2015-05-21

Ejabberd 用Elixir开发一个包过滤模块

过滤模块主要用于

创建一个模块骨架

在Ejabberd源码根目录下的lib目录中创建 filter_packet_demo.ex模块文件, 代码如下:

defmodule FilterPacketDemo do
  import Ejabberd.Logger
  @behaviour :gen_mod

  def start(_host, _opts) do
    info('Starting ejabberd module Filter Packet Demo')
    Ejabberd.Hooks.add(:filter_packet, :global, __ENV__.module, :on_filter_packet, 50)
    :ok
  end

  def stop(_host) do
    info('Stopping ejabberd module Filter Packet Demo')
    Ejabberd.Hooks.delete(:filter_packet, :global, __ENV__.module, :on_filter_packet, 50)
    :ok
  end

  def on_filter_packet({from, to, xml={:xmlel, "message", attributes, children}} = packet) do
    info("Filtering packet: #{inspect {from, to, xml}}")
    # 访问XML元素属性
    # attributes 是一个形如 [{"type", "chat"}, ...]的元组列表, 为了方便访问, 使用如下函数转换为关键字列表
    convert = fn {k,v} ->
        {String.to_atom(k), v}
    end
    attribute_keywords = attributes |> Enum.map convert
    type = attribute_keywords[:type]
    cond do
        type == "chat" ->
            dosomething()
        type == "headline" ->
            dosomething()
        type == "groupchat" ->
            dosomething()
        true ->
            true
    end
    packet
  end

  def dosomething do
    IO.puts "Do something."
  end
end

编译,安装,动态更新

# 编译
make
make install

启动

ejabberdctl live

进入调试控制台

ejabberdctl debug

在调试控制台中运行

(ejabberd@localhost)1> ejabberd_update:update().
{ok,[]}

参考资料

1. Elixir Sips: ejabberd with Elixir – Part 2
   https://blog.process-one.net/ejabberd-with-elixir-packet-filters/

Ejabberd

Elixir