How to use Firebase with Spring boot REST Application?

Question

I have a Spring Boot REST application that depends on the authentication done in Firebase.

On the client side Firebase generates a token whereby in the Spring Boot, I need to verify the UID.

But the code is in a callback mode, so how do I implement the function so that it can finish the task?

@RequestMapping(value = "/api/restCall", method = RequestMethod.POST,               consumes = "application/json", produces = "application/json") public Object restCall(@RequestBody Parameters requestBody) throws Exception {     String idToken = requestBody.getToken();     Task<FirebaseToken> task = FirebaseAuth.getInstance().verifyIdToken(idToken)             .addOnSuccessListener(new OnSuccessListener<FirebaseToken>() {             @Override                 public void onSuccess(FirebaseToken decodedToken) {                     String uid = decodedToken.getUid();                 }             });     return "???"; // what return here? } 

How do I return after onSuccess? DeferredResult?

Answer 1

To integrate Firebase with Spring, below is the sample code

In new Admin SDK the process is simple just use below code snippet.

FirebaseAuth.getInstance().deleteUser(uid); System.out.println("Successfully deleted user."); 

For more detail visit this URL https://firebase.google.com/docs/auth/admin/manage-users

This is for a legacy code. First add Firbase dependency

<dependency>     <groupId>com.google.firebase</groupId>     <artifactId>firebase-server-sdk</artifactId>     <version>3.0.1</version> </dependency> 

Sample Code

@Component public class FirebaseAuthenticationProvider implements AuthenticationProvider {      @Autowired     @Qualifier(value = UserServiceImpl.NAME)     private UserDetailsService userService;      public boolean supports(Class<?> authentication) {         return (FirebaseAuthenticationToken.class.isAssignableFrom(authentication));     }      public Authentication authenticate(Authentication authentication) throws AuthenticationException {         if (!supports(authentication.getClass())) {             return null;         }          FirebaseAuthenticationToken authenticationToken = (FirebaseAuthenticationToken) authentication;         UserDetails details = userService.loadUserByUsername(authenticationToken.getName());         if (details == null) {             throw new FirebaseUserNotExistsException();         }          authenticationToken = new FirebaseAuthenticationToken(details, authentication.getCredentials(),                 details.getAuthorities());          return authenticationToken;     }  } 

For Complete example please gone through github below link https://github.com/savicprvoslav/Spring-Boot-starter Complete BlogPost with CRUD operation: https://medium.com/techwasti/spring-boot-firebase-crud-b0afab27b26e

Answer 2

Here is my own attempt to answer my own question

@RequestMapping(value = "/api/restCall", method = RequestMethod.POST, consumes = "application/json", produces = "application/json") public Object restCall(@RequestBody Parameters requestBody,@RequestHeader(value = FIREBASETOKEN, required = true) String idToken) throws Exception {      // idToken comes from the HTTP Header     FirebaseToken decodedToken = FirebaseAuth.getInstance().verifyIdTokenAsync(idToken).get();     final String uid = decodedToken.getUid();      // process the code here     // once it is done     return object;  } 

You can try below code as well

FirebaseAuth.getInstance().deleteUser(uid); System.out.println("Successfully deleted user."); 

for More deetails URL https://firebase.google.com/docs/auth/admin/manage-users