In PyLink, each protocol module is a single file consisting of a protocol class, and a global `Class` attribute that is set equal to it (e.g. `Class = InspIRCdProtocol`). These classes should be based off of either [`classes.Protocol`](https://github.com/GLolol/PyLink/blob/0.4.0-dev/classes.py#L404), a boilerplate class that only defines a few variables, or [`ts6_common.TS6BaseProtocol`](https://github.com/GLolol/PyLink/blob/0.4.0-dev/protocols/ts6_common.py#L10), which includes elements of the TS6 protocol that are shared by both the InspIRCd and TS6 protocols. IRC objects initialize protocol modules by creating an instance of its class, and passing it the IRC object itself.
See also: [inspircd.html](inspircd.html) for an auto-generated specification of the InspIRCd protocol module.
## Tasks
Protocol modules have some *very****important*** jobs. If any of these aren't done correctly, you will be left with a very **broken, desynced** services server:
1) Handle incoming commands from the uplink IRCd.
2) Return [hook data](hooks-reference.md) for relevant commands, so that plugins can receive data from IRC.
3) Make sure channel/user states are kept correctly. Joins, quits, parts, kicks, mode changes, nick changes, etc. **must** be handled accurately.
4) Respond to both pings *and* pongs - the `irc.lastping` attribute **must** be set to the current time whenever a `PONG` is received from the uplink, so PyLink's internals don't [lag out the uplink thinking it isn't responding to our `PING`s](https://github.com/GLolol/PyLink/blob/0.4.0-dev/classes.py#L202-L204).
5) Implement a series of camelCase `commandServer/Client` functions - plugins use these for sending outgoing commands. See the `Outbound commands` section below for a list of which ones are needed.
## Core functions
The following functions *must* be implemented by any protocol module within its main class, since they are used by the IRC internals.
- **`connect`**`(self)` - Initializes a connection to a server.
- **`handle_events`**`(self, line)` - Handles inbound data (lines of text) from the uplink IRC server. Normally, this will pass commands to other command handlers within the protocol module, dropping commands that are unrecognized (wildcard handling), but it's really up to you how to structure your modules. You will want to be able to parse command arguments properly into a list: many protocols send RFC1459-style commands that can be parsed using the [`self.parseArgs(line)` function within the `Protocol` class](https://github.com/GLolol/PyLink/blob/c77d170765d20b0ac55b945fba4a6257fb15cf43/classes.py#L411).
- All of the outbound commands mentioned in the next section (minus raw numerics) should have their incoming version handled and [hook data](hooks-reference.md) returned.
### Outgoing command functions
- **`spawnClient`**`(self, nick, ident='null', host='null', realhost=None, modes=set(), server=None, ip='0.0.0.0', realname=None, ts=None, opertype=None)` - Spawns a client on the given IRC connection. Note that no nick collision / valid nickname checks are done here, and it is up to plugins to make sure they don't introduce anything invalid.
-`modes` is a set of `(mode char, mode arg)` tuples in the form of [`utils.parseModes()` output](using-utils.md#parseModes).
-`ident` and `host` default to "null", while `realhost` defaults to the same things as `host` if not defined.
-`realname` defaults to the real name specified in the PyLink config, if not given. `ts` defaults to the current time and `opertype` (the oper type name, if applicable) defaults to the simple text of `IRC Operator`.
- **`joinClient`**`(self, client, channel)` - Joins the client UID given to a channel.
- **`awayClient`**`(self, source, text)` - Sends an AWAY message from a PyLink client. `text` can be an empty string to unset AWAY status.
- **`inviteClient`**`(self, source, target, channel)` - Sends an INVITE from a PyLink client.
- **`kickClient`**`(self, source, channel, target, reason=None)` - Sends a kick from a PyLink client.
- **`kickServer`**`(self, source, channel, target, reason=None)` - Sends a kick from a PyLink server.
- **`killClient`**`(self, source, target, reason)` - Sends a kill from a PyLink client.
- **`killServer`**`(self, source, target, reason)` - Sends a kill from a PyLink server.
- **`knockClient`**`(self, source, target, text)` - Sends a `KNOCK` from a PyLink client.
- **`messageClient`**`(self, source, target, text)` - Sends a `PRIVMSG` from a PyLink client.
- **`modeClient`**`(self, source, target, modes, ts=None)` - Sends modes from a PyLink client. `modes` takes a set of `([+/-]mode char, mode arg)` tuples.
- **`modeServer`**`(self, source, target, modes, ts=None)` - Sends modes from a PyLink server.
- **`nickClient`**`(self, source, newnick)` - Changes the nick of a PyLink client.
- **`noticeClient`**`(self, source, target, text)` - Sends a `NOTICE` from a PyLink client.
- **`numericServer`**`(self, source, numeric, target, text)` - Sends a raw numeric `numeric` with `text` from the `source` server to `target`.
- **`partClient`**`(self, client, channel, reason=None)` - Sends a part from a PyLink client.
- **`pingServer`**`(self, source=None, target=None)` - Sends a `PING` to a target server. Periodic `PING`s are sent to our uplink automatically by the [`Irc`**`()`
internals]`**`(https://github.com/GLolol/PyLink/blob/0.4.0-dev/classes.py#L267-L272); plugins shouldn't have to use this.
- **`quitClient`**`(self, source, reason)` - Quits a PyLink client.
- **`sjoinServer`**`(self, server, channel, users, ts=None)` - Sends an SJOIN for a group of users to a channel. The sender should always be a Server ID (SID). TS is
optional, and defaults to the one we've stored in the channel state if not given. `users` is a list of `(prefix mode, UID)` pairs. Example uses:
- **`spawnServer`**`(self, name, sid=None, uplink=None, desc=None)` - Spawns a server off another PyLink server. `desc` (server description) defaults to the one in the config. `uplink` defaults to the main PyLink server, and `sid` (the server ID) is automatically generated if not given.
- **`topicClient`**`(self, source, target, text)` - Sends a topic change from a PyLink client.
- **`topicServer`**`(self, source, target, text)` - Sends a topic change from a PyLink server. This is usually used on burst.
- **`updateClient`**`(self, source, field, text)` - Updates the ident, host, or realname of a PyLink client. `field` should be either "IDENT", "HOST", "GECOS", or
"REALNAME". If changing the field given on the IRCd isn't supported, `NotImplementedError` should be raised.
## Variables to note
A protocol module should also set the following variables in their protocol class:
-`self.casemapping`: set this to `rfc1459` (default) or `ascii` to determine which case mapping should be used.
-`self.hook_map`: map a list of non-standard command names sent by the IRCd to those more commonly used: examples in the [TS6](https://github.com/GLolol/PyLink/blob/0.4.0-dev/protocols/ts6.py#L19) and [InspIRCd](https://github.com/GLolol/PyLink/blob/0.4.0-dev/protocols/inspircd.py#L24) modules.
