import urllib

from . import packet

class Payload(object):

"""Engine.IO payload."""

max_decode_packets = 16

def __init__(self, packets=None, encoded_payload=None):

self.packets = packets or []

if encoded_payload is not None:

self.decode(encoded_payload)

def encode(self, jsonp_index=None):

"""Encode the payload for transmission."""

encoded_payload = ''

for pkt in self.packets:

if encoded_payload:

encoded_payload += '\x1e'

encoded_payload += pkt.encode(b64=True)

if jsonp_index is not None:

encoded_payload = '___eio[' + \

str(jsonp_index) + \

']("' + \

encoded_payload.replace('"', '\\"') + \

'");'

return encoded_payload

def decode(self, encoded_payload):

"""Decode a transmitted payload."""

self.packets = []

if len(encoded_payload) == 0:

return

# JSONP POST payload starts with 'd='

if encoded_payload.startswith('d='):

encoded_payload = urllib.parse.parse_qs(

encoded_payload)['d'][0]

encoded_packets = encoded_payload.split('\x1e')

if len(encoded_packets) > self.max_decode_packets:

raise ValueError('Too many packets in payload')

self.packets = [packet.Packet(encoded_packet=encoded_packet)

for encoded_packet in encoded_packets]