Files
clever-show/messaging_lib.py
2020-01-13 18:32:06 +03:00

549 lines
19 KiB
Python

import io
import os
import sys
import json
import socket
import struct
import random
import logging
import threading
import collections
from contextlib import closing
try:
import selectors
except ImportError:
import selectors2 as selectors
class Namespace:
def __init__(self, **kwargs):
self.__dict__.update(kwargs)
def __getitem__(self, key):
return self.__dict__[key]
def __setitem__(self, key, value):
self.__dict__[key] = value
class PendingRequest(Namespace): pass
logger = logging.getLogger(__name__)
def get_ip_address():
try:
with closing(socket.socket(socket.AF_INET, socket.SOCK_DGRAM)) as ip_socket:
ip_socket.connect(("8.8.8.8", 80))
return ip_socket.getsockname()[0]
except OSError:
logger.warning("No network connection detected, using localhost")
return "localhost"
class _Singleton(type):
""" A metaclass that creates a Singleton base class when called. """
_instances = {}
def __call__(cls, *args, **kwargs):
if cls not in cls._instances:
cls._instances[cls] = super(_Singleton, cls).__call__(*args, **kwargs)
return cls._instances[cls]
class Singleton(_Singleton('SingletonMeta', (object,), {})): pass
class MessageManager:
def __init__(self):
self.income_raw = b""
self._jsonheader_len = None
self.jsonheader = None
self.content = None
@staticmethod
def _json_encode(obj, encoding="utf-8"):
return json.dumps(obj, ensure_ascii=False).encode(encoding)
@staticmethod
def _json_decode(json_bytes, encoding="utf-8"):
with io.TextIOWrapper(io.BytesIO(json_bytes), encoding=encoding, newline="") as tiow:
obj = json.load(tiow, object_pairs_hook=collections.OrderedDict)
return obj
@classmethod
def create_message(cls, content_bytes, content_type, message_type, content_encoding="utf-8",
additional_headers=None):
jsonheader = {
"byteorder": sys.byteorder,
"content-type": content_type,
"content-encoding": content_encoding,
"content-length": len(content_bytes),
"message-type": message_type,
}
if additional_headers:
jsonheader.update(additional_headers)
jsonheader_bytes = cls._json_encode(jsonheader, "utf-8")
message_hdr = struct.pack(">H", len(jsonheader_bytes))
message = message_hdr + jsonheader_bytes + content_bytes
return message
@classmethod
def create_json_message(cls, contents):
message = cls.create_message(cls._json_encode(contents), "json", "message")
return message
@classmethod
def create_simple_message(cls, command, args=None):
if args is None:
args = {}
message = cls.create_json_message({"command": command, "args": args})
return message
@classmethod
def create_request(cls, requested_value, request_id, args=None):
if args is None:
args = {}
contents = {"requested_value": requested_value,
"request_id": request_id,
"args": args,
}
message = cls.create_message(cls._json_encode(contents), "json", "request")
return message
@classmethod
def create_response(cls, requested_value, request_id, value):
contents = {"requested_value": requested_value,
"request_id": request_id,
"value": value,
}
message = cls.create_message(cls._json_encode(contents), "json", "response")
return message
def _process_protoheader(self):
header_len = 2
if len(self.income_raw) >= header_len:
self._jsonheader_len = struct.unpack(">H", self.income_raw[:header_len])[0]
self.income_raw = self.income_raw[header_len:]
def _process_jsonheader(self):
header_len = self._jsonheader_len
if len(self.income_raw) >= header_len:
self.jsonheader = self._json_decode(self.income_raw[:header_len], "utf-8")
self.income_raw = self.income_raw[header_len:]
for reqhdr in (
"byteorder",
"content-length",
"content-type",
"content-encoding",
"message-type",
):
if reqhdr not in self.jsonheader:
raise ValueError('Missing required header {}'.format(reqhdr))
def _process_content(self):
content_len = self.jsonheader["content-length"]
if not len(self.income_raw) >= content_len:
return
data = self.income_raw[:content_len]
self.income_raw = self.income_raw[content_len:]
if self.jsonheader["content-type"] == "json":
encoding = self.jsonheader["content-encoding"]
self.content = self._json_decode(data, encoding)
else:
self.content = data
def process_message(self):
if self._jsonheader_len is None:
self._process_protoheader()
if self._jsonheader_len is not None:
if self.jsonheader is None:
self._process_jsonheader()
if self.jsonheader:
if self.content is None:
self._process_content()
def message_callback(string_command):
def inner(f):
ConnectionManager.messages_callbacks[string_command] = f
logger.debug("Registered message function {} for {}".format(f, string_command))
def wrapper(*args, **kwargs):
return f(*args, **kwargs)
return wrapper
return inner
def request_callback(string_command):
def inner(f):
ConnectionManager.requests_callbacks[string_command] = f
logger.debug("Registered callback function {} for {}".format(f, string_command))
def wrapper(*args, **kwargs):
return f(*args, **kwargs)
return wrapper
return inner
class ConnectionManager(object):
messages_callbacks = {}
requests_callbacks = {}
def __init__(self, whoami="computer"):
self.selector = None
self.socket = None
self.addr = None
self._should_close = False
self._recv_buffer = b""
self._send_buffer = b""
self.whoami = whoami
self._send_queue = collections.deque()
self._received_queue = collections.deque()
self._request_queue = collections.OrderedDict()
self._send_lock = threading.Lock()
self._request_lock = threading.Lock()
self._close_lock = threading.Lock()
self.buffer_size = 1024
self.resume_queue = False
self.resend_requests = True
def _set_selector_events_mask(self, mode):
"""Set selector to listen for events: mode is 'r', 'w', 'rw'."""
if mode == "r":
events = selectors.EVENT_READ
elif mode == "w":
events = selectors.EVENT_WRITE
elif mode == "rw":
events = selectors.EVENT_READ | selectors.EVENT_WRITE
else:
raise ValueError("Invalid events mask mode {}.".format(mode))
key = self.selector.modify(self.socket, events, data=self)
logger.debug("Switched selector of {} to mode {}".format(self.addr, key.events))
return key
def connect(self, client_selector, client_socket, client_addr):
self.selector = client_selector
self.socket = client_socket
self.addr = client_addr
self._clear()
self._set_selector_events_mask('r')
if self.resend_requests:
self._resend_requests()
def _clear(self):
if not self.resume_queue: # maybe needs locks
self._recv_buffer = b''
self._send_buffer = b''
self._received_queue.clear()
self._send_queue.clear()
def close(self):
with self._close_lock:
self._should_close = True
self._set_selector_events_mask('w')
NotifierSock().notify()
def _close(self):
logger.info("Closing connection to {}".format(self.addr))
try:
logger.info("Unregistering selector of {}".format(self.addr))
self.selector.unregister(self.socket)
except AttributeError:
pass
except Exception as error:
logger.error("{}: Error during selector unregistering: {}".format(self.addr, error))
finally:
self.selector = None
try:
logger.info("Closing socket of of {}".format(self.addr))
self.socket.close()
except AttributeError:
pass
except OSError as error:
logger.error("{}: Error during socket closing: {}".format(self.addr, error))
finally:
self.socket = None
with self._close_lock:
self._should_close = False
self._clear()
logger.info("CLOSED connection to {}".format(self.addr))
def process_events(self, mask):
with self._close_lock:
close = self._should_close
if close:
self._close()
return
if mask & selectors.EVENT_READ:
self.read()
if mask & selectors.EVENT_WRITE:
self.write()
def read(self):
self._read()
while self._recv_buffer:
if not self._received_queue or (self._received_queue[0].content is not None):
self._received_queue.appendleft(MessageManager())
self._received_queue[0].income_raw += self._recv_buffer
self._recv_buffer = b''
self._received_queue[0].process_message()
# if something left after processing message - put it back
if self._received_queue[0].content and self._received_queue[0].income_raw:
self._recv_buffer = self._received_queue[0].income_raw + self._recv_buffer
self._received_queue[0].income_raw = b''
if self._received_queue:
if self._received_queue[0].content:
self.process_received(self._received_queue.popleft())
def _read(self):
try:
data = self.socket.recv(self.buffer_size)
except io.BlockingIOError:
# Resource temporarily unavailable (errno EWOULDBLOCK)
pass
else:
if data:
self._recv_buffer += data
logger.debug("Received {} bytes from {}".format(len(data), self.addr))
else:
logger.warning("Connection to {} lost!".format(self.addr))
raise RuntimeError("Peer closed.")
def process_received(self, income_message):
message_type = income_message.jsonheader["message-type"]
content = income_message.content if message_type != "filetransfer" else income_message.content[:256]
logger.debug(
"Received message! Header: {}, content: {}".format(income_message.jsonheader, content))
if message_type == "message":
self._process_message(income_message)
elif message_type == "response":
self._process_response(income_message)
elif message_type == "request":
self._process_request(income_message)
elif message_type == "filetransfer":
self._process_filetransfer(income_message)
def _process_message(self, message):
command = message.content["command"]
args = message.content["args"]
callback = self.messages_callbacks.get(command, None)
if callback is None:
logger.warning("Command {} does not exist!".format(command))
return
try:
callback(self, **args)
except Exception as error:
logger.error("Error during command {} execution: {}".format(command, error))
def _process_request(self, message):
command = message.content["requested_value"]
request_id = message.content["request_id"]
args = message.content["args"]
callback = self.requests_callbacks.get(command, None)
if callback is None:
logger.warning("Request {} does not exist!".format(command))
return
try:
value = callback(self, **args)
except Exception as error: # TODO send response error\cancel
logger.error("Error during request {} processing: {}".format(command, error))
else:
self._send_response(command, request_id, value)
def _process_response(self, message):
request_id, requested_value = message.content["request_id"], message.content["requested_value"]
with self._request_lock:
request = self._request_queue.pop(request_id, None)
if (request is not None) and (request.requested_value == requested_value):
value = message.content["value"]
logger.debug(
"Request {} successfully closed with value {}".format(request, message.content["value"])
)
f = request.callback
f(self, value, *request.callback_args, **request.callback_kwargs)
else:
logger.warning("Unexpected response!")
def _process_filetransfer(self, message): # TODO path?
if message.jsonheader["content-type"] == "binary":
filepath = message.jsonheader["filepath"]
try:
with open(filepath, 'wb') as f:
f.write(message.content)
except OSError as error:
logger.error("File {} can not be written due error: {}".format(filepath, error))
else:
logger.info("File {} successfully received ".format(filepath))
if self.whoami == "pi":
logger.info("Return rights to pi:pi after file transfer")
os.system("chown pi:pi {}".format(filepath))
def write(self):
with self._send_lock:
if (not self._send_buffer) and self._send_queue:
message = self._send_queue.popleft()
self._send_buffer += message
if self._send_buffer:
self._write()
else:
self._set_selector_events_mask('r') # we're done writing
def _write(self):
try:
sent = self.socket.send(self._send_buffer[:self.buffer_size])
except io.BlockingIOError:
# Resource temporarily unavailable (errno EWOULDBLOCK)
pass
except Exception as error:
logger.warning(
"Attempt to send message {} to {} failed due error: {}".format(self._send_buffer, self.addr, error))
raise error
else:
self._send_buffer = self._send_buffer[sent:]
left = len(self._send_buffer)
logger.debug("Sent message to {}: sent {} bytes, {} bytes left.".format(self.addr, sent, left))
def _send(self, data):
with self._send_lock:
self._send_queue.append(data)
if self.selector.get_key(self.socket).events != selectors.EVENT_WRITE:
self._set_selector_events_mask('rw')
NotifierSock().notify()
def get_response(self, requested_value, callback, request_args=None, # timeout=30,
callback_args=(), callback_kwargs=None):
if request_args is None:
request_args = {}
if callback_kwargs is None:
callback_kwargs = {}
request_id = str(random.randint(0, 9999)).zfill(4)
with self._request_lock:
self._request_queue[request_id] = PendingRequest(
requested_value=requested_value,
value=None,
# expires_on=Server.time_now()+timeout, #TODO
callback=callback,
callback_args=callback_args,
callback_kwargs=callback_kwargs,
request_args=request_args,
resend=True,
)
self._send(MessageManager.create_request(requested_value, request_id, request_args))
def _resend_requests(self):
with self._request_lock:
for request_id, request in self._request_queue.items(): #TODO filter
if request.resend:
self._send(MessageManager.create_request(
request.requested_value, request_id, request.request_args.update(resend=request.resend))
)
request.resend = False
def send_message(self, command, args=None):
self._send(MessageManager.create_simple_message(command, args))
def _send_response(self, requested_value, request_id, value):
self._send(MessageManager.create_response(requested_value, request_id, value))
def send_file(self, filepath, dest_filepath): # clever_restart=False
try:
with open(filepath, 'rb') as f:
data = f.read()
except OSError as error:
logger.warning("File can not be opened due error: ".format(error))
else:
logger.info("Sending file {} to {} (as: {})".format(filepath, self.addr, dest_filepath))
self._send(MessageManager.create_message(
data, "binary", "filetransfer", "binary", {"filepath": dest_filepath}
))
class NotifierSock(Singleton):
def __init__(self):
self._server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self._server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
self._server_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
self._sending_sock = socket.socket()
self._send_lock = threading.Lock()
self._receiving_sock = None
def init(self, selector, port=26000):
port += random.randint(0, 100) # local testing fix
self._server_socket.bind(('', port))
self._server_socket.listen(1)
self._sending_sock.connect(('127.0.0.1', port))
self._receiving_sock, _ = self._server_socket.accept()
logger.info("Notify socket: connected")
selector.register(self._receiving_sock, selectors.EVENT_READ, data=self)
logger.info("Notify socket: selector registered")
def get_sock(self):
return self._receiving_sock
def notify(self):
with self._send_lock:
if self._receiving_sock is None:
return
self._sending_sock.sendall(bytes(1))
logger.debug("Notify socket: notified")
def process_events(self, mask):
if mask & selectors.EVENT_READ and self._receiving_sock is not None:
try:
self._receiving_sock.recv(1024)
logger.debug("Notify socket: received")
except io.BlockingIOError:
pass
except Exception as e:
logger.error(e)
def close(self):
try:
self._server_socket.close()
self._sending_sock.close()
self._receiving_sock.close()
except (OSError, KeyError) as error:
logger.error("Error during unregistring notifier socket: {}".format(error))