objects) 来执行此操作，但在此之前，您需要将 numpy 数组转换为 io.BytesIO 或 io.StringIO

Answer 2

您不应该使用 StreamingResponse, as suggested by some other answer. If the numpy array is fully loaded into memory from the beginning, StreamingResponse does not make sense at all. Please have a look at . You should instead use Response, by passing the image bytes (after writing to BytesIO buffered stream, as described in the documentation) defining the media_type, as well as setting the Content-Disposition header, as described here，以便在浏览器中查看图像。下面的示例：

import io
import imageio
from imageio import v3 as iio
from fastapi import Response

@app.get("/image", response_class=Response)
def get_image():
    im = imageio.imread("test.jpeg") # 'im' could be an in-memory image (numpy array) instead
    with io.BytesIO() as buf:
        iio.imwrite(buf, im, plugin="pillow", format="JPEG")
        im_bytes = buf.getvalue()
        
    headers = {'Content-Disposition': 'inline; filename="test.jpeg"'}
    return Response(im_bytes, headers=headers, media_type='image/jpeg')

return numpy 数组作为来自 fastapi 的图像

return numpy array as image from fastapi

python

numpy

fastapi

python-imageio