I am trying to implement a code for image style transfer based on FastAPI. I found it effective to convert the byte of the image into base64 and transmit it.
So, I designed my client codeto encode the image into a base64 string and send it to the server, which received it succesfully. However, I face some difficulties in restoring the image bytes to ndarray.
I get the following this errors:
image_array = np.frombuffer(base64.b64decode(image_byte)).reshape(image_shape)
ValueError: cannot reshape array of size 524288 into shape (512,512,4)
This is my client code :
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))
and this is my server code:
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")
As previously mentioned here, as well as here and here, one should use UploadFile, in order to upload files from client apps (for async read/write have a look at this answer). For example:
server side:
@app.post("/upload")
def upload(file: UploadFile = File(...)):
try:
contents = file.file.read()
with open(file.filename, 'wb') as f:
f.write(contents)
except Exception:
return {"message": "There was an error uploading the file"}
finally:
file.file.close()
return {"message": f"Successfuly uploaded {file.filename}"}
client side:
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())
If, however, you still need to send a base64 encoded image, you can do it as previously described here (Option 2). On client side, you can encode the image to base64 and send it using a POST request as follows:
client side:
import base64
import requests
url = 'http://127.0.0.1:8000/upload'
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)
On server side you can receive the image using a Form field, and decode the image as follows:
server side:
@app.post("/upload")
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}"}