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#!/usr/bin/env python
from . import Stream, StreamError
from ..compat import str, bytes, urlparse
from ..utils import RingBuffer, swfdecompress, swfverify, urlget, urlopen
from ..packages.flashmedia import FLV, FLVError
from ..packages.flashmedia.tag import ScriptData
import base64
import hashlib
import hmac
import random
import zlib
class TokenGenerator(object):
def __init__(self, stream):
self.stream = stream
def generate(self):
raise NotImplementedError
class Auth3TokenGenerator(TokenGenerator):
def generate(self):
if not self.stream.swf:
raise StreamError("A SWF URL is required to create session token")
res = urlget(self.stream.swf, exception=StreamError)
data = swfdecompress(res.content)
md5 = hashlib.md5()
md5.update(data)
data = bytes(self.stream.sessionid, "ascii") + md5.digest()
sig = hmac.new(b"foo", data, hashlib.sha1)
b64 = base64.encodestring(sig.digest())
token = str(b64, "ascii").replace("\n", "")
return token
def cache_bust_string(length):
rval = ""
for i in range(length):
rval += chr(65 + int(round(random.random() * 25)))
return rval
class AkamaiHDStream(Stream):
Version = "2.5.8"
FlashVersion = "LNX 11,1,102,63"
StreamURLFormat = "{host}/{streamname}"
ControlURLFormat = "{host}/control/{streamname}"
ControlData = b":)"
TokenGenerators = {
"c11e59dea648d56e864fc07a19f717b9": Auth3TokenGenerator
}
StatusComplete = 3
StatusError = 4
Errors = {
1: "Stream not found",
2: "Track not found",
3: "Seek out of bounds",
4: "Authentication failed",
5: "DVR disabled",
6: "Invalid bitrate test"
}
def __init__(self, session, url, swf=None, seek=None):
Stream.__init__(self, session)
parsed = urlparse(url)
self.logger = self.session.logger.new_module("stream.akamaihd")
self.host = ("{scheme}://{netloc}").format(scheme=parsed.scheme, netloc=parsed.netloc)
self.streamname = parsed.path[1:]
self.swf = swf
self.seek = seek
def open(self):
self.guid = cache_bust_string(12)
self.islive = None
self.sessionid = None
self.flv = None
self.buffer = RingBuffer()
self.completed_handshake = False
url = self.StreamURLFormat.format(host=self.host, streamname=self.streamname)
params = self._create_params(seek=self.seek)
self.logger.debug("Opening host={host} streamname={streamname}", host=self.host, streamname=self.streamname)
try:
res = urlget(url, prefetch=False, params=params)
except Exception as err:
raise StreamError(str(err))
self.handshake(res.raw)
return self
def handshake(self, fd):
try:
self.flv = FLV(fd)
except FLVError as err:
raise StreamError(str(err))
self.buffer.write(self.flv.header.serialize())
self.logger.debug("Attempting to handshake")
for i, tag in enumerate(self.flv):
if i == 10:
raise StreamError("No OnEdge metadata in FLV after 10 tags, probably not a AkamaiHD stream")
self.process_tag(tag)
if self.completed_handshake:
self.logger.debug("Handshake successful")
break
def process_tag(self, tag):
if isinstance(tag.data, ScriptData) and tag.data.name == "onEdge":
self._on_edge(tag.data.value)
self.buffer.write(tag.serialize())
def send_token(self, token):
headers = { "x-Akamai-Streaming-SessionToken": token }
self.logger.debug("Sending new session token")
self.send_control("sendingNewToken", headers=headers,
swf=self.swf)
def send_control(self, cmd, headers={}, **params):
url = self.ControlURLFormat.format(host=self.host,
streamname=self.streamname)
headers["x-Akamai-Streaming-SessionID"] = self.sessionid
params = self._create_params(cmd=cmd, **params)
return urlopen(url, headers=headers, params=params,
data=self.ControlData, exception=StreamError)
def read(self, size=0):
if not self.flv:
return b""
if self.buffer.length == 0:
try:
tag = next(self.flv)
except StopIteration:
return b""
self.process_tag(tag)
return self.buffer.read(size)
def _create_params(self, **extra):
params = dict(v=self.Version, fp=self.FlashVersion,
r=cache_bust_string(5), g=self.guid)
params.update(extra)
return params
def _generate_session_token(self, data64):
swfdata = base64.decodestring(bytes(data64, "ascii"))
md5 = hashlib.md5()
md5.update(swfdata)
hash = md5.hexdigest()
if hash in self.TokenGenerators:
generator = self.TokenGenerators[hash](self)
return generator.generate()
else:
raise StreamError(("No token generator available for hash '{0}'").format(hash))
def _on_edge(self, data):
def updateattr(attr, key):
if key in data:
setattr(self, attr, data[key])
self.logger.debug("onEdge data")
for key, val in data.items():
if isinstance(val, str):
val = val[:50]
self.logger.debug(" {key}={val}",
key=key, val=val)
updateattr("islive", "isLive")
updateattr("sessionid", "session")
updateattr("status", "status")
updateattr("streamname", "streamName")
if self.status == self.StatusComplete:
self.flv = None
elif self.status == self.StatusError:
errornum = data["errorNumber"]
if errornum in self.Errors:
msg = self.Errors[errornum]
else:
msg = "Unknown error"
raise StreamError(msg)
if not self.completed_handshake:
if "data64" in data:
sessiontoken = self._generate_session_token(data["data64"])
else:
sessiontoken = None
self.send_token(sessiontoken)
self.completed_handshake = True
__all__ = ["AkamaiHDStream"]
|
