如何在Ruby中使用多个布尔变量重构方法

Question

我在ruby中有一个方法，它有条件地设置一些实例变量，我想知道如何重构它来清理它并使它不那么冗长。我的第一个问题是将不同的条件分解为多个较小的辅助方法，但我不确定这是否是正确的方法。任何建议都会有所帮助。

def admin_view
    if resource.present?
      if resource.ed_level == 'group'
        if current_user && (current_user.admin || resource.admins_byemail.include?(current_user.email))
          @admin_full = true
          @admin_edit = true
          @admin_view = true
        else
          @admin_full = false
          @admin_edit = false
          @admin_view = false
        end
      else
        if current_user && (current_user.admin || resource.admin_email_list('view').include?(current_user.email.downcase))
          if current_user.admin || (resource.admin_email_list('full').include?(current_user.email.downcase) && resource.ed_level != 'group')
            @admin_full = true
            @admin_edit = true
            @admin_view = true
          elsif resource.admin_email_list('edit').include?(current_user.email.downcase) && resource.ed_level != 'group'
            @admin_full = false
            @admin_edit = true
            @admin_view = true
          elsif resource.admin_email_list('view').include?(current_user.email.downcase) && resource.ed_level != 'group'
            @admin_full = false
            @admin_edit = false
            @admin_view = true
          end
        else
          @admin_full = false
          @admin_edit = false
          @admin_view = false
        end
      end
    else
      redirect_to school_missing_path
    end
  end

根据以下答案，我更新了我的代码如下。

 def admin_view
    if resource.present?
      if resource.ed_level == 'group'
        if current_user && (current_user.admin || resource.admins_byemail.include?(current_user.email))
          set_admin_permissions(full: true, edit: true, view: true)
        else
          set_admin_permissions(full: false, edit: false, view: false)
        end
      else
        if current_user && (current_user.admin || resource.admin_email_list('view').include?(current_user.email.downcase))
          if current_user.admin || (resource.admin_email_list('full').include?(current_user.email.downcase) && resource.ed_level != 'group')
            set_admin_permissions(full: true, edit: true, view: true)
          elsif resource.admin_email_list('edit').include?(current_user.email.downcase) && resource.ed_level != 'group'
            set_admin_permissions(full: false, edit: true, view: true)
          elsif resource.admin_email_list('view').include?(current_user.email.downcase) && resource.ed_level != 'group'
            set_admin_permissions(full: false, edit: false, view: true)
          end
        else
          set_admin_permissions(full: false, edit: false, view: false)
        end
      end
    else
      redirect_to school_missing_path
    end
  end

  private

  def set_admin_permissions(full:, edit:, view:)
    @admin_full = full
    @admin_edit = edit
    @admin_view = view
  end

Answer 1

首先，您可能希望使用CanCanCan来正确封装您的权限。这是一种更正式的方法，用于在控制器和视图代码中定义访问限制并对其进行测试。

话虽如此，如果您的代码结构稍有不同，您可以大大简化代码：

def admin_permissions
  return [ ] unless resource.present?

  case resource.ed_level
  when 'group'
    if current_user && (current_user.admin || resource.admins_byemail.include?(current_user.email))
      [ :full, :edit, :view ]
    else
      [ ]
    end
  else
    email = current_user && current_user.email.downcase

    if current_user && (current_user.admin || resource.admin_email_list('view').include?(email))
      if current_user.admin || resource.admin_email_list('full').include?(email)
        [ :full, :edit, :view ]
      elsif resource.admin_email_list('edit').include?(email)
        [ :edit, :view ]
      elsif resource.admin_email_list('view').include?(email)
        [ :view]
      end
    else
      [ ]
    end
  end
end

然后像这样使用：

@admin_privs = admin_permissions

定义一些这样的辅助方法：

def admin_full?
  @admin_privs and admin_privs.include?(:full)
end

def admin_edit?
  @admin_privs and admin_privs.include?(:edit)
end

def admin_view?
  @admin_privs and admin_privs.include?(:view)
end

就我个人而言，我发现通过应用“不要重复自己”来减少代码中的重复＆＃34; （DRY）原则经常暴露底层结构，并使其更容易重塑为更简洁和灵活的东西。

例如，这里有resource.ed_level != 'group'的许多测试，因为在测试的else块中断言相反，没有办法永远不会出现这种情况。

Answer 2

建立Maxim的想法，但注意到你的权限是分层的（即“完整”意味着编辑和视图以及“编辑”意味着视图），我会将你的帮助方法浓缩为：

def set_access_level(level)
  case level
  when :full
    @admin_full, @admin_edit, @admin_view = true, true, true
  when :edit
    @admin_full, @admin_edit, @admin_view = false, true, true
  when :view
    @admin_full, @admin_edit, @admin_view = false, false, true
  else
    @admin_full, @admin_edit, @admin_view = false, false, false
  end
end

然后您的代码变为：

def admin_view
  if resource.present?
    if resource.ed_level == 'group'
      if current_user && (current_user.admin || resource.admins_byemail.include?(current_user.email))
        set_access_level(:full)
      else
        set_access_level(:none)
      end
    else
      if current_user && (current_user.admin || resource.admin_email_list('view').include?(current_user.email.downcase))
        if current_user.admin || (resource.admin_email_list('full').include?(current_user.email.downcase) && resource.ed_level != 'group')
          set_access_level(:full)
        elsif resource.admin_email_list('edit').include?(current_user.email.downcase) && resource.ed_level != 'group'
          set_access_level(:edit)
        elsif resource.admin_email_list('view').include?(current_user.email.downcase) && resource.ed_level != 'group'
          set_access_level(:view)
        end
      else
        set_access_level(:none)
      end
    end
  else
    redirect_to school_missing_path
  end
end

Answer 3

只需制作一个setter辅助方法，如下所示：

def admin_view
  if resource.present?
    if resource.ed_level == 'group'
      if current_user && (current_user.admin || resource.admins_byemail.include?(current_user.email))
        set_values(true, true, true)
      else
        set_values(false, false, false)
      end
    else
      if current_user && (current_user.admin || resource.admin_email_list('view').include?(current_user.email.downcase))
        if current_user.admin || (resource.admin_email_list('full').include?(current_user.email.downcase) && resource.ed_level != 'group')
          set_values(true, true, true)
        elsif resource.admin_email_list('edit').include?(current_user.email.downcase) && resource.ed_level != 'group'
          set_values(false, true, true)
        elsif resource.admin_email_list('view').include?(current_user.email.downcase) && resource.ed_level != 'group'
          set_values(false, false, true)
        end
      else
        set_values(false, false, false)
      end
    end
  else
    redirect_to school_missing_path
  end
end

def set_values(full, edit, view)
  @admin_full = full
  @admin_edit = edit
  @admin_view = view
end

Answer 4

如果发现所有嵌套ifs和重复逻辑有点令人困惑。请记住，您可以使用return语句使代码更加干净。我不能保证下面的逻辑正是你所追求的，但在我看来，结构更具可读性。

def admin_view
   redirect_to school_missing_path unless resource.present?
   access_level = calc_access_level

end

def calc_access_level

    return :none unless resource.present?
    return :none unless current_user
    return :full if current_user.admin

    email_raw = current_user.email
    email = email_raw.downcase

    if (resource.ed_level == 'group')
      return resource.admins_byemail.include?(email_raw) ? :full, :none
    end

    ['view','full','edit'].each do |access_level|
      if resource.admin_email_list(access_level).include?(email)
        return access_level.to_sym
      end
    end

    return :none

end

def set_access_level(level)

  @admin_full, @admin_edit, @admin_view = false, false, false
  case level
  when :full
    @admin_full, @admin_edit, @admin_view = true, true, true
  when :edit
    @admin_edit, @admin_view = true, true
  when :view
    @admin_view = true
  end
end