Structuring RESTful API in Flask when some methods require authentication and some don't

Question

I'm making a new RESTful API in Flask that should accept both GET (for requesting the resource) and PATCH (for performing various incremental, non-idempotent updates) for a given object. The thing is that some of the data that's patched in must be authenticated, and some shouldn't be.

To clarify this with an example, let's say I'm building an app that let's everyone query how many times a resource has been clicked on and how many times its page has been viewed. It also let's people do an update on the resource in javascript saying the resource was clicked again (unauthenticated, since it's coming from the front-end). It additionally let's an authenticated backend increment the number of times the page has been viewed.

So, following RESTful principles, I'm thinking all three actions should be done on the same path-- something like /pages/some_page_name which should accept both GET and PATCH and should accept two different kinds of data with PATCH. The problem is that in Flask, it looks like authentication is always done with a decorator around a method, so if I have a method like @app.route('/pages/<page_id>', methods=['GET', 'PATCH']), my authentication would be done with a decorator like @auth.login_required for that whole method, which would force even the methods that don't require authentication to be authenticated.

So, my question is three-fold:

1. Am I right in structuring all three actions mentioned under the same path/ is this important?
2. If I am right, and this is important, how do I require authentication only for the one type of PATCH?
3. If this is not important, what's a better or simpler way to structure this API?

Answer 1

I see several problems with your design.

let's say I'm building an app that let's everyone query how many times a resource has been clicked on and how many times its page has been viewed

Hmm. This isn't really a good REST design. You can't have clients query select "properties" of resources, only the resources themselves. If your resource is a "page", then a GET request to /pages/some_page_name should return something like this (in JSON):

{
    'url': 'http://example.com/api/pages/some_page_name',
    'clicks': 35,
    'page_views': 102,
    <any other properties of a page resource here>
}

It also let's people do an update on the resource in javascript saying the resource was clicked again

"clicking something" is an action, so it isn't a good REST model. I don't know enough about your project so I can be wrong, but I think the best solution for this is to let the user click the thing, then the server will receive some sort of a request (maybe a GET to obtain the resource that was clicked?). The server is then in a position to increment the clicks property of the resource on its own.

(unauthenticated, since it's coming from the front-end).

This can be dangerous. If you allow changes to your resources from anybody, then you are open to attacks, which may be a problem. Nothing will prevent me from looking at your Javascript and reverse engineering your API, and then send bogus requests to artificially change the counters. This may be an acceptable risk, but make sure you understand this may happen.

It additionally let's an authenticated backend increment the number of times the page has been viewed.

Backend? Is this a client or a server? Sounds like it should be a client. Once again, "incrementing" is not a good match for REST type APIs. Let the server manage the counters based on the requests it receives from clients.

Assuming I understand what you are saying, it seems to me you only need to support GET. The server can update these counters on its own as it receives requests, clients do not need to bother with that.

UPDATE: After some additional info provided in the comments below, what I think you can do to be RESTful is to also implement a PUT request (or PATCH if you are into partial resource updates).

If you do a PUT, then the client will send the same JSON representation above, but it will increment the corresponding counter. You could add validation in the server to ensure that the counters are incremented sequentially, and return a 400 status code if it finds that they are not (maybe this validation is skipped for certain authenticated users, up to you). For example, starting from the above example, if you need to increment the clicks (but not the page views), then send a PUT request with:

{
    'url': 'http://example.com/api/pages/some_page_name',
    'clicks': 36,
    'page_views': 102
}

If you are using PATCH, then you can remove the items that don't change:

{
    'clicks': 36
}

I honestly feel this is not the best design for your problem. You have very specific client and server here, that are designed to work with each other. REST is a good design for decoupled clients and servers, but if you are on both sides of the line then REST doesn't really give you a lot.

Now regarding your authentication question, if your PUT/PATCH needs to selectively authenticate, then you can issue the HTTP Basic authentication exchange only when necessary. I wrote the Flask-HTTPAuth extension, you can look at how I implemented this exchange and copy the code into your view function, so that you can issue it only when necessary. I hope this clarifies things a bit.