问题：
调试时候跨域访问报：
Request header field authorization is not allowed by Access-Control-Allow-Headers in preflight response.
解决办法：
安装flask_cros
from flask_cors import CORS
CORS(app)
@app.after_request
def af_request(resp):
resp = make_response(resp)
resp.headers'Access-Control-Allow-Origin' = '*'
resp.headers'Access-Control-Allow-Methods' = '*'
resp.headers'Access-Control-Allow-Headers' = 'Authorization,content-type,token,id'
resp.headers'Access-Control-Request-Headers' = 'Origin,X-Requested-With,Accept,Authorization'
return resp