python: 基于fastapi的图片i/o的一个问题

Question

尝试做一个基于fastapi的图片风格迁移代码

我参考了Github中的很多文章和stack overflow做了代码，我发现把图片的byte转成base64传输很有效

所以，我将我的客户端代码设计成 base64 编码并发送了一个请求，我的服务器完美接收了它。

但是，我在将图像字节恢复到 ndarray 时遇到困难。

我的代码告诉我以下错误：

image_array = np.frombuffer(base64.b64decode(image_byte)).reshape(image_shape)

ValueError: cannot reshape array of size 524288 into shape (512,512,4)

这是我的客户端代码：

import base64
import requests
import numpy as np
import json
from matplotlib.pyplot import imread
from skimage.transform import resize


if __name__ == '__main__':
    path_to_img = "my image path"

    image = imread(path_to_img)
    image = resize(image, (512, 512))

    image_byte = base64.b64encode(image.tobytes())
    data = {"shape": image.shape, "image": image_byte.decode()}

    response = requests.get('http://127.0.0.1:8000/myapp/v1/filter/a', data=json.dumps(data))

并且，这是我的服务器代码：

import json
import base64
import uvicorn
import model_loader
import numpy as np

from fastapi import FastAPI
from typing import Optional


app = FastAPI()

@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/myapp/v1/filter/a")
async def style_transfer(data: dict):
    image_byte = data.get('image').encode()
    image_shape = tuple(data.get('shape'))
    image_array = np.frombuffer(base64.b64decode(image_byte)).reshape(image_shape)

if __name__ == '__main__':
    uvicorn.run(app, port='8000', host="127.0.0.1")

请检查我的代码并给我一些建议。我真的不知道我错过了什么。

Answer 1

如前所述here, here and here, one should use UploadFile，以便从客户端应用上传文件。例如：

服务器端：

@app.post("/upload")
async def upload(file: UploadFile = File(...)):
    try:
        contents = await file.read()
        with open(file.filename, 'wb') as f:
            f.write(contents)
    except Exception:
        return {"message": "There was an error uploading the file"}
    finally:
        await file.close()
        
    return {"message": f"Successfuly uploaded {file.filename}"}

客户端：

import requests

url = 'http://127.0.0.1:8000/upload'
file = {'file': open('images/1.png', 'rb')}
resp = requests.post(url=url, files=file) 
print(resp.json())

但是，如果您仍然需要发送 base64 编码图像，您可以按照前面所述 here（选项 2）进行操作。在客户端，您可以将图像编码为 base64 并使用 POST 请求发送它，如下所示：

with open("photo.png", "rb") as image_file:
    encoded_string = base64.b64encode(image_file.read())
    
payload ={"filename": "photo.png", "filedata": encoded_string}
resp = requests.post(url=url, data=payload)

在服务器端，您可以使用 Form 字段接收图像，并按如下方式解码图像：

@app.post("/upload")
async def upload(filename: str = Form(...), filedata: str = Form(...)):
    image_as_bytes = str.encode(filedata)  # convert string to bytes
    img_recovered = base64.b64decode(image_as_bytes)  # decode base64string
    try:
        with open("uploaded_" + filename, "wb") as f:
            f.write(img_recovered)
    except Exception:
        return {"message": "There was an error uploading the file"}
        
    return {"message": f"Successfuly uploaded {filename}"}

python: 基于fastapi的图片i/o的一个问题

python: A problem of image i/o based on fastapi

python

python-3.x

fastapi