""" A port of sseclient (https://pypi.org/project/sseclient/) that allows you to get server-side events with a POST request Copyright (c) 2015 Brent Tubbs Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.""" # # Distributed under the terms of the MIT license. # from __future__ import unicode_literals import codecs import re import time import warnings import six import requests __version__ = "0.0.27" # Technically, we should support streams that mix line endings. This regex, # however, assumes that a system will provide consistent line endings. end_of_field = re.compile(r"\r\n\r\n|\r\r|\n\n") class SSEClient(object): def __init__( self, method, url, last_id=None, retry=3000, session=None, chunk_size=1024, **kwargs ): self.url = url self.method = method self.last_id = last_id self.retry = retry self.chunk_size = chunk_size # Optional support for passing in a requests.Session() self.session = session # Any extra kwargs will be fed into the requests.get call later. self.requests_kwargs = kwargs # The SSE spec requires making requests with Cache-Control: nocache if "headers" not in self.requests_kwargs: self.requests_kwargs["headers"] = {} self.requests_kwargs["headers"]["Cache-Control"] = "no-cache" # The 'Accept' header is not required, but explicit > implicit self.requests_kwargs["headers"]["Accept"] = "text/event-stream" # Keep data here as it streams in self.buf = "" self._connect() def _connect(self): if self.last_id: self.requests_kwargs["headers"]["Last-Event-ID"] = self.last_id # Use session if set. Otherwise fall back to requests module. requester = self.session or requests self.resp = requester.request( self.method, self.url, stream=True, **self.requests_kwargs ) self.resp_iterator = self.iter_content() encoding = self.resp.encoding or self.resp.apparent_encoding self.decoder = codecs.getincrementaldecoder(encoding)(errors="replace") # TODO: Ensure we're handling redirects. Might also stick the 'origin' # attribute on Events like the Javascript spec requires. self.resp.raise_for_status() def iter_content(self): def generate(): while True: if ( hasattr(self.resp.raw, "_fp") and hasattr(self.resp.raw._fp, "fp") and hasattr(self.resp.raw._fp.fp, "read1") ): chunk = self.resp.raw._fp.fp.read1(self.chunk_size) else: # _fp is not available, this means that we cannot use short # reads and this will block until the full chunk size is # actually read chunk = self.resp.raw.read(self.chunk_size) if not chunk: break yield chunk return generate() def _event_complete(self): return re.search(end_of_field, self.buf) is not None def __iter__(self): return self def __next__(self): while not self._event_complete(): try: next_chunk = next(self.resp_iterator) if not next_chunk: raise EOFError() self.buf += self.decoder.decode(next_chunk) except ( StopIteration, requests.RequestException, EOFError, six.moves.http_client.IncompleteRead, ) as e: print(e) time.sleep(self.retry / 1000.0) self._connect() # The SSE spec only supports resuming from a whole message, so # if we have half a message we should throw it out. head, sep, tail = self.buf.rpartition("\n") self.buf = head + sep continue # Split the complete event (up to the end_of_field) into event_string, # and retain anything after the current complete event in self.buf # for next time. (event_string, self.buf) = re.split(end_of_field, self.buf, maxsplit=1) msg = Event.parse(event_string) # If the server requests a specific retry delay, we need to honor it. if msg.retry: self.retry = msg.retry # last_id should only be set if included in the message. It's not # forgotten if a message omits it. if msg.id: self.last_id = msg.id return msg if six.PY2: next = __next__ class Event(object): sse_line_pattern = re.compile("(?P[^:]*):?( ?(?P.*))?") def __init__(self, data="", event="message", id=None, retry=None): assert isinstance(data, six.string_types), "Data must be text" self.data = data self.event = event self.id = id self.retry = retry def dump(self): lines = [] if self.id: lines.append("id: %s" % self.id) # Only include an event line if it's not the default already. if self.event != "message": lines.append("event: %s" % self.event) if self.retry: lines.append("retry: %s" % self.retry) lines.extend("data: %s" % d for d in self.data.split("\n")) return "\n".join(lines) + "\n\n" @classmethod def parse(cls, raw): """ Given a possibly-multiline string representing an SSE message, parse it and return a Event object. """ msg = cls() for line in raw.splitlines(): m = cls.sse_line_pattern.match(line) if m is None: # Malformed line. Discard but warn. warnings.warn('Invalid SSE line: "%s"' % line, SyntaxWarning) continue name = m.group("name") if name == "": # line began with a ":", so is a comment. Ignore continue value = m.group("value") if name == "data": # If we already have some data, then join to it with a newline. # Else this is it. if msg.data: msg.data = "%s\n%s" % (msg.data, value) else: msg.data = value elif name == "event": msg.event = value elif name == "id": msg.id = value elif name == "retry": msg.retry = int(value) return msg def __str__(self): return self.data