WeeChat Relay Protocol
======================
Sébastien Helleu <flashcode@flashtux.org>


This document is the specification of WeeChat relay protocol: the protocol used
to relay WeeChat data to clients, which are mostly remote interfaces.

[WARNING]
This document is a *DRAFT*. +
The protocol is under heavy development and is *NOT READY* for usage. Stay tuned!


[[introduction]]
Introduction
------------

[[terminology]]
Terminology
~~~~~~~~~~~

The following terms are used in this document:

* 'relay': this is the WeeChat with relay plugin, which acts as "server" and
  allows 'clients' to connect
* 'client': this is another software, connected to 'relay' via a network
  connection; in most cases, this 'client' is a remote interface

[[network_diagram]]
Network diagram
~~~~~~~~~~~~~~~

The 'clients' are connected to 'relay' like shown in this diagram:

.......................................
                                                      ┌──────────┐
 ┌────────┐                                     ┌─────┤ client 1 │ Workstation (Linux, BSD, Mac OS X, Windows, ...)
 │  irc   │◄───┐   ╔═════════════╤═══════╗      │     └──────────┘
 └────────┘    └───╢             │       ║◄─────┘     ┌──────────┐
   ......          ║   WeeChat   │ Relay ║◄───────────┤ client 2 │ Mobile device (Android, iPhone, ...)
 ┌────────┐    ┌───╢             │       ║◄─────┐     └──────────┘
 │ jabber │◄───┘   ╚═════════════╧═══════╝      │        ......
 └────────┘                                     │     ┌──────────┐
   ......                                       └─────┤ client N │ Other devices
                                                      └──────────┘


└─────────────┘    └─────────────────────┘╘══════════╛└──────────────────────┘
network servers       ncurses interface      relay       remote interfaces
                                            protocol
........................................

[NOTE]
All clients here are clients using 'weechat' protocol in 'relay' plugin. The
'relay' plugin also allows IRC clients, then 'relay' plugin acts as an
'irc proxy' (not described in this document).

[[protocol_generalities]]
Protocol generalities
---------------------

* Connections from 'client' to 'relay' are made using TCP sockets on IP/port
  used by 'relay' plugin to listen to new connections
  (option 'relay.port.weechat' in WeeChat).
* Number of 'clients' is not limited.
* Each 'client' is independent from other clients.
* Messages from 'client' to 'relay' are called 'commands', they are sent as text
  (a string).
* Messages from 'relay' to 'client' are called 'messages', they are sent as
  binary data.

[[commands]]
Commands (client → relay)
-------------------------

Commands have format: "(id) command arguments\n".

Fields are:

* 'id': optional message identifier that will be sent in answer from 'relay';
  it must be enclosed in parentheses, and must not start with an underscore
  ("_") (ids starting with underscore are reserved for WeeChat 'event' messages)
* 'command': a command (see table below)
* 'arguments': optional arguments for command (many arguments are separated by
  spaces)

List of available commands (detail in next chapters):

[width="60%",cols="^3m,14",options="header"]
|=====================================================
| Command  | Description
| init     | Initialize connection with 'relay'
| hdata    | Request hdata
| info     | Request info
| infolist | Request infolist
| nicklist | Request nicklist
| input    | Send data to a buffer (text or command)
| sync     | Synchronize buffer(s) (get updates for buffer(s))
| desync   | Desynchronize buffer(s) (stop updates for buffer(s))
| quit     | Disconnect from 'relay'
|=====================================================

[[command_init]]
init
~~~~

Initialize connection with 'relay'. This must be first command sent to 'relay'.
If not sent, 'relay' will close connection on first command received, without
warning.

Syntax:

----------------------------------------
init [<option>=<value>,[<option>=<value>,...]]
----------------------------------------

Arguments:

* 'option': one of following options:
** 'password' (required): password used to authenticate on 'relay' (option
   'relay.network.password' in WeeChat)
** 'compression' (optional): compression type:
*** 'gzip': enable gzip compression for messages sent by 'relay'
*** 'off': disable compression

[NOTE]
Compression 'gzip' is enabled by default if 'relay' supports gzip compression.

Example:

----------------------------------------
init password=mypass,compression=gzip
----------------------------------------

[[command_hdata]]
hdata
~~~~~

Request hdata.

Syntax:

----------------------------------------
(id) hdata <path> [<keys>]
----------------------------------------

Arguments:

* 'path': path to a hdata, with format: "hdata:pointer/var/var/.../var", the
  last var is the hdata returned:
** 'hdata': name of hdata
** 'pointer': pointer ("0x12345") or list name (for example: "gui_buffers")
   (count allowed, see below)
** 'var': a variable name in parent hdata (previous name in path)
   (count allowed, see below)
* 'keys': comma-separated list of keys to return in hdata returned (if not
  specified, all keys are returned, which is not recommended on large hdata
  structures)

A count is allowed after pointer and variables, with format "(N)". Possible
values are:

* positive number: iterate using next element, N times
* negative number: iterate using previous element, N times
* '*': iterate using next element, until end of list

Examples:

----------------------------------------
# request all buffers, hdata of type "buffer" is returned
# keys number and name are returned for each buffer
hdata buffer:gui_buffers(*) number,name

# request all lines of all buffers, hdata of type "line_data" is returned
# all keys are returned
hdata buffer:gui_buffers(*)/lines/first_line(*)/data

# request full_name of first buffer
hdata buffer:gui_buffers full_name
----------------------------------------

[[command_info]]
info
~~~~

Request info.

Syntax:

----------------------------------------
(id) info <name>
----------------------------------------

Arguments:

* 'name': name of info to retrieve

Example:

----------------------------------------
info version
----------------------------------------

[[command_infolist]]
infolist
~~~~~~~~

Request infolist.

[IMPORTANT]
Content of infolist is a duplication of actual data. Wherever possible, use
command <<command_hdata,hdata>>, which is direct access to data (it is
faster, uses less memory and returns smaller objects in message).

Syntax:

----------------------------------------
(id) infolist <name> <arguments>
----------------------------------------

Arguments:

* 'name': name of infolist to retrieve
* 'arguments': arguments for infolist

Example:

----------------------------------------
infolist buffer
----------------------------------------

[[command_nicklist]]
nicklist
~~~~~~~~

Request nicklist, for one or all buffers.

Syntax:

----------------------------------------
(id) nicklist [<buffer>]
----------------------------------------

Arguments:

* 'buffer': pointer ('0x12345') or full name of buffer (for example:
  'core.weechat' or 'irc.freenode.#weechat')

Examples:

----------------------------------------
# request nicklist for all buffers
nicklist

# request nicklist for irc.freenode.#weechat
nicklist irc.freenode.#weechat
----------------------------------------

[[command_input]]
input
~~~~~

Send data to a buffer.

Syntax:

----------------------------------------
input <buffer> <data>
----------------------------------------

Arguments:

* 'buffer': pointer ('0x12345') or full name of buffer (for example:
  'core.weechat' or 'irc.freenode.#weechat')
* 'data': data to send to buffer: if beginning by '/', this will be executed as
   a command on buffer, otherwise text is sent as input of buffer

Examples:

----------------------------------------
input core.weechat /help filter
input irc.freenode.#weechat hello guys!
----------------------------------------

[[command_sync]]
sync
~~~~

Synchronize one or more buffers, to get updates.

Syntax:

----------------------------------------
sync [<buffer>[,<buffer>...] <options>]
----------------------------------------

Arguments:

* 'buffer': pointer ('0x12345') or full name of buffer (for example:
  'core.weechat' or 'irc.freenode.#weechat'); name '*' can be used to
  specify all buffers
* 'options': one of following keywords, separated by commas (default is
  'buffer,nicklist'):
** 'buffer': receive signals about buffer (new lines, buffer renamed/moved/...)
** 'nicklist': receive nicklist after changes

Examples:

----------------------------------------
# synchronize all buffers with nicklist (the 3 commands are equivalent)
sync
sync *
sync * buffer,nicklist

# synchronize core buffer
sync core.buffer

# synchronize #weechat channel, without nicklist
sync irc.freenode.#weechat buffer
----------------------------------------

[[command_desync]]
desync
~~~~~~

Desynchronize one or more buffers, to stop updates.

[NOTE]
This will remove 'options' for buffers. If some options are still active for
buffers, the client will still receive updates for buffers.

Syntax:

----------------------------------------
desync [<buffer>[,<buffer>...] <options>]
----------------------------------------

Arguments:

* 'buffer': pointer ('0x12345') or full name of buffer (for example:
  'core.weechat' or 'irc.freenode.#weechat'); name '*' can be used to
  specify all buffers
* 'options': one of following keywords, separated by commas (default is
  'buffer,nicklist'):
** 'buffer': receive signals about buffer (new lines, buffer renamed/moved...)
** 'nicklist': receive nicklist after changes

Examples:

----------------------------------------
# desynchronize all buffers
desync

# desynchronize nicklist for #weechat channel (keep buffer updates)
desync irc.freenode.#weechat nicklist

# desynchronize #weechat channel
desync irc.freenode.#weechat
----------------------------------------

[[command_quit]]
quit
~~~~

Disconnect from 'relay'.

Syntax:

----------------------------------------
quit
----------------------------------------

Example:

----------------------------------------
quit
----------------------------------------

[[messages]]
Messages (relay → client)
-------------------------

Messages are sent as binary data, using following format (with size in bytes):

.......................................
┌────────╥─────────────╥────╥────────┬──────────╥───────╥────────┬──────────┐
│ length ║ compression ║ id ║ type 1 │ object 1 ║  ...  ║ type N │ object N │
└────────╨─────────────╨────╨────────┴──────────╨───────╨────────┴──────────┘
 └──────┘ └───────────┘ └──┘ └──────┘ └────────┘         └──────┘ └────────┘
     4          1        ??      3        ??                 3        ??
 └────────────────────┘ └──────────────────────────────────────────────────┘
       header (5)                        compressed data (??)
 └─────────────────────────────────────────────────────────────────────────┘
                               'length' bytes
.......................................

* 'length' (unsigned integer): number of bytes of whole message (including
  this length)
* 'compression' (byte): flag:
** '0x00': following data is not compressed
** '0x01': following data is gzip-compressed
* 'id' (string): identifier sent by client (before command name); it can be
  empty (string with zero length and no content) if no identifier was given in
  command
* 'type' (3 chars): a type: 3 letters (see table below)
* 'object': an object (see table below)

[[message_compression]]
Compression
~~~~~~~~~~~

If flag 'compression' is equal to 0x01, then *all* data after is compressed
with gzip, and therefore must be uncompressed before being processed.

[[message_identifier]]
Identifier
~~~~~~~~~~

There are two different identifiers ('id'):

* 'id' sent by 'client': 'relay' will answer with same 'id' in its answer
* 'id' of an event: on some events, 'relay' will send message to 'client' using
  a speficic 'id', beginning with underscore (see table below)

WeeChat reserved identifiers:

[width="100%",cols="5m,5,3,10,8",options="header"]
|=====================================================
| Identifier               | Description             | Hdata type | Hdata content
| Recommended action in client

| _buffer_opened           | Buffer opened           | buffer |
  'number' (integer), 'full_name' (string), 'short_name' (string), +
  'nicklist' (integer), 'title' (string), 'local_variables' (hashtable), +
  'prev_buffer' (pointer), 'next_buffer' (pointer) |
  Open buffer

| _buffer_type_changed     | Type of buffer changed  | buffer |
  'number' (integer), 'full_name' (string), +
  'type' (integer) |
  Change type of buffer

| _buffer_moved            | Buffer moved            | buffer |
  'number' (integer), 'full_name' (string), +
  'prev_buffer' (pointer), 'next_buffer' (pointer) |
  Move buffer

| _buffer_merged           | Buffer merged           | buffer |
  'number' (integer), 'full_name' (string), +
  'prev_buffer' (pointer), 'next_buffer' (pointer) |
  Merge buffer

| _buffer_unmerged         | Buffer unmerged         | buffer |
  'number' (integer), 'full_name' (string), +
  'prev_buffer' (pointer), 'next_buffer' (pointer) |
  Unmerge buffer

| _buffer_renamed          | Buffer renamed          | buffer |
  'number' (integer), 'full_name' (string), 'short_name' (string),
  'local_variables' (hashtable) |
  Rename buffer

| _buffer_title_changed    | Title of buffer changed | buffer |
  'number' (integer), 'full_name' (string), 'title' (string) |
  Change title of buffer

| _buffer_localvar_added   | Local variable added    | buffer |
  'number' (integer), 'full_name' (string), 'local_variables' (hashtable) |
  Add local variable in buffer

| _buffer_localvar_changed | Local variable changed  | buffer |
  'number' (integer), 'full_name' (string), 'local_variables' (hashtable) |
  Change local variable inbuffer

| _buffer_localvar_removed | Local variable removed  | buffer |
  'number' (integer), 'full_name' (string), 'local_variables' (hashtable) |
  Remove local variable from buffer

| _buffer_line_added       | Line added in buffer    | line |
  'buffer' (pointer), 'date' (time), 'date_printed' (time), 'displayed' (char),
  'highlight' (char), 'prefix' (string), 'message' (string) |
  Display line in buffer

| _buffer_closing          | Buffer closing          | buffer |
  'number' (integer), 'full_name' (string) |
  Close buffer

| _nicklist                | Nicklist for a buffer   | nicklist_item |
  'group' (char), 'visible' (char), 'level' (integer), +
  'name' (string), 'color' (string), +
  'prefix' (string), 'prefix_color' (string) |
  Update nicklist

| _upgrade                 | WeeChat is upgrading +
  (_new in version 0.3.8_) | (empty) |
  (empty) |
  Desync from WeeChat (send command 'desync')

| _upgrade_ended           | Upgrade of WeeChat done +
  (_new in version 0.3.8_) | (empty) |
  (empty) |
  Resync with WeeChat (resend all commands sent on startup after the 'init')
|=====================================================

[[message_objects]]
Objects
~~~~~~~

Objects are identified by 3 letters, called 'type'. Following types are
available:

[width="60%",cols="^2m,5,7",options="header"]
|=====================================================
| Type | Value                | Length
| chr  | Signed char          | 1 byte
| int  | Signed integer       | 4 bytes
| lon  | Signed long integer  | 1 byte + length of long as string
| str  | String               | 4 bytes + length of string (without final '\0')
| buf  | Buffer of bytes      | 4 bytes + length of data
| ptr  | Pointer              | 1 byte + length of pointer as string
| tim  | Time                 | 1 byte + length of time as string
| htb  | Hashtable            | Variable
| hda  | Hdata content        | Variable
| inf  | Info: name + content | Variable
| inl  | Infolist content     | Variable
|=====================================================

[[object_char]]
Char
^^^^

A signed char is 1 byte.

Example:

.......................................
┌────┐
│ 41 │ ────► 65 (0x41: "A")
└────┘
.......................................

[[object_integer]]
Integer
^^^^^^^

A signed integer is 4 bytes, encoded as big-endian format (most significant byte
first).

Example:

.......................................
┌────┬────┬────┬────┐
│ 00 │ 00 │ 01 │ 04 │ ────► 260 (0x104)
└────┴────┴────┴────┘
.......................................

[[object_long_integer]]
Long integer
^^^^^^^^^^^^

A signed long integer is encoded as a string, with length on one byte.

Example:

.......................................
┌────╥────┬────┬────┐
│ 03 ║ 32 │ 36 │ 30 │ ────► 260
└────╨────┴────┴────┘
 └──┘ └────────────┘
length '2'  '6'  '0'
.......................................

[[object_string]]
String
^^^^^^

A string is a length (integer on 4 bytes) + content of string (without final '\0').

Example:

.......................................
┌────┬────┬────┬────╥────┬────┬────┬────┬────┐
│ 00 │ 00 │ 00 │ 05 ║ 68 │ 65 │ 6C │ 6C │ 6F │ ────► "hello"
└────┴────┴────┴────╨────┴────┴────┴────┴────┘
 └─────────────────┘ └──────────────────────┘
       length         'h'  'e'  'l'  'l'  'o'
.......................................

An empty string has a length of zero:

.......................................
┌────┬────┬────┬────┐
│ 00 │ 00 │ 00 │ 00 │ ────► ""
└────┴────┴────┴────┘
 └─────────────────┘
       length
.......................................

A 'NULL' string (NULL pointer in C) has a length of -1:

.......................................
┌────┬────┬────┬────┐
│ FF │ FF │ FF │ FF │ ────► NULL
└────┴────┴────┴────┘
 └─────────────────┘
       length
.......................................

[[object_buffer]]
Buffer
^^^^^^

Same format as <<object_string,string>>; content is just an array of bytes.

[[object_pointer]]
Pointer
^^^^^^^

A pointer is encoded as string (hex), with length on one byte.

Example:

.......................................
┌────╥────┬────┬────┬────┬────┬────┬────┬────┬────┐
│ 09 ║ 31 │ 61 │ 32 │ 62 │ 33 │ 63 │ 34 │ 64 │ 35 │ ────► 0x1a2b3c4d5
└────╨────┴────┴────┴────┴────┴────┴────┴────┴────┘
 └──┘ └──────────────────────────────────────────┘
length '1'  'a'  '2'  'b'  '3'  'c'  '4'  'd'  '5'
.......................................

A 'NULL' pointer has value 0:

.......................................
┌────╥────┐
│ 01 ║ 00 │ ────► NULL (0x0)
└────╨────┘
 └──┘ └──┘
length  0
.......................................

[[object_time]]
Time
^^^^

A time (number of seconds) is encoded as a string, with length on one byte.

Example:

.......................................
┌────╥────┬────┬────┬────┬────┬────┬────┬────┬────┬────┐
│ 0A ║ 31 │ 33 │ 32 │ 31 │ 39 │ 39 │ 33 │ 34 │ 35 │ 36 │ ────► 1321993456
└────╨────┴────┴────┴────┴────┴────┴────┴────┴────┴────┘
 └──┘ └───────────────────────────────────────────────┘
length '1'  '3'  '2'  '1'  '9'  '9'  '3'  '4'  '5'  '6'
.......................................

[[object_hashtable]]
Hashtable
^^^^^^^^^

A hashtable contains type for keys, type for values, number of items in
hashtable (integer on 4 bytes), and then keys and values of items.

.......................................
┌───────────┬─────────────┬───────╥───────┬─────────╥─────╥───────┬─────────┐
│ type_keys │ type_values │ count ║ key 1 │ value 1 ║ ... ║ key N │ value N │
└───────────┴─────────────┴───────╨───────┴─────────╨─────╨───────┴─────────┘
.......................................

Example:

.......................................
┌─────┬─────┬───╥──────┬─────╥──────┬─────┐
│ str │ str │ 2 ║ key1 │ abc ║ key2 │ def │ ────► { 'key1' => 'abc', 'key2' => 'def' }
└─────┴─────┴───╨──────┴─────╨──────┴─────┘
 └───┘ └───┘ └─┘ └──────────┘ └──────────┘
 type  type count   item 1       item 2
 keys values
.......................................

[[object_hdata]]
Hdata
^^^^^

A 'hdata' contains a path with hdata names, list of keys, number of set of
objects, and then set of objects (path with pointers, then objects).

.......................................
┌────────┬──────┬───────╥────────┬─────────────────────╥────────┬─────────────────────╥─────┐
│ h-path │ keys │ count ║ p-path │ value 1 ... value N ║ p-path │ value 1 ... value N ║ ... │
└────────┴──────┴───────╨────────┴─────────────────────╨────────┴─────────────────────╨─────┘
.......................................

* 'name' (string): name of hdata ('buffer', 'window', 'bar', ...)
* 'h-path' (string): path used to reach hdata (example:
  'buffer/lines/line/line_data'); the last element in path is the hdata returned
* 'keys' (string): string with list of 'key:type' (separated by commas),
  example: 'number:int,name:str'
* 'count' (integer): number of set of objects
* 'p-path': path with pointers to objects (number of pointers here is number of
  elements in path)
* 'values': list of values (number of values is number of keys returned for
  hdata)

Example of hdata with 2 buffers (weechat core and freenode server) and two keys
('number' and 'full_name'):

.......................................
# command
hdata buffer:gui_buffers(*) number,full_name

# response
┌────────┬──────────────────────────┬───╥─────────┬───┬──────────────╥─────────┬───┬────────────────────┐
│ buffer │ number:int,full_name:str │ 2 ║ 0x12345 │ 1 │ core.weechat ║ 0x6789a │ 2 │irc.server.freenode │
└────────┴──────────────────────────┴───╨─────────┴───┴──────────────╨─────────┴───┴────────────────────┘
 └──────┘ └────────────────────────┘ └─┘ └──────────────────────────┘ └────────────────────────────────┘
  hpath           keys              count          buffer 1                        buffer 2
.......................................

Example of hdata with lines of core buffer:

.......................................
# command
hdata buffer:gui_buffers(*)/lines/first_line(*)/data

# response
┌─────────────────────────────┬─────┬────╥──
│ buffer/lines/line/line_data │ ... │ 50 ║ ...
└─────────────────────────────┴─────┴────╨──
 └───────────────────────────┘ └───┘ └──┘
      h-path (hdata names)     keys  count

  ──╥───────────┬───────────┬───────────┬───────╥───────────┬───────────┬───────────┬───────╥──────────────┐
... ║ 0x23cf970 │ 0x23cfb60 │ 0x23d5f40 │ ..... ║ 0x23cf970 │ 0x23cfb60 │ 0x23d6110 │ ..... ║ ............ │
  ──╨───────────┴───────────┴───────────┴───────╨───────────┴───────────┴───────────┴───────╨──────────────┘
     └─────────────────────────────────┘ └─────┘ └─────────────────────────────────┘ └─────┘
              p-path (pointers)          objects          p-path (pointers)          objects
     └─────────────────────────────────────────┘ └─────────────────────────────────────────┘ └────────────┘
                        line 1                                      line 2                     lines 3-50
.......................................

Example of hdata with nicklist:

.......................................
# command
nicklist

# response
┌───────────────────┬────────────────────────────────────────────────────────────────────────────────┬────╥──
│ buffer/nick_group │ group:chr,visible:chr,name:str,color:str,prefix:str,prefix_color:str,level:int │ 12 ║ ...
└───────────────────┴────────────────────────────────────────────────────────────────────────────────┴────╨──
 └─────────────────┘ └──────────────────────────────────────────────────────────────────────────────┘ └──┘
        h-path                                            keys                                        count

  ──╥─────────┬─────────┬───┬───┬──────┬─┬─┬─┬───╥─────────┬─────────┬───┬───┬───────┬─┬─┬─┬───╥──
... ║ 0x12345 │ 0x6789a │ 1 │ 0 │ root │ │ │ │ 0 ║ 0x123cf │ 0x678d4 │ 1 │ 0 │ 000|o │ │ │ │ 1 ║ ...
  ──╨─────────┴─────────┴───┴───┴──────┴─┴─┴─┴───╨─────────┴─────────┴───┴───┴───────┴─┴─┴─┴───╨──
     └─────────────────┘ └──────────────────────┘ └─────────────────┘ └───────────────────────┘
            p-path               objects                 p-path                objects
     └──────────────────────────────────────────┘ └───────────────────────────────────────────┘
                 group (nicklist root)                          group (channel ops)

  ──╥─────────┬─────────┬───┬───┬──────────┬──────┬───┬────────────┬───╥──
... ║ 0x128a7 │ 0x67ab2 │ 0 │ 1 │ ChanServ │ blue │ @ │ lightgreen │ 0 ║ ...
  ──╨─────────┴─────────┴───┴───┴──────────┴──────┴───┴────────────┴───╨──
     └─────────────────┘ └────────────────────────────────────────────┘
            p-path                          objects
     └────────────────────────────────────────────────────────────────┘
                              nick (@ChanServ)
.......................................

[[object_info]]
Info
^^^^

A 'info' contains a name and a value (both are strings).

.......................................
┌──────┬───────┐
│ name │ value │
└──────┴───────┘
.......................................

* 'name' (string): name of info
* 'value' (string): value

Exemple of info 'version':

.......................................
┌─────────┬───────────────────┐
│ version │ WeeChat 0.3.7-dev │
└─────────┴───────────────────┘
.......................................

[[object_infolist]]
Infolist
^^^^^^^^

A 'infolist' contains a name, number of items, and then items (set of
variables).

.......................................
┌──────┬───────╥────────╥─────╥────────┐
│ name │ count ║ item 1 ║ ... ║ item N │
└──────┴───────╨────────╨─────╨────────┘
.......................................

An item is:

.......................................
┌───────╥────────┬────────┬─────────╥─────╥────────┬────────┬─────────┐
│ count ║ name 1 │ type 1 │ value 1 ║ ... ║ name N │ type N │ value N │
└───────╨────────┴────────┴─────────╨─────╨────────┴────────┴─────────┘
.......................................

* 'name' (string): name of infolist ('buffer', 'window', 'bar', ...)
* 'count' (integer): number of items
* 'item':
** 'count': number of variables in item
** 'name': name of variable
** 'type': type of variable ('int', 'str', ...)
** 'value': value of variable

Example of infolist with 2 buffers (weechat core and freenode server):

.......................................
# command
infolist buffer

# response
┌────────┬───╥────┬─────────┬─────┬─────────┬─────╥────┬─────────┬─────┬─────────┬─────┐
│ buffer │ 2 ║ 42 │ pointer │ ptr │ 0x12345 │ ... ║ 42 │ pointer │ ptr │ 0x6789a │ ... │
└────────┴───╨────┴─────────┴─────┴─────────┴─────╨────┴─────────┴─────┴─────────┴─────┘
 └──────┘ └─┘ └──────────────────────────────────┘ └──────────────────────────────────┘
   name  count              item 1                               item 2
.......................................

[[typical_session]]
Typical session
---------------

.......................................
          ┌────────┐                               ┌───────┐                  ┌─────────┐
          │ Client ├ ─ ─ ─ ─ ─ (network) ─ ─ ─ ─ ─ ┤ Relay ├──────────────────┤ WeeChat │
          └────────┘                               └───────┘                  └─────────┘
               ║                                       ║                           ║
               ╟─────────────────────────────────────► ║                           ║
               ║ open socket                           ║ add client                ║
               ║                                       ║                           ║
               ╟─────────────────────────────────────► ║                           ║
               ║ cmd: init password=xxx,...            ║ init/allow client         ║
               ║                                       ║                           ║
               ╟─────────────────────────────────────► ║                           ║
               ║ cmd: hdata buffer ...                 ╟─────────────────────────► ║
               ║      sync ...                         ║ request hdata             ║ read hdata values
               ║                                       ║                           ║
               ║                                       ║ ◄─────────────────────────╢
               ║ ◄─────────────────────────────────────╢                     hdata ║
create buffers ║                       msg: hda buffer ║                           ║
               ║                                       ║                           ║
               ║                ........               ║          ........         ║
               ║                                       ║                           ║
               ╟─────────────────────────────────────► ║                           ║
               ║ cmd: input ...                        ╟─────────────────────────► ║
               ║                                       ║ send data to buffer       ║ send data to buffer
               ║                                       ║                           ║
               ║                ........               ║          ........         ║
               ║                                       ║                           ║ signal received
               ║                                       ║ ◄─────────────────────────╢ (hooked by relay)
               ║ ◄─────────────────────────────────────╢                signal XXX ║
update buffers ║                msg: id: "_buffer_..." ║                           ║
               ║                                       ║                           ║
               ║                ........               ║          ........         ║
               ║                                       ║                           ║
               ╟─────────────────────────────────────► ║                           ║
               ║ cmd: quit                             ║ disconnect client         ║
               ║                                       ║                           ║
.......................................
