RESTful API design - naming an "activity" resource - node.js

Question

When designing the endpoints for an activity resource that provides information on the activity of other resources such as users and organisations we are struggling with naming conventions.
What would be more semantic:
/organisations/activity
/organisations/activity/${activityId}
/users/activity
/users/activity/${activityId}
OR
/activity/users/${activityId}
/activity/users
/activity/organisations/${activityId}
/activity/organisations

Answer 1

There's not a generic answer for this, especially since the mechanisms doing the lookup/retrieval at the other end, and associated back-ends vary so drastically, not to mention the use case purpose and intended application.
That said, assuming for all intents and purposes the "schema" (or ... endpoint convention from the point of view of the end user) was just going to be flat, I have seen many more of the latter activity convention, as that is the actual resource, which is what many applications and APIs are developed around.
I've come to expect the following style of representation from APIs today (how they achieve the referencings and mappings is a different story, but from the point of view of API reference)
-
{
"Activity": [
{
"date": "1970-01-01 08:00:00",
"some_other_resource_reference_uuid": "f1c4a41e-1639-4e35-ba98-e7b169d1c92d",
"user": "b3ababc4-461b-404a-a1a2-83b4ca8c097f",
"uuid": "0ccf1b41-aecf-45f9-a963-178128096c97"
}
],
"Users": [
{
"email": "johnanderson#mycompany.net",
"first": "John",
"last": "Anderson",
"user_preference_1": "somevalue",
"user_property_1": "somevalue",
"uuid": "b3ababc4-461b-404a-a1a2-83b4ca8c097f"
}
]
}
The StackExchange API allows retrieving objects through multiple methods also:
For example, the User type look like this:
-
{
"view_count": 1000,
"user_type": "registered",
"user_id": 9999,
"link": "http://example.stackexchange.com/users/1/example-user",
"profile_image": "https://www.gravatar.com/avatar/a007be5a61f6aa8f3e85ae2fc18dd66e?d=identicon&r=PG",
"display_name": "Example User"
}
And on the Question type, the same user is shown underneath the owner object :
-
{
"owner": {
"user_id": 9999,
"user_type": "registered",
"profile_image": "https://www.gravatar.com/avatar/a007be5a61f6aa8f3e85ae2fc18dd66e?d=identicon&r=PG",
"display_name": "Example User",
"link": "https://example.stackexchange.com/users/1/example-user"
},
"is_answered": false,
"view_count": 31415,
"favorite_count": 1,
"down_vote_count": 2,
"up_vote_count": 3,
"answer_count": 0,
"score": 1,
"last_activity_date": 1494871135,
"creation_date": 1494827935,
"last_edit_date": 1494896335,
"question_id": 1234,
"link": "https://example.stackexchange.com/questions/1234/an-example-post-title",
"title": "An example post title",
"body": "An example post body"
}
On the Posts Type reference (Using this as a separate example because there is only a handful of methods to reach this type), you'll see an example down the bottom :
Methods That Return This Type
  posts
  posts/{ids}
  users/{ids}/posts 2.2
  me/posts 2.2
So whilst you can access resources (or "types" as it is on StackExchange), through a number of ways including filters and complex queries, there still exists the ability to see the desired resource through a number of more direct transparent URI conventions.
Different applications will clearly have different requirements. For example, the Gmail API is user based all the way - this makes sense from a users point of view given that in the context of the authenticated credential, you're separating one users objects from another.
This doesn't mean google uses the same convention for all of their APIs, their Activities API resource is all about the activity
Even looking at the Twitter API, there is a Direct Messages endpoint resource that has sender and receiver objects within.
I've not seen many API's at all that are limited to accessing resources purely via a user endpoint, unless the situation obviously calls for it, i.e. the Gmail example above.
Regardless of how flexible a REST API can be, the minimum I have come to expect is that some kind of Activity, location, physical object, or other entity is usually it's own resource, and the user association is plugged in and referenced at various degrees of flexibility (at a minimum, the example given at the top of this post).

Answer 2

It should be pointed out that in a true REST api the uri holds no meaning. It's the link relationships from your organizations and users resources that matter.
Clients should just discover those urls, and should also adapt to the new situation if you decide that you want a different url structure after all.
That being said, it's nice to have a logical structure for this type of thing. However, either is fine. You're asking for an opinion, there is not really a standard or best practice. That said, I would choose option #1.