"""
AJAX/COMET fallback webclient
The AJAX/COMET web client consists of two components running on
twisted and django. They are both a part of the Evennia website url
tree (so the testing website might be located on
http://localhost:4001/, whereas the webclient can be found on
http://localhost:4001/webclient.)
/webclient - this url is handled through django's template
system and serves the html page for the client
itself along with its javascript chat program.
/webclientdata - this url is called by the ajax chat using
POST requests (long-polling when necessary)
The WebClient resource in this module will
handle these requests and act as a gateway
to sessions connected over the webclient.
"""
import html
import json
import re
import time
from django.conf import settings
from django.utils.functional import Promise
from twisted.internet.task import LoopingCall
from twisted.web import resource, server
from evennia.server import session
from evennia.utils import utils
from evennia.utils.ansi import parse_ansi
from evennia.utils.text2html import parse_html
from evennia.utils.utils import class_from_module, ip_from_request, to_bytes
_CLIENT_SESSIONS = utils.mod_import(settings.SESSION_ENGINE).SessionStore
_RE_SCREENREADER_REGEX = re.compile(
r"%s" % settings.SCREENREADER_REGEX_STRIP, re.DOTALL + re.MULTILINE
)
_SERVERNAME = settings.SERVERNAME
_KEEPALIVE = 30 # how often to check keepalive
# defining a simple json encoder for returning
# django data to the client. Might need to
# extend this if one wants to send more
# complex database objects too.
[docs]class LazyEncoder(json.JSONEncoder):
[docs] def default(self, obj):
if isinstance(obj, Promise):
return str(obj)
return super().default(obj)
[docs]def jsonify(obj):
return to_bytes(json.dumps(obj, ensure_ascii=False, cls=LazyEncoder))
#
# A session type handling communication over the
# web client interface.
#
[docs]class AjaxWebClientSession(session.Session):
"""
This represents a session running in an AjaxWebclient.
"""
[docs] def __init__(self, *args, **kwargs):
self.protocol_key = "webclient/ajax"
super().__init__(*args, **kwargs)
[docs] def get_client_session(self):
"""
Get the Client browser session (used for auto-login based on browser session)
Returns:
csession (ClientSession): This is a django-specific internal representation
of the browser session.
"""
if self.csessid:
return _CLIENT_SESSIONS(session_key=self.csessid)
[docs] def disconnect(self, reason="Server disconnected."):
"""
Disconnect from server.
Args:
reason (str): Motivation for the disconnect.
"""
csession = self.get_client_session()
if csession:
csession["webclient_authenticated_uid"] = None
csession.save()
self.logged_in = False
self.client.lineSend(self.csessid, ["connection_close", [reason], {}])
self.client.client_disconnect(self.csessid)
self.sessionhandler.disconnect(self)
[docs] def at_login(self):
csession = self.get_client_session()
if csession:
csession["webclient_authenticated_uid"] = self.uid
csession.save()
[docs] def data_in(self, **kwargs):
"""
Data User -> Evennia
Keyword Args:
kwargs (any): Incoming data.
"""
self.sessionhandler.data_in(self, **kwargs)
[docs] def data_out(self, **kwargs):
"""
Data Evennia -> User
Keyword Args:
kwargs (any): Options to the protocol
"""
self.sessionhandler.data_out(self, **kwargs)
[docs] def send_text(self, *args, **kwargs):
"""
Send text data. This will pre-process the text for
color-replacement, conversion to html etc.
Args:
text (str): Text to send.
Keyword Args:
options (dict): Options-dict with the following keys understood:
- raw (bool): No parsing at all (leave ansi-to-html markers unparsed).
- nocolor (bool): Remove all color.
- screenreader (bool): Use Screenreader mode.
- send_prompt (bool): Send a prompt with parsed html
"""
if args:
args = list(args)
text = args[0]
if text is None:
return
else:
return
flags = self.protocol_flags
text = utils.to_str(text)
options = kwargs.pop("options", {})
raw = options.get("raw", flags.get("RAW", False))
xterm256 = options.get("xterm256", flags.get("XTERM256", True))
useansi = options.get("ansi", flags.get("ANSI", True))
nocolor = options.get("nocolor", flags.get("NOCOLOR") or not (xterm256 or useansi))
screenreader = options.get("screenreader", flags.get("SCREENREADER", False))
prompt = options.get("send_prompt", False)
if screenreader:
# screenreader mode cleans up output
text = parse_ansi(text, strip_ansi=True, xterm256=False, mxp=False)
text = _RE_SCREENREADER_REGEX.sub("", text)
cmd = "prompt" if prompt else "text"
if raw:
args[0] = text
else:
args[0] = parse_html(text, strip_ansi=nocolor)
# send to client on required form [cmdname, args, kwargs]
self.client.lineSend(self.csessid, [cmd, args, kwargs])
[docs] def send_prompt(self, *args, **kwargs):
kwargs["options"].update({"send_prompt": True})
self.send_text(*args, **kwargs)
[docs] def send_default(self, cmdname, *args, **kwargs):
"""
Data Evennia -> User.
Args:
cmdname (str): The first argument will always be the oob cmd name.
*args (any): Remaining args will be arguments for `cmd`.
Keyword Args:
options (dict): These are ignored for oob commands. Use command
arguments (which can hold dicts) to send instructions to the
client instead.
"""
if not cmdname == "options":
self.client.lineSend(self.csessid, [cmdname, args, kwargs])
#
# AjaxWebClient resource - this is called by the ajax client
# using POST requests to /webclientdata.
#
[docs]class AjaxWebClient(resource.Resource):
"""
An ajax/comet long-polling transport
"""
client_protocol = class_from_module(settings.AJAX_PROTOCOL_CLASS)
isLeaf = True
allowedMethods = ("POST",)
[docs] def __init__(self):
self.requests = {}
self.databuffer = {}
self.last_alive = {}
self.keep_alive = None
def _responseFailed(self, failure, csessid, request):
"callback if a request is lost/timed out"
try:
del self.requests[csessid]
except KeyError:
# nothing left to delete
pass
def _keepalive(self):
"""
Callback for checking the connection is still alive.
"""
now = time.time()
to_remove = []
keep_alives = (
(csessid, remove)
for csessid, (t, remove) in self.last_alive.items()
if now - t > _KEEPALIVE
)
for csessid, remove in keep_alives:
if remove:
# keepalive timeout. Line is dead.
to_remove.append(csessid)
else:
# normal timeout - send keepalive
self.last_alive[csessid] = (now, True)
self.lineSend(csessid, ["ajax_keepalive", [], {}])
# remove timed-out sessions
for csessid in to_remove:
sessions = self.sessionhandler.sessions_from_csessid(csessid)
for sess in sessions:
sess.disconnect()
self.last_alive.pop(csessid, None)
if not self.last_alive:
# no more ajax clients. Stop the keepalive
self.keep_alive.stop()
self.keep_alive = None
[docs] def get_client_sessid(self, request):
"""
Helper to get the client session id out of the request.
Args:
request (Request): Incoming request object.
Returns:
csessid (int): The client-session id.
"""
return html.escape(request.args[b"csessid"][0].decode("utf-8"))
[docs] def get_client_page_id(self, request):
"""
Helper to get the client page id out of the request.
Args:
request (Request): Incoming request object.
Returns:
csessid (int): The client-page id.
"""
return html.escape(request.args[b"cuid"][0].decode("utf-8"))
[docs] def get_browserstr(self, request):
"""
Get browser-string out of the request.
Args:
request (Request): Incoming request object.
Returns:
str: The browser name.
"""
return html.escape(request.args[b"browserstr"][0].decode("utf-8"))
[docs] def at_login(self):
"""
Called when this session gets authenticated by the server.
"""
pass
[docs] def lineSend(self, csessid, data):
"""
This adds the data to the buffer and/or sends it to the client
as soon as possible.
Args:
csessid (int): Session id.
data (list): A send structure [cmdname, [args], {kwargs}].
"""
request = self.requests.get(csessid)
if request:
# we have a request waiting. Return immediately.
request.write(jsonify(data))
request.finish()
del self.requests[csessid]
else:
# no waiting request. Store data in buffer
dataentries = self.databuffer.get(csessid, [])
dataentries.append(jsonify(data))
self.databuffer[csessid] = dataentries
[docs] def client_disconnect(self, csessid):
"""
Disconnect session with given id.
Args:
csessid (int): Client page+session id.
"""
if csessid in self.requests:
self.requests[csessid].finish()
del self.requests[csessid]
if csessid in self.databuffer:
del self.databuffer[csessid]
[docs] def mode_init(self, request):
"""
This is called by render_POST when the client requests an init
mode operation (at startup)
Args:
request (Request): Incoming request.
"""
session_id = self.get_client_sessid(request)
page_id = self.get_client_page_id(request)
browserstr = self.get_browserstr(request)
remote_addr = ip_from_request(request)
host_string = "%s (%s:%s)" % (
_SERVERNAME,
request.getRequestHostname(),
request.getHost().port,
)
sess = self.client_protocol()
sess.client = self
sess.init_session("ajax/comet", remote_addr, self.sessionhandler)
sess.csessid = session_id + page_id
sess.browserstr = browserstr
csession = _CLIENT_SESSIONS(session_key=session_id)
uid = csession and csession.get("webclient_authenticated_uid", False)
if uid:
# the client session is already logged in
sess.uid = uid
sess.logged_in = True
# watch for dead links
self.last_alive[sess.csessid] = (time.time(), False)
if not self.keep_alive:
# the keepalive is not running; start it.
self.keep_alive = LoopingCall(self._keepalive)
self.keep_alive.start(_KEEPALIVE, now=False)
browserstr = f":{browserstr}" if browserstr else ""
sess.protocol_flags["CLIENTNAME"] = f"Evennia Webclient (ajax{browserstr})"
sess.protocol_flags["UTF-8"] = True
sess.protocol_flags["OOB"] = True
# actually do the connection
sess.sessionhandler.connect(sess)
return jsonify({"msg": host_string, "csessid": session_id})
[docs] def mode_keepalive(self, request):
"""
This is called by render_POST when the
client is replying to the keepalive.
Args:
request (Request): Incoming request.
"""
csessid = self.get_client_sessid(request) + self.get_client_page_id(request)
self.last_alive[csessid] = (time.time(), False)
return b'""'
[docs] def mode_receive(self, request):
"""
This is called by render_POST when the client is telling us
that it is ready to receive data as soon as it is available.
This is the basis of a long-polling (comet) mechanism: the
server will wait to reply until data is available.
Args:
request (Request): Incoming request.
"""
csessid = self.get_client_sessid(request) + self.get_client_page_id(request)
self.last_alive[csessid] = (time.time(), False)
dataentries = self.databuffer.get(csessid)
if dataentries:
# we have data that could not be sent earlier (because client was not
# ready to receive it). Return this buffered data immediately
return dataentries.pop(0)
else:
# we have no data to send. End the old request and start
# a new long-polling one
request.notifyFinish().addErrback(self._responseFailed, csessid, request)
if csessid in self.requests:
self.requests[csessid].finish() # Clear any stale request.
self.requests[csessid] = request
return server.NOT_DONE_YET
[docs] def mode_close(self, request):
"""
This is called by render_POST when the client is signalling
that it is about to be closed.
Args:
request (Request): Incoming request.
"""
csessid = self.get_client_sessid(request) + self.get_client_page_id(request)
try:
sess = self.sessionhandler.sessions_from_csessid(csessid)[0]
sess.sessionhandler.disconnect(sess)
except IndexError:
self.client_disconnect(csessid)
return b'""'
[docs] def render_POST(self, request):
"""
This function is what Twisted calls with POST requests coming
in from the ajax client. The requests should be tagged with
different modes depending on what needs to be done, such as
initializing or sending/receving data through the request. It
uses a long-polling mechanism to avoid sending data unless
there is actual data available.
Args:
request (Request): Incoming request.
"""
dmode = request.args.get(b"mode", [b"None"])[0].decode("utf-8")
if dmode == "init":
# startup. Setup the server.
return self.mode_init(request)
elif dmode == "input":
# input from the client to the server
return self.mode_input(request)
elif dmode == "receive":
# the client is waiting to receive data.
return self.mode_receive(request)
elif dmode == "close":
# the client is closing
return self.mode_close(request)
elif dmode == "keepalive":
# A reply to our keepalive request - all is well
return self.mode_keepalive(request)
else:
# This should not happen if client sends valid data.
return b'""'
