如何跟踪每个浏览器窗口的进程，并在每个事件中进行氮的访问？ [英] How to keep track of a process per browser window and access it at each event in Nitrogen?

问题描述

在氮气中，Erlang的Web框架，我有以下问题。我有一个过程，负责发送和接收消息到作为集线器的另一个进程。此过程充当接收邮件和更新页面的彗星进程。

问题是当用户处理一个按钮时，我会收到一个事件的调用。在一个事件中，如何获取该Pid。

启动通信并设置接收部分的代码看起来像这样，首先我有一个事件开始客户端进程通过调用wf：comet：

  event（start_chat） - > 
 Client = wf：comet（fun（） - > chat_client（）end）; 
  

客户端进程的代码如下，首先获取并加入一个房间，然后进入一个循环发送和接收消息到/从房间：

  chat_client（） - > 
房间= room_provider：get_room（），
房间：加入（房间），
 chat_client（房间）。 
 
 chat_client（房间） - > 
收到
 {send_message，Message}  - > 
房间：send_message（房间，消息）; 
 {message，From，Message}  - > 
 wf：insert_bottom（message，[#p {}，#span {text = Message}]），
 wf：comet_flush（）
 end，
 chat_client（Room）。 
  

现在，这里是问题。我有另一个事件，send_message：

  event（send_message） - > 
 Message = wf：q（message），
 ClientPid！ {send_message，Message}。 
  

除了ClientPid没有在那里定义，我看不到如何看待它。任何想法？

氮邮件列表中的相关威胁： http://groups.google.com/group/nitrogenweb/browse_thread/thread/c6d9927467e2a51a

解决方案

Nitrogen提供了一个名为 state 的页面实例的键值存储。从文档：

检索存储在指定键下的页面状态值。页面状态与会话状态不同，该页面状态被一个用户限定为一个氮页面的一系列请求：

  wf：state（Key） - >价值
  

存储当前用户的页面状态变量。页面状态与会话状态不同，该页面状态被一个用户限定为一个氮页面的一系列请求：

  wf：state（Key，Value） - >确定
  

清除用户的页面状态：

  wf：clear_state（） - > OK 
  

In Nitrogen, the Erlang web framework, I have the following problem. I have a process that takes care of sending and receiving messages to another process that acts as a hub. This process acts as the comet process to receive the messages and update the page.

The problem is that when the user process a button I get a call to event. How do I get ahold of that Pid at an event.

the code that initiates the communication and sets up the receiving part looks like this, first I have an event which starts the client process by calling wf:comet:

event(start_chat) -> 
  Client = wf:comet(fun() -> chat_client() end);

The code for the client process is the following, which gets and joins a room at the beginning and then goes into a loop sending and receiving messages to/from the room:

chat_client() -> 
  Room = room_provider:get_room(), 
  room:join(Room), 
  chat_client(Room).

chat_client(Room) -> 
  receive
    {send_message, Message} ->
      room:send_message(Room, Message);
    {message, From, Message} -> 
      wf:insert_bottom(messages, [#p{}, #span { text=Message }]), 
      wf:comet_flush()
  end, 
  chat_client(Room).

Now, here's the problem. I have another event, send_message:

event(send_message) ->
  Message = wf:q(message),
  ClientPid ! {send_message, Message}.

except that ClientPid is not defined there, and I can't see how to get ahold of it. Any ideas?

The related threat at the Nitrogen mailing list: http://groups.google.com/group/nitrogenweb/browse_thread/thread/c6d9927467e2a51a

解决方案

Nitrogen provides a key-value storage per page instance called state. From the documentation:

Retrieve a page state value stored under the specified key. Page State is different from Session State in that Page State is scoped to a series of requests by one user to one Nitrogen Page:

wf:state(Key) -> Value

Store a page state variable for the current user. Page State is different from Session State in that Page State is scoped to a series of requests by one user to one Nitrogen Page:

wf:state(Key, Value) -> ok

Clear a user's page state:

wf:clear_state() -> ok

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