mirror of https://gitlab.com/litecord/litecord.git
170 lines
4.3 KiB
Markdown
170 lines
4.3 KiB
Markdown
# Litecord Voice Server Protocol (LVSP)
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LVSP is a protocol for Litecord to communicate with an external component
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dedicated for voice data. The voice server is responsible for the
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Voice Websocket Discord and Voice UDP connections.
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LVSP runs over a *long-lived* websocket with TLS. The encoding is JSON.
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**TODO:** common logic scenarios:
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- initializing a voice channel
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- updating a voice channel
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- destroying a voice channel
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- user joining to a voice channel
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- user joining to a voice channel (while also initializing it, e.g
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first member in the channel)
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- user leaving a voice channel
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## OP code table
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"client" is litecord. "server" is the voice server.
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| opcode | name | sent by |
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| --: | :-- | :-- |
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| 0 | HELLO | server |
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| 1 | IDENTIFY | client |
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| 2 | RESUME | client |
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| 3 | READY | server |
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| 4 | HEARTBEAT | client |
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| 5 | HEARTBEAT\_ACK | server |
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| 6 | INFO | client / server |
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| 7 | VST\_REQUEST | client |
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## Message structure
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Message data is defined by each opcode.
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**Note:** the `snowflake` type follows the same rules as the Discord Gateway's
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snowflake type: A string encoding a Discord Snowflake.
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| field | type | description |
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| --: | :-- | :-- |
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| op | integer, opcode | operator code |
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| d | map[string, any] | message data |
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## High level overview
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- connect, receive HELLO
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- send IDENTIFY or RESUME
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- if RESUME, process incoming messages as they were post-ready
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- receive READY
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- start HEARTBEAT'ing
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- send INFO / VSU\_REQUEST messages as needed
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## Error codes
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| code | meaning |
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| --: | :-- |
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| 4000 | general error. Reconnect |
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| 4001 | authentication failure |
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| 4002 | decode error, given message failed to decode as json |
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## HELLO message
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Sent by the server when a connection is established.
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| field | type | description |
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| --: | :-- | :-- |
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| heartbeat\_interval | integer | amount of milliseconds to heartbeat with |
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## IDENTIFY message
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Sent by the client to identify itself.
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| field | type | description |
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| --: | :-- | :-- |
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| token | string | secret value kept between client and server |
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## RESUME message
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Sent by the client to resume itself from a failed websocket connection.
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The server will resend its data, then send a READY message.
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| field | type | description |
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| --: | :-- | :-- |
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| token | string | same value from IDENTIFY.token |
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| seq | integer | last sequence number to resume from |
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## READY message
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**TODO:** does READY need any information?
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| field | type | description |
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| --: | :-- | :-- |
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## HEARTBEAT message
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Sent by the client as a keepalive / health monitoring method.
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The server MUST reply with a HEARTBEAT\_ACK message back in a reasonable
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time period.
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**TODO:** specify sequence numbers in INFO messages
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| field | type | description |
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| --: | :-- | :-- |
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| s | integer | sequence number |
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## HEARTBEAT\_ACK message
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Sent by the server in reply to a HEARTBEAT message coming from the client.
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**TODO:** add sequence numbers to ACK
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| field | type | description |
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| --: | :-- | :-- |
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| s | integer | sequence number |
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## INFO message
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Sent by either client or server on creation of update of a given object (
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such as a channel's bitrate setting or a user joining a channel).
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| field | type | description |
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| --: | :-- | :-- |
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| type | InfoType | info type |
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| info | Union[ChannelInfo, VoiceInfo] | info object |
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### IntoType Enum
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| value | name | description |
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| --: | :-- | :-- |
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| 0 | CHANNEL | channel information |
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| 1 | VST | Voice State |
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### ChannelInfo object
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| field | type | description |
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| --: | :-- | :-- |
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| id | snowflake | channel id |
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| bitrate | integer | channel bitrate |
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### VoiceInfo object
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| field | type | description |
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| --: | :-- | :-- |
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| user\_id | snowflake | user id |
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| channel\_id | snowflake | channel id |
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| session\_id | string | session id |
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| deaf | boolean | deaf status |
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| mute | boolean | mute status |
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| self\_deaf | boolean | self-deaf status |
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| self\_mute | boolean | self-mute status |
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| suppress | boolean | supress status |
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## VST\_REQUEST message
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Sent by the client to request the creation of a voice state in the voice server.
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**TODO:** verify correctness of this behavior.
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**TODO:** add logic on client connection
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The server SHALL send an INFO message containing the respective VoiceInfo data.
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| field | type | description |
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| --: | :-- | :-- |
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| user\_id | snowflake | user id for the voice state |
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| channel\_id | snowflake | channel id for the voice state |
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