View Source Security
A great thing to do early on is to be explicit about your security configuration. To that end, once you've read this guide, we highly recommend that you place the configuration found at the bottom of your guide into your api modules, even if you are simply setting them to their default values. Especially the
Authorization in Ash is done via authorizers. Generally, you won't need to create your own authorizer, as the builtin policy authorizer
Ash.Policy.Authorizer should work well for any use case. Authorization is performed with a given actor and a query or changeset.
An actor is the "entity performing the action". This is generally a user, but could potentially be an organization, a group, whatever makes sense for your use case. By default, when using Ash in code, authorization does not happen.
# Does not perform authorization Api.read!(User)
However, if you either 1. provide an actor or 2. use the
authorize?: true option, then authorization will happen.
# Authorize with a `nil` actor (which is valid, i.e if no one is logged in and they are trying to list users) Api.read!(User, actor: nil) # Authorize with a `nil` actor Api.read!(User, authorize?: true) # Authorize with an actor Api.read!(User, actor: current_user) # Authorize with an actor, but being explicit Api.read!(User, actor: current_user, authorize?: true) # Skip authorization, but set an actor. The actor can be used in other things than authorization # so this may make sense depending on what you are doing. Api.read!(User, actor: current_user, authorize?: false)
Where to set the actor
When setting an actor, if you are building a query or changeset, you should do so at the time that you call the various
for_* functions. This makes the actor available in the context of any change that is run. For example:
# DO THIS Resource |> Ash.Query.for_read(:read, input, actor: current_user) |> Api.read() # DON'T DO THIS Resource |> Ash.Query.for_read(:read, input, actor: current_user) |> Api.read(actor: current_user)
The second option "works" in most cases, but not all, because some
changes might need to know the actor
Ash can store the actor, query context, or tenant in the process dictionary. This can help simplify things like live views, controllers, or channels where all actions performed share these pieces of context.
This can be useful, but the general recommendation is to be explicit by passing options.
# in socket connect, liveview mount, or a plug Ash.set_actor(current_user) # This will now use the actor set in the context. Api.read!(User)
The default behavior is illustrated above, but it can be customized with the options in the
Ash.Api.authorization section of the Api module you are calling.
Requires that an actor is set for all requests.
nil is still a valid actor, so this won't prevent providing
The default value for this is relatively loose, and we intend to change it in the 3.0 release (which is not scheduled for anytime soon). Right now, it is
:when_requested, but a better default would be
:by_default, and is what you should choose when starting out.
When to run authorization for a given request.
authorize?: trueon all requests to the Api.
authorize?: trueif the
authorize?option was not set (so it can be set to
authorize?: truewhenever an actor is set or
authorize?: trueis explicitly passed. This is the default behavior.