使用 Action Cable ruby​​ on rails 实时消息时出错

Question

我正在构建将保存到 sqlite 的文本消息系统，我得到的错误来自代码。在创建新消息时出现此错误

ActiveRecord::StatementInvalid (SQLite3::BusyException: database is locked: INSERT INTO "notifications" ("content", "user_id", "created_at", "updated_at") VALUES (?, ?, ?, ?)):
ActiveRecord::StatementInvalid (SQLite3::BusyException: database is locked: commit transaction): 

如果我删除这一行

ActionCable.server.broadcast "conversation_#{@conversation.id}", message: render_message(@message)

来自 app/controllers/messages_controller.rb

class MessagesController < ApplicationController
    before_action :authenticate_user!
    before_action :set_conversation
def index
    if current_user == @conversation.sender || current_user == @conversation.recipient
    @other = current_user == @conversation.sender ? @conversation.recipient : @conversation.sender
    @messages = @conversation.messages.order("created_at DESC")
    else
    redirect_to conversations_path, alert: "You don't have permission to view this."
    end
end
def create
    @message = @conversation.messages.new(message_params)
    @messages = @conversation.messages.order("created_at DESC")
if @message.save
   ActionCable.server.broadcast "conversation_#{@conversation.id}", message: render_message(@message)
   redirect_to conversation_messages_path(@conversation)
   end
 end
 private
 def render_message(message)
    self.render(partial: 'messages/message', locals: {message: message})
end
def set_conversation
   @conversation = Conversation.find(params[:conversation_id])
end
  def message_params
   params.require(:message).permit(:context, :user_id)
  end
end

我需要从这一行删除这部分 , remote: true

<%= form_for [@conversation, @conversation.messages.new], remote: true do |f| %>

来自 app/views/messages/index.html.erb

  <div class="panel-body">
    <div class="container text-center">
      <%= form_for [@conversation, @conversation.messages.new], remote: true do |f| %>
       <div class="form-group">
          <%= f.text_field :context, placeholder: "Add a personal message", class: "form-control" %>
          </div>
          <%= f.hidden_field :user_id, value: current_user.id %>
          <div>
            <%= f.submit "Send Message", class: "btn btn-normal" %>
          </div>
      <% end %>
    </div>
  </div>

如果我删除了前 2 行消息将起作用并保存到数据库中，但我不会在接收方进行实时更新，这是我的代码的其他部分

app/assets/javascripts/channels/messages.coffee

$(() ->
     App.messages = App.cable.subscriptions.create {channel: 'MessagesChannel', id: $('#conversation_id').val() },
    received: (data) ->
    $('#new_message')[0].reset()
    $('#chat').prepend data.message
 )

app/channels/messages_channel.rb

class MessagesChannel < ApplicationCable::Channel
  def subscribed
  stream_from "conversation_#{params[:id]}"
  end
end

最后这个app/views/conversations/index.html.erb

     <div class="container">
      <% @conversations.each do |conversation| %>
          <% other = current_user == conversation.sender ? conversation.recipient : conversation.sender %>
          <%= link_to conversation_messages_path(conversation) do %>
              <div class="row conversation">
                <% if conversation.messages.any? %>
                    <div class="col-md-2">
                      <%= image_tag avatar_url(other), class: "img-circle avatar-medium" %>
                    </div>
                    <div class="col-md-2">
                      <%= other.fullname %>
                      <%= conversation.messages.last.message_time %>
                    </div>
                    <div class="col-md-8">
                      <%= conversation.messages.last.context %>
                    </div>
                <% end %>
              </div>
          <% end %>
      <% end %>
    </div>

这里是 config/database.yml

default: &default
   adapter: sqlite3
   pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 30 } %>
   timeout: 30000
development:
   <<: *default
   database: db/development.sqlite3
test:
   <<: *default
   database: db/test.sqlite3
production:
   <<: *default
   database: db/production.sqlite3

Answer 1

Sqlite3 的并发支持很差，因此将 DB 切换到更强大的后端 MySQL 或 Postgres。