Handling User Preferences/States in REST API - rest

We're starting to migrate our Website to a REST Service based system and are in the process of developing the core right now.
In our current setup a user has one or more "accounts" assigned which define what data he can see on the website. Only one account can be active for a given user at any time. Right now we store the selected account in the database and use it to filter all queries.
Now I'm not sure how to handle this properly in a REST environment. Possible solutions I found are:
Sending the requested account with every request
Storing the current account in the auth token. (We're using JWT for that)
Having the current account stored on the server and calling a specific resource to change it
Each of these has its pros and cons for our setup. Currently we're using the 3rd approach in our Website. But what would be the correct way to handle such a thing in a REST environment?

Yea the design you are dealing with is fairly bad, and what you really want to do is remove the state completely out of this system.
For that reason the first option is by far superior:
Sending the requested account with every request
If this is simply an id, there's a very simple way to do this, just prefix all your (relevant) routes / uris with this account id. For example:
http://api.example.org/accounts/{id}/...
This way the 'state' is maintained by virtue of which url you are accessing, and the server can be unaware of the state.

Related

Making API requests to a 3rd party that requires authentication

Here is my scenario. Imagine there is a Yoga studio that uses a professional booking and reservation system that exposes an API. Through this API an application can make a reservation for a client. The API takes the client's userid and password to make the reservation. The booking API doesn't use OAuth or any social media sign-ins.
My desire is to create an Assistant Action that would retrieve the list of classes and allow the client to make a booking.
My puzzle is what design/architecture to look towards to supply the userid/password pair required by the booking API.
How have others solved this puzzle?
Should I store the userid/password as "user state" associated with the action?
First, you should have a conversation with the API provider about why they don't provide an OAuth-based solution. This is a security vulnerability waiting to happen, if it hasn't already.
Second, you need to think very carefully about your own risk profile in this case:
Google does not allow you to collect credential information (ie - passwords) through your Action.
Because of this, you must use Account Linking to authenticate them.
This means that you will need something (ie - a database or data store) to manage their account on your side.
This database would be a good place to keep the username/password you need to use for them for the API...
...but it now means that you need to take extreme care about protecting this database.
You don't really say how this API allows for accounts to be created and managed. If these accounts are just used for you (ie - the user doesn't necessarily see them), then you can mitigate some of that risk by treating the username/password as an opaque token that you manage and generate and that the user never sees.
If this is something that the user is aware of, then you'll need to approach the account linking in one of two ways:
Have them log into your service via an app or webapp using this credential info that you will need to save (ack!) and then link to the Assistant using OAuth.
Have them log into your service via an app or webapp using Google Sign-In, which will carry over to your Action. Then have them provide the credential info for the API, which you will need to save (ack!).

Storing semi persistant data for a SPA

I have a SPA website set up with a REST API. One of the issues I have come up against is how to access data unrelated to the resource being requested. Specifically, accessing the users account details so I can do things like hide admin actions when the user is not an admin.
I have an api endpoint that can get all this data so the simplest solution would be to on every page load request the profile api as well as the resource actually being accessed. This seems a little wasteful to be constantly requesting a resource that rarely changes.
Another option would be to store this data in local storage so it only has to be requested once but then I have the issue where the user updates their username or settings on one device and then the other one is left with outdated data in local storage.
I thought vuex might be able to persist this data when clicking on links and navigating to different pages but it seems like the data gets lost when the page changes.
From what I understand graphql would solve this problem by allowing the initial request to get the user data along with the other data. I'm not really sure how much more efficient this is than 2 requests and rewriting my whole api probably isn't the best solution to this.
Are there any well known solutions to this problem or is one of the options I have come up with the best way to handle this?

Creating user record / profile for first time sign in

I use an authentication service Auth0 to allow users to log into my application. The application is a Q&A platform much like stackoverflow. I store a user profile on my server with information such as: 'about me', votes, preferences, etc.
When new user signs in i need to do 1 of 2 things:
For an existing user - retrieve the user profile from my api server
For a new user - create a new profile on the database
After the user signs in, Auth0(the authentication service) will send me some details(unique id, name and email) about the user but it does not indicate whether this is a new user(a sign up) or a existing user(a sign in).
This is not a complex problem but it would be good to understand best practice. I can think of 2 less than ideal ways to deal with this:
**Solution 1 - GET request **
Send a get request to api server passing the unique id
If a record is found return it
Else create new profile on db and return the new profile
This seems incorrect because the GET request should not be writing to the server.
**Solution 2 - One GET and a conditional POST request **
Send a get request to api server passing the unique id
The server checks the db and returns the profile or an error message
If the api server returns an error message send a post request to create a new profile
Else redirect to the home page
This seems inefficient because we need 2 requests to achieve a simple result.
Can anyone shed some light on what's best practice?
There's an extra option. You can use a rule in Auth0 to send a POST to the /users/create endpoint in your API server when it's the first time the user is logging in, assuming both the user database in Auth0 and in your app are up-to-date.
It would look something like this:
[...]
var loginCount = context.stats.loginsCount;
if (loginCount == 1) {
// send POST to your API and create the user
// most likely you'll want to await for response before moving on with the login flow
}
[...]
If, on the other hand, you're referring to proper API design and how to implement a find-or-create endpoint that's RESTful, maybe this answer is useful.
There seems to be a bit of disagreement on the best approach and some interesting subtleties as discussed in this post: REST Lazy Reference Create GET or POST?
Please read the entire post but I lean towards #Cormac Mulhall and #Blake Mitchell answers:
The client wants the current state of the resource from the server. It is not aware this might mean creating a resource and it does not care one jolt that this is the first time anyone has attempted to get this resource before, nor that the server has to create the resource on its end.
The following quote from The RESTful cookbook provided by #Blake Mitchell makes a subtle distinction which also supports Mulhall's view:
What are idempotent and/or safe methods?
Safe methods are HTTP methods that do not modify resources. For instance, using GET or HEAD on a resource URL, should NEVER change the resource. However, this is not completely true. It means: it won't change the resource representation. It is still possible, that safe methods do change things on a server or resource, but this should not reflect in a different representation.
Finally this key distinction is made in Section 9.1.1 of the HTTP specification:
Naturally, it is not possible to ensure that the server does not
generate side-effects as a result of performing a GET request; in
fact, some dynamic resources consider that a feature. The important
distinction here is that the user did not request the side-effects,
so therefore cannot be held accountable for them.
Going back to the initial question, the above seems to support Solution 1 which is to create the profile on the server if it does not already exist.

Resource-Server for IdentityServer 4

My task is to implement a resource server(RS) for IdentityServer4(IS4). The RS should fetch data from a database and send the necessary information as a json object back to the caller (client). This is needed because we have to return complex objects.
I already setup IS4 succesfully and its already running in Docker for testing purpose. I also setup the needed database.
My understanding of the flow would be, the user requests data from the RS sending the access-token, the RS then validates the token, checking if the caller is allowed to access the api using the IS4, if everything is okay the RS returns the data to the caller.
My problem is, as I'm new to this subject, how would I implement a RS? Do I create an API which is added as a scope to the user? Or is there a RS already implemented in IS4?
So yes you'll need to write your own API to serve your own resources, IdentityServer will only manage your identities for you (as well as handling external logins if that's what you need). I'd recommend going to the IdentityServer docs and working through the quick starts in order as shown below:
This will give you a good start but you'll then need to go away and research APIs more generally, there's a tonne of good info online about building (RESTful) APIs. You may find it useful to sign up to something like PluralSight and work through a couple of their courses, they're often very good.
One other thing to bear in mind is that IdentityServer is for identity, in other words Authentication and not specifically for Authorisation so you may need to add something for this. You can of course use a users identity for authorisation purposes but in most cases you'll probably need to augment the info you store about their identity to authorise them for access. See this link for more info around this topic.

FOSOAuthServerBundle Create Client

I'm currently trying to setup FOSOAuthServerBundle with my Symfony2 app.
Everything seems to be setup and functional, anyway I'm stuck after the installation.
What is the proper workflow with URLs to get the access_token ?
I tried /oauth/v2/auth, but sounds like I need to define a Client object first.
How to create/generate Client ? Clients are always supposed to be created manually ?
FOSOAuthServerBundle doc is great, but seems to skip all the usage workflow. Am I supposed to check the OAuth2 doc for this ?
Thanks !
In short, yes. You should be using the oAuth2 RFC to determine which workflow you want to use. In regards to client registration the RFC specifically states that the means through which a client registers is beyond the scope of the specification (https://www.rfc-editor.org/rfc/rfc6749#section-2).
With that being said I can give you some insight into how I did this. My application is a mobile phone application that connects to several services running on various servers. I'm also using the Resource Owner Password Credentials Grant.
The way I approached this was: when the application loads, the first thing it does is to check if it has an oAuth2 client id. If it doesn't, then it POSTS to a create client endpoint I've setted up with the meta-data I need. The endpoint validates the POST, creates the client and returns the client information. The application stores the client id and the process doesn't have to be repeated the next time.
Application loads;
Application checks for oAuth2 client id;
If there is one, the process ends;
If there isn't, it posts to http://www.example.com/client;
If we get a 200, store the oAuth2 client id.
I could have also created the oAuth2 client when the user created an account in the application, but I wanted to make the registration process as fast as possible. Creating the client would have added some extra waiting time to the process.
Check this: http://blog.logicexception.com/2012/04/securing-syfmony2-rest-service-wiith.html
It's quite simple to convert to Doctrine, whether you use it.
There's a command-line that does exactly what you need: create a Client!