/
message.py
154 lines (114 loc) · 3.02 KB
/
message.py
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from util import get_info_hash, gen_id
def build_handshake(torrent):
# pstrlen
buffer = (19).to_bytes(1, 'big')
# pstr
buffer += 'BitTorrent protocol'.encode()
# reserved
buffer += (0).to_bytes(8, 'big')
# info hash
buffer += get_info_hash(torrent)
# peer id
buffer += gen_id()
return buffer
def build_keep_alive():
pass
def build_choke():
# length
buffer = (1).to_bytes(4, 'big')
# id
buffer += (0).to_bytes(1, 'big')
return buffer
def build_unchoke():
# length
buffer = (1).to_bytes(4, 'big')
# id
buffer += (1).to_bytes(1, 'big')
return buffer
def build_interested():
# length
buffer = (1).to_bytes(4, 'big')
# id
buffer += (2).to_bytes(1, 'big')
return buffer
def build_uninterested():
# length
buffer = (1).to_bytes(4, 'big')
# id
buffer += (3).to_bytes(1, 'big')
return buffer
def build_have(payload):
# length
buffer = (5).to_bytes(4, 'big')
# id
buffer += (4).to_bytes(1, 'big')
# piece index
buffer += (payload).to_bytes(4, 'big')
return buffer
def build_bitfield(bitfield):
# length
buffer = (len(bitfield)+1).to_bytes(4, 'big')
# id
buffer += (5).to_bytes(4, 'big')
# bitfield
buffer += bitfield
return buffer
def build_request(payload):
# length
buffer = (13).to_bytes(4, 'big')
# id
buffer += (6).to_bytes(1, 'big')
# piece index
buffer += (payload['index']).to_bytes(4, 'big')
# begin
buffer += (payload['begin']).to_bytes(4, 'big')
# piece length
buffer += (payload['length']).to_bytes(4, 'big')
return buffer
def build_piece(payload):
# length
buffer = (len(payload['block'])+9).to_bytes(4, 'big')
# id
buffer += (7).to_bytes(1, 'big')
# piece index
buffer += (payload['index']).to_bytes(4, 'big')
# begin
buffer += (payload['begin']).to_bytes(4, 'big')
# block
buffer += (payload['block'])
return buffer
def build_cancel(payload):
# length
buffer = (13).to_bytes(4, 'big')
# id
buffer += (8).to_bytes(1, 'big')
# piece index
buffer += (payload['index']).to_bytes(4, 'big')
# begin
buffer += (payload['begin']).to_bytes(4, 'big')
# piece length
buffer += (payload['length']).to_bytes(4, 'big')
return buffer
def build_port(payload):
# length
buffer = (3).to_bytes(4, 'big')
# id
buffer += (9).to_bytes(1, 'big')
# piece index
buffer += (payload).to_bytes(4, 'big')
return buffer
def parse_message(message):
msg_id = int(message[4:5].hex(), 16) if len(message)>4 else None
payload = message[5:] if len(message)>5 else None
if msg_id in {6, 7, 8}:
rest = payload[8:]
payload = {
'index': int(payload[0:4].hex(), 16),
'begin': int(payload[4:8].hex(), 16)
}
payload[('block' if msg_id==7 else 'length')] = rest
return {
'size': int(message[0:4].hex(), 16),
'id': msg_id,
'payload': payload
}