Ejabberd模块发送确认消息

问题描述

我使用的这个erlang代码发送消息确认。在使用这个我收到错误，错误日志在下面给出

This erlang code I am using to send message acknowledgement. While using this I am getting error, error log is given below

-module(mod_ack).
-behaviour(gen_mod).

%% public methods for this module
-export([start/2, stop/1]).
-export([on_user_send_packet/3]).

-include("logger.hrl").
-include("ejabberd.hrl").
-include("jlib.hrl").

%%add and remove hook module on startup and close

start(Host, _Opts) ->
    ?INFO_MSG("mod_echo_msg starting", []),
    ejabberd_hooks:add(user_send_packet, Host, ?MODULE, on_user_send_packet, 0),
    ok.

stop(Host) ->
    ?INFO_MSG("mod_echo_msg stopping", []),
    ejabberd_hooks:delete(user_send_packet, Host, ?MODULE, on_user_send_packet, 0),
    ok.

on_user_send_packet(From, To, Packet) ->
        return_message_reciept_to_sender(From, To, Packet),
        Packet.


return_message_reciept_to_sender(From, _To, Packet) ->
    IDS = xml:get_tag_attr_s("id", Packet),
    ReturnRecieptType = "serverreceipt",
%%    ?INFO_MSG("mod_echo_msg - MsgID: ~p To: ~p From: ~p", [IDS, _To, From]),
    send_message(From, From, ReturnRecieptType, IDS, "").


send_message(From, To, TypeStr, IDS, BodyStr) ->
    XmlBody = {xmlelement, "message",
           [{"type", TypeStr},
        {"from", jlib:jid_to_string(From)},
        {"to", jlib:jid_to_string(To)},
        {"id", IDS},
           [{xmlelement, "body", [],
         [{xmlcdata, BodyStr}]}]},
    ejabberd_router:route(From, To, XmlBody).

我已经删除了我使用on_user_send钩子的模块，但仍然收到错误也更新了错误日志。

I have removed the modules where i used on_user_send hook but still getting error also updated the error log.

2015-10-06 07：13：45.796 [错误]< 0.437。 0> @ejabberd_hooks：run_fold1：371 {function_clause，[{xml，get_tag_attr_s，[<id>>，{jid，<xxxxxx>>，<xxxxxx>> ，<< >>，<xxxxxx>>，
<xxxxxx>>，< >>}}，[{file，src / xml。 erl}，{line，210}]}，{mod_ack，return_message_reciept_to_sender，3，
[{file，src / mod_ack.erl}，{line，36}]}，{mod_ack，on_user_send_packet，4 ，[{文件， SRC / mod_ack.erl}，{线，30}]}，{ejabberd_hooks，safe_apply，3，[{文件， SRC / ejabberd_hooks.erl}，{线，385}]}， {ejabberd_hooks，run_fold1,4，[{文件， SRC / ejabberd_hooks.erl}，{线，368}]}，{ejabberd_c2s，session_established2,2，[{文件， SRC / ejabberd_c2s.erl}，{线，1296}]}，{p1_fsm，HANDLE_MSG，10，[{文件， SRC / p1_fsm.erl}，{线，582}]}，{proc_lib，init_p_do_apply，3，[{文件， proc_lib.erl }，{line，237}]}]}

2015-10-06 07:13:45.796 [error] <0.437.0>@ejabberd_hooks:run_fold1:371 {function_clause,[{xml,get_tag_attr_s,[<<"id">>,{jid,<<"xxxxxx">>,<<"xxxxxx">>,<<>>,<<"xxxxxx">>,<<"xxxxxx">>,<<>>}],[{file,"src/xml.erl"},{line,210}]},{mod_ack,return_message_reciept_to_sender,3,[{file,"src/mod_ack.erl"},{line,36}]},{mod_ack,on_user_send_packet,4,[{file,"src/mod_ack.erl"},{line,30}]},{ejabberd_hooks,safe_apply,3,[{file,"src/ejabberd_hooks.erl"},{line,385}]},{ejabberd_hooks,run_fold1,4,[{file,"src/ejabberd_hooks.erl"},{line,368}]},{ejabberd_c2s,session_established2,2,[{file,"src/ejabberd_c2s.erl"},{line,1296}]},{p1_fsm,handle_msg,10,[{file,"src/p1_fsm.erl"},{line,582}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,237}]}]}

推荐答案

定义user_send_p acket hook as a arity-4 function：

The ejabberd docs define the user_send_packet hook as an arity-4 function:

user_send_packet(Packet, C2SState, From, To) -> Packet

您正在注册一个arity-3功能，所以当ejabberd尝试调用您的 on_user_send_packet 函数，它传递4个参数并获取undef函数异常。

You are registering an arity-3 function, so when ejabberd tries to call your on_user_send_packet function, it passes 4 arguments and gets the undef function exception.

为了实际调用回调函数，您将需要将其参数列表与ejabberd将要发送的参数匹配，即：

In order for your callback function to actually be called, you will need to match its argument list to what ejabberd will be sending, i.e.:

on_user_send_packet(Packet, _C2SState, From, To)

这篇关于Ejabberd模块发送确认消息的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！