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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Copyright (C) 2018
# Matthias P. Braendli, matthias.braendli@mpb.li
#
# http://www.opendigitalradio.org
#
# This file is part of ODR-DabMod.
#
# ODR-DabMod is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# ODR-DabMod is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with ODR-DabMod. If not, see <http://www.gnu.org/licenses/>.
"""yamlrpc is json-rpc, except that it's yaml and not json."""
# This maybe won't work over ethernet, but for localhost it's ok
UDP_PACKETSIZE = 2048
# Same as jsonrpc version we're aiming to mirror in YAML
YAMLRPC_VERSION = "2.0"
import yaml
import socket
import struct
class ResponseError(Exception):
"""The response contains an error"""
def __init__(self, message):
self.message = message
def request(request_id: int, method: str, params) -> bytes:
r = {
'yamlrpc': YAMLRPC_VERSION,
'method': method,
'params': params,
'id': request_id}
return yaml.dump(r).encode()
def response_success(request_id: int, result) -> bytes:
r = {
'yamlrpc': YAMLRPC_VERSION,
'result': result,
'id': request_id}
return yaml.dump(r).encode()
def response_error(request_id: int, error) -> bytes:
r = {
'yamlrpc': YAMLRPC_VERSION,
'error': error,
'id': request_id}
return yaml.dump(r).encode()
def notification(method: str, params) -> bytes:
r = {
'yamlrpc': YAMLRPC_VERSION,
'method': method,
'params': params}
return yaml.dump(r).encode()
class Socket:
def __init__(self, bind_port: int):
self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
if bind_port > 0:
self.socket.bind(('127.0.0.1', bind_port))
self.socket.settimeout(3)
self._last_request_id = 0
def send_request(self, dest_port: int, method: str, params) -> int:
addr = ("127.0.0.1", dest_port)
self._last_request_id += 1
self.socket.sendto(request(self._last_request_id, method, params), addr)
return self._last_request_id
def receive_response(self, expected_msg_id: int):
try:
data, addr = self.socket.recvfrom(UDP_PACKETSIZE)
except socket.timeout as to:
raise TimeoutError()
y = yaml.load(data.decode())
if 'yamlrpc' not in y:
raise ValueError("Message is not yamlrpc")
if y['yamlrpc'] != YAMLRPC_VERSION:
raise ValueError("Invalid yamlrpc version")
# expect a response, with either 'error' or 'result' non-null
try:
msg_id = y['id']
except KeyError:
raise ValueError("Response is missing id")
if msg_id != expected_msg_id:
raise ValueError("Response id does not match request")
try:
result = y['result']
except KeyError:
try:
error = y['error']
raise ResponseError(error)
except KeyError:
raise ValueError("response is null")
return result
def call_rpc_method(self, dest_port: int, method: str, params):
msg_id = self.send_request(dest_port, method, params)
return self.receive_response(msg_id)
def receive_request(self):
try:
data, addr = self.socket.recvfrom(UDP_PACKETSIZE)
except socket.timeout as to:
raise TimeoutError("Timeout: " + str(to))
y = yaml.load(data.decode())
if 'yamlrpc' not in y:
raise ValueError("Message is not yamlrpc")
if y['yamlrpc'] != YAMLRPC_VERSION:
raise ValueError("Invalid yamlrpc version")
# expect a request
try:
method = y['method']
msg_id = y['id']
params = y['params']
except KeyError:
raise ValueError("Incomplete message")
return addr, msg_id, method, params
def send_success_response(self, addr, msg_id: int, result):
self.socket.sendto(response_success(msg_id, result), addr)
def send_error_response(self, addr, msg_id: int, error):
self.socket.sendto(response_error(msg_id, error), addr)
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