例如,您为用户/9运行一个GET请求,但没有id为#9的用户。 哪个是最佳响应码?

200好了 202年接受 204无内容 400错误请求 404未找到


当前回答

Just an addition from a developer that struggled many times with this situation. As you might have noticed it is always a discussion whether you return a 404 or 200 or 204 when a particular resource does not exist. The discussion above shows that this topic is pretty confusing and opinion based ( while there is a http-status-code standard existing ). I personally recommend, as it was not mentioned yet I guess, no matter how you decide DOCUMENT IT IN YOUR API-DEFINITION. Of course a client-side developer has in mind when he/she uses your particular "REST"- api to use his/her knowledge about Rest and expects that your api works this way. I guess you see the trap. Therefor I use a readme where I explicitly define in which cases I use which status code. This doesn't mean that I use some random definion. I always try to use the standard but to avoid such cases I document my usage. The client might think you are wrong in some specific cases but as it is documented, there is no need for additional discussions what saves time for you and the developer.

One sentence to the Ops question: 404 is a code that always comes in my mind when I think back about starting to develop backend-applications and I configured something wrong in my controller-route so that my Controller method is not called. With that in mind, I think if the request does reach your code in a Controller method, the client did a valid request and the request endpoint was found. So this is an indication not to use 404. If the db query returns not found, I return 200 but with an empty body.

其他回答

根据w3,我相信以下几点:

2xx:

这类状态代码表示成功接收、理解并接受了客户机的请求。

4xx:

4xx类状态代码用于客户端似乎出现错误的情况。

如果客户端请求/users,并且它有用户要列出,响应代码将是200 OK(客户端请求有效)。

如果客户端请求/users并且没有数据,响应代码仍然是200 OK。 被请求的实体/资源是一个用户列表,列表存在,只是其中没有任何用户(如果给出空响应,可以使用204 No Content,尽管我认为空列表[]会更好)。 客户端请求是有效的,资源也确实存在,因此4xx响应代码在这里没有意义。

另一方面,如果客户端请求/users/9,而该用户不存在,那么客户端就犯了一个错误,请求了一个不存在的资源,一个用户。在这种情况下,回答404 Not Found是有意义的。

TL;DR:使用404

请看这个博客。这解释得很好。

博客对204的评论总结如下:

204 No Content作为浏览器的响应代码并不是特别有用(尽管根据HTTP规范,浏览器需要将其理解为“不要更改视图”的响应代码)。 然而,No Content对于ajax web服务非常有用,它可能想要表示成功而不需要返回任何东西。(特别是在DELETE或post这样不需要反馈的情况下)。

因此,您的问题的答案是在您的情况下使用404。204是一个专门的响应代码,您不应该经常将其返回给浏览器以响应GET。

其他响应代码甚至比204和404更不合适:

200 should be returned with the body of whatever you successfully fetched. Not appropriate when the entity you're fetching doesn't exist. 202 is used when the server has begun work on an object but the object isn't fully ready yet. Certainly not the case here. You haven't begun, nor will you begin, construction of user 9 in response to a GET request. That breaks all sorts of rules. 400 is used in response to a poorly formatted HTTP request (for instance malformed http headers, incorrectly ordered segments, etc). This will almost certainly be handled by whatever framework you're using. You shouldn't have to deal with this unless you're writing your own server from scratch. Edit: Newer RFCs now allow for 400 to be used for semantically invalid requests.

维基百科对HTTP状态码的描述尤其有用。 您也可以在www.w3.org上看到HTTP/1.1 RFC2616文档中的定义

根据RFC7231 -第59页(https://www.rfc-editor.org/rfc/rfc7231#page-59) 404状态码响应的定义是:

6.5.4. 404 Not Found The 404 (Not Found) status code indicates that the origin server did not find a current representation for the target resource or is not willing to disclose that one exists. A 404 status code does not indicate whether this lack of representation is temporary or permanent; the 410 (Gone) status code is preferred over 404 if the origin server knows, presumably through some configurable means, that the condition is likely to be permanent. A 404 response is cacheable by default; i.e., unless otherwise indicated by the method definition or explicit cache controls (see Section 4.2.2 of [RFC7234]).

而引起质疑的主要是上述语境中对资源的定义。 根据同一个RFC(7231), resource的定义是:

Resources: The target of an HTTP request is called a "resource". HTTP does not limit the nature of a resource; it merely defines an interface that might be used to interact with resources. Each resource is identified by a Uniform Resource Identifier (URI), as described in Section 2.7 of [RFC7230]. When a client constructs an HTTP/1.1 request message, it sends the target URI in one of various forms, as defined in (Section 5.3 of [RFC7230]). When a request is received, the server reconstructs an effective request URI for the target resource (Section 5.5 of [RFC7230]). One design goal of HTTP is to separate resource identification from request semantics, which is made possible by vesting the request semantics in the request method (Section 4) and a few request-modifying header fields (Section 5). If there is a conflict between the method semantics and any semantic implied by the URI itself, as described in Section 4.2.1, the method semantics take precedence.

所以在我的理解中,404状态代码不应该用于成功的GET请求,结果为空。(例如:一个没有特定过滤器结果的列表)

TL; diana:

如果在/users/9上没有找到用户,则应该返回404。 如果在/users中没有找到用户?如果Id =9,则应该返回204。

长版:

在回顾了我自己对这些状态代码的使用和本文中的示例之后,我不得不说,如果在/users/9的url上没有找到用户#9,404是适当的响应。

今天在我的系统中,我们的Application Insights日志中充满了数百条记录的404错误,这使我们的日志变得混乱,因为我们决定在/users/9没有相关数据时返回404错误。然而,这并不意味着我们在设置响应时的方法是不正确的,相反,我认为这意味着我们在设置路由时的方法是不正确的。

如果您希望端点获得大量流量,并且担心记录太多404错误,那么您应该更改路由以符合您想要的状态码,而不是强制使用不适当的状态码。

我们已经决定对我们的代码做2个更改:

通过expect /users改变我们的工作路线?id = 9 将我们的错误代码更改为204,这样404就不会填满我们的AI日志。

最后,API的架构师需要了解他们的API将如何被使用,以及哪种路由将适合于该用例。

我相信在/users/9的情况下,您请求的资源是用户本身,用户#9;您要求服务器响应一个标识为“9”的对象,该对象恰好存在于包含单词“user”的路径中。如果没有找到该对象,则应该得到404。

但是,如果调用/users?id=9,我觉得你所请求的资源是用户控制器,同时也提供了更多的专一性,这样它就不会返回所有用户的完整列表。您要求服务器响应一个可以通过查询字符串中定义的ID号识别的特定用户。因此,如果没有找到数据,204对我来说是有意义的,因为即使没有找到数据,控制器也是。

查询字符串方法还完成了一些我认为不仅有助于API开发人员,而且有助于客户端开发人员(特别是初级开发人员或继承这段代码或调用它的代码的未来开发人员):

It becomes immediately clear to anyone involved that 9 is an ID, not some arbitrary number. This point may seem moot in such a basic example, but consider a system that uses GUIDs as row ID's or allows you to get data by a person's name, or even a system that is returning info for specific ZIP/postal codes instead of row ID's. It would be useful for all developers involved if, at a glance, they knew whether that identifying parameter was a first, last, full name, or a ZIP/postal code instead of an ID.

这样的事情可能是主观的,双方都有一些有趣和各种扎实的论点。然而,(在我看来)为丢失的数据返回404是不正确的。这里有一个简单的描述来说明这一点:

请求:能给我一些数据吗? 资源(API端点):我将在这里为您获取请求[发送潜在数据的响应]

没有问题,找到了端点,找到了表和列,因此查询了DB,并“成功”返回了数据!

现在,无论“成功响应”是否有数据都不重要,您要求“潜在”数据的响应,并且具有“潜在”数据的响应得到了满足。Null,空等是有效的数据。

200只代表我们的请求成功了。我正在请求数据,HTTP/REST没有任何问题,作为数据(尽管为空)返回我的“数据请求”是成功的。

返回一个200,让请求者在每个特定场景下处理空数据!

想想这个例子:

请求:查询用户ID为1234的“违规”表 资源(API端点):返回一个响应,但数据为空

此数据为空是完全有效的。这意味着用户没有违规行为。这是200,因为它是有效的,然后我可以这样做:

你没有违规,吃个蓝莓松饼!

如果你认为这是404,你在说什么?无法发现用户的违规行为?从语法上讲,这是正确的,但在REST世界中,成功或失败是关于请求的,这是不正确的。该用户的“违规”数据可以成功找到,没有违规-一个实数代表有效状态。


(厚颜无耻的注意。)

在你的标题中,你下意识地认为200是正确的回答:

对于有效请求但空数据,正确的REST响应代码是什么?


在选择使用哪种状态码时,抛开主观性和棘手的选择,以下是一些需要考虑的事情:

一致性。如果您使用404表示“无数据”,则在每次响应返回无数据时使用它。 同一个状态不要有多个意思。如果在没有找到资源时返回404(例如API端点不存在等),那么也不要因为没有返回数据而使用它。这只会让应对反应变成一种痛苦。 仔细考虑上下文。什么是“请求”?你说你想达到什么目的?