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I'm wondering what are the best ways to delete items from a subset in a restful way. I got users and series, each user has his own list of series (watching, completed, etc). For example, if we want to get a list from a user we can do it with: GET /users/:id_user/series

If we want to delete a serie from the list of that user (but we don't want to delete the serie itself), how should it be?

I thought about the possibility of using DELETE /users/:id_user/series/:id_serie, but I'm not sure if it's the correct way for this case (maybe PATCH?).

I got another case, we got series and reviews. We can get the reviews like this: GET /series/:serie_id/reviews. In the other case we didn't want to delete the serie itself when deleting from a user list of series, but in this case we want to delete the review because its existence depends on the serie. So I guess in this case DELETE /series/:serie_id/reviews/:review_id is correct.

Is this difference important in order to choose the rest operation to delete the object/item from the subset?

Manuel José Verdú Ramón
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1 Answers1

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How would you do it on the web?

You'd follow a link to a form, with input controls. You might have a something like a dropdown if you wanted to delete one series at a time, or lots of check boxes if you wanted to support a bulk delete. The user would provide input, hit the submit button, and the browser would create an application/x-www-form-urlencoded document and send it to the server.

What method would be used? Normally POST, because we are intending an edit to some resource on the server.

What resource would we be editing? Well, in trutch, it could be anything -- the server would include that information in the form metadata, so the client can just do what it is told.

So where should the server tell it to submit the form? Again, it could be anywhere... but a useful approach is to think about what resource in the client's cache is being updated. Because if we send the request to that resource, we get intelligent cache invalidation "for free".

So on the web, we would expect to see:

POST /users/:id_user/series

Does it have to be POST? On the HTML web, maybe it does, because the ubiquitous client of the web is a browser, not an editor.

It is okay to use POST.

But a perfectly valid alternative would be to edit the local copy of /users/:id_user/series, and then send back to the server a complete copy of the new version (PUT) or a patch-document describing the edits (PATCH). Notice that with both of these choices, the target uri is still /user/:id_user/series, so we still get the cache invalidation magic.

Creating a new resource in your model just to have something to DELETE is probably the wrong idea.

There are cases where an edit, or a delete, will necessarily impact more than one resource.

There are some specific circumstances when you can get the right magic cache invalidation with two resources (for instance, delete one document, and send back an updated copy of another).

But we don't, today, have a general purpose cache invalidation mechanism. (Closest thing I've been able to find is this, which seems to have stalled out in 2012.

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