Spring Social Facebook - spring-mvc

Question

I am developing with Spring Social and Thymeleaf from the quick start example, but I realised that it only supports one Facebook object per controller. This means the sample can't provide support for multiple users and I am guessing it has to do with the #Scope of the variable. Its runs in a Spring boot container and I wonder how I can configure this so that each session has its own Facebook object.

Answer 1

As you suggested, the Facebook object should be configured with request scope. If you're using the configuration support and/or Spring Boot, then it will be request scoped. Therefore, even though the controller is injected once with a Facebook instance, that instance is really a proxy that will delegate to a real FacebookTemplate instance that is created at request time for the authenticated user.
I can only assume that you're referring to the getting started guide example at http://spring.io/guides/gs/accessing-facebook/. In that case, it's using the most simple Spring Boot autoconfiguration possible for Spring Social, which includes a basic (yet not intended for production) implementation of UserIdSource which always returns "anonymous" as the user ID. Therefore, after you create the first Facebook connection, the second browser tries to find a connection for "anonymous", finds it, and gives you an authorized Facebook object.
This may seem peculiar, but it is an example app intended to get you started...and it does that. All you need to do to get a real UserIdSource is to add Spring Security to the project. That will tell Spring Social autoconfiguration to configure a UserIdSource that fetches the current user ID from the security context. This reflects a more real-world use of Spring Social, albeit obviously more involved and beyond the scope of the getting started guide.
But you can look at https://github.com/spring-projects/spring-social-samples/tree/master/spring-social-showcase-boot for a more complete example of Spring Social within Spring Boot.

Answer 2

Spring Boot autoconfigures a lot of things behind the scenes. It does autoconfigure the Facebook, LinkedIn and Twitter properties and sets up the connection factories for social providers.
However, the implementation of UserIdSource always returns “anonymous” as the user ID. Once the first Facebook connection is established the second browser will try to find a connection for “anonymous” which it finds and gives you an authorised Facebook object.
#Configuration
#EnableSocial
#ConditionalOnWebApplication
#ConditionalOnMissingClass("org.springframework.security.core.context.SecurityContextHolder")
protected static class AnonymousUserIdSourceConfig extends SocialConfigurerAdapter {
#Override
public UserIdSource getUserIdSource() {
return new UserIdSource() {
#Override
public String getUserId() {
return "anonymous";
}
};
}
}
Solution
The solution is to override the “anonymous” as the UserId for each new user/session. So for each session, we can simply return a SessionID, however, it may not be unique enough to identify users, especially if it’s being cached or stored somewhere in a connection database.
#Override
public String getUserId() {
RequestAttributes request = RequestContextHolder.currentRequestAttributes();
String uuid = (String) request.getAttribute("_socialUserUUID", RequestAttributes.SCOPE_SESSION);
if (uuid == null) {
uuid = UUID.randomUUID().toString();
request.setAttribute("_socialUserUUID", uuid, RequestAttributes.SCOPE_SESSION);
}
return uuid;
}
The solution for above problem has been talked about in detail over here