空表的正确 REST 响应? [英] Proper REST response for empty table?

问题描述

假设您想通过调用 GET 到 api/users 来获取用户列表，但目前该表已被截断，因此没有用户.这种情况下的正确响应是什么:404 或 204?

Let's say you want to get list of users by calling GET to api/users, but currently the table was truncated so there are no users. What is the proper response for this scenario: 404 or 204?

推荐答案

我想说，两者都不是.

404 状态代码应保留用于未找到资源的情况.在这种情况下，您的资源是用户集合.此集合存在，但当前为空.就我个人而言，如果我一天收到 200 第二天收到 404 只是因为有人碰巧删除了几个用户.我应该做些什么?我的网址有错吗?是否有人更改了 API 而忽略了重定向.

The 404 status code should be reserved for situations, in which a resource is not found. In this case, your resource is a collection of users. This collection exists but it's currently empty. Personally, I'd be very confused as an author of a client for your application if I got a 200 one day and a 404 the next day just because someone happened to remove a couple of users. What am I supposed to do? Is my URL wrong? Did someone change the API and neglect to leave a redirection.

这是 w3c 对 204 状态代码的描述的摘录

服务器已完成请求但不需要返回实体正文，并且可能想要返回更新的元信息.

The server has fulfilled the request but does not need to return an entity-body, and might want to return updated metainformation.

虽然在这种情况下这似乎是合理的，但我认为这也会让客户感到困惑.204 应该表示某些操作已成功执行，不需要返回数据.这非常适合作为对 DELETE 请求的响应，或者可能触发一些不需要返回数据的脚本.在 api/users 的情况下，您通常希望收到您的用户集合的表示.一次发送响应正文而另一次不发送是不一致的，并且可能会产生误导.

While this may seem reasonable in this case, I think it would also confuse clients. A 204 is supposed to indicate that some operation was executed successfully and no data needs to be returned. This is perfect as a response to a DELETE request or perhaps firing some script that does not need to return data. In case of api/users, you usually expect to receive a representation of your collection of users. Sending a response body one time and not sending it the other time is inconsistent and potentially misleading.

出于上述原因(一致性)，我将返回一个空集合的表示.假设您使用的是 XML.非空用户集合的正常响应正文可能如下所示:

For reasons mentioned above (consistency), I would return a representation of an empty collection. Let's assume you're using XML. A normal response body for a non-empty collection of users could look like this:

<users>
  <user>
    <id>1</id>
    <name>Tom</name>
  </user>
  <user>
    <id>2</id>
    <name>IMB</name>
  </user>
</users>

如果列表是空的，你可以用这样的东西来回应(同时仍然使用 200):

and if the list is empty, you could just respond with something like this (while still using a 200):

<users/>

无论哪种方式，客户端都会收到遵循某种众所周知的格式的响应正文.没有不必要的混淆和状态代码检查.此外，没有违反任何状态代码定义.大家都很开心.

Either way, a client receives a response body that follows a certain, well-known format. There's no unnecessary confusion and status code checking. Also, no status code definition is violated. Everybody's happy.

您可以对 JSON 或 HTML 或您使用的任何格式执行相同操作.

You can do the same with JSON or HTML or whatever format you're using.

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