REST API设计问题

Question

I am calling a REST API for a list of resources and getting the json response as below if atleast one resource is there.

{
"value": [
    "res1_id",
    "res2_id",
    "res3_id"
]
}

and the HTTP response code is 200.

But when no resource is there the server is returning HTTP response code as 404. My doubt it why it is designed that way(it is an enterprise product). I was expecting a empty list as below and HTTP response code 200:

{
"value": []
}

I am not able to understand what design decision has been taken into consideration to return 404 instead of an empty json. Please help me to understand the reasoning behind it.

Answer 1

What I am reading here is that you have a 'collection' resource. This collection resource contains a list of sub-resources.

There's two possible interpretations for this case.

1. The collection resource is 0-length.
2. The collection resource doesn't exist.

Most API's will treat a 0-length collection as a resource that still exists, with a 200 OK . An empty coffee cup is still a coffee cup. The coffee cup itself did not disappear after the last drop is gone.

There are cases where it might be desirable for a collection resource to 404. For example, if you want to indicate that a collection never existed or never has been created.

One way to think about this is the difference between an empty directory or a directory not existing. Both cases can 'tell' the developer something else.

Answer 2

You're trying to access a resource which does not exist. That's the reason for 404.

As a simple google search says

The HTTP 404, 404 Not Found, and 404 error message is a Hypertext Transfer Protocol (HTTP) standard response code, in computer network communications, to indicate that the client was able to communicate with a given server, but the server could not find what was requested.

For your case

{
"value": []
}

This can be a status code 200 which means the resource is accessed and data is returned which is an empty array or you can customize it to a 404. But for that you've mentioned best is to return 200.

Answer 3

Some companies prefer making their errors known instead of hiding them. I know where I work we shy away from try catch blocks because we want our applications to blow up during testing so we can fix the problem. Not hide it. So it's possible that the dev that created the API wants you to use the status code of the response as a way of telling if the service was successful.

Answer 4

A status code of 404 is the correct response for when there is no resource to return based on a request you made. You asked for data and there is no data. It returns an empty response. They're relying on you to base your interpretation of the results on the status code.

https://en.wikipedia.org/wiki/HTTP_404