渲染:json => “在这里串"的预期结果 [英] render :json => 'string here' expected result

问题描述

我已经做过一千遍了，但是我对render :json处理字符串的方式仍然不满意.

I have done this a thousand times but I'm still not comfortable with how the render :json handles strings.

要设置范围，让我们来谈谈Rails 3

To set a scope let's talk about Rails 3

这是现在的行为:

...
render :json => 'This is the string'
...

将返回浏览器:

This is the string

那实际上不是有效的JSON响应:S

That's actually not a valid JSON response :S

理想情况下，它应该呈现如下内容:

Ideally it should be rendering something like this:

"This is the string"

即使导轨向导说:

您不需要在要呈现的对象上调用to_json. 如果使用:json选项，render将自动调用to_json 为你.

You don’t need to call to_json on the object that you want to render. If you use the :json option, render will automatically call to_json for you.

然后调用"This is the string".to_json实际上会按预期返回"\"This is the string\"".

And calling "This is the string".to_json is actually returning "\"This is the string\"" as expected.

"This is the string".to_json #=> "\"This is the string\""

我错了吗?

推荐答案

我同意一开始这是意外行为，但实际上有一定道理.

I agree that this is unexpected behavior at first, but it actually makes some good sense.

例如，考虑一下您希望这样做:

Consider, for example, what you would expect this to do:

output = {'foo' => 'bar'}.to_json
render :json => output

即使to_json有点多余，您也希望结果为{foo: "bar"}.但是，请注意，{'foo' => 'bar'}.to_json的结果实际上是一个字符串.因此，以上代码块等效于:

Even though the to_json is kinda redundant, you expect the result to be {foo: "bar"}. However, note that the result of {'foo' => 'bar'}.to_json is actually a string. So, the above code block is equivalent to:

render :json => '{foo: "bar"}'

如果render对传递给:json的字符串进行JSON编码，则将得到"{foo: \"bar\"}"，这肯定是不是预期的行为.

If render were to JSON-encode strings passed to :json, you would get "{foo: \"bar\"}", which is definitely not expected behavior.

这就是问题所在:render检查:json参数是否为字符串.如果是这样，则假定它是JSON字符串，并且您已经运行了to_json，并将字符串传递.如果不是，它将在对象上运行to_json.

So here's the deal: render checks to see if the :json argument is a string. If so, it assumes that it's a JSON string and you already ran to_json, and passes the string along. If not, it runs to_json on the object.

我认为文档可能应该澄清这一点，但是您已经掌握了.尽管乍看之下并不完全直观，但如果以其他方式起作用，我会感到惊讶.

I think the documentation should probably clarify that, but there you have it. Though it's not exactly intuitive at first glance, I would be surprised if it worked any other way.

这篇关于渲染:json => “在这里串"的预期结果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！