docs/: Start work on writing-plugins.md, improvements to example plugin

docs/technical/README.md

@@ -5,7 +5,7 @@ Any documentation here is provided for reference only.
 
 ### Introduction
 
-PyLink aims to be a modular, plugin-based IRC PseudoService framework. It uses swappable protocol modules and a hook-based system for calling plugins, allowing them to function regardless of the IRCd used.
+PyLink is an a modular, plugin-based IRC PseudoService framework. It uses swappable protocol modules and a hook-based system for calling plugins, allowing them to function regardless of the IRCd used.
 
 <img src="core-structure.png" width="50%" height="50%">
 

docs/technical/plugin_example.py

@@ -1,5 +1,4 @@
 # plugin_example.py: An example PyLink plugin.
-# You can add copyright notices and license information here.
 
 # These two lines add PyLink's root directory to the PATH, so that importing things like
 # 'utils' and 'log' work.
@@ -24,6 +23,8 @@ import random
 def hook_privmsg(irc, source, command, args):
     channel = args['target']
     text = args['text']
+    # irc.pseudoclient stores the IrcUser object of the main PyLink client.
+    # (i.e. the user defined in the bot: section of the config)
     if utils.isChannel(channel) and irc.pseudoclient.nick in text:
         utils.msg(irc, channel, 'hi there!')
         log.info('%s said my name on channel %s (PRIVMSG hook caught)' % (source, channel))
@@ -37,6 +38,9 @@ utils.add_hook(hook_privmsg, 'PRIVMSG')
 # source: The UID/numeric of the calling user.
 # args: A list of command args (excluding the command name) that the command was called with.
 def randint(irc, source, args):
+    # The docstring here is used as command help by the 'help' command, and formatted using the
+    # same line breaks as the raw string. You shouldn't make this text or any one line too long,
+    # to prevent flooding users or getting long lines cut off.
     """[<min>] [<max>]
     Returns a random number between <min> and <max>. <min> and <max> default
     to 1 and 10 respectively, if both aren't given."""
@@ -47,8 +51,8 @@ def randint(irc, source, args):
        rmin, rmax = 1, 10
     n = random.randint(rmin, rmax)
     utils.msg(irc, source, str(n))
-# You can also bind a command function multiple times, to different command names via a
-# second argument. Note that no checking is done at the moment to prevent multiple
-# plugins from binding to the same command names (the older command just gets replaced
-# by the new one!)
+# You can also bind a command function multiple times, and/or to different command names via a
+# second argument.
+# Note: no checking is done at the moment to prevent multiple plugins from binding to the same
+# command name. The older command just gets replaced by the new one!
 utils.add_cmd(randint, "random")

docs/technical/writing-plugins.md

@@ -0,0 +1,49 @@
+# Writing plugins for PyLink
+
+PyLink plugins are modules that extend its functionality by giving it something to do. Without any plugins loaded, PyLink can only sit on a server and do absolutely nothing.
+
+This guide, along with the sample plugin [`plugin-example.py`](plugin-example.py), aim to show the basics of writing plugins for PyLink.
+
+### Receiving data from IRC
+
+Plugins have three main ways of communicating with IRC: hooks, WHOIS handlers, and commands sent in PM to the main PyLink client. A simple plugin can use one, or any mixture of these.
+
+### Hooks
+
+Hooks are probably the most versatile form of communication. Each hook payload is formatted as a Python `dict`, with different data keys depending on the command.
+For example, a `PRIVMSG` payload would give you the fields `target` and `text`, while a `PART` payload would only give you `channels` and `reason` fields.
+
+There are many hook types available (one for each supported IRC command), and you can read more about them in the [PyLink hooks reference](hooks-reference.md).
+
+Plugins can bind to hooks using the `utils.add_hook()` function like so: `utils.add_hook(function_name, 'PRIVMSG')`, where `function_name` is your function definition, and `PRIVMSG` is whatever hook name you want to bind to. Once set up, `function_name` will be called whenever the protocol module receives a `PRIVMSG` command.
+
+Each hook-bound function takes 4 arguments: `irc, source, command, args`.
+- **irc**: The IRC object where the hook was called. Plugins are globally loaded, so there will be one of these per network.
+- **source**: The numeric of the sender. This will usually be a UID (for users) or a SID (for server).
+- **command**: The true command name where the hook originates. This may or may not be the same as the name of the hook, depending on context.
+- **args**: The hook data (a `dict`) associated with the command. Again, the available data keys differ by hook name
+(see the [hooks reference](hooks-reference.md) for a list of which can be used).
+
+Hook functions do not return anything, and can raise exceptions to be caught by the core.
+
+### PyLink commands
+
+For plugins that interact with IRC users, there is also the option of binding to PM commands. 
+
+Commands are bound to using the `utils.add_cmd()` function: `utils.add_cmd(testcommand, "hello")`. Here, `testcommand` is the name of your function, and `hello` is the (optional) name of the command to bind to; if it is not specified, it'll use the same name as the function.
+Now, your command function will be called whenever someone PMs the PyLink client with the command (e.g. `/msg PyLink hello`, case-insensitive).
+
+Each command function takes 3 arguments: `irc, source, args`.
+- **irc**: The IRC object where the command was called.
+- **source**: The numeric of the sender. This will usually be a UID (for users) or a SID (for server).
+- **args**: A `list` of space-separated command args (excluding the command name) that the command was called with. For example, `/msg PyLink hello world 1234` would give an `args` list of `['world', '1234']`
+
+Command handlers do not return anything, and can raise exceptions to be caught by the core.
+
+### WHOIS handlers
+
+The third option, `WHOIS` handlers, are a lot more limited compared to the other options. They are solely used for `WHOIS` replies, **and only work on IRCds where WHOIS commands are sent to remote servers!** This includes Charybdis and UnrealIRCd, but **not** InspIRCd, which handles all `WHOIS` requests locally (the only thing sent between servers is an IDLE time query).
+
+WHOIS replies are special in that any plugins wishing to add lines to a WHOIS reply must do so after the regular WHOIS lines (handled by the core), but before a special "End of WHOIS" line. This means that the regular hooks mechanism, which are only called after core handling, won't work here.
+
+\- section under construction -