/
stream.py
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/
stream.py
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# encoding: utf-8
from __future__ import unicode_literals
from .util import PY_3_OR_HIGHER
if PY_3_OR_HIGHER:
import urllib.request as urllib_request
import urllib.error as urllib_error
else:
import urllib2 as urllib_request
import urllib2 as urllib_error
import json
from ssl import SSLError
import socket
import codecs
import sys, select, time
from .api import TwitterCall, wrap_response, TwitterHTTPError
CRLF = b'\r\n'
MIN_SOCK_TIMEOUT = 0.0 # Apparenty select with zero wait is okay!
MAX_SOCK_TIMEOUT = 10.0
HEARTBEAT_TIMEOUT = 90.0
Timeout = {'timeout': True}
Hangup = {'hangup': True}
DecodeError = {'hangup': True, 'decode_error': True}
HeartbeatTimeout = {'hangup': True, 'heartbeat_timeout': True}
class HttpChunkDecoder(object):
def __init__(self):
self.buf = bytearray()
self.munch_crlf = False
def decode(self, data): # -> (bytearray, end_of_stream, decode_error)
chunks = []
buf = self.buf
munch_crlf = self.munch_crlf
end_of_stream = False
decode_error = False
buf.extend(data)
while True:
if munch_crlf:
# Dang, Twitter, you crazy. Twitter only sends a terminating
# CRLF at the beginning of the *next* message.
if len(buf) >= 2:
buf = buf[2:]
munch_crlf = False
else:
break
header_end_pos = buf.find(CRLF)
if header_end_pos == -1:
break
header = buf[:header_end_pos]
data_start_pos = header_end_pos + 2
try:
chunk_len = int(header.decode('ascii'), 16)
except ValueError:
decode_error = True
break
if chunk_len == 0:
end_of_stream = True
break
data_end_pos = data_start_pos + chunk_len
if len(buf) >= data_end_pos:
chunks.append(buf[data_start_pos:data_end_pos])
buf = buf[data_end_pos:]
munch_crlf = True
else:
break
self.buf = buf
self.munch_crlf = munch_crlf
return bytearray().join(chunks), end_of_stream, decode_error
class JsonDecoder(object):
def __init__(self):
self.buf = ""
self.raw_decode = json.JSONDecoder().raw_decode
def decode(self, data):
chunks = []
buf = self.buf + data
while True:
try:
buf = buf.lstrip()
res, ptr = self.raw_decode(buf)
buf = buf[ptr:]
chunks.append(res)
except ValueError:
break
self.buf = buf
return chunks
class Timer(object):
def __init__(self, timeout):
# If timeout is None, we never expire.
self.timeout = timeout
self.reset()
def reset(self):
self.time = time.time()
def expired(self):
"""
If expired, reset the timer and return True.
"""
if self.timeout is None:
return False
elif time.time() - self.time > self.timeout:
self.reset()
return True
return False
class SockReader(object):
def __init__(self, sock, sock_timeout):
self.sock = sock
self.sock_timeout = sock_timeout
def read(self):
try:
ready_to_read = select.select([self.sock], [], [], self.sock_timeout)[0]
if ready_to_read:
return self.sock.read()
except SSLError as e:
# Code 2 is error from a non-blocking read of an empty buffer.
if e.errno != 2:
raise
return bytearray()
class TwitterJSONIter(object):
def __init__(self, handle, uri, arg_data, block, timeout, heartbeat_timeout):
self.handle = handle
self.uri = uri
self.arg_data = arg_data
self.timeout_token = Timeout
self.timeout = None
self.heartbeat_timeout = HEARTBEAT_TIMEOUT
if timeout and timeout > 0:
self.timeout = float(timeout)
elif not (block or timeout):
self.timeout_token = None
self.timeout = MIN_SOCK_TIMEOUT
if heartbeat_timeout and heartbeat_timeout > 0:
self.heartbeat_timeout = float(heartbeat_timeout)
def __iter__(self):
timeouts = [t for t in (self.timeout, self.heartbeat_timeout, MAX_SOCK_TIMEOUT)
if t is not None]
sock_timeout = min(*timeouts)
sock = self.handle.fp.raw._sock if PY_3_OR_HIGHER else self.handle.fp._sock.fp._sock
sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
headers = self.handle.headers
sock_reader = SockReader(sock, sock_timeout)
chunk_decoder = HttpChunkDecoder()
utf8_decoder = codecs.getincrementaldecoder("utf-8")()
json_decoder = JsonDecoder()
timer = Timer(self.timeout)
heartbeat_timer = Timer(self.heartbeat_timeout)
while True:
# Decode all the things:
try:
data = sock_reader.read()
except SSLError:
yield Hangup
break
dechunked_data, end_of_stream, decode_error = chunk_decoder.decode(data)
unicode_data = utf8_decoder.decode(dechunked_data)
json_data = json_decoder.decode(unicode_data)
# Yield data-like things:
for json_obj in json_data:
yield wrap_response(json_obj, headers)
# Reset timers:
if dechunked_data:
heartbeat_timer.reset()
if json_data:
timer.reset()
# Yield timeouts and special things:
if end_of_stream:
yield Hangup
break
if decode_error:
yield DecodeError
break
if heartbeat_timer.expired():
yield HeartbeatTimeout
break
if timer.expired():
yield self.timeout_token
def handle_stream_response(req, uri, arg_data, block, timeout, heartbeat_timeout):
try:
handle = urllib_request.urlopen(req,)
except urllib_error.HTTPError as e:
raise TwitterHTTPError(e, uri, 'json', arg_data)
return iter(TwitterJSONIter(handle, uri, arg_data, block, timeout, heartbeat_timeout))
class TwitterStream(TwitterCall):
"""
The TwitterStream object is an interface to the Twitter Stream
API. This can be used pretty much the same as the Twitter class
except the result of calling a method will be an iterator that
yields objects decoded from the stream. For example::
twitter_stream = TwitterStream(auth=OAuth(...))
iterator = twitter_stream.statuses.sample()
for tweet in iterator:
# ...do something with this tweet...
Per default the ``TwitterStream`` object uses
[public streams](https://dev.twitter.com/docs/streaming-apis/streams/public).
If you want to use one of the other
[streaming APIs](https://dev.twitter.com/docs/streaming-apis), specify the URL
manually:
- [Public streams](https://dev.twitter.com/docs/streaming-apis/streams/public): stream.twitter.com
- [User streams](https://dev.twitter.com/docs/streaming-apis/streams/user): userstream.twitter.com
- [Site streams](https://dev.twitter.com/docs/streaming-apis/streams/site): sitestream.twitter.com
Note that you require the proper
[permissions](https://dev.twitter.com/docs/application-permission-model) to
access these streams. E.g. for direct messages your
[application](https://dev.twitter.com/apps) needs the "Read, Write & Direct
Messages" permission.
The following example demonstrates how to retrieve all new direct messages
from the user stream::
auth = OAuth(
consumer_key='[your consumer key]',
consumer_secret='[your consumer secret]',
token='[your token]',
token_secret='[your token secret]'
)
twitter_userstream = TwitterStream(auth=auth, domain='userstream.twitter.com')
for msg in twitter_userstream.user():
if 'direct_message' in msg:
print msg['direct_message']['text']
The iterator will yield until the TCP connection breaks. When the
connection breaks, the iterator yields `{'hangup': True}`, and
raises `StopIteration` if iterated again.
Similarly, if the stream does not produce heartbeats for more than
90 seconds, the iterator yields `{'hangup': True,
'heartbeat_timeout': True}`, and raises `StopIteration` if
iterated again.
The `timeout` parameter controls the maximum time between
yields. If it is nonzero, then the iterator will yield either
stream data or `{'timeout': True}` within the timeout period. This
is useful if you want your program to do other stuff in between
waiting for tweets.
The `block` parameter sets the stream to be fully non-blocking. In
this mode, the iterator always yields immediately. It returns
stream data, or `None`. Note that `timeout` supercedes this
argument, so it should also be set `None` to use this mode.
"""
def __init__(self, domain="stream.twitter.com", secure=True, auth=None,
api_version='1.1', block=True, timeout=None,
heartbeat_timeout=90.0):
uriparts = (str(api_version),)
class TwitterStreamCall(TwitterCall):
def _handle_response(self, req, uri, arg_data, _timeout=None):
return handle_stream_response(
req, uri, arg_data, block,
_timeout or timeout, heartbeat_timeout)
TwitterCall.__init__(
self, auth=auth, format="json", domain=domain,
callable_cls=TwitterStreamCall,
secure=secure, uriparts=uriparts, timeout=timeout, gzip=False)