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Add ._get_cdn_client as alternative ._get_exported_client version

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Lonami Exo
2017-09-30 17:51:07 +02:00
parent a35c4b15db
commit d28f370ab6
2 changed files with 38 additions and 31 deletions
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32
telethon/crypto/cdn_decrypter.py
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@@ -10,7 +10,7 @@ from ..errors import CdnFileTamperedError
class CdnDecrypter:
"""Used when downloading a file results in a 'FileCdnRedirect' to
both prepare the redirect, decrypt the file as it downloads, and
ensure the file hasn't been tampered.
ensure the file hasn't been tampered. https://core.telegram.org/cdn
"""
def __init__(self, cdn_client, file_token, cdn_aes, cdn_file_hashes):
self.client = cdn_client
@@ -19,46 +19,26 @@ class CdnDecrypter:
self.cdn_file_hashes = cdn_file_hashes
@staticmethod
def prepare_decrypter(client, client_cls, cdn_redirect):
def prepare_decrypter(client, cdn_client, cdn_redirect):
"""Prepares a CDN decrypter, returning (decrypter, file data).
'client' should be the original TelegramBareClient that
tried to download the file.
'client_cls' should be the class of the TelegramBareClient.
'client' should be an existing client not connected to a CDN.
'cdn_client' should be an already-connected TelegramBareClient
with the auth key already created.
"""
# TODO Avoid the need for 'client_cls=TelegramBareClient'
# https://core.telegram.org/cdn
cdn_aes = AESModeCTR(
key=cdn_redirect.encryption_key,
# 12 first bytes of the IV..4 bytes of the offset (0, big endian)
iv=cdn_redirect.encryption_iv[:12] + bytes(4)
)
# Create a new client on said CDN
dc = client._get_dc(cdn_redirect.dc_id, cdn=True)
session = Session(client.session)
session.server_address = dc.ip_address
session.port = dc.port
cdn_client = client_cls( # Avoid importing TelegramBareClient
session, client.api_id, client.api_hash,
timeout=client._sender.connection.get_timeout()
)
# This will make use of the new RSA keys for this specific CDN.
#
# We assume that cdn_redirect.cdn_file_hashes are ordered by offset,
# and that there will be enough of these to retrieve the whole file.
#
# This relies on the fact that TelegramBareClient._dc_options is
# static and it won't be called from this DC (it would fail).
cdn_client.connect()
# CDN client is ready, create the resulting CdnDecrypter
decrypter = CdnDecrypter(
cdn_client, cdn_redirect.file_token,
cdn_aes, cdn_redirect.cdn_file_hashes
)
cdn_file = client(GetCdnFileRequest(
cdn_file = cdn_client(GetCdnFileRequest(
file_token=cdn_redirect.file_token,
offset=cdn_redirect.cdn_file_hashes[0].offset,
limit=cdn_redirect.cdn_file_hashes[0].limit