如何在 Rails 中使用 websockets

Question

我正在尝试将 Web 套接字集成到我的 Rails 应用程序中 link：https://github.com/websocket-rails/websocket-rails/wiki/Installation-and-Setup

我使用 Ruby 2.0 和 Rails3。相关文件内容：

宝石文件：

gem 'websocket-rails

events.rb

WebsocketRails::EventMap.describe do
subscribe :awesomeness_approval, :to => ChatController, :with_method =>   :awesomeness_approval
end

development.rb

... config.middleware.delete Rack::Lock ...

chat_controller.rb

class ChatController < WebsocketRails::BaseController
def initialize_session
# perform application setup here
controller_store[:message_count] = 0
end

def awesomeness_approval
if message[:awesomeness] > 5
trigger_success {:m => 'awesome level is sufficient'}
else
trigger_failure {:m => 'awesome level is insufficient'}
end
end
end

chat.js

var dispatcher = new WebSocketRails('localhost:3000/websocket');
dispatcher.on_open = function(data) {
  console.log('Connection has been established: ', data);
}

var success = function(response) {
  console.log("You are awesome because: "+response.message);
}

var failure = function(response) {
  console.log("You are not very awesome because: "+response.message);
}

var message = { awesomeness: 4 }
dispatcher.trigger('awesomeness_approval', message, success, failure);

当我尝试启动 rails 服务器时，出现以下错误：

w/app/controllers/chat_controller.rb:9: syntax error, unexpected =>, expecting '}' (SyntaxError)
    trigger_success {:m => 'awesome level is sufficient'}

...

/app/controllers/chat_controller.rb:11: syntax error, unexpected =>, expecting '}'
    trigger_failure {:m => 'awesome level is insufficient'}

但是，如果我注释掉以上几行，我就可以启动服务器，并且浏览器可以连接到网络套接字。在浏览器控制台上看到以下输出：

"Connection has been established: " Object { connection_id: "f66c4298eb103312e181" } chat.js:3

请帮忙。

Answer 1

您的错误来自方法调用中的语法歧义。

写的时候

trigger_success {:m => 'awesome level is sufficient'}

左大括号被解释为方法块参数的开始。但是，您希望它是一个散列。解释为一个块，它确实是错误的语法，因为块不允许简单的哈希火箭。

你可以解决这个歧义，你可以使用括号：

trigger_success({:m => 'awesome level is sufficient'})

这样，对于 ruby 解析器来说，您实际上是想将单个散列参数传递给该方法并且当前已被解析。

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