Ruby on Rails：使用函数从模型中检索数据

Question

在我的 RoR 应用程序中，我试图在视图上显示来自关联表的信息。

我有这样的数据表：

Email
id      subject
1       This week's work
2       Presentation
3       Spreadsheets

Recipients
email_id       group_id
1              2
2              2
3              1
1              3

Groups
id        name
1         Managers
2         Employees
3         Directors

Contactgroups
group_id        contact_id
1               1
2               1
1               3
3               2

Contacts
id          email
1           Gary
2           Dave
3           Annie

我想做的是显示收到电子邮件的组列表以及每个组成员。例如，电子邮件 1 "This week's work" 被发送到组 1 "Managers" 和 3 "Directors"，"Managers" 组由联系人 Gary 和 Annie 以及 "Directors" 组组成由联系人 "Dave" 组成。因此，在 show.html.erb 页面上，我想显示电子邮件的详细信息以及它被发送到的组和他们的每个联系人。

为了做到这一点，在 show.html.erb 页面上我有代码：

<p>
  <strong>Groups Sent To:</strong></br>
  <% @recipients.each do |recipient| %>
        <%= recipient.group.name %>
        <% for i in 0..count_group_members(recipient.group.id)-1 do %>
            <%= group_member_name(recipient.group.id, i) %>
        <% end %></br>
  <% end %>
</p>

在我的 emails_controller 中有代码：

class EmailsController < ApplicationController
    helper_method :count_group_members, :group_member_name
    def index
        @useraccounts = Useraccount.where(user_id: session[:user_id])
        accountsarray = [0]
        @useraccounts.each do |f|
            accountsarray << f.account_id
        end
        # find all emails where the account_id is in the array - and so belongs to the user
        @emails = Email.where(account_id: [accountsarray])
    end
    def show
        @email = Email.find(params[:id])
        @account = Account.find_by_id(@email.account_id)
        @recipients = Recipient.where(email_id: @email.id)
    end
    def new
        @email = Email.new
        @email.recipients.build
        @useraccounts = Useraccount.where(user_id: session[:user_id])
    end
    def edit
        @email = Email.find(params[:id])
        @useraccounts = Useraccount.where(user_id: session[:user_id])
    end
    def create
        @email = Email.new(email_params)
        if @email.save
            redirect_to @email
        else
            render 'new'
        end
    end
    def update
        @email = Email.find(params[:id])
        if @email.update(email_params)
            redirect_to @email
        else
            render 'edit'
        end
    end
    def destroy
        @email = Email.find(params[:id])
        @email.destroy
        redirect_to emails_path
    end
    def count_group_members(group)
        Contactgroup.where(group_id: group).count
    end
    def group_member_name(group, i)
        contact = Contactgroup.where(group_id: group).offset(i).pluck(:contact_id)
        Contact.where(id: contact).pluck(:firstname)
    end
    private
    def email_params
        params.require(:email).permit(:subject, :message, :account_id, { contact_ids: [] }, { group_ids: [] })
    end
end

问题在于，在 show.html.erb 视图中，用户会看到如下信息：

群组发送至：

经理 ["Gary", "Annie"] ["Annie"]

董事["Dave"]

当我想要的是显示为：

群组发送至：

经理加里，安妮

董事戴夫

有人可以帮我解决这个问题吗？

Answer 1

我需要做的就是更改控制器中的以下行：

def group_member_name(group, i)
    contact = Contactgroup.where(group_id: group).offset(i).pluck(:contact_id)
    Contact.find_by_id(contact).firstname
end

Ruby on Rails：使用函数从模型中检索数据

Ruby on Rails: Using functions to retrieve data from model

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ruby-on-rails

datatables

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