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* src/ejabberd_commands.erl: New 'ejabberd commands': separate

command definition and calling interface (EJAB-694)
* src/ejabberd_commands.hrl: Likewise

SVN Revision: 1633
This commit is contained in:
Badlop 2008-10-12 11:53:25 +00:00
parent be2f6e0517
commit dda582db13
3 changed files with 384 additions and 0 deletions

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@ -1,5 +1,9 @@
2008-10-12 Badlop <badlop@process-one.net>
* src/ejabberd_commands.erl: New 'ejabberd commands': separate
command definition and calling interface (EJAB-694)
* src/ejabberd_commands.hrl: Likewise
* src/mod_proxy65/mod_proxy65.erl: Update so the listener starts
correctly (EJAB-303)
* src/mod_proxy65/mod_proxy65_service.erl: Likewise

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src/ejabberd_commands.erl Normal file
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%%%----------------------------------------------------------------------
%%% File : ejabberd_commands.erl
%%% Author : Badlop <badlop@process-one.net>
%%% Purpose : Management of ejabberd commands
%%% Created : 20 May 2008 by Badlop <badlop@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2008 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License
%%% along with this program; if not, write to the Free Software
%%% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
%%% 02111-1307 USA
%%%
%%%----------------------------------------------------------------------
%%% @headerfile "ejabberd_commands.hrl"
%%% @doc Management of ejabberd commands.
%%%
%%% An ejabberd command is an abstract function identified by a name,
%%% with a defined number and type of calling arguments and type of
%%% result, that can be defined in any Erlang module and executed
%%% using any valid frontend.
%%%
%%%
%%% == Define a new ejabberd command ==
%%%
%%% ejabberd commands can be defined and registered in
%%% any Erlang module.
%%%
%%% Some commands are procedures; and their purpose is to perform an
%%% action in the server, so the command result is only some result
%%% code or result tuple. Other commands are inspectors, and their
%%% purpose is to gather some information about the server and return
%%% a detailed response: it can be integer, string, atom, tuple, list
%%% or a mix of those ones.
%%%
%%% The arguments and result of an ejabberd command are strictly
%%% defined. The number and format of the arguments provided when
%%% calling an ejabberd command must match the definition of that
%%% command. The format of the result provided by an ejabberd command
%%% must be exactly its definition. For example, if a command is said
%%% to return an integer, it must always return an integer (except in
%%% case of a crash).
%%%
%%% If you are developing an Erlang module that will run inside
%%% ejabberd and you want to provide a new ejabberd command to
%%% administer some task related to your module, you only need to:
%%% implement a function, define the command, and register it.
%%%
%%%
%%% === Define a new ejabberd command ===
%%%
%%% An ejabberd command is defined using the Erlang record
%%% 'ejabberd_commands'. This record has several elements that you
%%% must define. Note that 'tags', 'desc' and 'longdesc' are optional.
%%%
%%% For example let's define an ejabberd command 'pow' that gets the
%%% integers 'base' and 'exponent'. Its result will be an integer
%%% 'power':
%%%
%%% <pre>#ejabberd_commands{name = pow, tags = [test],
%%% desc = "Return the power of base for exponent",
%%% longdesc = "This is an example command. The formula is:\n"
%%% " power = base ^ exponent",
%%% module = ?MODULE, function = pow,
%%% args = [{base, integer}, {exponent, integer}],
%%% result = {power, integer}}</pre>
%%%
%%%
%%% === Implement the function associated to the command ===
%%%
%%% Now implement a function in your module that matches the arguments
%%% and result of the ejabberd command.
%%%
%%% For example the function calc_power gets two integers Base and
%%% Exponent. It calculates the power and rounds to an integer:
%%%
%%% <pre>calc_power(Base, Exponent) ->
%%% PowFloat = math:pow(Base, Exponent),
%%% round(PowFloat).</pre>
%%%
%%% Since this function will be called by ejabberd_commands, it must be exported.
%%% Add to your module:
%%% <pre>-export([calc_power/2]).</pre>
%%%
%%% Only some types of result formats are allowed.
%%% If the format is defined as 'rescode', then your function must return:
%%% ok | true | atom()
%%% where the atoms ok and true as considered positive answers,
%%% and any other response atom is considered negative.
%%%
%%% If the format is defined as 'restuple', then the command must return:
%%% {rescode(), string()}
%%%
%%% If the format is defined as '{list, something()}', then the command
%%% must return a list of something().
%%%
%%%
%%% === Register the command ===
%%%
%%% Define this function and put inside the #ejabberd_command you
%%% defined in the beginning:
%%%
%%% <pre>commands() ->
%%% [
%%%
%%% ].</pre>
%%%
%%% You need to include this header file in order to use the record:
%%%
%%% <pre>-include("ejabberd_commands.hrl").</pre>
%%%
%%% When your module is initialized or started, register your commands:
%%%
%%% <pre>ejabberd_commands:register_commands(commands()),</pre>
%%%
%%% And when your module is stopped, unregister your commands:
%%%
%%% <pre>ejabberd_commands:unregister_commands(commands()),</pre>
%%%
%%% That's all! Now when your module is started, the command will be
%%% registered and any frontend can access it. For example:
%%%
%%% <pre>$ ejabberdctl help pow
%%%
%%% Command Name: pow
%%%
%%% Arguments: base::integer
%%% exponent::integer
%%%
%%% Returns: power::integer
%%%
%%% Tags: test
%%%
%%% Description: Return the power of base for exponent
%%%
%%% This is an example command. The formula is:
%%% power = base ^ exponent
%%%
%%% $ ejabberdctl pow 3 4
%%% 81
%%% </pre>
%%%
%%%
%%% == Execute an ejabberd command ==
%%%
%%% ejabberd commands are mean to be executed using any valid
%%% frontend. An ejabberd commands is implemented in a regular Erlang
%%% function, so it is also possible to execute this function in any
%%% Erlang module, without dealing with the associated ejabberd
%%% commands.
%%%
%%%
%%% == Frontend to ejabberd commands ==
%%%
%%% Currently there are two frontends to ejabberd commands: the shell
%%% script {@link ejabberd_ctl. ejabberdctl}, and the XML-RPC server
%%% mod_xmlrpc.
%%%
%%%
%%% === ejabberdctl as a frontend to ejabberd commands ===
%%%
%%% It is possible to use ejabberdctl to get documentation of any
%%% command. But ejabberdctl does not support all the argument types
%%% allowed in ejabberd commands, so there are some ejabberd commands
%%% that cannot be executed using ejabberdctl.
%%%
%%% Also note that the ejabberdctl shell administration script also
%%% manages ejabberdctl commands, which are unrelated to ejabberd
%%% commands and can only be executed using ejabberdctl.
%%%
%%%
%%% === ejabberd_xmlrpc as a frontend to ejabberd commands ===
%%%
%%% ejabberd_xmlrpc provides an XML-RPC server to execute ejabberd commands.
%%% ejabberd_xmlrpc is a contributed module published in ejabberd-modules SVN.
%%%
%%% Since ejabberd_xmlrpc does not provide any method to get documentation
%%% of the ejabberd commands, please use ejabberdctl to know which
%%% commands are available, and their usage.
%%%
%%% The number and format of the arguments provided when calling an
%%% ejabberd command must match the definition of that command. Please
%%% make sure the XML-RPC call provides the required arguments, with
%%% the specified format. The order of the arguments in an XML-RPC
%%% call is not important, because all the data is tagged and will be
%%% correctly prepared by mod_xmlrpc before executing the ejabberd
%%% command.
%%% TODO: consider this feature:
%%% All commands are catched. If an error happens, return the restuple:
%%% {error, flattened error string}
%%% This means that ecomm call APIs (ejabberd_ctl, ejabberd_xmlrpc) need to allows this.
%%% And ejabberd_xmlrpc must be prepared to handle such an unexpected response.
-module(ejabberd_commands).
-author('badlop@process-one.net').
-export([init/0,
list_commands/0,
get_command_format/1,
get_command_definition/1,
get_tags_commands/0,
register_commands/1,
unregister_commands/1,
execute_command/2
]).
-include("ejabberd_commands.hrl").
-include("ejabberd.hrl").
init() ->
ets:new(ejabberd_commands, [named_table, set, public,
{keypos, #ejabberd_commands.name}]).
%% @spec ([ejabberd_commands()]) -> ok
%% @doc Register ejabberd commands.
%% If a command is already registered, a warning is printed and the old command is preserved.
register_commands(Commands) ->
lists:foreach(
fun(Command) ->
case ets:insert_new(ejabberd_commands, Command) of
true ->
ok;
false ->
?WARNING_MSG("This command is already defined:~n~p", [Command])
end
end,
Commands).
%% @spec ([ejabberd_commands()]) -> ok
%% @doc Unregister ejabberd commands.
unregister_commands(Commands) ->
lists:foreach(
fun(Command) ->
ets:delete_object(ejabberd_commands, Command)
end,
Commands).
%% @spec () -> [{Name::atom(), Args::[aterm()], Desc::string()}]
%% @doc Get a list of all the available commands, arguments and description.
list_commands() ->
Commands = ets:match(ejabberd_commands,
#ejabberd_commands{name = '$1',
args = '$2',
desc = '$3',
_ = '_'}),
[{A, B, C} || [A, B, C] <- Commands].
%% @spec (Name::atom()) -> {Args::[aterm()], Result::rterm()} | {error, command_unknown}
%% @doc Get the format of arguments and result of a command.
get_command_format(Name) ->
Matched = ets:match(ejabberd_commands,
#ejabberd_commands{name = Name,
args = '$1',
result = '$2',
_ = '_'}),
case Matched of
[] ->
{error, command_unknown};
[[Args, Result]] ->
{Args, Result}
end.
%% @spec (Name::atom()) -> ejabberd_commands() | command_not_found
%% @doc Get the definition record of a command.
get_command_definition(Name) ->
case ets:lookup(ejabberd_commands, Name) of
[E] -> E;
[] -> command_not_found
end.
%% @spec (Name::atom(), Arguments) -> ResultTerm | {error, command_unknown}
%% @doc Execute a command.
execute_command(Name, Arguments) ->
case ets:lookup(ejabberd_commands, Name) of
[Command] ->
execute_command2(Command, Arguments);
[] ->
{error, command_unknown}
end.
execute_command2(Command, Arguments) ->
Module = Command#ejabberd_commands.module,
Function = Command#ejabberd_commands.function,
apply(Module, Function, Arguments).
%% @spec () -> [{Tag::string(), [CommandName::string()]}]
%% @doc Get all the tags and associated commands.
get_tags_commands() ->
CommandTags = ets:match(ejabberd_commands,
#ejabberd_commands{
name = '$1',
tags = '$2',
_ = '_'}),
Dict = lists:foldl(
fun([CommandNameAtom, CTags], D) ->
CommandName = atom_to_list(CommandNameAtom),
case CTags of
[] ->
orddict:append("untagged", CommandName, D);
_ ->
lists:foldl(
fun(TagAtom, DD) ->
Tag = atom_to_list(TagAtom),
orddict:append(Tag, CommandName, DD)
end,
D,
CTags)
end
end,
orddict:new(),
CommandTags),
orddict:to_list(Dict).

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%%%----------------------------------------------------------------------
%%%
%%% ejabberd, Copyright (C) 2002-2008 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License
%%% along with this program; if not, write to the Free Software
%%% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
%%% 02111-1307 USA
%%%
%%%----------------------------------------------------------------------
-record(ejabberd_commands, {name, tags = [],
desc = "", longdesc = "",
module, function,
args = [], result = rescode}).
%% @type ejabberd_commands() = #ejabberd_commands{
%% name = atom(),
%% tags = [atom()],
%% desc = string(),
%% longdesc = string(),
%% module = atom(),
%% function = atom(),
%% args = [aterm()],
%% result = rterm()
%% }.
%% desc: Description of the command
%% args: Describe the accepted arguments.
%% This way the function that calls the command can format the
%% arguments before calling.
%% @type atype() = integer | string | {tuple, [aterm()]} | {list, aterm()}.
%% Allowed types for arguments are integer, string, tuple and list.
%% @type rtype() = integer | string | atom | {tuple, [rterm()]} | {list, rterm()} | rescode | restuple.
%% A rtype is either an atom or a tuple with two elements.
%% @type aterm() = {Name::atom(), Type::atype()}.
%% An argument term is a tuple with the term name and the term type.
%% @type rterm() = {Name::atom(), Type::rtype()}.
%% A result term is a tuple with the term name and the term type.