Use protocol buffers

pytchat/paramgen/arcparam.py

@@ -1,111 +1,53 @@
-from base64 import urlsafe_b64encode as b64enc
-from functools import reduce
-import math
-import random
-import urllib.parse
+from .pb.header_pb2 import Header
+from .pb.replay_pb2 import Continuation
+from urllib.parse import quote
+import base64
 
 '''
 Generate continuation parameter of youtube replay chat.
 
-Author: taizan-hokuto (2019) @taizan205
+Author: taizan-hokuto
 
-ver 0.0.1 2019.10.05
+ver 0.0.1 2019.10.05 : Initial release.
+ver 0.0.2 2020.05.30 : Use Protocol Buffers.
 '''
 
 
-def _gen_vid(video_id):
-    """generate video_id parameter.
-    Parameter
-    ---------
-        video_id : str
-
-    Return
-    ---------
-        bytes : base64 encoded video_id parameter.
-    """
-    header_magic = b'\x0A\x0F\x1A\x0D\x0A'
-    header_id = video_id.encode()
-    header_sep_1 = b'\x1A\x13\xEA\xA8\xDD\xB9\x01\x0D\x0A\x0B'
-    header_terminator = b'\x20\x01'
-
-    item = [
-        header_magic,
-        _nval(len(header_id)),
-        header_id,
-        header_sep_1,
-        header_id,
-        header_terminator
-    ]
-
-    return urllib.parse.quote(
-        b64enc(reduce(lambda x, y: x+y, item)).decode()
-    ).encode()
+def _gen_vid(video_id) -> str:
+    header = Header()
+    header.info.video.id = video_id
+    header.terminator = 1
+    return base64.urlsafe_b64encode(header.SerializeToString()).decode()
 
 
-def _nval(val):
-    """convert value to byte array"""
-    if val < 0:
-        raise ValueError
-    buf = b''
-    while val >> 7:
-        m = val & 0xFF | 0x80
-        buf += m.to_bytes(1, 'big')
-        val >>= 7
-    buf += val.to_bytes(1, 'big')
-    return buf
+def _build(video_id, seektime, topchat_only) -> str:
+    chattype = 1
+    if topchat_only:
+        chattype = 4
 
-
-def _build(video_id, seektime, topchat_only):
-    switch_01 = b'\x04' if topchat_only else b'\x01'
+    fetch_before_start = 0
     if seektime < 0:
-        times = _nval(0)
-        switch = b'\x04'
+        fetch_before_start = 1
     elif seektime == 0:
-        times = _nval(1)
-        switch = b'\x03'
-    else:
-        times = _nval(int(seektime*1000000))
-        switch = b'\x03'
-    parity = b'\x00'
+        seektime = 1/1000000
 
-    header_magic = b'\xA2\x9D\xB0\xD3\x04'
-    sep_0 = b'\x1A'
-    vid = _gen_vid(video_id)
-    time_tag = b'\x28'
-    timestamp1 = times
-    sep_1 = b'\x30\x00\x38\x00\x40\x00\x48'
-    sep_2 = b'\x52\x1C\x08\x00\x10\x00\x18\x00\x20\x00'
-    chkstr = b'\x2A\x0E\x73\x74\x61\x74\x69\x63\x63\x68\x65\x63\x6B\x73\x75\x6D\x40'
-    sep_3 = b'\x00\x58\x03\x60'
-    sep_4 = b'\x68' + parity + b'\x72\x04\x08'
-    sep_5 = b'\x10' + parity + b'\x78\x00'
-
-    body = b''.join([
-        sep_0,
-        _nval(len(vid)),
-        vid,
-        time_tag,
-        timestamp1,
-        sep_1,
-        switch,
-        sep_2,
-        chkstr,
-        sep_3,
-        switch_01,
-        sep_4,
-        switch_01,
-        sep_5
-    ])
-
-    return urllib.parse.quote(
-        b64enc(header_magic +
-               _nval(len(body)) +
-               body
-               ).decode()
-    )
+    continuation = Continuation()
+    entity = continuation.entity
+    entity.header = _gen_vid(video_id)
+    entity.timestamp = int(seektime*1000000)
+    entity.s6 = 0
+    entity.s7 = 0
+    entity.s8 = fetch_before_start
+    entity.s9 = 3
+    entity.s10 = ''
+    entity.s12 = chattype
+    entity.chattype.value = chattype
+    entity.s15 = 0
+    return quote(
+        base64.urlsafe_b64encode(continuation.SerializeToString()).decode())
 
 
-def getparam(video_id, seektime=0, topchat_only=False):
+def getparam(video_id, seektime=0, topchat_only=False) -> str:
     '''
     Parameter
     ---------