save base64 image from browser post request

image_save_server.py

"""
// js code
function di(page) {
    var canName = "page_" + page;
    var canvas = document.getElementById(canName);
    var dataUrl = canvas.toDataURL(); 
    //console.log(dataUrl)
	$.post('http://localhost:19290/'+page+'.png', dataUrl)
}
for (let i = 69; i <= 75; i++) {
    di(i)
}
"""
from flask import Flask, request
from flask_cors import CORS
import base64   

def save_img(file_name, img_base64):
    with open(file_name,'wb') as f:
        img = base64.b64decode(img_base64) 
        f.write(img)  

app = Flask(__name__)
CORS(app, supports_credentials=True)  # 设置跨域

@app.route('/<file_name>', methods=['POST'])
def a(file_name):
    img = request.get_data().decode("utf-8")
    img = img.replace("data:image/png;base64,", "")
    save_img('abc/'+file_name, img)
    return ""

if __name__ == '__main__':
    app.run(port=19290, debug=True)