有没有办法提前退出或“返回"?从 Rails 的角度来看? [英] Is there a way to do an early exit or "return" from a view in Rails?

问题描述

Rails 是否提供任何方式来提前退出或从正在呈现的视图中返回"?

Does Rails offer any way to exit early or "return" from a view that is being rendered?

例如，我有一个结构如下的视图:

For example, I have a view structured as follows:

<h1>Your records summary</h1>

<% if @current_user.has_records? %>
  <p>You don't have any records.</p>
<% else %>
  ... long block of view emission code here ...
<% end %>

在非 erb 代码中，我只需要从 if 条件中return，并且不需要将那个长块放在 else.它看起来像:

In non-erb code, I'd just return from that if condition, and wouldn't need to put that long block inside an else. It would look like:

<h1>Your records summary</h1>

<% if @current_user.has_records? %>
  <p>You don't have any records.</p>
  <% return (or something) %>
<% end %>
... long block of view emission code here ...

有没有办法在 erb 中做类似的事情?

Is there a way to do something like that in the erb?

需要明确的是，我不是在要求替代方法，例如已经建议的方法.我不是 Rails 菜鸟.我真的只是想知道 Ruby 是否为我的建议提供了一种机制.

To be clear, I'm not asking for alternate approaches, such as have been suggested. I'm not a Rails noob. I really just want to know whether Ruby provides a mechanism for what I suggested or not.

推荐答案

IIRC 没有用于提前退出模板的内置机制.这符合(我认为)视图层的行为方式，尽管 erb 不是一个模板引擎.

IIRC there's no built-in mechanism for exiting a template early. This is in line with how (I think) a view layer should behave, although erb isn't quite a template engine.

旧的解决方案是将模板包装在 catch 中，然后从模板中抛出一些东西，例如符号.

The old-timey solution was to wrap your template in a catch and throw something from within the template, like a symbol.

您还可以将 eval 嵌入到 Lamba 中，从而允许 return 工作.

You could also embed the eval inside a lamba, allowing return to work.

尽管如此.

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