如何在 fastapi 的一个响应中返回图像和 json？

Question

I get an image, change it, then it is classified using a neural network, should return a new image and json with a response. How to do it with one endpoint? image is returned with Streaming Response but how to add json to it?

import io
from starlette.responses import StreamingResponse

app = FastAPI()

@app.post("/predict")
def predict(file: UploadFile = File(...)):
    img = file.read()
    new_image = prepare_image(img)
    result = predict(new_image)
    return StreamingResponse(io.BytesIO(new_image.tobytes()), media_type="image/png")

Answer 1

I added json to response headers. change from:

@app.post("/predict")
def predict(file: UploadFile = File(...)):
    img = file.read()
    new_image = prepare_image(img)
    result = predict(new_image)
    return StreamingResponse(io.BytesIO(new_image.tobytes()), media_type="image/png")

to

@app.post("/predict/")
def predict(file: UploadFile = File(...)):
    file_bytes = file.file.read()
    image = Image.open(io.BytesIO(file_bytes))
    new_image = prepare_image(image)
    result = predict(image)
    bytes_image = io.BytesIO()
    new_image.save(bytes_image, format='PNG')
    return Response(content = bytes_image.getvalue(), headers = result, media_type="image/png")