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REST service to return only current user-related resources

I have a REST service implemented using Spring MVC (RestControllers) with token based security (using Spring Security). How can i filter resources depending on user identity? Let's say user has some reports. How can I let authorized user by performing a call to /reports to see only his reports?
Obviously i can make userId to be a request parameter or path variable, but something tells me that this is a bad practice.
I assume i can achieve that using Spring Security features, but how exactly could i do that and, more important, where is the most appropriate place to apply such filtering? Should controllers perform calls to services passing user identity or should it be somehow retrieved at repositories level (I use Spring Data JPA)?
Thanks in advance

You have Authentication object whenever a user is successfully logged in.
It contains Object principal Object credentials and Set authorities.
All you need to do is override UserDetailsService to add new parameters for your authenticated user. Add your userId in authentication as shown in blog
Now when you do
SecurityContextHolder.getContext().getAuthentication().getPrincipal()
this will return you the User object of the spring security.
You can get the user id from here and use this in controller to do necessary actions.

Spring Security: Different authentication methods depending on entity

first post here, hope im doing right.
In a project, we have a scenario where we have a single web application with multiple entities. Currently, the login is managed via default JDBC Spring Security provider, working fine.
For a new requirement, we need that each entity can have their own login method (currently 2 methods would be available, the JDBC one, which is the current one, and the second method would be authentication via SAML, with each entity defining their own IdP, but this is another story)
I need some guidelines on how this can be achieved, I have done some search and I have found providers for different URL's, etc... But not different login methods for the same app and url's depending on the user type or entity.
Is a good approach to have a custom single entry point where we can check the entity user and then use the suitable authentication provider?
Kind regards,
Alex

As each of your users might be using a different IDP you will in any case need to determine the username before proceeding with initialization of the authentication process - but you already know this.
One approach to take (similar to what Microsoft is using with the Office 365 for corporate users) is:
display a login page with fields for standard username + password
once user enters username and blurs the input field, you make an AJAX call (to your custom API made for this purpose) and fetch information about authentication type + IDP to use for this user
in case the type is password you simply let user continue with filling in the password field and POST to the same place as you're used to for processing with the JDBC provider
in case the type is federated authentication you initialize authentication with the correct IDP by redirecting to /saml/login?idp=xyz and continue with the SAML flow
It's possible to avoid any APIs by submitting the form once user enters the username, or let user click a "Continue" button. It would then make sense to use a custom EntryPoint which:
redirects user to the main login page in case it wasn't provided with a username
displays either login page with username/password or redirects to the correct IDP, once username was provided

GAE HttpServletRequest - How can I use getUserPrincipal with my own login mechanism?

Precedent
In GAE, when we use the built-in Users Service to log in a user, GAE automagically sets the HttpServletRequest so that:
getUserPrincipal() returns the user name or null if no user is logged in
isUserInRole() verifies if the user meets a role
My question
I am now implementing an independent login mechanism for which I need to track whether the user is logged-in through the duration of the session.
I see that many of people use HttpServletRequest's getSession.setAttribute with custom parameters as the mean to store login data for the session.
However, I wonder if there is a way of leveraging the built-in functions getUserPrincipal and isUserInRolethe same way that GAE uses them. Or is this functionality reserved by GAE for their internal Users Service and not accessible to us users?

Spring Security allowing alternative to username

I'm using Spring security 3.x. In my login page, there is an additional field that the user would scan an ID card to populate. If they do this, the username is not required (it is looked up against the ID scanned), but the password still is.
The problem is that the username is required by my custom AuthenticationProvider. The ID is captured in a filter before this (UsernamePasswordAuthenticationFilter). I don't know how to connect them so my AuthProvider knows it doesn't require username (and also, how does it get the ID at this point since it is passed an Authentication object?).

You might need a special kind of Authentication interface that is not a UsernamePasswordAuthenticationToken and hence doesn't require the username and password both.
Then your AuthenticationProcessingFilter/AuthenticationProvider may create one of them.
Have a look at spring-cas-client and CasAuthenticationToken as an example.

The filter I was extending was FORM_LOGIN_FILTER, which is correct, however I needed to perform all the retrievals (j_username, j_password) here and call the authentication manager manually, instead of calling the super() method which passes the retrievals and auth manager calls to Spring. This also required extending the UsernamePasswordAuthenticationToken. Once I do this, they are connected.

Designing RESTful login service

I went through a similar question here. But I am yet not clear over concepts. Here is my scenario...
My client (a mobile device app) has a login screen to enter username, password. After submission, he should see the list of books in the database plus the list of books subscribed by that user.
I am having a /LoginService which accepts username, password & checks a mysql database for credential validation. Only after authorization....I have a /BookService ; GET on which returns all the books in database.
Should I use GET, POST or PUT on my loginservice ? Since a login request is a read-only operation, I should use GET - but this sounds stupid for browser(as the submitted data is visible).
What are accesstokens (mentioned in the linked answer above), and how to generate them using Java ? I am using Jersey for development. Are they a secure way of authorization ?
Thanks !

As far as I understand you are trying to implement stetefull communication between client and server. So you login with first request and then use some kind of token to make further requests.
Generally I can recommend you to have stateless communication. This means, that you authenticate and authorize each request. In this scenario you don't need LoginRestService. Important points here are:
Client can provide userName and password through HTTP Headers (non-standard, something like UserName: user and Password: secret).
At the server side you can use
Use AOP: just wrap you BooksService with AuthAdvice (which you should write yourself). In advise you access somehow (with Jersey functionality) HTTP request, take correspondent headers from it, authenticate and authorize user (that you load from DB), put user in ThreadLocal (so that it would be available to the rest of your app) if needed and just invoke correspondent method or throw exception if something wrong with credentials.
Use Jersey functionality: (sorry I'm not very familliar with Jersey, I'm using CXF, but conceptually it should be the same) just create some kind of AuthHendler and put it in request pre-processing pipeline. In this handler you need tho make exactly the same as in AuthAdvice
Now each of your request would be authenticated and authorized when it reaches BooksService. Generally stateless implementation is much better for scalability.
If you want to go statefull way, than you can just use HttpSession. LoginService.login() should be POST request because you actually making some side-effects at the server. Service will perform authentication of your user according to provided username and password and put loaded User object to session. At this point, the server side session is created and client has session ID in the cookies. So further requests should automatically send it to the server. In order to authorize requests to BooksService you still need some kind of Advice of Handler (see stateless solution). The only difference: this time user is taken from the HttpSession (you should check that you are logged in!).
Update: And use HTTPS! :)

I've got nothing to dispute in Easy Angel's answer, but got the impression you'd like some additional comment on the concepts too.
The problem is clearer if you think in terms of resources rather than services. Think of your proposed login as generating a new authorization resource, rather than querying a login service. Then you see that POST makes perfect sense.
The authorization token would be a key for your user into the session object (as explained in EA's answer). You'd probably want to generate it by concatenating some information that uniquely identifies that user and hashing it. I certainly agree that a stateless authentication method would be preferable, if you're aiming to get all the benefits of REST.

Use what is available in HTTP: HTTP AUTH over SSL.
Protect all your resources with HTTP AUTH and the browser will take care of providing a login for the user.
If you need session information on top of that, use cookies or a session parameter.
Cookies were made for exactly these kinds of purposes and usually work well.