Shrink continuation cursor for YouTube comments

This commit is contained in:
Omar Roth 2019-09-04 15:47:27 -04:00
parent fded5fd900
commit 7b53b6bfef
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GPG Key ID: B8254FB7EC3D37F2
3 changed files with 46 additions and 13 deletions

View File

@ -461,7 +461,7 @@ def produce_channel_videos_url(ucid, page = 1, auto_generated = nil, sort_by = "
case sort_by
when "newest"
# Empty tags can be omitted
# meta.write(Bytes[0x18,0x00])
# data.write(Bytes[0x18,0x00])
when "popular"
data.write Bytes[0x18, 0x01]
when "oldest"

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@ -57,14 +57,22 @@ class RedditListing
})
end
def fetch_youtube_comments(id, db, continuation, format, locale, thin_mode, region, sort_by = "top")
def fetch_youtube_comments(id, db, cursor, format, locale, thin_mode, region, sort_by = "top")
video = get_video(id, db, region: region)
session_token = video.info["session_token"]?
case cursor
when nil, ""
ctoken = produce_comment_continuation(id, cursor: "", sort_by: sort_by)
continuation ||= ctoken
# when .starts_with? "Ug"
# ctoken = produce_comment_reply_continuation(id, video.ucid, cursor)
when .starts_with? "ADSJ"
ctoken = produce_comment_continuation(id, cursor: cursor, sort_by: sort_by)
else
ctoken = cursor
end
if !continuation || continuation.empty? || !session_token
if !session_token
if format == "json"
return {"comments" => [] of String}.to_json
else
@ -73,6 +81,7 @@ def fetch_youtube_comments(id, db, continuation, format, locale, thin_mode, regi
end
post_req = {
page_token: ctoken,
session_token: session_token,
}
@ -89,7 +98,7 @@ def fetch_youtube_comments(id, db, continuation, format, locale, thin_mode, regi
headers["x-youtube-client-name"] = "1"
headers["x-youtube-client-version"] = "2.20180719"
response = client.post("/comment_service_ajax?action_get_comments=1&ctoken=#{continuation}&continuation=#{continuation}&hl=en&gl=US", headers, form: post_req)
response = client.post("/comment_service_ajax?action_get_comments=1&hl=en&gl=US", headers, form: post_req)
response = JSON.parse(response.body)
if !response["response"]["continuationContents"]?
@ -216,8 +225,8 @@ def fetch_youtube_comments(id, db, continuation, format, locale, thin_mode, regi
end
if body["continuations"]?
continuation = body["continuations"][0]["nextContinuationData"]["continuation"]
json.field "continuation", continuation
continuation = body["continuations"][0]["nextContinuationData"]["continuation"].as_s
json.field "continuation", cursor.try &.starts_with?("E") ? continuation : extract_comment_cursor(continuation)
end
end
end
@ -563,6 +572,29 @@ def content_to_comment_html(content)
return comment_html
end
def extract_comment_cursor(continuation)
continuation = URI.unescape(continuation)
data = IO::Memory.new(Base64.decode(continuation))
# 0x12 0x26
data.pos += 2
data.read_byte # => 0x12
video_id = Bytes.new(data.read_bytes(VarInt))
data.read video_id
until data.peek[0] == 0x0a
data.read_byte
end
data.read_byte # 0x0a
data.read_byte if data.peek[0] == 0x0a
cursor = Bytes.new(data.read_bytes(VarInt))
data.read cursor
String.new(cursor)
end
def produce_comment_continuation(video_id, cursor = "", sort_by = "top")
data = IO::Memory.new
@ -652,7 +684,7 @@ def produce_comment_reply_continuation(video_id, ucid, comment_id)
VarInt.to_io(data, comment_id.size)
data.print comment_id
data.write(Bytes[0x22, 0x02, 0x08, 0x00]) # ??
data.write(Bytes[0x22, 0x02, 0x08, 0x00]) # ?
data.write(Bytes[ucid.size + video_id.size + 7])
data.write(Bytes[ucid.size])

View File

@ -267,8 +267,8 @@ def get_referer(env, fallback = "/", unroll = true)
end
struct VarInt
def self.from_io(io : IO, format = IO::ByteFormat::BigEndian) : Int32
result = 0_i32
def self.from_io(io : IO, format = IO::ByteFormat::NetworkEndian) : Int32
result = 0_u32
num_read = 0
loop do
@ -276,18 +276,19 @@ struct VarInt
raise "Invalid VarInt" if !byte
value = byte & 0x7f
result |= value.to_i32 << (7 * num_read)
result |= value.to_u32 << (7 * num_read)
num_read += 1
break if byte & 0x80 == 0
raise "Invalid VarInt" if num_read > 5
end
result
result.to_i32
end
def self.to_io(io : IO, value : Int32)
io.write_byte 0x00 if value == 0x00
value = value.to_u32
while value != 0
byte = (value & 0x7f).to_u8