1 files changed, 611 insertions, 0 deletions
diff --git a/youtube/proto_debug.py b/youtube/proto_debug.py
new file mode 100644
index 0000000..d793fe1
--- /dev/null
+++ b/youtube/proto_debug.py
@@ -0,0 +1,611 @@
+# TODO: clean this file up more and heavily refactor
+
+''' Helper functions for reverse engineering protobuf.
+
+Basic guide:
+
+Run interactively with python3 -i proto_debug.py
+
+The function dec will decode a base64 string
+(regardless of whether it includes = or %3D at the end) to a bytestring
+
+The function pb (parse_protobuf) will return a list of tuples.
+Each tuple is (wire_type, field_number, field_data)
+
+The function enc encodes as base64 (inverse of dec)
+The function uenc is like enc but replaces = with %3D
+
+See https://developers.google.com/protocol-buffers/docs/encoding#structure
+
+Example usage:
+>>> pb(dec('4qmFsgJcEhhVQ1lPX2phYl9lc3VGUlY0YjE3QUp0QXcaQEVnWjJhV1JsYjNNWUF5QUFNQUU0QWVvREdFTm5Ua1JSVlVWVFEzZHBYM2gwTTBaeFRuRkZiRFZqUWclM0QlM0Q%3D'))
+[(2, 80226972, b'\x12\x18UCYO_jab_esuFRV4b17AJtAw\x1a@EgZ2aWRlb3MYAyAAMAE4AeoDGENnTkRRVUVTQ3dpX3h0M0ZxTnFFbDVjQg%3D%3D')]
+
+>>> pb(b'\x12\x18UCYO_jab_esuFRV4b17AJtAw\x1a@EgZ2aWRlb3MYAyAAMAE4AeoDGENnTkRRVUVTQ3dpX3h0M0ZxTnFFbDVjQg%3D%3D')
+[(2, 2, b'UCYO_jab_esuFRV4b17AJtAw'), (2, 3, b'EgZ2aWRlb3MYAyAAMAE4AeoDGENnTkRRVUVTQ3dpX3h0M0ZxTnFFbDVjQg%3D%3D')]
+
+>>> pb(dec(b'EgZ2aWRlb3MYAyAAMAE4AeoDGENnTkRRVUVTQ3dpX3h0M0ZxTnFFbDVjQg%3D%3D'))
+[(2, 2, b'videos'), (0, 3, 3), (0, 4, 0), (0, 6, 1), (0, 7, 1), (2, 61, b'CgNDQUESCwi_xt3FqNqEl5cB')]
+
+>>> pb(dec(b'CgNDQUESCwi_xt3FqNqEl5cB'))
+[(2, 1, b'CAA'), (2, 2, b'\x08\xbf\xc6\xdd\xc5\xa8\xda\x84\x97\x97\x01')]
+
+>>> pb(b'\x08\xbf\xc6\xdd\xc5\xa8\xda\x84\x97\x97\x01')
+[(0, 1, 10893665244101960511)]
+
+>>> pb(dec(b'CAA'))
+[(0, 1, 0)]
+
+The function recursive_pb will try to do dec/pb recursively automatically.
+It's a dumb function (so might try to dec or pb something that isn't really
+base64 or protobuf) so be careful.
+The function pp will pretty print the recursive structure:
+
+>>> pp(recursive_pb('4qmFsgJcEhhVQ1lPX2phYl9lc3VGUlY0YjE3QUp0QXcaQEVnWjJhV1JsYjNNWUF5QUFNQUU0QWVvREdFTm5Ua1JSVlVWVFEzZHBYM2gwTTBaeFRuRkZiRFZqUWclM0QlM0Q%3D'))
+
+('base64p',
+ [
+  [2, 80226972,
+   [
+    [2, 2, b'UCYO_jab_esuFRV4b17AJtAw'],
+    [2, 3,
+     ('base64p',
+      [
+       [2, 2, b'videos'],
+       [0, 3, 3],
+       [0, 4, 0],
+       [0, 6, 1],
+       [0, 7, 1],
+       [2, 61,
+        ('base64?',
+         [
+          [2, 1, b'CAA'],
+          [2, 2,
+           [
+            [0, 1, 10893665244101960511],
+           ]
+          ],
+         ]
+        )
+       ],
+      ]
+     )
+    ],
+   ]
+  ],
+ ]
+)
+
+
+- base64 means a base64 encode with equals sign paddings
+- base64s means a base64 encode without padding
+- base64p means a url base64 encode with equals signs replaced with %3D
+- base64? means the base64 type cannot be inferred because of the length
+
+make_proto is the inverse function. It will take a recursive_pb structure and
+make a ctoken out of it, so in general,
+x == make_proto(recursive_pb(x))
+
+There are some other functions I wrote while reverse engineering stuff
+that may or may not be useful.
+'''
+
+
+import urllib.request
+import urllib.parse
+import re
+import time
+import json
+import os
+import pprint
+
+
+# ------ from proto.py -----------------------------------------------
+from math import ceil
+import base64
+import io
+
+
+def byte(n):
+    return bytes((n,))
+
+
+def varint_encode(offset):
+    '''In this encoding system, for each 8-bit byte, the first bit is 1 if there are more bytes, and 0 is this is the last one.
+    The next 7 bits are data. These 7-bit sections represent the data in Little endian order. For example, suppose the data is
+    aaaaaaabbbbbbbccccccc (each of these sections is 7 bits). It will be encoded as:
+    1ccccccc 1bbbbbbb 0aaaaaaa
+
+    This encoding is used in youtube parameters to encode offsets and to encode the length for length-prefixed data.
+    See https://developers.google.com/protocol-buffers/docs/encoding#varints for more info.'''
+    needed_bytes = ceil(offset.bit_length()/7) or 1 # (0).bit_length() returns 0, but we need 1 in that case.
+    encoded_bytes = bytearray(needed_bytes)
+    for i in range(0, needed_bytes - 1):
+        encoded_bytes[i] = (offset & 127) | 128  # 7 least significant bits
+        offset = offset >> 7
+    encoded_bytes[-1] = offset & 127 # leave first bit as zero for last byte
+
+    return bytes(encoded_bytes)
+
+
+def varint_decode(encoded):
+    decoded = 0
+    for i, byte in enumerate(encoded):
+        decoded |= (byte & 127) << 7*i
+
+        if not (byte & 128):
+            break
+    return decoded
+
+
+def string(field_number, data):
+    data = as_bytes(data)
+    return _proto_field(2, field_number, varint_encode(len(data)) + data)
+
+
+nested = string
+
+
+def uint(field_number, value):
+    return _proto_field(0, field_number, varint_encode(value))
+
+
+def _proto_field(wire_type, field_number, data):
+    ''' See https://developers.google.com/protocol-buffers/docs/encoding#structure '''
+    return varint_encode((field_number << 3) | wire_type) + data
+
+
+def percent_b64encode(data):
+    return base64.urlsafe_b64encode(data).replace(b'=', b'%3D')
+
+
+def unpadded_b64encode(data):
+    return base64.urlsafe_b64encode(data).replace(b'=', b'')
+
+
+def as_bytes(value):
+    if isinstance(value, str):
+        return value.encode('utf-8')
+    return value
+
+
+def read_varint(data):
+    result = 0
+    i = 0
+    while True:
+        try:
+            byte = data.read(1)[0]
+        except IndexError:
+            if i == 0:
+                raise EOFError()
+            raise Exception('Unterminated varint starting at ' + str(data.tell() - i))
+        result |= (byte & 127) << 7*i
+        if not byte & 128:
+            break
+
+        i += 1
+    return result
+
+
+def read_group(data, end_sequence):
+    start = data.tell()
+    index = data.original.find(end_sequence, start)
+    if index == -1:
+        raise Exception('Unterminated group')
+    data.seek(index + len(end_sequence))
+    return data.original[start:index]
+
+
+def parse(data, include_wire_type=False):
+    '''Returns a dict mapping field numbers to values
+
+    data is the protobuf structure, which must not be b64-encoded'''
+    if include_wire_type:
+        return {field_number: [wire_type, value]
+                for wire_type, field_number, value in read_protobuf(data)}
+    return {field_number: value
+            for _, field_number, value in read_protobuf(data)}
+
+
+base64_enc_funcs = {
+    'base64': base64.urlsafe_b64encode,
+    'base64s': unpadded_b64encode,
+    'base64p': percent_b64encode,
+    'base64?': base64.urlsafe_b64encode,
+}
+
+
+def _make_protobuf(data):
+    # must be dict mapping field_number to [wire_type, value]
+    if isinstance(data, dict):
+        new_data = []
+        for field_num, (wire_type, value) in sorted(data.items()):
+            new_data.append((wire_type, field_num, value))
+        data = new_data
+    if isinstance(data, str):
+        return data.encode('utf-8')
+    elif len(data) == 2 and data[0] in list(base64_enc_funcs.keys()):
+        return base64_enc_funcs[data[0]](_make_protobuf(data[1]))
+    elif isinstance(data, list):
+        result = b''
+        for field in data:
+            if field[0] == 0:
+                result += uint(field[1], field[2])
+            elif field[0] == 2:
+                result += string(field[1], _make_protobuf(field[2]))
+            else:
+                raise NotImplementedError('Wire type ' + str(field[0])
+                    + ' not implemented')
+        return result
+    return data
+
+
+def make_protobuf(data):
+    return _make_protobuf(data).decode('ascii')
+
+
+make_proto = make_protobuf
+
+
+def _set_protobuf_value(data, *path, value):
+    if not path:
+        return value
+    op = path[0]
+    if op in base64_enc_funcs:
+        inner_data = b64_to_bytes(data)
+        return base64_enc_funcs[op](
+            _set_protobuf_value(inner_data, *path[1:], value=value)
+        )
+    pb_dict = parse(data, include_wire_type=True)
+    pb_dict[op][1] = _set_protobuf_value(
+        pb_dict[op][1], *path[1:], value=value
+    )
+    return _make_protobuf(pb_dict)
+
+
+def set_protobuf_value(data, *path, value):
+    '''Set a field's value in a raw protobuf structure
+
+    path is a list of field numbers and/or base64 encoding directives
+
+    The directives are
+        base64: normal base64 encoding with equal signs padding
+        base64s ("stripped"): no padding
+        base64p: %3D instead of = for padding
+
+    return new_protobuf, err'''
+    try:
+        new_protobuf = _set_protobuf_value(data, *path, value=value)
+        return new_protobuf.decode('ascii'), None
+    except Exception:
+        return None, traceback.format_exc()
+
+
+def b64_to_bytes(data):
+    if isinstance(data, bytes):
+        data = data.decode('ascii')
+    data = data.replace("%3D", "=")
+    return base64.urlsafe_b64decode(data + "="*((4 - len(data) % 4) % 4))
+# --------------------------------------------------------------------
+
+
+dec = b64_to_bytes
+
+
+def get_b64_type(data):
+    '''return base64, base64s, base64p, or base64?'''
+    if isinstance(data, str):
+        data = data.encode('ascii')
+    if data.endswith(b'='):
+        return 'base64'
+    if data.endswith(b'%3D'):
+        return 'base64p'
+    # Length of data means it wouldn't have an equals sign,
+    # so we can't tell which type it is.
+    if len(data) % 4 == 0:
+        return 'base64?'
+
+    return 'base64s'
+
+
+def enc(t):
+    return base64.urlsafe_b64encode(t).decode('ascii')
+
+
+def uenc(t):
+    return enc(t).replace("=", "%3D")
+
+
+def b64_to_ascii(t):
+    return base64.urlsafe_b64decode(t).decode('ascii', errors='replace')
+
+
+def b64_to_bin(t):
+    decoded = base64.urlsafe_b64decode(t)
+    # print(len(decoded)*8)
+    return " ".join(["{:08b}".format(x) for x in decoded])
+
+
+def bytes_to_bin(t):
+    return " ".join(["{:08b}".format(x) for x in t])
+
+
+def bin_to_bytes(t):
+    return int(t, 2).to_bytes((len(t) + 7) // 8, 'big')
+
+
+def bytes_to_hex(t):
+    return ' '.join(hex(n)[2:].zfill(2) for n in t)
+
+
+tohex = bytes_to_hex
+fromhex = bytes.fromhex
+
+
+def aligned_ascii(data):
+    return ' '.join(' ' + chr(n) if n in range(32, 128) else ' _' for n in data)
+
+
+def parse_protobuf(data, mutable=False, spec=()):
+    data_original = data
+    data = io.BytesIO(data)
+    data.original = data_original
+    while True:
+        try:
+            tag = read_varint(data)
+        except EOFError:
+            break
+        wire_type = tag & 7
+        field_number = tag >> 3
+
+        if wire_type == 0:
+            value = read_varint(data)
+        elif wire_type == 1:
+            value = data.read(8)
+        elif wire_type == 2:
+            length = read_varint(data)
+            value = data.read(length)
+        elif wire_type == 3:
+            end_bytes = varint_encode((field_number << 3) | 4)
+            value = read_group(data, end_bytes)
+        elif wire_type == 5:
+            value = data.read(4)
+        else:
+            raise Exception("Unknown wire type: " + str(wire_type) + ", Tag: " + bytes_to_hex(varint_encode(tag)) + ", at position " + str(data.tell()))
+        if mutable:
+            yield [wire_type, field_number, value]
+        else:
+            yield (wire_type, field_number, value)
+
+
+read_protobuf = parse_protobuf
+
+
+def pb(data, mutable=False):
+    return list(parse_protobuf(data, mutable=mutable))
+
+
+def bytes_to_base4(data):
+    result = ''
+    for b in data:
+        result += str(b >> 6) + str((b >> 4) & 0b11) + str((b >> 2) & 0b11) + str(b & 0b11)
+    return result
+
+
+import re
+import struct
+import binascii
+
+
+# Base32 encoding/decoding must be done in Python
+_b32alphabet = b'abcdefghijklmnopqrstuvwxyz012345'
+_b32tab2 = None
+_b32rev = None
+
+bytes_types = (bytes, bytearray)  # Types acceptable as binary data
+
+
+def _bytes_from_decode_data(s):
+    if isinstance(s, str):
+        try:
+            return s.encode('ascii')
+        except UnicodeEncodeError:
+            raise ValueError('string argument should contain only ASCII characters')
+    if isinstance(s, bytes_types):
+        return s
+    try:
+        return memoryview(s).tobytes()
+    except TypeError:
+        raise TypeError("argument should be a bytes-like object or ASCII "
+                        "string, not %r" % s.__class__.__name__) from None
+
+
+def b32decode(s, casefold=False, map01=None):
+    """Decode the Base32 encoded bytes-like object or ASCII string s.
+
+    Optional casefold is a flag specifying whether a lowercase alphabet is
+    acceptable as input.  For security purposes, the default is False.
+
+    RFC 3548 allows for optional mapping of the digit 0 (zero) to the
+    letter O (oh), and for optional mapping of the digit 1 (one) to
+    either the letter I (eye) or letter L (el).  The optional argument
+    map01 when not None, specifies which letter the digit 1 should be
+    mapped to (when map01 is not None, the digit 0 is always mapped to
+    the letter O).  For security purposes the default is None, so that
+    0 and 1 are not allowed in the input.
+
+    The result is returned as a bytes object.  A binascii.Error is raised if
+    the input is incorrectly padded or if there are non-alphabet
+    characters present in the input.
+    """
+    global _b32rev
+    # Delay the initialization of the table to not waste memory
+    # if the function is never called
+    if _b32rev is None:
+        _b32rev = {v: k for k, v in enumerate(_b32alphabet)}
+    s = _bytes_from_decode_data(s)
+    if len(s) % 8:
+        raise binascii.Error('Incorrect padding')
+    # Handle section 2.4 zero and one mapping.  The flag map01 will be either
+    # False, or the character to map the digit 1 (one) to.  It should be
+    # either L (el) or I (eye).
+    if map01 is not None:
+        map01 = _bytes_from_decode_data(map01)
+        assert len(map01) == 1, repr(map01)
+        s = s.translate(bytes.maketrans(b'01', b'O' + map01))
+    if casefold:
+        s = s.upper()
+    # Strip off pad characters from the right.  We need to count the pad
+    # characters because this will tell us how many null bytes to remove from
+    # the end of the decoded string.
+    l = len(s)
+    s = s.rstrip(b'=')
+    padchars = l - len(s)
+    # Now decode the full quanta
+    decoded = bytearray()
+    b32rev = _b32rev
+    for i in range(0, len(s), 8):
+        quanta = s[i: i + 8]
+        acc = 0
+        try:
+            for c in quanta:
+                acc = (acc << 5) + b32rev[c]
+        except KeyError:
+            raise binascii.Error('Non-base32 digit found') from None
+        decoded += acc.to_bytes(5, 'big')
+    # Process the last, partial quanta
+    if padchars:
+        acc <<= 5 * padchars
+        last = acc.to_bytes(5, 'big')
+        if padchars == 1:
+            decoded[-5:] = last[:-1]
+        elif padchars == 3:
+            decoded[-5:] = last[:-2]
+        elif padchars == 4:
+            decoded[-5:] = last[:-3]
+        elif padchars == 6:
+            decoded[-5:] = last[:-4]
+        else:
+            raise binascii.Error('Incorrect padding')
+    return bytes(decoded)
+
+
+def dec32(data):
+    if isinstance(data, bytes):
+        data = data.decode('ascii')
+    return b32decode(data + "="*((8 - len(data)%8)%8))
+
+
+_patterns = [
+    (b'UC', 24), # channel
+    (b'PL', 34), # playlist
+    (b'LL', 24), # liked videos playlist
+    (b'UU', 24), # user uploads playlist
+    (b'RD', 15), # radio mix
+    (b'RD', 43), # radio mix
+    (b'', 11),   # video
+    (b'Ug', 26), # comment
+    (b'Ug', 49), # comment reply (of form parent_id.reply_id)
+    (b'9', 22), # comment reply id
+]
+def is_youtube_object_id(data):
+    try:
+        if isinstance(data, str):
+            data = data.encode('ascii')
+    except Exception:
+        return False
+
+    for start_sequence, length in _patterns:
+        if len(data) == length and data.startswith(start_sequence):
+            return True
+
+    return False
+
+
+def recursive_pb(data):
+    try:
+        # check if this fits the basic requirements for base64
+        if isinstance(data, str) or all(i > 32 for i in data):
+            if len(data) > 11 and not is_youtube_object_id(data):
+                raw_data = b64_to_bytes(data)
+                b64_type = get_b64_type(data)
+
+                rpb = recursive_pb(raw_data)
+                if rpb == raw_data:
+                    # could not interpret as protobuf, probably not b64
+                    return data
+                return (b64_type, rpb)
+            else:
+                return data
+    except Exception as e:
+        return data
+
+    try:
+        result = pb(data, mutable=True)
+    except Exception as e:
+        return data
+
+    for tuple in result:
+        if tuple[0] == 2:
+            tuple[2] = recursive_pb(tuple[2])
+
+    return result
+
+
+
+def indent_lines(lines, indent):
+    return re.sub(r'^', ' '*indent, lines, flags=re.MULTILINE)
+
+
+def _pp(obj, indent):   # not my best work
+    if isinstance(obj, tuple):
+        if len(obj) == 3:   # (wire_type, field_number, data)
+            return obj.__repr__()
+        else:   # (base64, [...])
+            return ('(' + obj[0].__repr__() + ',\n'
+                    + indent_lines(_pp(obj[1], indent), indent) + '\n'
+                    + ')')
+    elif isinstance(obj, list):
+        # [wire_type, field_number, data]
+        if (len(obj) == 3
+            and not any(isinstance(x, (list, tuple)) for x in obj)
+        ):
+            return obj.__repr__()
+
+        # [wire_type, field_number, [...]]
+        elif (len(obj) == 3
+            and not any(isinstance(x, (list, tuple)) for x in obj[0:2])
+        ):
+            return ('[' + obj[0].__repr__() + ', ' + obj[1].__repr__() + ',\n'
+                    + indent_lines(_pp(obj[2], indent), indent) + '\n'
+                    + ']')
+        else:
+            s = '[\n'
+            for x in obj:
+                s += indent_lines(_pp(x, indent), indent) + ',\n'
+            s += ']'
+            return s
+    else:
+        return obj.__repr__()
+
+
+def pp(obj, indent=1):
+    '''Pretty prints the recursive pb structure'''
+    print(_pp(obj, indent))
+
+
+desktop_user_agent = 'Mozilla/5.0 (Windows NT 6.1; rv:52.0) Gecko/20100101 Firefox/52.0'
+desktop_headers = (
+    ('Accept', '*/*'),
+    ('Accept-Language', 'en-US,en;q=0.5'),
+    ('X-YouTube-Client-Name', '1'),
+    ('X-YouTube-Client-Version', '2.20180830'),
+) + (('User-Agent', desktop_user_agent),)
+
+mobile_user_agent = 'Mozilla/5.0 (Linux; Android 7.0; Redmi Note 4 Build/NRD90M) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Mobile Safari/537.36'
+mobile_headers = (
+    ('Accept', '*/*'),
+    ('Accept-Language', 'en-US,en;q=0.5'),
+    ('X-YouTube-Client-Name', '2'),
+    ('X-YouTube-Client-Version', '2.20180830'),
+) + (('User-Agent', mobile_user_agent),)