Flask OpenCV Send and Receive Images in Bytes

The following has worked for me. I don't have the client code but I have a curl request. That should do the trick,

SERVER

from flask import requestfrom PIL import Imageimport io@app.route("/add_face", methods=["POST"])def predict():    image = request.files["image"]    image_bytes = Image.open(io.BytesIO(image.read()))

CLIENT SIDE

curl -X POST -F image=@PATH/TO/FILE 'http://localhost:5000/add_face'

It is easier to send images in base64 format, by doing that you get rid of problems about sending/receiving binary data since you just work with a string. Also it is more convenient in web stuff. Tested code below:Server side:

from flask import Flask, render_template, requestimport pandas as pdimport cv2import numpy as npimport base64app = Flask(__name__)@app.route('/add_face', methods=['GET', 'POST'])def add_face():    if request.method == 'POST':        #  read encoded image        imageString = base64.b64decode(request.form['img'])        #  convert binary data to numpy array        nparr = np.fromstring(imageString, np.uint8)        #  let opencv decode image to correct format        img = cv2.imdecode(nparr, cv2.IMREAD_ANYCOLOR);        cv2.imshow("frame", img)        cv2.waitKey(0)    return "list of names & faces"if __name__ == '__main__':    app.run(debug=True, port=5000)

Client side:

import requestsimport base64URL = "http://localhost:5000/add_face"#  first, encode our image with base64with open("block.png", "rb") as imageFile:    img = base64.b64encode(imageFile.read())response = requests.post(URL, data={"name":"obama", "img":str(img)})print(response.content)

You can use COLOR instead of ANYCOLOR if you are sure about your input images.