FRP with Flask (REST API) VPS Tunnel

api_server.py

from flask import Flask, request
from flask_ipfilter import IPFilter, Whitelist
import requests

app = Flask(__name__)
HTTP_METHODS = ['GET', 'HEAD', 'POST', 'PUT', 'DELETE', 'CONNECT', 'OPTIONS', 'TRACE', 'PATCH'] # getting all methods work on the target
ip_filter = IPFilter(app, ruleset=Whitelist())

ip_filter.ruleset.permit("xxx.xxx.xx.x") # whitelisting my office public IP

@app.route('/', defaults={'path': ''}, methods=HTTP_METHODS)
@app.route('/<path:path>', methods=HTTP_METHODS)
def forward_request(path):
    url = f'http://xx.xxx.xx.xx:83/{path}'
    headers = {'Content-Type': 'application/xml'}
    xml_data = request.data

    response = requests.post(url, headers=headers, data=xml_data)

    return response.content, response.status_code

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8080)

frpc.toml

[common]                                                                                                            
server_addr = xx.xx.xx.xxx                                                                                          
server_port = 8080                                                                                                  
vhostHTTPPort = 8083                                                                                                
                                                                                                                    
[http]
type = http
local_ip = 127.0.0.1
local_port = 8080
#remote_port = 8383
custom_domains = "api.test.com"