N2O 协议在使用 gproc:send 时发送空数据

Question

我创建了一个 N2o 协议，通过不同的应用程序系列路由消息，（在此之前我使用牛仔 websocket 处理程序来完成这项工作）

例如，我的协议中有这段代码可以向已注册的进程发送消息

> info({text,<<"REG:",Msg/binary>> }, Req, State) ->    
> {[{_,Family}]}=jiffy:decode(Msg),     Test = gproc:reg({p, l, Family},
> 1),   {reply, <<"process registered successfully">>, Req, State};




info({text,<<"TRANSMIT:",Msg/binary>> }=M, Req, State) ->
    {[{_,Type},{_,Action},{_,From},{_,To},{_,Message}]}=jiffy:decode(Msg),
     gproc:send({p, l, To}, {self(),<<"Hi I am a good message!">>}),
      {reply, <<"message transmitted successfully">>, Req, State};

在我的 HTML 客户端中，首先我根据

协议注册

var msg = {family: "JS"}; websocket.send("REG:"+JSON.stringify(msg) );

并且我验证了我的 html 进程已正确注册

然后，从我的同一个 HTML 客户端，我调用了传输协议方法，如：

msg = {Type: "TRANSMIT:", Action: "Chat", From: "JS", To: "JS", Message:"Hello I am Js"}; websocket.send("TRANSMIT: "+JSON.stringify(msg) );

基本上在这个阶段我应该在我的 HTML 客户端收到一条包含 "Hello I am Js" 的消息，但我总是收到一个空数据字符串，如：

MessageEvent {isTrusted: true, data: "", origin: "ws://192.168.1.20:8000", lastEventId: "", source: null…}

信息：

收到回复短信如下：

注册过程中：

MessageEvent {isTrusted: true, data: "process registered successfully", origin: "ws://192.168.1.20:8000", lastEventId: "", source: null…}

提交消息时：

MessageEvent {isTrusted: true, data: "message transmitted successfully", origin: "ws://192.168.1.20:8000", lastEventId: "", source: null…}

此外，当我使用我的 cowboy ws 处理程序时，我没有遇到此类问题。

Answer 1

The heart protocol defined client originated messages N2O, PING and server originated messages PONG, IO and NOP. IO message contains EVAL that contains UTF-8 JavaScript string and DATA reply contains any binary string, including BERT encoded data. "PING" and "N2O," are defined as text 4-bytes messages and second could be followed by any text string. NOP is 0-byte acknowledging packet.

来自 N2O 文档：http://synrc.com/apps/n2o/doc/web/protocols.htm#sec11

如果您想违反 N2O 协议，您应该创建自己的原始自定义协议模块：

-module(protocol).
-include_lib("n2o/include/wf.hrl").
-compile(export_all).

event(Event)      -> ok.
finish(State,Ctx) -> {ok,State,Ctx}.
init(State,Ctx)   -> wf:reg(topic), {ok,State,Ctx#cx{module=protocol}}.

info({text,Text}=Message, Req, State) -> {reply, Text, Req, State};
info(Message, Req, State) -> {unknown,Message, Req, State}.

并确保在 sys.config 中只为所有处理程序启用 protocol：

{n2o, [{protocols,[protocol]},
       {query,protocol},
       {session,protocol},
       {route,protocol}]},

用法：

wscat -c ws://127.0.0.1:9000/
connected (press CTRL+C to quit)
> echo
< echo

N2O 协议在使用 gproc:send 时发送空数据

N2O protocol send an empty data when using gproc:send

erlang

websocket

cowboy

n2o