2014-09-29

Ejabberd-路由表

ejabberd内部模块可以通过一个XMPP名称(-define(PROCNAME, ejabberd_mod_echo).),添加自身到服务器的路由表中,这些模块被称为服务,服务模块必须同时实现gen_server和gen_mod行为

例子

mod_echo.erl是一个使用路由机制的例子.

API

ejabberd_router:register_route(Host)
ejabberd_router:unregister_route(Host),
* Host = string()

gen_server API

下面上个函数用作模块的API

start_link(Host, Opts) ->
    Proc = gen_mod:get_module_proc(Host, ?PROCNAME),
    gen_server:start_link({local, Proc}, ?MODULE, [Host, Opts], []).

start(Host, Opts) ->
    Proc = gen_mod:get_module_proc(Host, ?PROCNAME),
    ChildSpec = {Proc,{?MODULE, start_link, [Host, Opts]}, temporary, 1000, worker, [?MODULE]},
    supervisor:start_child(ejabberd_sup, ChildSpec).

stop(Host) ->
    Proc = gen_mod:get_module_proc(Host, ?PROCNAME),
    gen_server:call(Proc, stop),
    supervisor:terminate_child(ejabberd_sup, Proc),
    supervisor:delete_child(ejabberd_sup, Proc).

gen_server 回调

下面的函数必须定义并导出.

init([Host, Opts]) -> {ok, State} |
                      {ok, State, Timeout} |
                      ignore |
                      {stop, Reason}

handle_info(Info, State) -> {noreply, State} |
                            {noreply, State, Timeout} |
                            {stop, Reason, State}
* Info = {route, From, To, Packet}
* To = From = #jid (see jlib core module)
* Packet = {xmlelement, Name, Attrs, SubEl}

terminate(Reason, State) -> void()

handle_call(stop, _From, State) -> {stop, normal, ok, State}.

handle_cast(_Msg, State) -> {noreply, State}.

code_change(_OldVsn, State, _Extra) -> {ok, State}.

init函数用于初始化模块.Host为模块所在虚拟主机名称,Opts为在配置文件中设置的模块选项,这些选项可以通过gen_mod:get_opt/3函数获取.ejabberd_router:register_route/1函数在init回调中执行.

terminate/2用于停止模块. ejabberd_router:unregister_route函数在此回调中被调用.

handle_info/2用于获取发送给该模块的XMPP包. ejabberd_router:route/1用于对包进行重新路由.

All other callbacks can be written as shown above.

Ejabberd

XMPP, ejabberd