当使用者要求与不存在的资源相关的资源集合时，我应该发送什么API响应？

Question

Let's say I have a resource

/providers/123

When a consumer sends a GET for that, it receives 200 OK and a record for the provider identified by 123, or a 404 Not Found if there is no provider with id 123. Fine.

Now let's say I have another resource

/providers/123/publications

which represents a collection of publications authored by provider 123. When a consumer sends a GET for that:

• If the provider exists and has some publications, they get 200 OK with the collection of publications.
• If the provider exists and has no publications, they get 200 OK with a collection that is empty.

But what if the provider doesn't exist? 404? 200 with empty set? 200 with empty set and a warning? Something else?

Answer 1

404 for sure. The URL refers to a resource that does not exist.

Don't give any more information than is required.

Answer 2

Depends on your end user (the entity making the API calls)

If its a human being then 200 with an error saying that the provider doesnt exist seems the best. This case is applicable mostly with single calls to your API

If the end user is a robot parsing data from your resultset then 200 with an empty set will be a good choice.This case is applicable when API calls are made in bulk.

Example: This Geonames API gives country code from latitude and longitude, but if I have invalid latitude and longitude, it will throw an error message

http://api.geonames.org/countryCode?lat=181&lng=181&username=demo